Construction of 2D/2D BiOIO3/Bi2O2CO3 composite structures with face-to-face contacts can facilitate carrier transfer via a built-in electric field and a polar field for pyro–photo-electric catalysis

Abstract

Multi-field catalysis is considered as one of the feasible ways to solve the problem of severe recombination of photogenerated carriers. A rational design scheme for the inner field is of great significance for multi-field catalysis. In this paper, we firstly designed and prepared a composite BiOIO₃/Bi₂O₂CO₃ catalyst with a built-in electric field and a polarized electric field using a one-step hydrothermal method. The 2D/2D layered structure can increase the effective contact area, which resolves the problem of poor contact at the interface of heterogeneous junction catalysts to some extent. The current density of the composite photoanode reached 0.177 μA cm⁻² at 1.23 V vs. RHE, which was 1.26 times higher than that of bare BiOIO₃ under multiple excitations of light and temperature changes. The test results show that carriers are transferred to the O-site at the end of the [IO₃]⁻ pyramid and to the [CO₃]²⁻ middle layer, respectively, and that the built-in electric field of the layered composite structure and the polarized electric field resulting from the uneven potential distribution caused by pyroelectric polarization significantly reduce the carrier recombination. In the process, the electrons and holes eventually achieve spatial separation under the influence of the heterojunction, which enhances the carrier transfer kinetics. This work demonstrates that multi-field catalysis utilizing pyroelectric polarization and other field-based factors has great potential for development, and also provides a reference for the integrated application of pyroelectric polarization and photoelectrocatalysis.