NiFeCo-based high entropy alloys nanoparticles coated with N-doped graphene layers as hydrogen evolution catalyst in alkaline solution

Electrochemical water splitting is an environmentally friendly technology for producing hydrogen energy. Recent studies have shown that high entropy alloys (HEAs) and N-doped graphene layers coated alloys have superior HER performance compared to traditional alloys. This paper presents a simple method for synthesizing N-doped graphene layers coated HEAs with controllable thickness. NiFeCo-based alloy materials are prepared using this method and used as HER catalysts in alkaline conditions. Experimental results and density functional theory (DFT) calculations demonstrate that the CuNiFeCoCrTi@N-doped graphene nanoparticles (CuNiFeCoCrTi@NC) with a graphene shell of 2–3 layers exhibit the best hydrogen evolution performance. The improvement of hydrogen evolution performance should be related to the unique properties of HEAs and coating the surface of alloys with thin graphene shell. This study presents a simple and efficient method for synthesizing HEA@NC NPs, which can be used as an efficient electrocatalyst in alkaline water splitting systems.