N, S-GQDs and Au nanoparticles co-modified ultrathin Bi2MoO6 nanosheet with enhanced charge transport dynamics for full-spectrum-light-driven molecular oxygen activation

Abstract

It is a great challenge to achieve ultrafast charge transfer and simultaneously strengthen light adsorption for full-spectrum-light-activated photocatalysis. In this work, N and S co-doped graphene quantum dots (N, S-GQDs) and Au nanoparticles are successfully co-modified on atomic ultrathin Bi2MoO6 nanosheet, and the prepared hybrid material displays exceptional performance in charge carrier transfer and light harvest. The obtained hybrid material possesses excellent photocatalytic activity in molecular oxygen activation for oxytetracycline (OTC) degradation with 3.69-fold higher reaction rate than pristine Bi2MoO6 under visible light irradiation. In addition, it also possesses near-infrared-light-driven catalytic activity, about 24.47% of OTC can be degraded under near-infrared light irradiation. Moreover, the hybrid material displays outstanding catalytic performance for actual wastewater treatment, and it also possesses high photostability. The mechanism exploration reveals that the boosted photocatalytic performance is originated from three aspects. The up-conversion photoluminescence feature of N, S-GQDs broadens photoresponse range, and the light nanoantenna and SPR effect of Au nanoparticle enhance light absorption intensity. Meanwhile, both N, S-GQDs and Au nanoparticles accelerate charge carrier transfer, the surface charge transfer efficiency of pristine Bi2MoO6 and hybrid material are calculated to be 33.74% and 53.04%, respectively. Furthermore, the possible photodegradation pathway of OTC is also inquired according to liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS). This work provides inspiration to rationally design high-performance full-spectrum-light-driven catalysts in molecular oxygen activation for environmental modification.