Amorphous-crystalline junction oxygen vacancy-enriched CoPi/ZnIn2S4/a-B-TiO2 catalyst for oxygen evolution reaction

Abstract

The construction of oxygen vacancies (Ovs) has become an important means to regulate the electronic structure and catalytic properties of semiconductor materials. However, the inactivation and low density of Ovs affect the improvement of catalytic activity. Here, we propose a new method for constructing riched Ovs through in situ B-doping and amorphous-crystalline junction to improve photoelectrocatalytic water oxidation performance, of which the photocurrent density can reach 6.3 mA/cm2 at 1.23 V vs. RHE. The capability of B-doped and amorphous-crystalline junction introduced substantial Ovs was proved through STEM and EPR. The catalytic mechanism of the system was studied by DFT calculation and COMSOL simulation, where the electric field deviation can promote the charge separation of the composite. Meanwhile, ZnIn2S4 and a-B-TiO2 further improve the light absorption capacity of the catalyst, and CoPi facilitates the adsorption and activation of H2O molecules on the catalyst surface. This work highlights the critical role of amorphous-crystalline junction and B-doped for improving the Ovs concentration.