Rational design and preparation of nanoheterostructures based on zinc titanate for solar-driven photocatalytic conversion of CO2 to valuable fuels

Abstract

Photocatalytic reduction of CO2 with H2O on photocatalysts to produce fuels presents great potential to simultaneously address energy and environmental issues. Herein, zinc titanate-based heterostructured nanohybrids including Zn2Ti3O8/ZnTiO3 and Zn2TiO4/R-TiO2 were designed and prepared through a two-step chemical route. When used as photocatalyst for converting CO2 with H2O under UV-light irradiation, the zinc titanate-based heterostructured nanohybrids show high photocatalytic performance, with CH4 and CO yields significantly higher than those obtained with Zn2Ti3O8, Zn2TiO4, and rutile TiO2 as the photocatalysts. The existence of heterojunctions in the nanohybrids was demonstrated by experimental results, and electrochemical impedance spectra also reveal a favorable zinc titanate-based heterostructure. Moreover, based on theoretical calculations, the observed reduced band gap further revealed the effective light-absorption of the heterostructured nanohybrids in CO2 reduction. It is thus concluded that the synergistic effect of the heterostructure promotes charge separation and fast electron transport, resulting in its enhanced photocatalytic performance in CO2 reduction.