Electrospinning-Derived FeCrNiZrMn High-Entropy Alloy on Carbon Nanofibers for Hydrogen Evolution

Abstract

Due to increasing demand for sustainable energy systems, hydrogen energy, as a green and low-carbon energy carrier, has considerable potential for development. The electrocatalytic water splitting is one of the key ways to produce green hydrogen, but high costs and resource limitations of Pt-based catalysts limit their large-scale use. As a result, exploring high-performance, low-cost non-noble metal HER catalysts have emerged as a research focus. This work has been focused on the investigation of FeCrNiZrMn/CNFs high-entropy alloy catalysts. A series of catalyst materials were prepared through electrospinning techniques with subsequent high-temperature carbonization at 700°C–900°C. The experimental results showed that the FeCrNiZrMn/CNFs synthesized at 800°C could form uniformly distributed and crystallographically stable high-entropy alloy nanoparticles, achieving exceptional performance for the HER under alkaline conditions, with an overpotential of 57 mV at 10 mA/cm2 and a Tafel slope of 29.2 mV/dec, and maintaining 99.3% voltage stability during a 16-h constant current test. Theoretical results from DFT suggested that the high-entropy alloy surface has diverse hydrogen adsorption sites and a tunable electronic structure. The differential charge density analysis furthers interpretation of the electron transfer behavior during hydrogen adsorption, and reveals the intrinsic mechanism of its efficient catalysis.