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Modulating the Electron Mediators for Spatially Separated H2 and O2 Evolutions in Photocatalytic Water Splitting
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DOI:10.1002/anie.1501510.png)
Abstract
En 中文
A fundamental obstacle in photocatalytic overall water splitting lies in the simultaneous evolution of H2 and O2 gases, which complicates gas separation. Decoupling hydrogen and oxygen evolution via a redox electron mediator offers an attractive route to overcome this limitation; however, its success critically depends on the development of electron mediators that satisfy both suitable redox potentials and rapid interfacial charge-transfer kinetics. Here, we demonstrate tunable redox potential in cobalt bipyridine complexes, [Co(bpy)2Cl2]Cl, through ligand functionalization. Electron-donating groups (-OCH3, -CH3) induce negative shifts in the redox potential, whereas electron-withdrawing substituents (-Cl) leads to positive shifts, yielding a broad potential range from 0.15 to 0.62 V versus NHE. The optimized electron mediator, [Co(bpy-CH3)2Cl2]Cl, exhibits enhanced electron transfer and water oxidation activity on BiVO4 photocatalyst. Coupled with selective assembling of Pt on the electron-rich {010} facets, an Pt-Cl interfacial charge-transfer channel was established, which accelerates electron transfer and promotes the adsorption/desorption of electron mediator. This integrated system achieves efficient photocatalytic water oxidation with an apparent quantum efficiency of up to 90% at 420 nm. Using [Co(bpy-CH3)2Cl2]Cl electron mediator, the work demonstrated the spatial separation of hydrogen and oxygen evolution reactions in particulate photocatalytic water splitting.
Keywords:
electron mediator
photocatalysis
water splitting
Journal
IF:
16.9
Papers:
4.7K
Citations:
368
