Coordination of Ti3+ and Ni3+ to promote the electrocatalytic OER properties of SrTiO3@TiO2 heterojunctions

Abstract

Limited current and overpotential are critical factors for efficient hydrogen production through photoelectrochemical water oxidation. To enhance the oxygen evolution reaction (OER), transition metal Co, Ni and Cu doped strontium titanate-rich SrTiO₃@TiO₂(STO@T) materials were prepared by the hydrothermal method. The SrTiO₃@TiO₂ heterojunction serves as the photosensitive layer, while the introduced transition metal acts as a catalyst layer, with M-STO@T (where M = Ni, Co, Cu) containing Ni³⁺ and Co³⁺ as high-valence metal sites for OER activation. The introduction of transition metals induces the formation of Ti³⁺ ions and produces impurity energy levels in the band gap to broaden the visible light response. The experimental results show that the Ni-STO@T catalyst has good photocatalytic performance. This study also provides some inspiration for the formation mechanism of Ti³⁺ formed by transition metal doped STO@T.