Facile preparation and modification of SrTiO3 through Ni–Cd co-doping as an efficient visible-light-driven photocatalyst

Visible light-driven Ni–Cd co-doped SrTiO3 photocatalyst was prepared through a co-precipitation technique. The influence of various amounts of doped elements on the properties of the pure SrTiO3 phase has been explored. The characterization was performed employing the X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman, X-ray photoelectron spectroscopy (XPS), field emission-scanning electron microscopy (FESEM), UV–visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL), electrochemical impedance spectroscopy (EIS), and transient photocurrent experiments. By Ni–Cd co-doping, the average particle size was reduced from 100 to 65 nm, the band gap value was lowered from 3.2 to 2.78 eV, and the powder's surface area was increased by about 2.3 times compared with the pure phase. Low PL peak intensity, small EIS radius, and higher photocurrent density of the 5 wt% doped sample indicate higher charge transfer efficiency than the pure sample. The effect of different photocatalytic experiment parameters on the photodegradation performance has been studied. In this regard, a 60-min visible light irradiation time, 1 g mL−1 initial dye concentration, and 0.7 g L−1 powder dosage were found to be the best values. After 60 min of visible light irradiation, doped SrTiO3 with 5 wt% Ni–Cd thoroughly degraded methylene blue (MB) dye. Additionally, the superoxide radical and holes also play a significant role in photodegradation as determined by the scavenger trapping test. Compared with MB, the prepared sample demonstrated less degradation ability for methyl orange (MO) and Rhodamine-B (RhB) dyes.