Hydrothermal synthesis of single-crystal Cr-doped SrTiO3 for efficient visible-light responsive photocatalytic hydrogen evolution

Abstract

Visible-light-driven Cr-doped SrTiO _3 nanocubes were successfully synthesized by hydrothermal method in alkaline KOH conditions. X-ray diffraction spectroscopy (XRD), Raman spectra, x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to characterize the samples, and the Cr-doped SrTiO _3 possess cubic morphology with about 30–50 nm in size, and single-crystal feature. In addition, the Cr-doped SrTiO _3 extended light-harvesting properties to visible-light region which was testified by UV–vis absorption spectra, and excellent charge transfer and separation efficiency were approved by photo fluorescence spectra (PL), electrochemical impedance spectroscopy (EIS) and photocurrent response measurements. Among the synthesized photocatalysts, SrTiO _3 nanocubes doped with 2% Cr by molar ratio exhibits the highest photocatalytic activity, achieving 11.66 μ mol of H _2 evolution during 5 h visible-light irradiation. This study provides a facile and effective way to enhance the performance of SrTiO _3 -based photocatalysts.

Keywords

• strontium titanate (SrTiO3)
• Cr doping
• hydrogen evolution
• photocatalysis