Lattice-matched Cu3P/Cu2Se heterojunction catalysts for efficient hydrogen evolution reactions

The research and development of efficient electrocatalysts for the hydrogen evolution reaction (HER) are indispensable for the large-scale popularization of hydrogen energy. As most existing electrocatalysts are powder materials, many conductive agents and binders are required for electrocatalytic performance test. Besides the tedious the preparation process of the electrode, the long-term cycle stability of the electrode is also low. In this study, Cu(OH)2 precursors were prepared on copper foam by anodic oxidation. Subsequently, lattice-matched Cu3P/Cu2Se heterojunction catalysts were obtained via simultaneous phosphorization and selenization. The results showed that the synergistic effect of the two phases and heterogeneous interface significantly improved the electrochemical HER performance. The overpotential of the lattice-matched Cu3P/Cu2Se catalyst was only 166 mV and the Tafel slope was 187.90 mV dec−1 at 10 mA cm−2. After testing for 10 h at 10 mA cm−2, the overpotential stabilized at 250 mV. The overpotential of the lattice-matched Cu3P/Cu2Se was lower than that of the individual Cu3P and Cu2Se catalysts. Thus, synergism between the heterostructure and interface is an effective approach for enhancing the electrocatalytic activity and durability. It was proved that element doping and constructing defects are feasible strategies to improve the electrocatalytic performance of catalysts.