Noble Metal-Free Heterojunction of Ultrathin Ti3C2 MXene/WO3 for Boosted Visible-Light-Driven Photoreactivity

Developing highly efficient, robust, and noble metal-free photocatalytic systems is essential for the large-scale implementation of solar-to-chemical energy conversion. Herein, a novel sandwich-like hierarchical heterostructure of Ti3C2 MXene/WO3 is created by in situ growth of ultrathin WO3 nanosheets onto the surface of few-layer Ti3C2 nanosheets via a one-pot solvothermal synthesis strategy. The resultant Ti3C2/WO3 heterostructure holds a large interface contact area, an intimate electronic interaction, and a short carrier migration distance, which is beneficial for bulk-to-surface and interfacial charge transfer. Meanwhile, the excellent electrical conductivity of Ti3C2 and the Schottky junction at the interface of WO3 and Ti3C2 expedites the spatial charge separation and transportation. As expected, the as-prepared Ti3C2/WO3 nanohybrids exhibit a superior visible-light-driven photoactivity and stability toward tetracycline hydrochloride (TC) decomposition. Across a range of Ti3C2 concentrations, 3 wt% Ti3C2/WO3 achieves the greatest photodegradation rate of 16.08 x 10(-3) min(-1) that is approximately ninefold larger than that of pristine WO3. In addition to the underlying photocatalytic mechanism, three TC degradation pathways are identified, highlighting the important roles of center dot O-2(-) and h(+). This study shows the potential of earth-abundant MXene family materials in the fabrication of high-performance and low-cost photocatalysts applicable for environment purification.