RESUMO
The catalytic efficiency of photocatalysts highly depends on electron transport and mass transfer. Herein, we designed and prepared an effective H2WO4/Ti3C2/g-C3N4 (HTC) Z-scheme heterojunction through interfacial engineering strategy. The results manifested that 97.4% of Cr(VI) (80 µM, 50 mL) could be removed by HTC heterojunction within 10 min under visible light irradiation. The reduction rate constant of Cr(VI) for H2WO4/g-C3N4 (HC) heterojunction increased by a factor of 21 after introducing the conductive Ti3C2. Moreover, 96% of tetracycline (TC, 10 mg L-1, 50 mL) could be degraded by HTC heterojunction within 30 min. The electronic conductivity and ionic diffusion coefficient of HC heterojunction increased by a factor of 64 and 1064 after adding Ti3C2, respectively. This result indicated that the introduction of highly conductive Ti3C2 significantly improved the electron and mass transfer of the heterojunction. Meanwhile, the HCT heterojunction displayed favorable photocurrent, and keep excellent photostability during the long-term test. Moreover, density functional theory (DFT) calculations demonstrated that the internal electric field (IEF) from g-C3N4 to H2WO4 in HCT heterojunction promotes the combination of the photoinduced electrons in the H2WO4 conduction band (CB) with photoinduced holes in the g-C3N4 valence band (VB), thus accelerating the charge transfer in the HCT Z-scheme heterojunction. The antibacterial efficiency of HTC heterojunction against E. coli and S. aureus could reach up to 98.4% and 99.7%, respectively. The degradation intermediates and the potential degradation mechanism of TC were analyzed and proposed based on the results of HPLC-MS analysis. Moreover, the toxicity of TC and degradation intermediates were estimated by Toxicity Estimation Software (T.E.S.T.) based on quantitative structure-activity relationship (QSAR). This work provided a valuable guideline for designing the effective MXene-based Z-scheme heterojunction for environmental remediation.