Chemical short-range order in multi-principal element alloy with ordering effects on water electrolysis performance

The superior electrocatalytic activity of multi-principal element alloys (MPEAs) is typically attributed to synergistic effects of their multi components in random solid solutions. Strategies to control the functional atoms with a chemically ordered atomic distribution and the specific atomic configuration in the MPEAs remain a challenging research topic. Here, we have discovered non-random, chemical shortrange order (CSRO) in a Fe10Co5Ni10Cu15Al60 MPEA induced by magnetic characteristics of elements, leading to ultralow overpotential for dual-electrode water splitting in alkaline condition. Atomicresolution imaging and elemental mapping assisted by statistical analysis and density functional theory (DFT) simulations revealed that CSRO in the MPEA originated from the nearest-neighbor preference of M-Cu (M = Fe, Co, Ni, and Al) pairs and repulsion of same-element pairs (Fe-Fe, Co-Co, Ni-Ni, Cu-Cu, and Al-Al). Such preferential atomic pairs facilitated H2O/H* adsorption/desorption during the hydrogen evolution reaction and reduced the energy barrier for the rate-determining step of the oxygen evolution reaction, thereby promoting excellent overall water splitting performance. The achieved current density (130 mA cm-2) of the low-cost MPEA was -4 times higher than that of the Pt/C||RuO2 dual-electrode their multi-functional applications, potentially spurring the development of numerous highperformance MPEA-based devices for the energy and environmental sectors.