Photoelectrochemical water splitting with In2O3−x nanofilm/black Ti–Si–O composite photoanode

Abstract

Fabricating TiO₂ with heterostructures is one of the important ways to enhance its photocatalytic activity. In this work, we fabricated black Si-doped TiO₂ nanotubes (Ti–Si–O) through anodization and Sn reduction, and constructed In₂O_3−x nanofilm/black Ti–Si–O composite photoanode through electrochemical deposition and Ar annealing. The composition evolution, morphology, optical properties and photoelectrochemical performance of the composite photoanode were investigated. The In₂O_3−x/black Ti–Si–O composite photoanode exhibited excellent PEC hydrogen production performance, with a high photocurrent density of 3.76 mA cm⁻² at 0 V Ag/AgCl, which was 2.16 times that of the black Ti–Si–O photoanode. The synergistic effects of Si doping, Ti³⁺/O vacancies and the modification with In₂O_3−x nanofilms provide a beneficial approach to design of high-efficiency photoanodes.