Ti3C2 Mxene modified SnNb2O6 nanosheets Schottky photocatalysts with directed internal electric field for tetracycline hydrochloride removal and hydrogen evolution

Abstract

The development of efficient and stable noble-metal-free photocatalysts remains a challenge in pollutant degradation and hydrogen production. Transition metal carbide (Mxene), with metallic conductivity, exhibits tremendous potential for photocatalysis in recent years. Herein, novel 2D/2D ultrathin Ti3C2 Mxene/SnNb2O6 nanosheets with an interfacial Schottky junction are designed and constructed via an ultrasonication-assisted hydrothermal method. This 2D/2D van der Waals heterojunction displays a large interfacial contact area and the loading of Mxene broadens the visible-light absorption. Meanwhile, the theoretical calculation and UPS demonstrate that an internal electric field provides a driving force for charges separation between SnNb2O6 and Ti3C2. As a result, this 2D/2D Ti3C2/SnNb2O6 composite shows remarkably enhanced photocatalytic activity and improved chemical stability for pollutants (tetracycline hydrochloride and Rhodamine B) degradation and hydrogen evolution. The optimal reaction rate over the TCS-5 sample is 2.53 times for TC·HCl and 15.56 times for RhB compared with pristine SnNb2O6, even at a low catalyst dosage (0.25 mg/mL). Furthermore, this multifunctional photocatalyst also exhibits enhanced H2 production amount. This work offers a rational protocol to design efficient 2D/2D Schottky junction photocatalysts and expand the utilization of Mxene as a promising cocatalyst for energy and environmental application.