| 1. |
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| 2. |
- Biaobiao, Zhang, et al.
(författare)
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Modifying Ru-bda Backbone with Steric Hindrance and Hydrophilicity: Influence of Secondary Coordination Environments on Water-Oxidation Mechanism.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Understanding the seven coordination and O−O coupling pathway of the distinguished Ru-bda catalysts is essential for the development of next generation efficient water-oxidation catalysts based on earth-abundant metals. This work reports the synthesis, characterization and catalytic properties of a monomeric ruthenium catalyst Ru-bnda (H2bnda = 2,2'-bi(nicotinic acid)-6,6'-dicarboxylic acid) featuring steric hindrance and enhanced hydrophilicity on the backbone. Combining experimental evidence with systematic density functional theory calculations on the Ru-bnda and related catalysts Ru-bda, Ru-pda and Ru-biqa, we emphasized that seven coordination clearly determines presence of RuV=O with high spin density on the ORuV=O atom, i.e. oxo with radical properties, which is one of the necessary conditions for reacting through the O−O coupling pathway. However, an additional factor to make the condition sufficient is the favorable intermolecular face-to-face interaction for the generation of the pre-reactive [RuV=O···O=RuV], which is significantly influenced by the secondary coordination environments. This work provides a new understanding of the structure-activity relationship of water-oxidation catalysts and their potential to adopt I2M pathway for O−O bond formation.
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| 3. |
- Cai, Bin, et al.
(författare)
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Organic Polymer Dots Photocatalyst for CO2 Reduction in Aqueous Solution
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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.
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| 4. |
- Cai, Bin, et al.
(författare)
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Organic Polymer Dots Photocatalyze CO2 Reduction in Aqueous Solution
- 2023
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Ingår i: Angewandte Chemie International Edition. - : John Wiley & Sons. - 1433-7851 .- 1521-3773. ; 62:45
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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.
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| 5. |
- Cheng, Fangwen, et al.
(författare)
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Interfacial Property Tuning Enables Copper Electrodes in High-Performance n-i-p Perovskite Solar Cells
- 2023
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 145:36, s. 20081-20087
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Tidskriftsartikel (refereegranskat)abstract
- Developing cost-effective metal electrodes is essential for reducing the overall cost of perovskite solar cells (PSCs). Although copper is highly conductive and economical, it is rarely used as a positive electrode in efficient n-i-p PSCs due to its unmatched Fermi level and low oxidation threshold. We report herein that modification for the inner surface of electrodes using mercaptopyridine-based molecules readily tunes the electronic and chemical properties of copper, which has been achieved by fine-tuning the substituents of mercaptopyridines. The systematic adjustment for the Fermi level and oxidation potential of copper facilitates interfacial hole extraction and enhances the oxidation resistance of copper electrodes, which enables pure copper electrodes to be used in high-performance n-i-p PSCs with different hole transport materials. The resulting PSCs with copper electrodes display excellent power conversion efficiency and long-term stability, even comparable to those of the gold electrodes, showing great potential in the manufacturing and commercialization of PSCs.
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| 6. |
- Fan, Ting, et al.
(författare)
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Why Is There a Barrier in the Coupling of Two Radicals in the Water Oxidation Reaction?
- 2016
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 6:12, s. 8308-8312
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Tidskriftsartikel (refereegranskat)abstract
- Two radicals can form a bond without an energetic barrier. However, the radical coupling mechanism in ruthenium catalyzed water oxidation has been found to be associated with substantial activation energies. Here we have investigated the coupling reaction of [Ru=O(bda)L-2](+) catalysts with different axial L ligands. The interaction between the two oxo radical moieties at the Ru(V) state was found to have a favorable interaction in the transition state in comparison to the prereactive complex. To further understand the existence of the activation energy, the activation energy has been decomposed into distortion energy and interaction energy. No correlation between the experimental rates and the calculated coupling barriers of different axial L was found, showing that more aspects such as solvation, supramolecular properties, and solvent dynamics likely play important roles in the equilibrium between the free Ru-v=0 monomer and the [Ru-v=O center dot center dot center dot O=Ru-v] dimer. On the basis of our findings, we give general guidelines for the design of catalysts that operate by the radical coupling mechanism.
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| 7. |
- Fu, Xianbiao, et al.
(författare)
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High-Entropy Alloy Nanosheets for Fine-Tuning Hydrogen Evolution
- 2022
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 12:19, s. 11955-11959
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Tidskriftsartikel (refereegranskat)abstract
- The electrolysis of water is promising for hydrogen production. The development of high-performance and low-cost hydrogen evolution reaction (HER) electrocatalysts is particularly important for the wide application of water electrolyzers. Tuning the hydrogen binding energy (HBE) of materials is an effective way to optimize the HER electrocatalysts, particularly for applications in an acidic environment. Here, we report the discovery of a Pt-free combination, PdMoGaInNi, which has the HBE optimum, via computer-facilitated screening. As the exploratory example of the two-dimensional high-entropy alloy (HEA) for HER, the PdMoGaInNi HEA nanosheets were synthesized to realize the predicted Pt-free combination with optimal HBE. The PdMoGaInNi HEA nanosheets exhibit a high HER activity with low overpotentials of 13 mV at 10 mA cm-2, outperforming commercial Pd/C and Pt/C catalysts. Given the high entropy, lattice distortion, and sluggish diffusion effects of HEA, the PdMoGaInNi shows great long-term durability for at least 200 h in a proton exchange membrane water electrolyzer.
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| 8. |
- Guo, Yaxiao, et al.
(författare)
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Molybdenum and boron synergistically boosting efficient electrochemical nitrogen fixation
- 2020
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Ingår i: Nano Energy. - : Elsevier Ltd. - 2211-2855 .- 2211-3282. ; 78
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Tidskriftsartikel (refereegranskat)abstract
- Ammonia production consumes ~2% of the annual worldwide energy supply, therefore strategic alternatives for the energy-intensive ammonia synthesis through the Haber-Bosch process are of great importance to reduce our carbon footprint. Inspired by MoFe-nitrogenase and the energy-efficient and industrially feasible electrocatalytic synthesis of ammonia, we herein establish a catalytic electrode for artificial nitrogen fixation, featuring a carbon fiber cloth fully grafted by boron-doped molybdenum disulfide (B-MoS2/CFC) nanosheets. An excellent ammonia production rate of 44.09 μg h–1 cm–2 is obtained at −0.2 V versus the reversible hydrogen electrode (RHE), whilst maintaining one of the best reported Faradaic efficiency (FE) of 21.72% in acidic aqueous electrolyte (0.1 M HCl). Further applying a more negative potential of −0.25 V renders the best ammonia production rate of 50.51 μg h–1 cm–2. A strong-weak electron polarization (SWEP) pair from the different electron accepting and back-donating capacities of boron and molybdenum (2p shell for boron and 5d shell for molybdenum) is proposed to facilitate greatly the adsorption of non-polar dinitrogen gas via N≡N bond polarization and the first protonation with large driving force. In addition, for the first time a visible light driven photo-electrochemical (PEC) cell for overall production of ammonia, hydrogen and oxygen from water + nitrogen, is demonstrated by coupling a bismuth vanadate BiVO4 photo-anode with the B-MoS2/CFC catalytic cathode.
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| 9. |
- Huang, Xiaofeng, et al.
(författare)
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Solvent Gaming Chemistry to Control the Quality of Halide Perovskite Thin Films for Photovoltaics
- 2022
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Ingår i: ACS CENTRAL SCIENCE. - : American Chemical Society (ACS). - 2374-7943 .- 2374-7951. ; 8:7, s. 1008-1016
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Tidskriftsartikel (refereegranskat)abstract
- Research on solvent chemistry, particularly for halide perovskite intermediates, has been advancing the development of perovskite solar cells (PSCs) toward commercial applications. A predictive understanding of solvent effects on the perovskite formation is thus essential. This work systematically discloses the relationship among the basicity of solvents, solvent-contained intermediate structures, and intermediate-to-perovskite alpha-FAPbI(3) evolutions. Depending on their basicity, solvents exhibit their own favorite bonding selection with FA(+) or Pb2+ cations by forming either hydrogen bonds or coordination bonds, resulting in two different kinds of intermediate structures. While both intermediates can be evolved into alpha-FAPbI(3) below the delta-to-alpha thermodynamic temperature, the hydrogen-bond-favorable kind could form defect-less alpha-FAPbI(3) via sidestepping the break of strong coordination bonds. The disclosed solvent gaming mechanism guides the solvent selection for fabricating high-quality perovskite films and thus high-performance PSCs and modules.
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| 10. |
- Huang, Xiaofeng, et al.
(författare)
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Solvent racing crystallization : Low-solvation dispersion cosolvents for high-quality halide perovskites in photovoltaics
- 2023
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Ingår i: Joule. - : Elsevier. - 2542-4351. ; 7:7, s. 1556-1573
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Tidskriftsartikel (refereegranskat)abstract
- The solvation capacity of dispersion solvents plays a crucial role in the solution processing of metal halide perovskites. For instance, N,N-dimethylformamide (DMF), a widely used dispersion solvent, possesses high solvation capacity but often generates suboptimal film quality due to slow crystallization kinetics. We propose using low-solvation binary cosolvents (nitrile-and ether-type solvents) to achieve a balance between solvation (i.e., sufficient solubility of precursors) and desolvation (i.e., rapid crystallization of films) pro-cesses during perovskite synthesis. The polarity and hydrogen -bonding property of these cosolvents synergistically enhance their solvation capacity, facilitating perovskite precursor dissolution. Moreover, the low-solvation cosolvents accelerate the crystalliza-tion of well-defined intermediate films, yielding higher-quality pe-rovskites than those synthesized with DMF. The optimized modules achieved an active-area efficiency of 22.27%, with a certified aper-ture-area efficiency of 16.10% and corresponding active-area effi-ciency of 20.75%. This research on solvation regulation provides universal guidelines for innovatively preparing high-quality halide perovskites.
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