| 1. |
|
|
| 2. |
- Huang, Jing, et al.
(författare)
-
Covalently linking CuInS2 quantum dots with a Re catalyst by click reaction for photocatalytic CO2 reduction
- 2018
-
Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 47:31, s. 10775-10783
-
Tidskriftsartikel (refereegranskat)abstract
- Covalently linking photosensitizers and catalysts in an inorganic-organic hybrid photocatalytic system is beneficial for efficient electron transfer between these components. However, general and straightforward methods to covalently attach molecular catalysts on the surface of inorganic semiconductors are rare. In this work, a classic rhenium bipyridine complex (Re catalyst) has been successfully covalently linked to the low toxicity CuInS2 quantum dots (QDs) by click reaction for photocatalytic CO2 reduction. Covalent bonding between the CuInS2 QDs and the Re catalyst in the QD-Re hybrid system is confirmed by UV-visible absorption spectroscopy, Fourier-transform infrared spectroscopy and energy-dispersive X-ray measurements. Time-correlated single photon counting and ultrafast time-resolved infrared spectroscopy provide evidence for rapid photo-induced electron transfer from the QDs to the Re catalyst. Upon photo-excitation of the QDs, the singly reduced Re catalyst is formed within 300 fs. Notably, the amount of reduced Re in the linked hybrid system is more than that in a sample where the QDs and the Re catalyst are simply mixed, suggesting that the covalent linkage between the CuInS2 QDs and the Re catalyst indeed facilitates electron transfer from the QDs to the Re catalyst. Such an ultrafast electron transfer in the covalently linked CuInS2 QD-Re hybrid system leads to enhanced photocatalytic activity for CO2 reduction, as compared to the conventional mixture of the QDs and the Re catalyst.
|
|
| 3. |
- Liu, Aijie, et al.
(författare)
-
In Situ Preparation and Immobilization of Semiconducting Polymer Dots on Microbeads for Efficient and Stable Photocatalytic Hydrogen Evolution
- 2021
-
Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 4:5, s. 4308-4312
-
Tidskriftsartikel (refereegranskat)abstract
- Organic semiconducting polymers dots (Pdots) have recently shown efficient photocatalytic activity for hydrogen evolution in an aqueous phase. However, colloidal Pdots face problems of aggregation and precipitation during the photocatalytic reaction due to unavoidable collisions between particles, thus resulting in a short catalytic lifetime. In this work, in situ preparation of PFBT Pdots on the surface of microbeads is reported. Results indicate that, with this facile method and support of a template, the photocatalytic properties of PFBT Pdots can be highly enhanced.
|
|
| 4. |
- Pati, Palas Baran, et al.
(författare)
-
An experimental and theoretical study of an efficient polymer nano-photocatalyst for hydrogen evolution
- 2017
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 10:6, s. 1372-1376
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, we report a highly efficient organic polymer nano-photocatalyst for light driven proton reduction. The system renders an initial rate of hydrogen evolution up to 50 +/- 0.5 mmol g(-1) h(-1), which is the fastest rate among all other reported organic photocatalysts. We also experimentally and theoretically prove that the nitrogen centre of the benzothiadiazole unit plays a crucial role in the photocatalysis and that the Pdots structure holds a close to ideal geometry to enhance the photocatalysis.
|
|
| 5. |
- Pati, Palas Baran, et al.
(författare)
-
Insights into the Mechanism of a Covalently Linked Organic Dye-Cobaloxime Catalyst System for Dye-Sensitized Solar Fuel Devices
- 2017
-
Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 10:11, s. 2480-2495
-
Tidskriftsartikel (refereegranskat)abstract
- A covalently-linked organic dye-cobaloxime catalyst system is developed by facile click reaction for mechanistic studies and application in a dye sensitized solar fuel device based on mesoporous NiO. This system has been systematically investigated by photophysical measurements, density functional theory, time resolved fluorescence, transient absorption spectroscopy as well as photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer to reduce the catalyst unit. Moreover, they suggest that the dye undergoes structural changes in the excited state and that excitation energy transfer occurs between neighboring molecules. The photoelectrochemical experiments also show the hydrogen production by this system-based NiO photocathode. The axial chloride ligands of the catalyst are released during photocatalysis to create the active sites for proton reduction. A working mechanism of the dye-catalyst on photocathode is eventually proposed on the basis of this study.
|
|
| 6. |
- Tian, Haining, 1983-, et al.
(författare)
-
Hydrogen evolution by a photoelectrochemical cell based on a Cu2O-ZnO-[FeFe] hydrogenase electrode
- 2018
-
Ingår i: Journal of Photochemistry and Photobiology A. - : Elsevier BV. - 1010-6030 .- 1873-2666. ; 366, s. 27-33
-
Tidskriftsartikel (refereegranskat)abstract
- A Cu2O-ZnO-hydrogenase photocathode possessed enzyme/semiconductor junction has been constructed by immobilizing a biological protein catalyst, hydrogenase-CrHydA1 enzyme on the ZnO protected Cu2O electrode. With light illumination, a photocurrent of 0.8 mA/cm2 at 0.15 V vs. RHE was obtained and hydrogen was successfully detected from the photocathode in photoelectrochemical measurements with Faradaic efficiency of ca. 1%. The construction as well as the stability of the system are also reported. The result shows that this biohybrid photocathode is capable of photocatalytic proton reduction under mild conditions.
|
|
| 7. |
- Tian, Lei, et al.
(författare)
-
Mechanistic Insights into Solid-State p-Type Dye-Sensitized Solar Cells
- 2019
-
Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 123:43, s. 26151-26160
-
Tidskriftsartikel (refereegranskat)abstract
- The study of p-type dye sensitized solar cells (p-DSCs) is appealing but challenging. Although the devices have been studied for 20 years, the light conversion efficiency lags far behind those of n-DSCs. Very recently, on the basis of a core-shell structure, a novel solid-state p-DSC (p-ssDSCs) has been fabricated, which showed great enhancement in open-circuit voltage and dye regeneration rate. To further improve the performance of such devices, charge diffusion, recombination process, and the main limiting factors have to be understood. In the present paper, core-shell p-ssDSCs with ZnO as an electron conductor were fabricated by atomic layer deposition. The charge transport time was determined to be ca. 0.1 ms, which is about 2 orders of magnitude faster than those of typical liquid devices with I-/I-3(-) as a redox mediator. As a consequence, the devices exhibit the highest reported charge diffusion coefficient (D-d)' among p-DSCs. It is ascribed to an electron-limiting diffusion process by the ambipolar diffusion model, suggesting a different charge-transport-determining mechanism in contrast to liquid p-DSCs. The charge recombination rate is 1-2 orders of magnitude slower than its charge transport time, mandating that the estimated charge collection efficiency is near unity. Detailed analysis of the incident photon-to-electron conversion efficiency suggests that the energy conversion efficiency in these p-ssDSCs is currently limited by a large fraction of dyes that is not fully electrically connected in the device.
|
|
| 8. |
|
|
| 9. |
- Tian, Lei, et al.
(författare)
-
Solid state p-type dye sensitized NiO-dye-TiO2 core-shell solar cells
- 2018
-
Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 54:30, s. 3739-3742
-
Tidskriftsartikel (refereegranskat)abstract
- Solid state p-type dye sensitized NiO-dye-TiO2 core-shell solar cells with an organic dye PB6 were successfully fabricated for the first time. With Al2O3 as an inner barrier layer, the recombination process between injected holes in NiO and injected electrons in TiO2 was significantly suppressed and the charge transport time was also improved.
|
|
| 10. |
- Tian, Lei, et al.
(författare)
-
Ultrafast dye regeneration in a core-shell NiO-dye-TiO2 mesoporous film
- 2018
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : The Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 20:1, s. 36-40
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, a core-shell NiO-dye-TiO2 mesoporous film was fabricated for the first time, utilizing atomic layer deposition technique and a newly designed triphenylamine dye. The structure of the film was confirmed by SEM, TEM, and EDX. Excitation of the dye led to efficient and fast charge separation, by hole injection into NiO, followed by an unprecedentedly fast dye regeneration (t1/2 [less-than-or-equal] 500 fs) by electron transfer to TiO2. The resulting charge separated state showed a pronounced transient absorption spectrum caused by the Stark effect, and no significant decay was found within 1.9 ns. This indicates that charge recombination between NiO and TiO2 is much slower than that between the NiO and the reduced dye in the absence of the TiO2 layer (t1/2 [approximate] 100 ps).
|
|
| 11. |
- Tian, Lei, et al.
(författare)
-
Understanding the Role of Surface States on Mesoporous NiO Films
- 2020
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 142:43
-
Tidskriftsartikel (refereegranskat)abstract
- Surface states of mesoporous NiO semiconductor films have particular properties differing from the bulk and are able to dramatically influence the interfacial electron transfer and adsorption of chemical species. To achieve a better performance of NiO-based p-type dye-sensitized solar cells (p-DSCs), the function of the surface states has to be understood. In this paper, we applied a modified atomic layer deposition procedure that is able to passivate 72% of the surface states on NiO by depositing a monolayer of Al2O3. This provides us with representative control samples to study the functions of the surface states on NiO films. A main conclusion is that surface states, rather than the bulk, are mainly responsible for the conductivity in mesoporous NiO films. Furthermore, surface states significantly affect dye regeneration (with I–/I3– as redox couple) and hole transport in NiO-based p-DSCs. A new dye regeneration mechanism is proposed in which electrons are transferred from reduced dye molecules to intra-bandgap states, and then to I3– species. The intra-bandgap states here act as catalysts to assist I3– reduction. A more complete mechanism is suggested to understand the particular hole transport behavior in p-DSCs, in which the hole transport time is independent of light intensity. This is ascribed to the percolation hole hopping on the surface states. When the concentration of surface states was significantly reduced, the light-independent charge transport behavior in pristine NiO-based p-DSCs transformed into having an exponential dependence on light intensity, similar to that observed in TiO2-based n-type DSCs. These conclusions on the function of surface states provide new insight into the electronic properties of mesoporous NiO films.
|
|
| 12. |
- Xu, Bo, 1980-, et al.
(författare)
-
An Indacenodithieno[3,2-b]thiophene-Based Organic Dye for Solid-State p-Type Dye-Sensitized Solar Cells
- 2019
-
Ingår i: ChemSusChem. - : WILEY-V C H VERLAG GMBH. - 1864-5631 .- 1864-564X. ; 12:14, s. 3243-3248
-
Tidskriftsartikel (refereegranskat)abstract
- An indacenodithieno[3,2-b]thiophene (IDTT) unit is used as a linker moiety to design a new p-type dye-TIP-for solid-state p-type dye-sensitized solar cells. Solar cells based on the TIP dye offered an efficiency of 0.18 % with an open-circuit photovoltage of 550 mV and a short-circuit photocurrent density of 0.86 mA cm(-2), which is better than those of two reference dyes, PB6 and BH4. Charge lifetime experiments reveal that the IDTT linker-based TIP dye significantly suppresses charge recombination losses in the devices.
|
|
| 13. |
- Xu, Bo, 1980-, et al.
(författare)
-
Solution-processed nanoporous NiO-dye-ZnO photocathodes : Toward efficient and stable solid-state p-type dye-sensitized solar cells and dye-sensitized photoelectrosynthesis cells
- 2019
-
Ingår i: Nano Energy. - : Elsevier BV. - 2211-2855 .- 2211-3282. ; 55, s. 59-64
-
Tidskriftsartikel (refereegranskat)abstract
- A solution-processed NiO-dye-ZnO photocathode was developed for applications in both solid-state p-type dye-sensitized solar cells (p-ssDSCs) and p-type dye-sensitized photoelectrosynthesis cells (p-DSPECs). In p-ssDSCs, the solar cell using ZnO as electron transport material showed a short circuit current, up to 680 mu A cm(-2), which is 60-fold larger than that previously reported device using TiO2 as electron transport material with similar architecture. In the p-DSPECs, a remarkable photocurrent of 100 mu A cm(-2) was achieved in a pH = 5.0 acetate buffer solution under a bias potential at 0.05 V vs RHE with platinum as the proton reduction catalyst. A Faradaic efficiency approaching 100% for the H-2 evolution reaction was obtained after photoelectrolysis for 9 h. Importantly, the solution-processed NiO-dye-ZnO photocathode exhibited excellent long-term stability in both p-ssDSCs and p-DSPECs. To the best of our knowledge, this is the first study where a solution-processable, nanoporous NiO-dye-ZnO photocathode is used for both p-ssDSCs and p-DSPECs having both excellent device performance and stability.
|
|
| 14. |
- Amaro-Gahete, Juan, et al.
(författare)
-
Catalytic systems mimicking the [FeFe]-hydrogenase active site for visible-light-driven hydrogen production
- 2021
-
Ingår i: Coordination chemistry reviews. - : Elsevier. - 0010-8545 .- 1873-3840. ; 448
-
Forskningsöversikt (refereegranskat)abstract
- A global hydrogen economy could ensure environmentally sustainable, safe and cost-efficient renewable energy for the 21st century. Solar hydrogen production through artificial photosynthesis is a key strategy, and the activity of natural hydrogenase metalloenzymes an inspiration for the design of synthetic catalyst systems. [FeFe]-hydrogenase enzymes, present in anaerobic bacteria and green algae, are the most efficient class of biological catalysts for hydrogen evolution. The enzymes operate in an aqueous environment, utilizing electrons that ultimately stem from photosynthesis as the only energy source. Functional synthetic models of the [FeFe]-hydrogenase enzyme active site have garnered intense interest as potential catalysts for the reduction of protons to molecular hydrogen. Herein, we take an extensive journey through the field of biomimetic hydrogenase chemistry for lightdriven hydrogen production. We open with a brief presentation of the structure and redox mechanism of the natural enzyme. Synthetic methodologies, structural characteristics, and hydrogen generation metrics relevant to the synthetic diiron catalysts ([2Fe2S]) are discussed. We first examine multicomponent photocatalysis systems with the [2Fe2S] cluster, followed by photosensitizer-[2Fe2S] dyads and molecular triads. Finally, strategies for the incorporation of [2Fe2S] complexes into supramolecular assemblies, semiconductor supports, and hybrid heterogeneous platforms are laid out. We analyze the individual properties, scope, and limitations of the components present in the photocatalytic reactions. This review illuminates the most useful aspects to rationally design a wide variety of biomimetic catalysts inspired by the diiron subsite of [FeFe]-hydrogenases, and establishes design features shared by the most stable and efficient hydrogen producing photosystems. (C) 2021 The Author(s). Published by Elsevier B.V.
|
|
| 15. |
- Amaro-Gahete, Juan, et al.
(författare)
-
Hydroxyl-Decorated Diiron Complex as a [FeFe]-Hydrogenase Active Site Model Complex : Light-Driven Photocatalytic Activity and Heterogenization on Ethylene-Bridged Periodic Mesoporous Organosilica
- 2022
-
Ingår i: Catalysts. - : MDPI. - 2073-4344. ; 12:3
-
Tidskriftsartikel (refereegranskat)abstract
- A biomimetic model complex of the [FeFe]-hydrogenase active site (FeFeOH) with an ethylene bridge and a pendant hydroxyl group has been synthesized, characterized and evaluated as catalyst for the light-driven hydrogen production. The interaction of the hydroxyl group present in the complex with 3-isocyanopropyltriethoxysilane provided a carbamate triethoxysilane bearing a diiron dithiolate complex (NCOFeFe), thus becoming a potentially promising candidate for anchoring on heterogeneous supports. As a proof of concept, the NCOFeFe precursor was anchored by a grafting procedure into a periodic mesoporous organosilica with ethane bridges (EthanePMO@NCOFeFe). Both molecular and heterogenized complexes were tested as catalysts for light-driven hydrogen generation in aqueous solutions. The photocatalytic conditions were optimized for the homogenous complex by varying the reaction time, pH, amount of the catalyst or photosensitizer, photon flux, and the type of light source (light-emitting diode (LED) and Xe lamp). It was shown that the molecular FeFeOH diiron complex achieved a decent turnover number (TON) of 70 after 6 h, while NCOFeFe and EthanePMO@NCOFeFe had slightly lower activities showing TONs of 37 and 5 at 6 h, respectively.
|
|
| 16. |
- Axelsson, Martin, 1993-, et al.
(författare)
-
A benzothiadiazole based molecule for CO2 capture and reduction in multiple reduced states
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Using small organic molecular redox carriers to reversibly capture CO2 is a promising approach to mitigate the ongoing climate crisis. Some variants of this type of molecule can catalyse the reduction of CO2 into valuable chemicals. 2,1,3-benzothiadiazole (BT) is an interesting unit due to its proven interaction with CO2 upon reduction and the ease to tune its structure. In this work, the molecule 2,1,3-benzothiadiazole-4,7-dicarbonitrile (BTDN) is studied for CO2 and reduction at its different reduced states. The work is carried out with a combination of (spectro-)electrochemical and computational studies. In cyclic voltammetry, one can see a clear interaction between BTDN and CO2 upon BTDN’s second reduction and the appearance of a large current in its third reduction, in the presence of CO2. DFT calculations show a large variety of possible CO2-bound species that can potentially match the experimental data. The binding of CO2 on BTDN is shown to be irreversible upon the oxidation of the species, especially with low concentrations of CO2. From gas chromatography and NMR experiments, small amounts of CO and oxalate were detected after bulk electrolysis.
|
|
| 17. |
- Axelsson, Martin, 1993-
(författare)
-
Illuminating Benzothiadiazole : Mechanistic Insights into its Role in Fuel-Forming Reactions
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Development and understanding of catalytic reactions involved in fuel formation are crucial to be able to make the energy transition into a sustainable future. One intriguing type of catalyst for these types of reactions is organic material catalysts, which combine some of the tunable nature of molecular catalysts with the scalability and robust nature of material catalysts. The understanding of the catalytic mechanisms in these types of materials is still a work in progress. In the last decade D-A type polymers have gotten a lot of attention as potential photocatalysts for fuel-forming reactions but currently, the mechanisms in which these reactions take place are very limited.This thesis focuses on the molecular unit benzothiadiazole (BT) and its role in catalytic fuel-forming reactions across various molecules and polymers. In paper I: The hydrogen evolution reaction (HER) is investigated on the small molecule 2,1,3-benzothiadiazole-4,7dicarbonitrile (BT). The study reveals that BTDN serves as an electrocatalyst for the HER. Some catalytic intermediates were identified spectroscopically and a catalytic mechanism was proposed.In papers II and III: Polymeric nanoparticles (Pdots) based on the polymer poly(9,9- dioctylfluorene-alt-2,1,3-benzothiadiazole (PFBT) were investigated for photocatalytic fuel-forming reactions. First, the HER was explored and it emphasised the significance of proton binding to the BT unit as a catalytic intermediate. It also showed that changing to basic conditions can quench the HER and make place for CO2 reduction to CO and that PFBT Pdots exhibit good selectivity in catalyzing this reaction.Finally, in Paper IV, the binding and reduction of CO2 on the molecule BTDN were investigated. It was shown that BTDN can bind CO2 in multiple reduced states and reduce it to CO and oxalate in a third reduction, albeit with seemingly low efficiencies.
|
|
| 18. |
- Axelsson, Martin, et al.
(författare)
-
Small Organic Molecule Based on Benzothiadiazole for Electrocatalytic Hydrogen Production
- 2021
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 143:50, s. 21229-21233
-
Tidskriftsartikel (refereegranskat)abstract
- A small organic molecule 2,1,3-benzothiadiazole-4, 7-dicarbonitrile (BTDN) is assessed for electrocatalytic hydrogen evolution on glassy carbon electrode and shows a hydrogen production Faradaic efficiency of 82% in the presence of salicylic acid. The key catalytic intermediates of reduced species BTDN-. and protonated intermediates are characterized or hypothesized by using various spectroscopic methods and density functional theory (DFT)-based calculations. With the experimental and theoretical results, a catalytic mechanism of BTDN for electrocatalytic H-2 evolution is proposed.
|
|
| 19. |
- Axelsson, Martin, 1993-, et al.
(författare)
-
The Role of Benzothiadiazole Unit in Organic Polymers on Photocatalytic Hydrogen Production
- 2024
-
Ingår i: JACS Au. - : American Chemical Society (ACS). - 2691-3704. ; 4:2, s. 570-577
-
Tidskriftsartikel (refereegranskat)abstract
- Organic polymers based on the donor–acceptor structure are a promising class of efficient photocatalysts for solar fuel production. Among these polymers, poly(9,9-dioctylfluorene-alt-1,2,3-benzothiadiazole) (PFBT) consisting of fluorene donor and benzothiadiazole acceptor units has shown good photocatalytic activity when it is prepared into polymer dots (Pdots) in water. In this work, we investigate the effect of the chemical environment on the activity of photocatalysis from PFBT Pdots for hydrogen production. This is carried out by comparing the samples with various concentrations of palladium under different pH conditions and with different sacrificial electron donors (SDs). Moreover, a model compound 1,2,3-benzothiadiazole di–9,9-dioctylfluorene (BTDF) is synthesized to investigate the mechanism for protonation of benzothiadiazole and its kinetics in the presence of an organic acid–salicylic acid by cyclic voltammetry. We experimentally show that benzothiadiazole in BTDF can rapidly react with protons with a fitted value of 0.1–5 × 1010 M–1 s–1 which should play a crucial role in the photocatalytic reaction with a polymer photocatalyst containing benzothiadiazole such as PFBT Pdots for hydrogen production in acidic conditions. This work gives insights into why organic polymers with benzothiadiazole work efficiently for photocatalytic hydrogen production.
|
|
| 20. |
- Bagnall, Andrew J., et al.
(författare)
-
Ultrafast Electron Transfer from CuInS2 Quantum Dots to a Molecular Catalyst for Hydrogen Production : Challenging Diffusion Limitations
- 2024
-
Ingår i: ACS Catalysis. - 2155-5435. ; 14:6, s. 4186-4201
-
Tidskriftsartikel (refereegranskat)abstract
- Systems integrating quantum dots with molecular catalysts are attracting ever more attention, primarily owing to their tunability and notable photocatalytic activity in the context of the hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR). CuInS2 (CIS) quantum dots (QDs) are effective photoreductants, having relatively high-energy conduction bands, but their electronic structure and defect states often lead to poor performance, prompting many researchers to employ them with a core–shell structure. Molecular cobalt HER catalysts, on the other hand, often suffer from poor stability. Here, we have combined CIS QDs, surface-passivated with l-cysteine and iodide from a water-based synthesis, with two tetraazamacrocyclic cobalt complexes to realize systems which demonstrate high turnover numbers for the HER (up to >8000 per catalyst), using ascorbate as the sacrificial electron donor at pH = 4.5. Photoluminescence intensity and lifetime quenching data indicated a large degree of binding of the catalysts to the QDs, even with only ca. 1 μM each of QDs and catalysts, linked to an entirely static quenching mechanism. The data was fitted with a Poissonian distribution of catalyst molecules over the QDs, from which the concentration of QDs could be evaluated. No important difference in either quenching or photocatalysis was observed between catalysts with and without the carboxylate as a potential anchoring group. Femtosecond transient absorption spectroscopy confirmed ultrafast interfacial electron transfer from the QDs and the formation of the singly reduced catalyst (CoII state) for both complexes, with an average electron transfer rate constant of ≈ (10 ps)−1. These favorable results confirm that the core tetraazamacrocyclic cobalt complex is remarkably stable under photocatalytic conditions and that CIS QDs without inorganic shell structures for passivation can act as effective photosensitizers, while their smaller size makes them suitable for application in the sensitization of, inter alia, mesoporous electrodes.
|
|
| 21. |
- Banin, U., et al.
(författare)
-
Nanotechnology for catalysis and solar energy conversion
- 2021
-
Ingår i: Nanotechnology. - : Institute of Physics Publishing (IOPP). - 0957-4484 .- 1361-6528. ; 32:4
-
Tidskriftsartikel (refereegranskat)abstract
- This roadmap on Nanotechnology for Catalysis and Solar Energy Conversion focuses on the application of nanotechnology in addressing the current challenges of energy conversion: 'high efficiency, stability, safety, and the potential for low-cost/scalable manufacturing' to quote from the contributed article by Nathan Lewis. This roadmap focuses on solar-to-fuel conversion, solar water splitting, solar photovoltaics and bio-catalysis. It includes dye-sensitized solar cells (DSSCs), perovskite solar cells, and organic photovoltaics. Smart engineering of colloidal quantum materials and nanostructured electrodes will improve solar-to-fuel conversion efficiency, as described in the articles by Waiskopf and Banin and Meyer. Semiconductor nanoparticles will also improve solar energy conversion efficiency, as discussed by Boschloo et al in their article on DSSCs. Perovskite solar cells have advanced rapidly in recent years, including new ideas on 2D and 3D hybrid halide perovskites, as described by Spanopoulos et al 'Next generation' solar cells using multiple exciton generation (MEG) from hot carriers, described in the article by Nozik and Beard, could lead to remarkable improvement in photovoltaic efficiency by using quantization effects in semiconductor nanostructures (quantum dots, wires or wells). These challenges will not be met without simultaneous improvement in nanoscale characterization methods. Terahertz spectroscopy, discussed in the article by Milot et al is one example of a method that is overcoming the difficulties associated with nanoscale materials characterization by avoiding electrical contacts to nanoparticles, allowing characterization during device operation, and enabling characterization of a single nanoparticle. Besides experimental advances, computational science is also meeting the challenges of nanomaterials synthesis. The article by Kohlstedt and Schatz discusses the computational frameworks being used to predict structure-property relationships in materials and devices, including machine learning methods, with an emphasis on organic photovoltaics. The contribution by Megarity and Armstrong presents the 'electrochemical leaf' for improvements in electrochemistry and beyond. In addition, biohybrid approaches can take advantage of efficient and specific enzyme catalysts. These articles present the nanoscience and technology at the forefront of renewable energy development that will have significant benefits to society.
|
|
| 22. |
- Besharat, Zahra, et al.
(författare)
-
In-situ evaluation of dye adsorption on TiO2 using QCM
- 2017
-
Ingår i: EPJ Photovoltaics. - : EDP Sciences. - 2105-0716. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- We measured the adsorption characteristics of two organic dyes; triphenylamine-cyanoacrylic acid (TPA-C) and phenoxazine (MP13), on TiO2, directly in a solution based on quartz crystal microbalance (QCM). Monitoring the adsorbed amount as a function of dye concentration and during rinsing allows determination of the equilibrium constant and distinction between chemisorbed and physisorbed dye. The measured equilibrium constants are 0.8 mM(-1) for TPA-C and 2.4 mM(-1) for MP13. X-ray photoelectron spectroscopy was used to compare dried chemisorbed layers of TPA-C prepared in solution with TPA-C layers prepared via vacuum sublimation; the two preparation methods render similar spectra except a small contribution of water residues (OH) on the solution prepared samples. Quantitative Nanomechanical Mapping Atomic Force Microscopy (QNM-AFM) shows that physisorbed TPA-C layers are easily removed by scanning the tip across the surface. Although not obvious in height images, adhesion images clearly demonstrate removal of the dye.
|
|
| 23. |
- Brnovic, Andjela, et al.
(författare)
-
Mechanistic Insights into the Photocatalytic Hydrogen Production of Y5 and Y6 Nanoparticles
- 2023
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 127:26, s. 12631-12639
-
Tidskriftsartikel (refereegranskat)abstract
- Utilization of solarenergy in organic semiconductorsrelies oncomplicated photophysical processes due to the strong electron-holeinteractions. To gain a better understanding of these processes andtheir effect on the photocatalytic performance of non-fullerene acceptors(NFAs) within nanoparticles (NPs), we compared the excited-state dynamicsand photocatalytic hydrogen production activity of two NFA-based NPs,Y5 and Y6. Our results show that under LED light irradiation, Y5 NPsexhibit 14 times better hydrogen production activity than Y6 NPs.The hydrogen production activity was also evaluated under Xenon lightirradiation (AM1.5G, 100 mW & BULL;cm(-2)) for Y5 NPs,yielding 410 mmol/g after 24 h. Time-resolved spectroscopy experimentsrevealed a longer triplet lifetime for Y5 compared to Y6 NPs, andthe lifetime was reduced upon addition of the electron donor ascorbate.This suggests the involvement of the triplet state in reductive quenchingand better hydrogen evolution reaction performance for Y5 NPs. Thegood agreement between fluorescence and triplet lifetimes observedfor Y5 NPs was attributed to reverse intersystem crossing, which repopulatesthe excited singlet state through thermally activated delayed fluorescence(TADF). The absence of TADF in Y6 NPs could limit its efficiency forhydrogen evolution reaction, in addition to the intrinsically shortertriplet lifetime and reduction potential difference, making it animportant factor to consider in Y series-based NPs.
|
|
| 24. |
- Cai, Bin, et al.
(författare)
-
Organic Polymer Dots Photocatalyst for CO2 Reduction in Aqueous Solution
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Developing low-cost and efficient photocatalysts to convert CO2 into valuable fuels is desirable to realize a carbon-neutral society. In this work, we report that polymer dots (Pdots) of poly[(9,9′-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-thiadiazole)] (PFBT) without adding any extra co-catalyst can photocatalytic reduction of CO2 into CO in aqueous solution, rendering a CO production rate of 57 μmol g-1 h-1 with a detectable selectivity of up to 100%. 5 cycles of CO2 re-purging experiments show no distinct decline in CO amount and reaction rate, indicating the promising photocatalytic stability of PFBT Pdots in photocatalytic CO2 reduction reaction. Mechanistic study reveals that photo-excited PFBT Pdots are reduced by TEOA first, then the reduced PFBT Pdots can bind CO2 and reduce it into CO via their intrinsic active sites. This work highlights the application of organic Pdots for CO2 reduction in the aqueous solution, which therefore provides a strategy to develop highly efficient and environmental-friendly nanoparticular photocatalysts for CO2 reduction.
|
|
| 25. |
- Cai, Bin, et al.
(författare)
-
Organic Polymer Dots Photocatalyze CO2 Reduction in Aqueous Solution
- 2023
-
Ingår i: Angewandte Chemie International Edition. - : John Wiley & Sons. - 1433-7851 .- 1521-3773. ; 62:45
-
Tidskriftsartikel (refereegranskat)abstract
- Developing low-cost and efficient photocatalysts to convert CO2 into valuable fuels is desirable to realize a carbon-neutral society. In this work, we report that polymer dots (Pdots) of poly[(9,9 ' -dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-thiadiazole)] (PFBT), without adding any extra co-catalyst, can photocatalyze reduction of CO2 into CO in aqueous solution, rendering a CO production rate of 57 mu mol g(-1) h(-1 )with a detectable selectivity of up to 100 %. After 5 cycles of CO2 re-purging experiments, no distinct decline in CO amount and reaction rate was observed, indicating the promising photocatalytic stability of PFBT Pdots in the photocatalytic CO2 reduction reaction. A mechanistic study reveals that photoexcited PFBT Pdots are reduced by sacrificial donor first, then the reduced PFBT Pdots can bind CO(2 )and reduce it into CO via their intrinsic active sites. This work highlights the application of organic Pdots for CO2 reduction in aqueous solution, which therefore provides a strategy to develop highly efficient and environmentally friendly nanoparticulate photocatalysts for CO2 reduction.
|
|
