Oxygen vacancy mediated photocatalysis of Ti3C2 MXene quantum dots/W18O49 hybrid membrane for peroxymonosulfate-enhanced oxidation degradation

Abstract

Photocatalytic membrane technology shows great prospects in water decontamination. Coupling photocatalysis with peroxymonosulfate (PMS) can boost oxidation capacity by combining their superiorities sufficiently. Herein, 0D Ti3C2 MXene quantum dots (TMQDs) embedded oxygen vacancy-rich 3D sea urchin-like W18O49 microspheres (OTW) were synthesized via facile interface engineering combined with green plasma etching strategy. The visible-light driving flow-through membrane reactor was capable of degrading cyclophosphamide, a typical anticancer drug, and other common pollutants (5-fluorouracil, carbamazepine, bisphenol A, rhodamine B), with the removal and mineralization efficiencies of 10 μM pollutants reaching over 99 % and 63 %−79 % in 60 min with 0.5 mM PMS. Moreover, the long-term reliability of OTW membrane was validated through continuous treatment of 20 L sewage. Significantly, the newly designed photocatalytic membrane exhibited good tolerance to wide pH ranges, common coexisting substances in water, and various actual water matrix. The results of experimental and DFT theoretical calculations revealed that Schottky junction formed on the TMQDs/W18O49 interfaces and tunable O-defects could optimize electronic configuration, improve solar energy utilization, prevent photogenerated carriers’ recombination, promote H2O and PMS dissociation, making it possible that more •OH and SO4•− radicals participated in the oxidation degradation reaction. This study offers a design idea for preparing efficient and robust photocatalytic membrane via interface engineering and defect engineering strategies, which might contribute to bridging the translational gap between emerging photocatalytic techniques and practical environmental applications in near future.