Enhanced photocatalytic antibacterial performance by hierarchical TiO2/W18O49 Z-scheme heterojunction with Ti3C2Tx-MXene cocatalyst

Construction of multiple electronic transmission channels in a photocatalytic system is in favor of boosting the charge separation to realize a high photocatalytic antibacterial property. Herein, a novel hierarchical ternary photocatalyst consisting of TiO2/W18O49 Z-scheme heterojunction and Ti3C2Tx-MXene cocatalyst was synthesized via a simple two-step solvothermal method. Dual charge transfer routes were realized in this TiO2/W18O49/Ti3C2Tx-MXene composite. The electrons on TiO2 can transfer either through the Z-scheme mode to combine with the holes of W18O49, or through the Schottky-junction to Ti3C2Tx-MXene cocatalyst. The TiO2/W18O49/Ti3C2Tx-MXene composite maintained high photooxidation-reduction capacity and possessed fast charge separation behavior. As a result, the TiO2/W18O49/Ti3C2Tx-MXene heterojunction had a high photocatalytic bactericidal rate of 93.7% for Escherichia coli (E. coil) under light (λ ≥ 365 nm, 6 h), which was 3.3, 5.5, 3.1 and 2.9 times that of MXene (28.6%), TiO2 (17.0%), W18O49 (30.0%) and TiO2/MXene (32.8%), respectively. In addition, the ternary heterojunction illustrated good biocompatibility. This work provides a simple method of constructing multiple electronic transmission channels for high bactericidal performance and proves the effectiveness of photocatalytic materials in the biological field.