Introducing Bidirectional Axial Coordination into BiVO4 @Metal Phthalocyanine Core-Shell Photoanodes for Efficient Water Oxidation

Abstract

Core-shell photoanodes have shown great potential for photoelectrochemical (PEC) water oxidation. However, the construction of a high-quality interface between the core and shell, as well as a highly catalytic surface, remains a challenge. Herein, guided by computation, we present a BiVO₄ photoanode coated with ZnCoFe polyphthalocyanine using pyrazine as a coordination agent. The bidirectional axial coordination of pyrazine plays a dual role by facilitating intimate interfacial contact between BiVO₄ and ZnCoFe polyphthalocyanine, as well as regulating the electron density and spin configuration of metal sites in ZnCoFe phthalocyanine, thereby promoting the potential-limiting step of *OOH desorption. The resulting photoanode displayed a high photocurrent density of 5.7±0.1 mA cm^-2 at 1.23 V_RHE . This study introduces a new approach for constructing core-shell photoanodes, and uncovers the key role of pyrazine axial coordination in modulating the catalytic activity of metal phthalocyanine.

Keywords: Axial Coordination; BiVO4; Metal Polyphthalocyanine; Water Oxidation.