Modulating electronic structures of bimetallic Co-Fe sulfide ultrathin nanosheet supported on g-C3N4 for highly electrocatalytic hydrogen evolution performance

Heteroatom doping is a possible way to regulate the catalytic capability of electrocatalysts for hydrogen evolution reaction (HER). This work focuses on the development of bimetallic Cobalt-Iron sulfide ultrathin nanosheets supported on the graphitic carbon nitride (g-C3N4) catalyst as efficient HER electrocatalysts (CoS2/FeS2/CN) with good stability at wide pH value. The ultrathin nanosheet exposes more active sites and enhances the catalyst activity. Electrochemical experiments demonstrate that adding g-C3N4 and Fe to CoS2 increases its catalytic activity and stability. Furthermore, g-C3N4 and Fe co-doped with CoS2 can modulate electronic structures on the interface. The CoS2/FeS2/CN exhibits outstanding HER performance, reaching a current density of 10 mA cm-2 with overpotentials of only 76.5 mV in an acidic solution and 175.6 mV in an alkaline solution. It also demonstrates exceptional durability, superior to commercial platinum/carbon catalysts. This work introduces a promising approach for designing low-cost, high-performance HER electrocatalysts with a wide pH range.