Enhancing H<sub>2</sub> Evolution by Adjusting Oxygen Species at Perovskite SrTiO<sub>3</sub>
Juan Xie, Penghui Bai, Chenjie Wang, Ning Chen, Weifeng Chen, Ming Duan, Hu Wang
Abstract
It is commonly believed that active oxygen species over ABO3 perovskite play an important role in improving catalytic activity. In this paper, SrTiO3 (STO) was prepared and doped with an extremely low concentration of NiP. By adjusting the doping process, the content of three kinds of oxygen species can be transformed accordingly, which consequently influences the catalytic activity in water splitting under visible light irradiation. The transformation of oxygen species and the improvement mechanism of hydrogen generation were investigated. X-ray absorption fine structure (XAFS), X-ray absorption spectroscopy (XAS), and density functional theory (DFT) calculation confirmed that Ni occupied the Ti sites and P coordinated with lattice oxygen on the STO surface. Structural evolution not only forms reactive lattice oxygen but also regulates oxygen vacancies and adsorbed oxygen. Reactive lattice oxygen serves as the reaction site during the hydrogen evolution reaction. In summary, constructing reactive lattice oxygen and adjusting the ratio of different oxygen species are effective ways to fabricate high-performance photocatalysts for H2 evolution.