Photocatalytic performance of Bi/Zn co-doped sol-gel synthesized TiO₂ nanoparticles

BACKGROUND: Semiconductor photocatalysts based on TiO2 nanoparticles were synthesized via the sol-gel method and subsequently modified using monometallic (Bi-TiO2, Zn-TiO2) and bimetallic (Bi/Zn-TiO2) doping through the wet-impregnation technique. The prepared photocatalysts underwent comprehensive characterization using X-ray diffraction analysis, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse-reflectance spectroscopy, field emission scanning electron microscopy, photoluminescence, and thermal gravimetric analysis. The photocatalytic performance of these well-characterized photocatalysts was assessed for the degradation of the model organic pollutant, nitrobenzene.RESULTS: Among the various doped TiO2 catalysts, Bi/Zn co-doping at a ratio of 0.25:0.75 (w/w) exhibited the most remarkable synergistic effect, achieving approximately 82% degradation of a 50 ppm nitrobenzene solution within just 90 min of reaction time under ultraviolet light irradiation. The rate constant for this process was determined to be 1.79 x 10(-2) min(-1), suggesting a pseudo-first-order kinetics model.CONCLUSION: The successful co-doping of Bi and Zn metals to TiO2 resulted in improved photocatalytic performance. The enhanced performance could be attributed to the improved charge transfer facilitated by the synergistic effect among doped metals and TiO2. This finding highlights the significance of bimetallic doping and its potential applications in improving the photocatalytic efficiency of TiO2 nanoparticles for environmental remediation. (c) 2023 Society of Chemical Industry (SCI).