A Facile Design for Water-Oxidation Molecular Catalysts Precise Assembling on Photoanodes

Regulating the interfacial charge transfer behavior between cocatalysts and semiconductors remains a critical challenge for attaining efficient photoelectrochemical water oxidation reactions. Herein, using bismuth vanadate (BiVO4) photoanode as a model, it introduces an Au binding bridge as holes transfer channels onto the surfaces of BiVO4, and the cyano-functionalized cobalt cubane (Co4O4) molecules are preferentially immobilized on the Au bridge due to the strong adsorption of cyano groups with Au nanoparticles. This orchestrated arrangement facilitates the seamless transfer of photogenerated holes from BiVO4 to Co4O4 molecules, forming an orderly charge transfer pathway connecting the light-absorbing layer to reactive sites. An exciting photocurrent density of 5.06 mA cm-2 at 1.23 V versus the reversible hydrogen electrode (3.4 times that of BiVO4) is obtained by the Co4O4@Au(A)/BiVO4 photoanode, where the surface charge recombination is almost completely suppressed accompanied by a surface charge transfer efficiency over 95%. This work represents a promising strategy for accelerating interfacial charge transfer and achieving efficient photoelectrochemical water oxidation reaction. The BiVO4 photoanode's surface is adorned with assemblies of Au@Co4O4 aggregates, which consist of cyano-functionalized Co4O4 molecules and Au nanoparticles. This distinctive arrangement results in the remarkable performance of the Au@Co4O4(A)/BiVO4 photoanode, which attains an impressive photocurrent density of 5.06 mA cm-2 and near-unit charge-transfer efficiency at 1.23 V vs. RHE.image