The Electron Migration Pathways in S-Scheme GaP-TiO2 Photocatalysts and Their Implications for Photocatalytic Hydrogen Production

Abstract

The connection between GaP and TiO2 represents a promising strategy for enhancing the separation of photogenerated electrons and holes, improving photocatalytic efficiency. GaP-TiO2 photocatalysts (0.4-7.6 wt% GaP) are prepared by wet impregnation of commercial GaP onto TiO2 synthesized by sol-gel method in the reverse micellar environment. GaP-TiO2 photocatalysts are researched regarding surface element composition and structural, textural, optical, and electronic properties. The results describe in detail and demonstrate the successful formation of the S-scheme heterostructure in the GaP-TiO2 composite and migration path of charge carriers. This heterostructure, coupled with the photocurrent doubling effect originating from using methanol in the reaction system, reflects the increased hydrogen production in the photocatalytic decomposition of aqueous methanol solution. The enhanced performance of these photocatalysts is attributed to the synergistic interaction between GaP and TiO2, which improves charge separation and reduces recombination, thereby boosting overall photocatalytic activity.

Keywords: Photocatalysts, GaP, heterojunction, migration pathway, hydrogen production