Recent advances in TiO₂ modification for improvement in photocatalytic purification of indoor VOCs

TiO₂-based photocatalytic oxidation technology has been widely used for the purification of indoor VOCs. However, the fast recombination rates of photoexcited charge carriers and wide energy band gaps have limited the practical application of TiO₂-based photocatalysts. Therefore, developing highly efficient catalysts is crucial for efficiently separating charge carriers and hindering their recombination, fully utilizing visible light. There are four main methods to improve TiO₂ photocatalytic activity: increasing e^--h⁺ separation rates and decreasing e^--h⁺ recombination rates, increasing visible light photocatalytic activity, increasing surface-active sites, and increasing physicochemical stability. Metal and non-metal doping, coupling of different semiconductors, surface and interface design, and TiO₂ immobilization are usually used to enhance the photocatalytic activity of TiO₂. This review aims to improve photocatalytic purification efficiency for indoor VOCs, and may provide new insights and guidance for the design of novel photocatalysts based on the intrinsic characteristics of VOCs, such as high volatility, low molecular weight, low polarity, high hydrophobicity, strong chemical activity and high toxicity.