Controlled synthesis of large-area MoS2/MoO2 heterostructure via one-step, two-stage chemical vapor deposition for electrocatalytic hydrogen evolution reaction

Two-dimensional (2D) materials and heterostructures with tunable dimensions present exciting opportunities for functional applications in next-generation devices. However, conventional methods such as two-step chemical vapor deposition (CVD) or mechanical exfoliation for constructing heterostructures often encounter issues such as interfacial contamination and limited structural diversity, making it difficult to meet the demands of diverse applications. Herein, we present a one-step, two-stage CVD strategy that enables the controllable synthesis of high-quality, large-area MoS2/MoO2 heterostructures. By precisely regulating the concentration of the metal source precursor, the MoS2/MoO2 heterostructure structures can be effectively extended to different dimensions, including 2D/0D, 2D/1D, and 2D/2D. Furthermore, this synthesis strategy exhibits excellent universality, as demonstrated by its application to the MoSe2/MoO2 heterostructure system. Compared to individual MoS2 and MoO2, the MoS2/MoO2 heterostructure demonstrates significantly enhanced electrocatalytic hydrogen evolution performance. Kelvin probe force microscopy further confirms the existence of a Schottky barrier height at the MoS2/MoO2 interface, which effectively facilitates interfacial charge transfer. This work demonstrates a simple and efficient strategy for fabricating multidimensional heterostructures, providing important experimental support for future functional devices based on heterostructure materials.