Fabrication of MoS2/WSe2 heterostructures as electrocatalyst for enhanced hydrogen evolution reaction

Two-dimensional material based heterostructures produce novel phenomena due to distinctive interactions between stacked layers. This paper details fabrication of van der Waals heterostructure consisting of layered MoS2 and WSe2 on FTO substrates by combining solution bath and radio-frequency sputtering. Raman scattering confirmed WSe2/MoS2 heterostructure formation, X-ray photoelectron spectroscopy surface profile detailed the heterostructure composition, and depth profile showed heterostructure interfacial structure with stacked WSe2 and MoS2 layers on the FTO substrate. Surface properties confirmed the WSe2/MoS2 heterostructure formed a multi-structured array of nanograins, and high resolution electron micrographs confirmed vertically formed layered fringes. Hydrogen evolution showed enhanced electrocatalytic behavior with 116 mV overpotential at 10 mA/cm2 and 76 mV/decade Tafel slope. Electrocatalytic property robustness was confirmed by over 20 h continuous hydrogen evolution reaction in an acidic solution. Enhanced electrocatalytic outcomes were due to increased interfacial hole-electron separation, dispersing active facets through the interface. The stacked layered structure provides a new avenue for two-dimensional heterostructures for energy harvesting devices.