Interfacial charge regulation in acid-treated microporous carbon/titanium dioxide composites for efficient photocatalytic toluene mineralization

초록

The photocatalytic removal of volatile organic compounds from indoor air continues to be constrained by two key limitations of conventional titanium dioxide (TiO2) catalysts: insufficient adsorption capacity and rapid charge carrier recombination. To overcome these dual constraints, an interface engineering strategy is employed by integrating TiO2 with microporous activated carbon functionalized via mineral-acid treatment. The resulting acid-treated carbons are denoted as AC-X, where X indicates the acid type: N (nitric, HNO3), C (hydrochloric, HCl), S (sulfuric, H2SO4), and P (phosphoric, H3PO4). The acid-induced oxygenated surface groups on AC-X simultaneously enhance toluene adsorption and facilitate interfacial charge transfer in the resulting TiO2–AC-X composites, designated as TA-N, TA-C, TA-S, and TA-P, respectively. Among these, TA-N shows the highest toluene removal efficiency (98.7%), carbon dioxide yield (93.8%), and a dynamic clean air delivery rate of 9.87 L mg−1 min−1. It further exhibits robust performance across a range of relative humidity (0–80%), toluene concentrations (1–10 ppm), and flow rates (100–300 mL min−1) with an apparent quantum yield of 0.03%. Mechanistic analysis confirms the critical role of oxygenated surface groups in promoting pollutant adsorption and accelerating oxidative mineralization, demonstrating the potential of acid-functionalized TA composites as a robust next-generation platform for indoor air purification.

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