| 1. |
- Alvarado Ávila, María Isabel, et al.
(författare)
-
Cellulose as sacrificial agents for enhanced photoactivated hydrogen production
- 2023
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry (RSC). - 2398-4902. ; 7:8, s. 1981-1991
-
Tidskriftsartikel (refereegranskat)abstract
- The search for new energy sources together with the need to control greenhouse gas emissions has led to continued interest in low-emitting renewable energy technologies. In this context, water splitting for hydrogen production is a reasonable alternative to replace fossil fuels due to its high energy density producing only water during combustion. Cellulose is abundant in nature and as residuals from human activity, and therefore a natural, ecological, and carbon-neutral source for hydrogen production. In the present work, we propose a sustainable method for hydrogen production using sunlight and cellulose as sacrificial agents during the photocatalytic water splitting process. Platinum (Pt) catalyst activates hydrogen production, and parameters such as pH of the system, cellulose concentration, and Pt loading were studied. Using different biomasses, we found that the presence of hemicellulose and xyloglucan as part of the molecular composition considerably increased the H-2 production rate from 36 mu mol L-1 in one hour for rapeseed cellulose to 167.44 mu mol L-1 for acid-treated cellulose isolated from Ulva fenestrata algae. Carboxymethylation and TEMPO-oxidation of cellulosic biomass both led to more stable suspensions with higher rates of H-2 production close to 225 mu mol L-1, which was associated with their water solubility properties. The results suggest that cellulosic biomass can be an attractive alternative as a sacrificial agent for the photocatalytic splitting of water for H-2 production.
|
|
| 2. |
- Anikina, Ekaterina, et al.
(författare)
-
Elucidating hydrogen storage properties of two-dimensional siligraphene (SiC8) monolayers upon selected metal decoration
- 2020
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry (RSC). - 2398-4902. ; 4:11, s. 5578-5587
-
Tidskriftsartikel (refereegranskat)abstract
- Density functional theory calculations with dispersion corrections were employed to investigate the hydrogen (H-2) adsorptive properties of siligraphene (SiC8), pristine and decorated with selected alkali (Li, Na, and K) and alkaline-earth (Be, Mg, and Ca) metals. We found that all the considered metals (Me), except Mg and Be, bind strongly to SiC8 even at high doping concentrations (SiC8Me2) by donating a major portion of their valence electrons to SiC8. Ab initio molecular dynamics (AIMD) simulations confirmed the thermal stabilities of SiC8Me2 (Me = Li, Na, K, Ca) at 300 K. We showed that Li, Na, and Ca-doped SiC8 adsorbed multiple H-2 molecules with binding energies (E-bind) at least two times stronger than that of the pristine SiC8 (Epristinebind = -70 meV per H-2). Overall, both SiC8Li2 and SiC8Ca2 adsorbed two and four H-2 molecules per metal adatom, respectively, having E-bind within the desirable range for an effective adsorption/desorption process. The resulting gravimetric densities of SiC8Li2 and SiC8Ca2 were 5.5 wt% and 7.3 wt%, respectively, surpassing the U.S. Department of Energy's 2025 goal of 5.5 wt%. The estimated H-2 desorption temperatures exceed substantially the boiling point of liquid nitrogen, confirming the potential of light metal decorated SiC8 as a promising material for H-2 storage.
|
|
| 3. |
- Anikina, Ekaterina, et al.
(författare)
-
Li-decorated carbyne for hydrogen storage : charge induced polarization and van't Hoff hydrogen desorption temperature
- 2020
-
Ingår i: Sustainable Energy & Fuels. - : ROYAL SOC CHEMISTRY. - 2398-4902. ; 4:2, s. 691-699
-
Tidskriftsartikel (refereegranskat)abstract
- We have studied carbyne as a promising hydrogen storage material. Density functional theory simulations with vdW corrections have been used to investigate lithium sorption on carbyne and the interaction of pristine and Li-functionalized carbon chains with molecular hydrogen. We showed that Li adatoms at small concentrations stay atomically dispersed on carbyne, donating 0.9e to the chain. Moreover, in the presence of Li, hydrogen adsorption energy increases by more than 5 times in comparison with pristine carbyne. Overall, up to three hydrogen molecules per Li adatom have an adsorption energy close to the range of 200-600 meV per H-2, which is necessary for effective sorption/desorption cycles. The resulting theoretical uptake (7.1 wt%) is higher than the U.S. Department of Energy's ultimate goal (6.5 wt%). The calculated van't Hoff desorption temperatures exceed considerably the boiling point of liquid nitrogen. Our results confirm the potential of Li-decorated carbyne for hydrogen storage.
|
|
| 4. |
- Bayrak Pehlivan, Ilknur, et al.
(författare)
-
The climatic response of thermally integrated photovoltaic-electrolysis water splitting using Si and CIGS combined with acidic and alkaline electrolysis
- 2020
-
Ingår i: Sustainable Energy & Fuels. - : ROYAL SOC CHEMISTRY. - 2398-4902. ; 4:12, s. 6011-6022
-
Tidskriftsartikel (refereegranskat)abstract
- The Horizon 2020 project PECSYS aims to build a large area demonstrator for hydrogen production from solar energy via integrated photovoltaic (PV) and electrolysis systems of different types. In this study, Si- and CIGS-based photovoltaics are developed together with three different electrolyzer systems for use in the corresponding integrated devices. The systems are experimentally evaluated and a general model is developed to investigate the hydrogen yield under real climatic conditions for various thin film and silicon PV technologies and electrolyser combinations. PV characteristics using a Si heterojunction (SHJ), thin film CuInxGa1-xSe2, crystalline Si with passivated emitter rear totally diffused and thin film Si are used together with temperature dependent catalyst load curves from both acidic and alkaline approaches. Electrolysis data were collected from (i) a Pt-IrO2-based acidic electrolysis system, and (ii) NiMoW-NiO-based and (iii) Pt-Ni foam-based alkaline electrolysis systems. The calculations were performed for mid-European climate data from Julich, Germany, which will be the installation site. The best systems show an electricity-to-hydrogen conversion efficiency of 74% and over 12% solar-to-hydrogen (STH) efficiencies using both acidic and alkaline approaches and are validated with a smaller lab scale prototype. The results show that the lower power delivered by all the PV technologies under low irradiation is balanced by the lower demand for overpotentials for all the electrolysis approaches at these currents, with more or less retained STH efficiency over the full year if the catalyst area is the same as the PV area for the alkaline approach. The total yield of hydrogen, however, follows the irradiance, where a yearly hydrogen production of over 35 kg can be achieved for a 10 m(2) integrated PV-electrolysis system for several of the PV and electrolyser combinations that also allow a significant (100-fold) reduction in necessary electrolyser area for the acidic approach. Measuring the catalyst systems under intermittent and ramping conditions with different temperatures, a 5% lowering of the yearly hydrogen yield is extracted for some of the catalyst systems while the Pt-Ni foam-based alkaline system showed unaffected or even slightly increased yearly yield under the same conditions.
|
|
| 5. |
- Benedek, Peter, et al.
(författare)
-
Surface phonons of lithium ion battery active materials
- 2019
-
Ingår i: Sustainable Energy & Fuels. - : ROYAL SOC CHEMISTRY. - 2398-4902. ; 3:2, s. 508-513
-
Tidskriftsartikel (refereegranskat)abstract
- Surfaces of active materials are understood to play an important role in the performance and lifetime of lithium-ion batteries, but they remain poorly characterized and therefore cannot yet be systematically designed. Here, we combine inelastic neutron scattering and ab initio simulations to demonstrate that the structure of the surface of active materials differs from the interior of the particle. We use LiFePO4 (LFP) as a model system, and we find that carbon coating influences the Li-O bonding on the (010) LFP surface relative to the bulk. Our results highlight how coatings can be used to systematically engineer the vibrations of atoms at the surface of battery active materials, and thereby impact lithium ion transport, charge transfer, and surface reactivity.
|
|
| 6. |
- Björk, Anders, et al.
(författare)
-
Making an ultralow platinum content bimetallic catalyst on carbon fibres for electro-oxidation of ammonia in wastewater
- 2019
-
Ingår i: Sustainable Energy & Fuels. - 2398-4902.
-
Tidskriftsartikel (refereegranskat)abstract
- Electrocatalysis of wastewater containing ammonia is a promising alternative to chemical and biological water purification for several reasons, one being that energy-rich hydrogen gas is generated as a by-product while the reaction can be strictly controlled to meet demands. An objective has been to reduce the loading of expensive platinum (Pt) in the catalyst electrodes, and to reduce the poisoning of the metal surface during the electrolysis. Herein, the co-deposition of a copper–platinum (Cu–Pt) bimetallic alloy onto carbon filaments, stripped from their polymeric coating, is shown to give an electrocatalytic performance superior to that of pure Pt at a content of less than 3 wt% Pt. The key to the enhanced performance was to take advantage of micrometer-sized carbon filaments to distribute a very large bimetallic alloy surface uniformly over the filaments. The Cu–Pt-alloy-coated filaments also suffer less electrode poisoning than pure Pt, and are bonded more strongly to the carbon fibre due to better mechanical interlocking between the bimetallic alloy and the carbon filaments. High-resolution electron microscopy studies combined with a tuned electro-deposition process made it possible to tailor the catalyst micro/nano morphology to reach a uniform coverage, surrounding the entire carbon filaments. The results are promising steps towards large-scale wastewater treatment, combined with clean energy production from regenerated hydrogen.
|
|
| 7. |
- Carlson, Annika, et al.
(författare)
-
Fuel cell evaluation of anion exchange membranes based on poly(phenylene oxide) with different cationic group placement
- 2020
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 4:5, s. 2274-2283
-
Tidskriftsartikel (refereegranskat)abstract
- Four novel poly(phenylene oxide)-based anion exchange membranes were investigated for electrochemical performance, ionic conductivity and water transport properties in an operating anion exchange membrane fuel cell (AEMFC), using Pt/C gas diffusion electrodes with Tokuyama ionomer. The poly(phenylene oxide)-membranes have a 1- or 5-carbon alkyl spacer between the backbone and a trimethylalkylammonium (TMA) or piperidinium (Pip) cationic group, and ion-exchange capacities (IECs) between 1.5 and 1.9 mequiv g(-1). The polymer with a 5-carbon alkyl spacer, a TMA cationic group, and a higher IEC showed the highest ion conductivity and performance in the AEMFC. The results also show that introducing a 5-carbon alkyl spacer does not improve performance unless the IEC is increased and that exchanging the TMA with a Pip cationic group results in lower fuel cell performance despite a higher IEC. A discrepancy in ion conductivity between fuel cell and ex situ test was observed for the 5-carbon spacer polymers and is attributed to a higher sensitivity for dehydration. Similar water flux under load, from the anode to the cathode with increased water content at both electrodes, was observed for all membranes and only varied with membrane thickness. The deviation in fuel cell performance observed between the membranes could not be explained by differences in water flux or ionic conduction, suggesting that the electrode-membrane interaction plays a major role. Nevertheless, the study emphasizes that high membrane conductivity (for the lambda-range in a fuel cell) and efficient water transport (obtained by lower membrane thickness) promote higher electrochemical performance.
|
|
| 8. |
- Carlson, Annika, et al.
(författare)
-
Fuel cell evaluation of anion exchange membranes based on poly(phenylene oxide) with different cationic group placement
- 2020
-
Ingår i: Sustainable Energy & Fuels. - 2398-4902. ; 4:5, s. 2274-2283
-
Tidskriftsartikel (refereegranskat)abstract
- Four novel poly(phenylene oxide)-based anion exchange membranes were investigated for electrochemical performance, ionic conductivity and water transport properties in an operating anion exchange membrane fuel cell (AEMFC) , using Pt/C gas diffusion electrodes with Tokuyama ionomer. The poly(phenylene oxide)-membranes have a 1- or 5-carbon alkyl spacer between the backbone and a trimethylalkylammonium (TMA) or piperidinium (Pip) cationic group, and ion-exchange capacities (IECs) between 1.5 and 1.9 mequiv g-1. The polymer with a 5-carbon alkyl spacer, a TMA cationic group, and a higher IEC showed the highest ion conductivity and performance in the AEMFC. The results also show that introducing a 5-carbon alkyl spacer does not improve performance unless the IEC is increased and that exchanging the TMA with a Pip cationic group results in lower fuel cell performance despite a higher IEC. A discrepancy in ion conductivity between fuel cell and ex-situ test was observed for the 5-carbon spacer polymers and is attributed to a higher sensitivity for dehydration. Similar water flux under load, from the anode to the cathode with increased water content at both electrodes, was observed for all membranes and only varied with membrane thickness. The deviation in fuel cell performance observed between the membranes could not be explained by differences in water flux or ionic conduction, suggesting that the electrodes – membrane interaction plays a major role. Nevertheless, the study emphasizes that high membrane conductivity (for the λ-range in a fuel cell) and an efficient water transport (obtained by lower membrane thickness) promote higher electrochemical performance.
|
|
| 9. |
- Cheah, You Wayne, 1993, et al.
(författare)
-
Role of transition metals on MoS 2 -based supported catalysts for hydrodeoxygenation (HDO) of propylguaiacol
- 2021
-
Ingår i: Sustainable Energy and Fuels. - : Royal Society of Chemistry (RSC). - 2398-4902. ; 5:7, s. 2097-2113
-
Tidskriftsartikel (refereegranskat)abstract
- Transition metal sulfides (TMSs) are typically used in the traditional petroleum refining industry for hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) applications. Bio-oils require an upgrading process like catalytic hydrodeoxygenation (HDO) to produce advanced biofuels and chemicals. Herein, MoS /γ-Al O promoted by transition metals like nickel (Ni), copper (Cu), zinc (Zn), and iron (Fe) was evaluated for the HDO of a bio-oil model compound, 4-propylguaiacol (PG) in a batch reactor at 340 °C under 50 bar H pressure. The catalyst screening results showed that the sulfided Ni-promoted catalyst gave a high 94% yield of deoxygenated cycloalkanes, however for the sulfided Cu-promoted catalyst, 42% of phenolics remain in the reaction medium after 5 h. The results also revealed that the sulfided Zn and Fe-promoted catalysts gave a final yield of 16% and 19% at full PG conversion, respectively, for deoxygenated aromatics. A kinetic model considering the main side reactions was developed to elucidate the reaction pathway of demethoxylation and dehydroxylation of PG. The developed kinetic model was able to describe the experimental results well with a coefficient of determination of 97% for the Ni-promoted catalyst system. The absence of intermediates like 4-propylcyclohexanone and 4-propylcyclohexanol during the reaction implies that direct deoxygenation (DDO) is the dominant pathway in the deoxygenation of PG employing sulfided catalysts. The current work also demonstrated that the activity of the transition metal promoters sulfides for HDO of PG could be correlated to the yield of deoxygenated products from the hydrotreatment of Kraft lignin. 2 2 3 2
|
|
| 10. |
- Cheah, You Wayne, 1993, et al.
(författare)
-
Thermal annealing effects on hydrothermally synthesized unsupported MoS2 for enhanced deoxygenation of propylguaiacol and kraft lignin
- 2021
-
Ingår i: Sustainable Energy and Fuels. - 2398-4902. ; 5:20, s. 5270-5286
-
Tidskriftsartikel (refereegranskat)abstract
- Catalytic hydrodeoxygenation (HDO) is an important hydrotreating process that is used to improve the quality of bio-oils to produce biomass-derived fuel components and chemicals. Molybdenum disulfide (MoS2) has been widely used as a catalyst in hydrodesulfurization (HDS) applications for several decades, which can be further improved for effective unsupported catalyst synthesis. Herein, we studied a universally applicable post-annealing treatment to a hydrothermally synthesized MoS2 catalyst towards developing efficient unsupported catalysts for deoxygenation. The effect of the annealing treatment on the catalyst was studied and evaluated for HDO of 4-propylguaiacol (PG) at 300 °C with 50 bar H2 pressure. The annealing of the as-synthesized catalyst under nitrogen flow at 400 °C for 2 h was found to enhance the HDO activity. This enhancement is largely induced by the changes in the microstructure of MoS2 after the annealing in terms of slab length, stacking degree, defect-rich sites and the MoS2 edge-to-corner site ratio. Besides, the effect of hydrothermal synthesis time and acid addition combined with the annealing treatment on the MoS2 catalytic activity was also studied for the same model reaction. The annealed MoS2 with a synthesis time of 12 h under an acidic environment was found to have improved crystallinity and exhibit the highest deoxygenation degree among all the studied catalysts. An acidic environment during the synthesis was found to be crucial in facilitating the growth of MoS2 micelles, resulting in smaller particles that affected the HDO activity. The annealed unsupported MoS2 with the best performance for PG hydrodeoxygenation was further evaluated for the hydrotreatment of kraft lignin and demonstrated a high deoxygenation ability. The results also indicate a catalyst with high activity for deoxygenation and hydrogenation reactions can suppress char formation and favor a high lignin bio-oil yield. This research uncovers the importance of a facile pretreatment on unsupported MoS2 for achieving highly active HDO catalysts.
|
|
| 11. |
- Cid Gomes, Leandro, et al.
(författare)
-
Light-driven (cross-)dimerization of terpenes as a route to renewable C15-C30 crudes for fuel and lubricant oil applications
- 2023
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 7:3, s. 868-882
-
Tidskriftsartikel (refereegranskat)abstract
- Non-fossil hydrocarbons are desirable for transport fuels and lubricant oils to reach a fossil carbon neutral economy. Herein, we show the production of such end-products from crude raw materials via the photosensitized dimerization of terpenes. Terpenes are hydrocarbons originating from renewable sources, such as forestry, industrial bio-waste and photosynthetically active microorganisms. Under irradiation at 365 nm, we observed high conversions of terpenes with conjugated diene segments into their dimers (e.g. 96.1 wt%, 12 h for α-phellandrene), and remarkable results were obtained using simulated and natural sunlight (90.8 wt% and 46.6 wt%, respectively, for α-phellandrene). We show that the lower reactivities of some isomeric monoterpenes could be overcome by a cross-photodimerization with α-phellandrene. We also utilized the cross-photodimerization approach to obtain C15 and C30 products, combining mixtures of isoprene, monoterpenes and sesquiterpenes. Hydrogenation of the terpene dimers gave materials with physical properties suitable as high energy density fuels and lubricant oils. Finally, our preliminary analysis based on recent literature points to the commercial viability of this route to produce fuels and lubricant oils, as well as to a potential for reduction of the environmental impact compared to fossil-based routes.
|
|
| 12. |
- Cid Gomes, L., et al.
(författare)
-
Light-driven (cross-)dimerization of terpenes as a route to renewable C15-C30 crudes for fuel and lubricant oil applications
- 2023
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 7:3, s. 868-882
-
Tidskriftsartikel (refereegranskat)abstract
- Non-fossil hydrocarbons are desirable for transport fuels and lubricant oils to reach a fossil carbon neutral economy. Herein, we show the production of such end-products from crude raw materials via the photosensitized dimerization of terpenes. Terpenes are hydrocarbons originating from renewable sources, such as forestry, industrial bio-waste and photosynthetically active microorganisms. Under irradiation at 365 nm, we observed high conversions of terpenes with conjugated diene segments into their dimers (e.g. 96.1 wt%, 12 h for α-phellandrene), and remarkable results were obtained using simulated and natural sunlight (90.8 wt% and 46.6 wt%, respectively, for α-phellandrene). We show that the lower reactivities of some isomeric monoterpenes could be overcome by a cross-photodimerization with α-phellandrene. We also utilized the cross-photodimerization approach to obtain C15 and C30 products, combining mixtures of isoprene, monoterpenes and sesquiterpenes. Hydrogenation of the terpene dimers gave materials with physical properties suitable as high energy density fuels and lubricant oils. Finally, our preliminary analysis based on recent literature points to the commercial viability of this route to produce fuels and lubricant oils, as well as to a potential for reduction of the environmental impact compared to fossil-based routes.
|
|
| 13. |
- Damas, Giane Benvinda, et al.
(författare)
-
Carbon dioxide reduction mechanism on Ru-based electrocatalysts [Ru(bpy)(2)(CO)(2)](2+) : insights from first-principles theory
- 2021
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 5:23, s. 6066-6076
-
Tidskriftsartikel (refereegranskat)abstract
- Solar fuel production through the so-called artificial photosynthesis has attracted a great deal of attention to the development of a new world energy matrix that is renewable and environmentally friendly. This process is characterized by light absorption with enough photon energy to generate conduction electrons, which drive the carbon dioxide reduction to produce organic fuels. It is also common to couple Ru-complex electrocatalysts to form a more efficient and selective hybrid system for this application. In this work, we have undertaken a thorough investigation of the redox reaction mechanism of Ru-based electrocatalysts by means of density functional theory (DFT) methods under the experimental conditions that have been previously reported. More specifically, we have studied the electrochemistry and catalytic activity of the [Ru(bpy)(2)(CO)(2)](2+) coordination complex. Our theoretical assessment supports the following catalytic cycle: (i) [Ru(bpy)(2)(CO)(2)](2+) is transformed into [Ru(bpy)(2)(CO)](0) upon two-electron reduction and CO release; (ii) [Ru(bpy)(2)(CO)](0) is protonated to form the [Ru(bpy)(2)(CO)H](+) hydride complex; (iii) CO2 is activated by the hydride complex through an electrophilic addition to form the [Ru(bpy)(2)(CO)(OCHO)](+) intermediate; (iv) the resulting formic acid ligand is released in solution; and, finally, (v) the CO ligand is reattached to the complex to recover the initial [Ru(bpy)(2)(CO)(2)](2+) catalyst.
|
|
| 14. |
- Das, Biswanath, et al.
(författare)
-
Structural features of molecular electrocatalysts in multi-electron redox processes for renewable energy : recent advances
- 2019
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry (RSC). - 2398-4902. ; 3:9, s. 2159-2175
-
Forskningsöversikt (refereegranskat)abstract
- Understanding the structural features of molecular electrocatalysts for carbon dioxide reduction and water oxidation is essential for manufacturing next generation catalysts for renewable energy. We will discuss the crucial structural motifs of those catalysts that have shown novel characteristics in recent years in terms of electrocatalytic efficacy (high TON, TOF and low overpotential), product selectivity and mechanisms. Both inorganic and organic homogeneous catalysts are scrutinized in this review. We will also highlight electrocatalysts with dual activity (i.e. they are able to catalyze both water oxidation and CO2 reduction) as an interesting prospect from the point of view of a single catalyst electrolyzer: a possible design for future easy-to-manufacture effective electrolyzers. This discussion will enrich the overall knowledge on the electrocatalyst design, an important step towards the development of efficient catalysts with cutting edge designs for a renewable energy future and practical applications.
|
|
| 15. |
- Davidsson Kurland, Simon, 1986, et al.
(författare)
-
The energetic implications of introducing lithium-ion batteries into distributed photovoltaic systems
- 2019
-
Ingår i: Sustainable Energy and Fuels. - : Royal Society of Chemistry (RSC). - 2398-4902. ; 3:5, s. 1182-1190
-
Tidskriftsartikel (refereegranskat)abstract
- Batteries for stationary applications can prove to be crucial for enabling high penetration of solar energy, but production and use of batteries comes with an energetic cost. This study quantifies how adding a lithium-ion (Liion) battery affects the energetic performance of a typical residential photovoltaic (PV) system for a wide range of climatic conditions. If all generated power is either self-consumed or made available via the existing distribution grid, the PV system has an energy return on investment (EROI) of between 14 (Alaska) and 27 (Arizona). While adding a 12 kWh Li-ion battery increases self-consumption considerably, this has the negative effect of decreasing the EROI by more than 20%. In a situation where all excess power generation is curtailed, the EROI can be as low as 7 (Alaska and Washington), although it can also be as high as 15 (Florida). Introducing a battery increases EROI but is still considerably lower than in cases where use excess power generation is added to the grid. Doubling the battery size increases the average self-consumption marginally, but further decreases EROI of the system because the extra energy invested to build the additonal battery is used inefficienctly. The results show that installing PV systems in locations with good solar resources and a grid that can accept excess prodution is desirable for maximizing net energy return from distributed PV. Batteries have a benefit when excess electricity generation can not be fed into the grid. Oversizing batteries has the effect of significantly reducing the EROI of the PV system.
|
|
| 16. |
- Davidsson Kurland, Simon, et al.
(författare)
-
The energetic implications of introducing lithium-ion batteries into distributed photovoltaic systems
- 2019
-
Ingår i: Sustainable Energy & Fuels. - 2398-4902. ; 3:5, s. 1182-1190
-
Tidskriftsartikel (refereegranskat)abstract
- Batteries for stationary applications can prove to be crucial for enabling high penetration of solar energy, but production and use of batteries comes with an energetic cost. This study quantifies how adding a lithium-ion (Li-ion) battery affects the energetic performance of a typical residential photovoltaic (PV) system under a wide range of climatic conditions. If all generated power is either self-consumed or made available via an existing distribution grid, the PV system will have an energy return on investment (EROI) of between 14 (Alaska) and 27 (Arizona). While adding a 12 kW h Li-ion battery increases self-consumption considerably, this has a negative effect of decreasing the EROI by more than 20%. In a situation where all excess power generation is curtailed, the EROI can be as low as 7 (Alaska and Washington), although it can also be as high as 15 (Florida). Introducing a battery increases the EROI but it is still considerably lower than in cases where excess power generation is added to the grid. Doubling the battery size increases the average self-consumption marginally, but further decreases the EROI of the system because the extra energy invested to build the additional battery is used inefficiently. The results show that installing PV systems in locations with good solar resources and a grid that can accept excess production is desirable for maximizing the net energy return from distributed PV systems. Batteries have a benefit when excess electricity generation cannot be fed into the grid. Oversizing batteries has the effect of significantly reducing the EROI of the PV system.
|
|
| 17. |
- Esmieu, Charlène, et al.
(författare)
-
From protein engineering to artificial enzymes - biological and biomimetic approaches towards sustainable hydrogen production
- 2018
-
Ingår i: Sustainable Energy & Fuels. - : ROYAL SOC CHEMISTRY. - 2398-4902. ; 2:4, s. 724-750
-
Forskningsöversikt (refereegranskat)abstract
- Hydrogen gas is used extensively in industry today and is often put forward as a suitable energy carrier due its high energy density. Currently, the main source of molecular hydrogen is fossil fuels via steam reforming. Consequently, novel production methods are required to improve the sustainability of hydrogen gas for industrial processes, as well as paving the way for its implementation as a future solar fuel. Nature has already developed an elaborate hydrogen economy, where the production and consumption of hydrogen gas is catalysed by hydrogenase enzymes. In this review we summarize efforts on engineering and optimizing these enzymes for biological hydrogen gas production, with an emphasis on their inorganic cofactors. Moreover, we will describe how our understanding of these enzymes has been applied for the preparation of bio-inspired/-mimetic systems for efficient and sustainable hydrogen production.
|
|
| 18. |
- Fan, Ke, et al.
(författare)
-
Amorphous WO3 induced lattice distortion for a low-cost and high-efficient electrocatalyst for overall water splitting in acid
- 2020
-
Ingår i: Sustainable Energy & Fuels. - : ROYAL SOC CHEMISTRY. - 2398-4902. ; 4:4, s. 1712-1722
-
Tidskriftsartikel (refereegranskat)abstract
- The development of highly active and durable catalysts for water oxidation under acidic conditions is necessary but challenging for renewable energy conversion. Ir-based catalysts are highly efficient for water oxidation in acid, but their large scale application is hindered by the high cost and scarcity of iridium. Herein, we use an amorphous WO3 induced lattice distortion (AWILD) strategy to reduce the Ir content to only 2 wt% in the final material. The optimized hybrid nitrogen-doped carbon (NC)/WO3/IrO2 can efficiently catalyze water oxidation with a low overpotential of 270 mV at 10 mA cm(-2) current density (eta (10)) and a high turnover frequency of over 2 s(-1) at 300 mV overpotential in 0.5 M H2SO4, a performance that surpasses that of commercial IrO2 significantly. Introducing the layer of amorphous WO3 between IrO2 nanoparticles and NC can distort the lattice of IrO2, exposing more highly active sites for water oxidation. The AWILD effect compensates for the lower Ir content and dramatically reduces the cost of the catalyst without sacrificing the catalytic activity. Additionally, this catalyst also exhibits high activity in acid for hydrogen evolution with only 65 mV of eta (10) attributed to the AWILD effect, exhibiting efficient bifunctionality as a Janus catalyst for overall water splitting. The AWILD approach provides a novel and efficient strategy for low-cost and highly efficient electrocatalysts for acidic overall water splitting with an extremely low content of noble metals.
|
|
| 19. |
- Ghosh, Sourav, et al.
(författare)
-
Investigating the stable operating voltage for the MnFe2O4 Li-ion battery anode
- 2021
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 5:6, s. 1904-1913
-
Tidskriftsartikel (refereegranskat)abstract
- Template-free synthesis of MnFe2O4 nanopowder is carried out by co-precipitation in a basic medium, evaluating the effects of cation ratio and reaction temperature on the phase composition crystallinity of the resulting powder. Single-phase samples of the target spinel are obtained at the stoichiometric Mn : Fe = 1 : 2 ratio under reflux conditions (100 degrees C), as confirmed by X-ray diffraction (XRD) and Fourier Transformed Infrared (FTIR) spectroscopy. Transmission electron microscopy (TEM) images confirmed that nanostructured MnFe2O4 particles are obtained, which is further supported by Debye-Scherrer calculations from XRD data and by AFM measurements. The produced oxide demonstrated considerable thermal stability according to TGA data. Magnetic characteristics are strongly dependent on the content of magnetic phase and phase composition, achieving a maximum of 54 emu g(-1) for single-phase stoichiometric MnFe2O4. Further, the electrochemical stability of this material as the anode is investigated in Li-ion batteries (LIBs). When the MnFe2O4 electrode is operated in the potential window of 0.01-3.0 V, the reversible capacity is enhanced by almost 45% (802 mA h g(-1)) after the 100(th) cycle with reference to the 2(nd) cycle reversible capacity (548 mA h g(-1)). Methodically dQ/dV plots are analyzed and compared to understand processes behind the evolution of extra capacity beyond its theoretical limit. Further, the upper cut-off potential is tuned to identify a stable operating potential window for the MnFe2O4 anode in LIBs.
|
|
| 20. |
- Gumbo, Maureen, et al.
(författare)
-
A single site catalyst supported in mesoporous UiO-66 for catalytic conversion of carbon dioxide to formate
- 2024
-
Ingår i: Sustainable Energy and Fuels. - 2398-4902. ; 8:4, s. 777-788
-
Tidskriftsartikel (refereegranskat)abstract
- Carbon dioxide utilisation strategies are of paramount importance, yielding various products such as methanol and formate. Formate is an excellent hydrogen carrier in fuel cells, making it a highly exploitable chemical on the hydrogen energy storage front. Formate has an energy content that is at least five times greater than that of commercially available lithium-ion batteries. Herein, we have prepared mesoporous metal-organic frameworks (MOFs) (m-UiO-66 and m-UiO-66-NH2), using a Zr-based secondary building unit (SBU) and terephthalate linkers. The MOFs were used to support the half-sandwich (tetrazolylpyridyl)iridium(iii) complex to make single-site catalyst (Ir(iii)@m-UiO-66 and Ir(iii)@m-UiO-66-NH2) for CO2 conversion to formate. Both Ir(iii)@m-UiO-66 and Ir(iii)@m-UiO-66-NH2 exhibited improved activity for CO2 hydrogenation to formate in a heterogeneous system. Ir(iii)@m-UiO-66-NH2 and Ir(iii)@m-UiO-66 had turnover numbers of 3313 and 3076 TON, respectively, under optimized conditions. X-ray photoelectron spectroscopy (XPS) showed possible interaction of the complex with the MOF as evidenced by a downfield shift in the binding energies of the Ir 4f electronic environment. The catalysts showed post-catalysis stability, as confirmed by PXRD, FTIR, and XPS. The Ir 4f binding energies of the materials after catalysis showed an up-field shift confirming the presence of Ir-H species which are the active species for catalysis.
|
|
| 21. |
- Hedström, Svante, et al.
(författare)
-
Photodriven CO dimerization on Cu2O from an electronic-structure perspective
- 2020
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry (RSC). - 2398-4902. ; 4:2, s. 670-677
-
Tidskriftsartikel (refereegranskat)abstract
- Electrochemically driven CO2 reduction into alcohols and hydrocarbons is a topic of intense study. Photocatalytic approaches, which instead are powered by light, are also reported, but these generally rely on two-component catalysts and yield only moderately reduced products with a single carbon atom. In this report, we use density functional theory, including its linear-response time-dependent implementation, to investigate the feasibility of photocatalytically driving the dimerization of CO chemisorbed on Cu2O, a crucial step in the chemical conversion of CO2 into C-2 products, such as ethanol and ethylene. We find that CO dimerization into OCCO is greatly aided by the photoinduced population of a low-lying LUMO that is bonding with respect to the C-C bond of two adjacently chemisorbed CO molecules.
|
|
| 22. |
- Huang, Shoushuang, et al.
(författare)
-
An advanced electrocatalyst for efficient synthesis of ammonia based on chemically coupled NiS@MoS2 heterostructured nanospheres
- 2021
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 5:10, s. 2640-2648
-
Tidskriftsartikel (refereegranskat)abstract
- The electrochemical reduction of nitrogen, as a sustainable alternative to the known Haber-Bosch process, possesses promising application prospects in the development of renewable energy storage systems. However, the yield of NH3 and Faraday efficiency are usually very low owing to the loss of active electrocatalysts and competitive hydrogen evolution reactions. Herein, uniform NiS@MoS2 core-shell microspheres are controllably prepared as a potential catalyst for an ambient electrocatalytic N-2 reduction reaction. The NiS@MoS2 microspheres possess highly active intrinsic, sufficient accessible active sites, high structural porosity, and convenient transport channels, consequently boosting the transmission of electrons and mass. Additionally, the interfacial interaction between NiS and MoS2 facilitates electron transfer, which further improves the catalytic activity by optimizing the free energies of reaction intermediates. As a result, the titled NiS@MoS2 shows excellent electrochemical activity and selectivity, capable of achieving a relatively high NH3 yield of 9.66 mu g h(-1) mg(cat)(-1) at -0.3 V (vs. the reversible hydrogen electrode, RHE) and a high FE of 14.8% at -0.1 V vs. RHE in 0.1 M Na2SO4. The work demonstrated here may open a new avenue for the rational design and synthesis of catalysts for the electrochemical synthesis of ammonia.
|
|
| 23. |
- Karka, Paraskevi, 1982, et al.
(författare)
-
Hydrothermal liquefaction integrated with wastewater treatment plants - life cycle assessment and technoeconomic analysis of process system options
- 2024
-
Ingår i: Sustainable Energy and Fuels. - 2398-4902. ; In Press
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study is the formulation of various scenarios based on two different conceptual design configurations for a sewage sludge-to-fuel pathway via HTL, co-located with a wastewater treatment plant (WWTP), and biocrude upgrading. The first concept refers to decentralized HTL plants assessed for three scenarios of different aqueous phase treatment technologies, coupled with two scenarios of technologies for hydrogen production and a centralized biocrude upgrading plant for diesel and gasoline production. The second concept refers to a decentralized HTL plant followed by a first step of hydrodeoxygenation to stabilize and transfer the treated biocrudes in a central oil refinery for further treatment (e.g., at the FCC cracking units). All cases are assessed with respect to their environmental impacts and their economic profile using the Life Cycle Assessment (LCA) methodology and technoeconomic analysis (TEA). The impact assessment was based on the eighteen mid- and the three endpoint categories of the ReCiPe method. The Global Warming Potential metric ranges between 0.3 and 2.5 kg CO2-eq. per kg biofuel blend corresponding to GHG emission savings of 35% to 90% compared to fossil diesel. TEA results show production costs of 60-80 € per MW h product. Analysis of results provides background information for design specifications targeting improvement of the environmental and economic performance and, thus, highlighting opportunities for biofuel production and synergies with existing fossil fuel infrastructures.
|
|
| 24. |
- Kawde, Anurag, et al.
(författare)
-
Photo-electrochemical hydrogen production from neutral phosphate buffer and seawater using micro-structured p-Si photo-electrodes functionalized by solution-based methods
- 2018
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry (RSC). - 2398-4902. ; 2:10, s. 2215-2223
-
Tidskriftsartikel (refereegranskat)abstract
- Solar fuels such as H2 generated from sunlight and seawater using earth-abundant materials are expected to be a crucial component of a next generation renewable energy mix. We herein report a systematic analysis of the photo-electrochemical performance of TiO2 coated, microstructured p-Si photoelectrodes (p-Si/TiO2) that were functionalized with CoOx and NiOx for H2 generation. These photocathodes were synthesized from commercial p-Si wafers employing wet chemical methods. In neutral phosphate buffer and standard 1 sun illumination, the p-Si/TiO2/NiOx photoelectrode showed a photocurrent density of 1.48 mA cm2 at zero bias (0 VRHE), which was three times and 15 times better than the photocurrent densities of p-Si/TiO2/CoOx and p-Si/TiO2, respectively. No decline in activity was observed over a five hour test period, yielding a Faradaic efficiency of 96% for H2 production. Based on the electrochemical characterizations and the high energy resolution fluorescence detected X-ray absorption near edge structure (HERFD-XANES) and emission spectroscopy measurements performed at the Ti Ka1 fluorescence line, the superior performance of the p-Si/TiO2/ NiOx photoelectrode was attributed to improved charge transfer properties induced by the NiOx coating on the protective TiO2 layer, in combination with a higher catalytic activity of NiOx for H2-evolution. Moreover, we report here an excellent photo-electrochemical performance of p-Si/TiO2/NiOx photoelectrode in corrosive artificial seawater (pH 8.4) with an unprecedented photocurrent density of 10 mA cm2 at an applied potential of 0.7 VRHE, and of 20 mA cm2 at 0.9 VRHE. The applied bias photon-to-current conversion efficiency (ABPE) at 0.7 VRHE and 10 mA cm2 was found to be 5.1%
|
|
| 25. |
- Khossossi, Nabil, et al.
(författare)
-
Hydrogen storage characteristics of Li and Na decorated 2D boron phosphide
- 2020
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry (RSC). - 2398-4902. ; 4:9, s. 4538-4546
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Solid-state systems serve as a candidate for clean energy applications driven by current technological demands. In this effort, density functional theory (DFT) has become a valuable asset to investigate the intrinsic electronic properties and holds a substantial promise for guiding the discovery of new materials. Herein, we have investigated the Li and Na decorated 2D boron phosphide (BP) monolayer as a potential candidate for hydrogen storage due to its lightweight and structural stability. Li and Na adatoms prefer to adsorb at the center of the hexagon with the binding energies 0.36 and 0.26 eV, respectively. The thermodynamic stabilities of BP monolayer in cases of 4Li@BP and 4Na@BP systems were evaluated at room temperature using ab initio molecular dynamics (AIMD) simulations. The study of the electronic structure revealed that the semiconducting BP sheets become metallic after the adatom adsorption. It was found that the dispersed Li and Na atoms on the monolayer surface significantly increase both the hydrogen binding energies and the hydrogen storage capacities. With one-sided coverage of Li and Na atoms, four H2 molecules were adsorbed with a gravimetric capacity of 4.917 and 4.558 wt%, respectively. For double-sided adatom coverage, a total of 16H2 molecules was captured around 4Li@BP and 4Na@BP complex with a gravimetric capacity of 7.402 and 6.446 wt%, respectively. These results suggest that boron phosphide (BP) can act as an effective substrate for H2 storage by carefully engineering it with metal decoration.
|
|
