Coupled Heterostructure of Mo–Fe Selenide Nanosheets Supported on Carbon Paper as an Integrated Electrocatalyst for Efficient Hydrogen Evolution

Hydrogen evolution reaction (HER) driven by high-performance and low-cost electrocatalysts has been well-identified as one of the most promising technologies to explore sustainable power sources. In this work, the authors demonstrated a series of Fe–Mo selenide composite nanomaterials with adjustable HER catalytic activities by a simple one-step hydrothermal reaction. The heterostructured catalyst exhibited significant enhancement in HER activity compared to the pristine MoSe2 and FeSe2 catalysts. It is found that the optimized Mo–Fe selenide can drive the HER at a current density of 10 mA cm–2 by an overpotential of 86.9 mV in acidic solution. Also, it possesses outstanding kinetics (Tafel slope of 57.7 mV dec–1) of the electrochemical reaction. Besides the synergistic effect of different chemicals, the coupled Mo–Fe selenide achieved the electronic modulation of the heterointerface, where electrons were accelerated to transfer from dispersed FeSe2 to the active edges on 1T-MoSe2 and further activated the electrochemical performance.