Carbon Quantum Dots Bridged TiO 2 /CdIn 2 S 4 toward Photocatalytic Upgrading of Polycyclic Aromatic Hydrocarbons to Benzaldehyde.

Conversion of hazardous compounds to value-added chemicals using clean energy possesses massive industrial interest. This applies especially to the hazardous compounds that are frequently released in daily life. In this work, a S-scheme photocatalyst is optimized by rational loading of carbon quantum dots (CQDs) during the synthetic process. As a bridge, the presence of CQDs between TiO 2 and CdIn 2 S 4 improves the electron extraction from TiO 2 and supports the charge transport in S-scheme. Thanks to this, the TiO 2 /CQDs/CdIn 2 S 4 presents outstanding photoactivity in converting the polycyclic aromatic hydrocarbons (PAHs) released by cigarette to value-added benzaldehyde. The optimized photocatalyst performs 87.79% conversion rate and 72.76% selectivity in 1 h reaction under a simulated solar source, as confirmed by FT-IR and GC-MS. A combination of experiments and theoretical calculations are conducted to demonstrate the role of CQDs in TiO 2 /CQDs/CdIn 2 S 4 toward photocatalysis.