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- Hu, Qiyu, et al.
(författare)
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Advances in bridging homogeneous and heterogeneous water oxidation catalysis by insolubilized polyoxometalate clusters
- 2024
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435 .- 2155-5435. ; 14:8, s. 5898-5910
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Forskningsöversikt (refereegranskat)abstract
- The water oxidation half-reaction is vital in numerous alternative-energy blueprints and technologies since it can provide four protons and four electrons necessary for transforming renewable energy into chemicals and fuels. Significant progress has been made in recent decades in regard to the development of heterogeneous and homogeneous water oxidation catalysts (WOCs). However, homogeneous and heterogeneous catalysts are two parallel frontiers in catalysis science, each possessing their individual advantages and disadvantages. It is urgently required to construct desirable catalysts combining the merits and overcoming the natural shortcomings of homogeneous and heterogeneous WOCs. This Perspective demonstrates an overview of recent progress in utilizing insoluble polyoxometalate (POM) clusters as a promising bridge between homogeneous and heterogeneous WOCs and discusses the characterization methods for the stability, the origin of enhanced activities, electron transfer dynamics, and structure-property correlation of insoluble POM cluster WOCs. This Perspective not only guides the design of robust and efficient insoluble POM cluster catalysts applied for energy transformation but also provides important insights into the design of POM-based heterogeneous catalysts applied in other important fields.
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| 3. |
- Hu, Qiyu, et al.
(författare)
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Developing insoluble polyoxometalate clusters to bridge homogeneous and heterogeneous water oxidation photocatalysis
- 2023
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Ingår i: Angewandte Chemie International Edition. - : John Wiley & Sons. - 1433-7851 .- 1521-3773. ; 2:32
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Tidskriftsartikel (refereegranskat)abstract
- Cluster catalysts are attractive for their atomically precise structures, defined compositions, tunable coordination environments, uniform active sites, and their ability to transfer multiple electrons, but they suffer from poor stability and recyclability. Here, we report a general approach to the direct insolubilization of a water soluble polyoxometalate (POM) [{(B-α-PW9O34)Co3(OH)(H2O)2(O3PC(O)-(C3H6NH3)PO3)}2Co]14- (Co7) and formation of a series of POM-based solid catalysts with the counter-cations Ag+, Cs+, Sr2+, Ba2+, Pb2+, Y3+, and Ce3+. They exhibit improved catalytic activities for visible-light-driven water oxidation following the trend CsCo7>SrCo7>AgCo7>CeIII Co7>BaCo7>YCo7>PbCo7. While CsCo7 exhibits mainly homogeneous catalysis, the others are predominantly heterogeneous catalysts. An optimal oxygen yield of 41.3 % and a high apparent quantum yield (AQY) of 30.6 % for SrCo7 is obtained, which is comparable to that of the parent homogeneous POM. Band gap structures, UV/Vis spectra, and real-time laser flash photolysis experiments collectively suggest that easier electron transfer from the solid POM catalyst to the photosensitizer promotes photocatalytic water oxidation performance. These solid POM catalysts exhibit good stability, which is directly confirmed by a combination of Fourier-transform infrared spectroscopy, electron microscopy, X-ray diffraction patterns, Raman spectroscopy, X-ray photoelectron spectroscopy, five cycles of tests, and poisoning experiments.
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- Li, Xinbao, et al.
(författare)
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Dehydrogenation mechanisms of liquid organic hydrogen carriers over Pt, Pd, Rh, and Ni surfaces : Cyclohexane as a model compound
- 2021
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332. ; 543
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Tidskriftsartikel (refereegranskat)abstract
- In order to make a better understanding of dehydrogenation mechanisms of liquid organic hydrogen carriers, cyclohexane was selected as a model compound to carry out its decomposition studies over Pt(1 1 1), Pd(1 1 1), Rh(1 1 1), and Ni(1 1 1) surfaces via periodic density functional theory calculations. The adsorption geometries and adsorption energies of reaction intermediates were presented. Similar linear relationships of the adsorption energies with respect to the number of hydrogen removal over these four surfaces were revealed for C6Hx* (x = 8–12). Seven elementary reactions for cyclohexane successive dehydrogenation to C6H5* were considered. The initial dehydrogenation of C6H12* to generate C6H11* were identified as the rate-determining steps over all surfaces, association with activation energies of 1.04, 1.06, 0.96, and 1.14 eV for Pt(1 1 1), Pd(1 1 1), Rh(1 1 1), and Ni(1 1 1), respectively. The reactivity of dehydrogenation was in the order of Rh(1 1 1) > Pt(1 1 1) > Pd(1 1 1) > Ni(1 1 1).
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