Surface-engineering of CaTiO3 for photocatalytic hydrogen evolution reaction through enhanced oxygen vacancy

Abstract

Surface engineering has been an important strategy in attaining a higher catalytic activity in comparison with pristine samples. CaTiO3 is a well-known photoactive material but lacks photo-to-electron conversion efficiency. Herein, we demonstrate a simple path-way that could achieve a higher surface area, active site exposure, and oxygen vacancies. The experimental results using different concentrations of HNO3 illustrated the selective leaching of Ca(II) ions, which leads to the partial conversion of Ti4+ to Ti3+ and the formation of oxygen vacancy. This eventually resulted in an engineered electronic state that modifies the band alignment and improves the charge transfer and migration rate. The optimized photocatalyst (CTO-5) exhibits approximately six times enhanced hydrogen evolution rate of 58.1 μmol∙g−1 h−1 than the pristine CaTiO3 (8.7 μmol∙g−1 h−1). Our work offers new intuitions into the rational design of photocatalysts with surface-engineering methodology without using any noble metal.