Mo-ion doping evoked visible light response in TiO₂ nanocrystals for highly-efficient removal of benzene

In this work, Mo ions were employed to evoke the visible light response of TiO₂ nanocrystals to enhance its photocatalytic removal ability of indoor gaseous benzene. The photocatalytic reaction rate constant of the optimal Mo-TiO₂ was 0.0065 min⁻¹, which was 4.81 times higher than that of undoped TiO₂. Density functional theory (DFT) calculations using a novelty charge compensation structure model were performed to investigate the effect of Mo-doping on the electronic structure of TiO₂. The theoretical results indicated that the reduction of bandgap energy could be attributed to the introduced Mo-d states. PL and I-t results showed that Mo ions with proper concentration could suppress the recombination of carriers. The feasible reaction pathways were also revealed based on the detected intermediates. The catalysts also exhibited good long-term stability in the recycling experiments for 6 runs. Furthermore, 1 kg of Mo-TiO₂ nanocrystals could be produced with uniform morphology and clean surface by one batch synthesis. These promising results not only provide a facile synthesis route of Mo-TiO₂ but also can promote the practical application of TiO₂-based photocatalysts in environmental remediation.