| 1. |
- Boot-Handford, M. E., et al.
(författare)
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Carbon capture and storage update
- 2014
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Ingår i: Energy and Environmental Sciences. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 7:1, s. 130-189
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Forskningsöversikt (refereegranskat)abstract
- In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coat (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.
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| 2. |
- Bounioux, C., et al.
(författare)
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Thermoelectric composites of poly(3-hexylthiophene) and carbon nanotubes with a large power factor
- 2013
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Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 6:3, s. 918-925
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Tidskriftsartikel (refereegranskat)abstract
- Composite films of poly(3-hexylthiophene) and single- as well as multi-walled carbon nanotubes are demonstrated to offer a competitive thermoelectric performance. The power factor significantly exceeds values obtained with either constituent alone provided that the conjugated polymer is sufficiently p-doped. The use of single-walled carbon nanotubes consistently results in a higher electrical conductivity with a maximum value above 10(3) S cm(-1) and thus gives rise to a power factor of 25 +/- 6 mu W m(-1) K-2 for a filler content of only 8 wt% and a maximum 95 +/- 12 mu W m(-1) K-2 for 42-81 wt%. Moreover, a carbon nanotube content of 8-10 wt% does not compromise the low bulk thermal conductivity of the polymer matrix, which promises a high figure of merit of at least ZT > 10(-2) at room-temperature. All samples are cast on plastic substrates, emphasising their suitability for large-area, flexible thermoelectric applications.
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| 3. |
- Caspeta-Guadarrama, Luis, 1974, et al.
(författare)
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The role of biofuels in the future energy supply
- 2013
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Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 6:4, s. 1077-1082
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Forskningsöversikt (refereegranskat)abstract
- In recent years several different arguments have been raised against the use of biofuels and their role in our future energy supply. These arguments can be divided into issues related to costs, food versus fuel, and lack of sustainability. Here we address these three points and argue that biofuels represent an essential contribution to our future energy supply and more importantly will contribute to a reduction in carbon dioxide emissions.
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| 4. |
- De La Fuente Durán, Ana, et al.
(författare)
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Origins of hydrogen peroxide selectivity during oxygen reduction on organic mixed ionic-electronic conducting polymers
- 2023
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Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 16:11, s. 5409-5422
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical reduction of atmospheric oxygen provides carbon emission-free pathways for the generation of electricity from chemical fuels and for the distributed production of green chemical oxidants like hydrogen peroxide. Recently, organic mixed ionic-electronic conducting polymers (OMIECs) have been reported as a new class of active electrode materials for the oxygen reduction reaction. This work sets out to identify the operative oxygen reduction mechanism of OMIECs through a multi-faceted experimental and theoretical approach. Using a combination of pH-dependent electrochemical characterization, operando UV-Vis and Raman spectroscopy, and ab initio calculations, we find that the n-type OMIEC, p(NDI-T2 P75), displays pH-dependent activity for the selective reduction of oxygen to the 2-electron hydrogen peroxide product. We use microkinetic simulations of the electrochemical behavior to rationalize our experimental observations through a polaron-mediated, non-adsorptive pathway involving chemical reduction of oxygen to the 1-electron superoxide intermediate followed by pH-dependent catalytic disproportionation to hydrogen peroxide. Finally, this pathway is applied to understand the experimental oxygen reduction reactivity across several n- and p-type OMIECs.
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| 5. |
- Dreos, Ambra, 1987, et al.
(författare)
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Exploring the potential of a hybrid device combining solar water heating and molecular solar thermal energy storage
- 2017
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 10:3, s. 728-734
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Tidskriftsartikel (refereegranskat)abstract
- A hybrid solar energy system consisting of a molecular solar thermal energy storage system (MOST) combined with a solar water heating system (SWH) is presented. The MOST chemical energy storage system is based on norbornadiene- quadricyclane derivatives allowing for conversion of solar energy into stored chemical energy at up to 103 kJ mol(-1) (396 kJ kg(-1)). It is demonstrated that 1.1% of incoming solar energy can be stored in the chemical system without significantly compromising the efficiency of the solar water heating system, leading to efficiencies of combined solar water heating and solar energy storage of up to 80%. Moreover, prospects for future improvement and possible applications are discussed.
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| 6. |
- Fan, Qunping, 1989, et al.
(författare)
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Over 14% efficiency all-polymer solar cells enabled by a low bandgap polymer acceptor with low energy loss and efficient charge separation
- 2020
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 13:12, s. 5017-5027
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Tidskriftsartikel (refereegranskat)abstract
- Obtaining both high open-circuit voltage (V-oc) and short-circuit current density (J(sc)) has been a major challenge for efficient all-polymer solar cells (all-PSCs). Herein, we developed a polymer acceptor PF5-Y5 with excellent optical absorption capability (onset extending to similar to 880 nm and maximum absorption coefficient exceeding 105 cm(-1) in a film), high electron mobility (3.18 x 10(3) cm(2) V-1 s(-1)) and high LUMO level (-3.84 eV) to address such a challenge. As a result, the PBDB-T:PF5-Y5-based all-PSCs achieved a high power conversion efficiency of up to 14.45% with both a high Voc (0.946 V) and a high Jsc (20.65 mA cm(-2)), due to the high and broad absorption coverage, small energy loss (0.57 eV) and efficient charge separation and transport in the device, which are among the best values in the all-PSC field. In addition, the all-PSC shows a similar to 15% improvement in PCE compared to its counterpart small molecule acceptor (Y5)-based device. Our results suggest that PF5-Y5 is a very promising polymer acceptor candidate for applications in efficient all-PSCs.
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| 7. |
- Felekidis, Nikolaos, et al.
(författare)
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Open circuit voltage and efficiency in ternary organic photovoltaic blends
- 2016
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Ingår i: Energy and Environmental Sciences. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 9:1, s. 257-266
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Tidskriftsartikel (refereegranskat)abstract
- Organic bulk heterojunction solar cells based on ternary blends of two donor absorbers and one acceptor are investigated by experiments and modeling. The commonly observed continuous tunability of the open circuit voltage VOC with the donor1: donor2 ratio can quantitatively be explained as quasi-Fermi level splitting due to photocreated charges filling a joint density of states that is broadened by Gaussian disorder. On this basis, a predictive model for the power conversion efficiency that accounts for the composition-dependent absorption and the shape of the current-voltage characteristic curve is developed. When all other parameters, most notably the fill factor, are constant, we find that for state-of-the-art absorbers, having a broad and strong absorption spectrum, ternary blends offer no advantage over binary ones. For absorbers with a more narrow absorption spectrum ternary blends of donors with complementary absorption spectra, offer modest improvements over binary ones. In contrast, when, upon blending, transport and/or recombination kinetics are improved, leading to an increased fill factor, ternaries may offer significant advantages over binaries.
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| 8. |
- Gusak, Viktoria, 1983, et al.
(författare)
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Diffusion and adsorption of dye molecules in mesoporous TiO2 photoelectrodes studied by indirect nanoplasmonic sensing
- 2013
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Ingår i: Energy and Environmental Sciences. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 6:12, s. 3627-3636
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we used Hidden Interface-Indirect Nanoplasmonic Sensing (HI-INPS) for real time monitoring of dye impregnation (adsorption-diffusion process) of mesoporous TiO2 electrodes of the kind used in dye-sensitized solar cells. We measured the dye percolation time (i.e. the time to diffuse to the bottom of a TiO2 photoelectrode film) for dye Z907 in a 1 : 1 volume mixture of acetonitrile and tert-butanol for different dye concentrations and for different thicknesses of the TiO2 film, while the total amount of adsorbed dye was simultaneously measured by optical absorption spectroscopy. The experimental data for the impregnation process were analyzed by employing a diffusion-front model, combining diffusion and Langmuir type adsorption, which allows extraction of the effective diffusion coefficient for the system. The latter value is about 15 mu m(2) s(-1) for the combined adsorption-diffusion movement of dye molecules through the TiO2 structure, which is an order of magnitude or more smaller than that for "free" diffusion of dye molecules in bulk solvents.
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| 9. |
- Kanchiralla, Fayas Malik, 1989, et al.
(författare)
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Role of biofuels, electro-fuels, and blue fuels for shipping: environmental and economic life cycle considerations
- 2024
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Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 17:17, s. 6393-6418
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Tidskriftsartikel (refereegranskat)abstract
- The global shipping industry is under increasing scrutiny for its contribution to greenhouse gas emissions, and it is a challenge to find sustainable and cost-efficient solutions to meet new and stringent climate reduction targets. This study uses life cycle assessment and life cycle costing to evaluate five main decarbonization strategies to reduce climate impact from ships: uptake of e-fuels, blue-fuels, biofuels, battery electric propulsion, and onboard carbon capture technology. The environmental impact, the economic performance, and the total costs of abating carbon emissions of a total of 23 decarbonization pathways are investigated. The life cycle assessment and life cycle costing are performed on prospective scenarios considering three ship types: bulk carrier, container ship, and cruise ship, and incorporate future development uncertainties. The results show that electro-fuels in the form of e-ammonia, e-methanol, and e-liquid hydrogen in fuel cells offer the highest climate mitigation potential of more than 85% compared to the use of marine gas oil in internal combustion engines. Biofuel options have a reduction potential of up to 78%, while blue-fuel and onboard carbon capture have lower climate reduction potentials of up to 62% and 56%, respectively. Bio-methanol has the most promising cost outlook with a carbon abatement cost of around 100 per tCO2eq. Onboard carbon capture technologies have a carbon abatement cost of around 150-190 per tCO2eq. While they can serve as a short-term transitional solution, they have a higher environmental impact and offer limited potential for climate mitigation. E-Ammonia appears as one of the most cost-effective solutions among e-fuels. Development of policy measures and investments in renewable energy infrastructure are necessary for the growth of e-fuels production, as affordable and renewable electricity is vital for the viability of e-fuels in shipping. The uncertainty and sensitivity analysis show the influence of primary energy sources on carbon abatement costs which will be key to understand the effectiveness of policies and to develop strategies to support the shipping industry's transition to a sustainable future. This study analyses different decarbonization strategies for shipping including uptake of e-fuels, blue fuels and biofuels, battery electric propulsion and onboard carbon capture technology from a life cycle perspective.
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| 10. |
- Lari, Giacomo M., et al.
(författare)
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Environmental and economical perspectives of a glycerol biorefinery
- 2018
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Ingår i: Energy and Environmental Sciences. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 11:5, s. 1012-1029
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Tidskriftsartikel (refereegranskat)abstract
- Glycerol conversion into chemicals and fuel additives is pursued to valorise a burgeoning by-product in the bioenergy sector. To this aim, heterogeneous catalysts have been developed that enable, in many cases, efficient and green transformations. Still, the evaluation of the environmental and economic footprint that would be associated with their large-scale application has often been neglected, limiting their commercial attractiveness. Furthermore, the impact of integrating different glycerol upgrading routes within a biorefinery, which is highly instrumental to determine the effective sustainability and profitability of biodiesel production from vegetable oils, has not been assessed. Here, the manufacture of the most relevant chemical derivatives of glycerol is considered, i.e., lactic acid, acrylic acid, glycerol carbonate, propanediols, epichlorohydrin and allyl alcohol. State-of-the-art catalysts for each upgrading route are briefly reviewed. Based on their performances, processes are rigorously modelled and relevant indicators, the global warming potential, the cumulative energy demand and the operating costs, quantified by life-cycle analysis. Glycerol-based processes are generally found more attractive than the conventional technologies nowadays applied for the production of the same chemicals, among which the paths to lactic acid and glycerol carbonate are particularly promising. In addition, the process variables mostly contributing to the environmental and cost metrics are identified. Accordingly, future studies should target further optimisation mainly in relation to selectivity, solvent volatility, reactants ratio and catalyst stability. Finally, the processes are integrated simulating a prospective glycerol biorefinery and the advantages deriving from the exchange of heat between the different routes quantified. If the glycerol feed is split equally among all routes the CO 2 emissions and energy requirements are decreased by 15 and 32%, respectively, and the profit is increased by 5% as compared to the sum of the individual glycerol-based processes. In order to minimise the ecological impact of the biorefinery, glycerol should be rather divided in an 80:20 mass ratio among 1,2-propanediol and glycerol carbonate production, which are expected to have a significant market size. The innovative approach outlined in this work holds potential to guide both fundamental chemical research and process design in the development of CO 2 and other bio-refineries.
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