High-entropy metal sulfide nanoparticles with optimized metal composition as highly efficient electrocatalysts for N2 reduction to NH3

Eco-friendly electrocatalytic nitrogen reduction reaction (NRR) is aimed to replace the traditional polluting industrial process, but NRR needs electrocatalysts with high selectivity and activity to boost desired NH 3 yield rate and Faradic efficiency (FE). In this work, high-entropy sulfides (HES) (FeCoNiMoM)S x (M=Cr, Cu, Mn) were synthesized via a two-step solvothermal method. The optimized composition for HES is (FeCoNiMoCr)S x , with promising NRR performance that NH 3 yield rate reached 47.97 µg/(h·mg cat ) at −0.7 V vs RHE and FE was 26.1% at −0.4 V vs RHE. Comprehensive characterization and electrochemical testing were performed to investigate the effects of the metal component on NRR performance. It reveals that (FeCoNiMoCr)S x shows more intense charge transport, more electrocatalytic active sites, higher selectivity, etc, resulting from the electron transport and element synergy of HES. Also, it is proved to have targeted NRR selectivity and limiting competitive hydrogen evolution reaction. The results offer promising guidance for further improving the NRR electrocatalysts based on transition elements.