Synthesis and Catalytic Performance of Mo₂C/MoS₂ Composite Heterojunction Catalysts

Hydrogen, as a clean, safe, and efficient energy carrier, is one of the hot energy sources that have attracted much attention. Mo₂C, due to the introduction of C atoms, makes the atomic spacing of the Mo lattice decrease and changes the width of the d-band, which makes the electronic properties of Mo₂C similar to that of Pt noble metals, exhibiting excellent electrochemical hydrogen precipitation performance. MoS₂, due to its special crystal structure and tunable electronic structure, has been widely studied. In this paper, Mo₂C nanoparticles were prepared by high-temperature carbonization, and then two-dimensional layered MoS₂ were be loaded on Mo₂C nanoparticles by the hydrothermal method to synthesize Mo₂C/MoS₂ composite catalysts. Their electrochemical hydrogen precipitation (HER) performance under acidic conditions was tested. The above catalysts were also characterized by modern material testing methods such as XRD, SEM, TEM, and XPS. The results showed that the composite catalysts exhibited the most excellent electrochemical hydrogen precipitation performance at Mo₂C/MoS₂-3, with the lowest overpotential at a current density of 10 mA cm^-2, Tafel slope, and electrochemical impedance. At the same time, the electrochemically active area was dramatically enhanced, with good stability under prolonged testing. The catalytic activity was significantly improved compared with that of Mo₂C and MoS₂. The characterization and experimental results indicate that the heterogeneous structure of Mo₂C and MoS₂ formed a built-in electric field between the two, which accelerated the electron transfer efficiency and provided more active sites. The Mo₂C/MoS₂ composite catalyst is a low-cost, easy-to-prepare, and high-efficiency electrochemical hydrogen precipitation catalyst, providing a new idea for developing green and clean energy.