Construction of a CuInS2/La2Ti2O7 heterojunction for highly efficient hydrogen evolution

Abstract

La₂Ti₂O₇ has been perceived as a potential photocatalytic material candidate for hydrogen evolution in recent years. However, its wide band gap brings about a narrow light absorption range and thereby results in poor photocatalytic activity. Herein, to enhance the light absorption capability, as well as promote the separation of photogenerated carriers, a CuInS₂/La₂Ti₂O₇ heterojunction photocatalyst was designed. A narrow band-gap semiconductor, CuInS₂, was grown in situ on the surface of La₂Ti₂O₇ by a solvothermal method. The effects and related mechanisms of CuInS₂ loading on the photocatalytic activity were systematically investigated. The composite photocatalysts present a much better hydrogen evolution performance than the single materials. The highest hydrogen evolution rate reaches 64.41 μmol g⁻¹ h⁻¹. The enhancement of hydrogen evolution performance can be ascribed to the improvement of light absorption, as well as the acceleration of separation of photogenerated carriers, due to the loading of CuInS₂ and the formation of a type II heterojunction between two materials.