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