Ultra-fast synthesis of the high performance photocatalytic Ti3+ self-doped strontium titanate by an electrochemical assist in molten salt: effect of electrochemical potential

Abstract

A simple and fast synthesis of highly photocatalytic Ti³⁺ self-doped SrTiO₃ is favorable for applications. In this paper, an electrochemically assisted ultra-fast synthesis of Ti³⁺ self-doped SrTiO₃ of only 5 minutes in molten SrCl₂–NaCl with SrO was developed, which greatly reduced the traditional synthesis time. During the process, a metallic titanium anode and an iron oxide cathode were dissolved and reduced to form Tiⁿ⁺ and O²⁻ ions under a constant potential, respectively, and self-assembled with SrO dissolved in SrCl₂–NaCl. The effect of electrochemical potential on the structure and photocatalytic performance of the Ti³⁺ self-doped SrTiO₃ was investigated. The results indicated that the photocatalytic performance of STO-U was improved with increasing potential. The product prepared at a high constant potential of 1.8 V is a regular cubic particle of 30–100 nm with oxygen vacancy defects of 21.31%, specific surface area of 21.3826 m² g⁻¹, band gap of 3.03 eV, and strong absorption in the wavelength range of 400 to 800 nm. Its degradation rate for RhB reached 96.85% within 210 minutes, and showed good performance in five-cycle stability tests.