Hierarchical Ni3S2@2D Co MOF nanosheets as efficient hetero-electrocatalyst for hydrogen evolution reaction in alkaline solution

Developing efficient and stable non-noble metal electrocatalysts for alkaline hydrogen evolution poses a challenge for current research. Herein, a novel hierarchical hetero-electrocatalyst of Ni3S2@2D Co MOF was synthesized with cobalt metal-organic frameworks (Co-MOFs) crystallization on carbon paper (CP) and in-situ electrodeposition of Ni3S2 nanosheets. The catalyst Ni3S2@2D Co-MOF/CP exhibited an excellent hydrogen evolution reaction (HER) activity with a low overpotential of 140 mV and a small Tafel slope of 90.3 mV dec−1 at a current density of -10 mA cm−2. This catalyst demonstrated a lower overpotential (395 mV) than commercial Pt/C catalyst at a high current density (>130 mA cm−2). The efficient and stable HER performance of Ni3S2@2D Co-MOF/CP was attributed to nickel sulfide honeycomb nanosheets grown on two-dimensional MOF frameworks, which were conducive to charge transfer and hydrogen evolution. The electron-rich nickel sulfide surface significantly diminished H* adsorption and reduced energy barrier of H2 generation to promote HER process. This work provides a new strategy for practical preparation of efficient and stable transition metal electrocatalysts.