Boosting electrocatalytic oxygen evolution over Prussian blue analog/transition metal dichalcogenide nanoboxes by photo-induced electron transfer

Abstract

Solar-assisted electrocatalytic water oxidation holds great promise in modern energy conversion and storage devices. Herein, we present the design and construction of an advanced class of Prussian blue analog (PBA)/transition metal dichalcogenide (TMD) hybrids, which combine the intrinsic electrocatalytic activity of TMDs for the oxygen evolution reaction (OER) and the sunlight response of TMDs and PBAs. Consequently, the porous framework, engineered surface defects, and abundant oxygen vacancies endow them with remarkably enhanced electrocatalytic performance toward OER due to the enlarged electrolyte-accessible surface, high structural integrity, and abundant electron and mass transfer routes. Moreover, they could also enable photo-assisted oxidation reactions with significantly high current density and low overpotential. Mechanistic investigations reveal that the OER improvement can mainly be ascribed to the combination of photo-driven and electricity-driven water oxidation reaction, where the photogenerated electron transfer from PBAs to TMDs results in photogenerated holes in PBAs that are more beneficial for the oxidation of H₂O, as well as affording decreased activation energy of TMDs for the OER. This work manifests the photo-assisted electrocatalytic water oxidation ability of PBA/TMD hybrids and offers a new avenue for the design and construction of high-performance electrocatalysts for water splitting upon light irradiation.