Defective TiO2 for CO2 photoreduction: Influence of alkaline agent and reduction temperature modulation

Abstract

This study investigates the synthesis and characterization of Black TiO2 photocatalyst (TiO2-x) through the sol-gel method combined with NaBH4 reduction at different temperatures (350 degrees C, 500 degrees C, and 650 degrees C). The photocatalytic performance for CO2 reduction was evaluated, revealing that TiO2-x_500 degrees C sample exhibited the highest efficiency. This enhanced performance is mainly attributed to a higher concentration of oxygen vacancies and successful nitrogen doping resulting from ammonia water addition during synthesis. Comprehensive characterization techniques, including Raman spectroscopy, and XPS confirmed the presence of defects and their correlation with increased photocatalytic activity. These findings confirm the importance of defect engineering and doping in optimizing TiO2-based photocatalysts for CO2 photoreduction.