Co-embedding oxygen vacancy and copper particles into titanium-based oxides (TiO2, BaTiO3, and SrTiO3) nanoassembly for enhanced CO2 photoreduction through surface/interface synergy

Photocatalytic CO2 reduction into valuable fuel and chemical production has been regarded as a prospective strategy for tackling with the issues of the increasing of greenhouse gases and shortage of sustainable energy. A composite photocatalysis system employing a semiconductor enriched with oxygen vacancy and coupled with metallic cocatalyst can facilitate charge separation and transfer electrons. In this work, mesoporous TiO2 and titanium-based perovskite oxides (BaTiO3 and SrTiO3) nanoparticle assembly incorporated with abundant oxygen vacancy and copper particles have been successfully synthesized for CO2 photoreduction. As an example, the TiO2 decorated with different amounts of Cu particles has an impact on photocatalytic CO2 reduction into CH4 and CO. Particularly, the optimal TiO2/Cu-0.1 exhibits nearly 13.5 times higher CH4 yield (22.27 μmol g-1 h-1) than that of pristine TiO2 (1.65 μmol g-1 h-1). The as-obtained BaTiO3/Cu-0.1 and SrTiO3/Cu-0.1 also show enhanced CH4 yields towards photocatalytic CO2 reduction compared with pristine ones. Based on the temperature programmed desorption (TPD) and photo/electrochemical measurements, the co-embedding of Cu particles and abundant oxygen vacancy into the titanium-based oxides could promote CO2 adsorption capacity as well as separation and transfer of photoinduced electron-hole pairs, and finally result in efficient CO2 photoreduction upon the TiO2/Cu, SrTiO3/Cu, and BaTiO3/Cu composites.