Unveiling the intrinsic properties of single NiZnFeOx entity for promoting electrocatalytic oxygen evolution

Abstract

Although considerable research efforts have been devoted to the design and development of non-noble electrocatalysts for oxygen evolution reaction (OER), substantial enhancement of OER performance with commercial-scale water electrolysis remains a big challenge. This could result from the difficulties in detecting the intrinsic properties and overlooking the assembly process for electrochemical OER process. Here, we employ a microjet collision method to investigate the intrinsic OER activities of individual NiZnFeOx entities with and without a moderate magnetic field. Our results demonstrate that single NiZnFeOx nanoparticles (NPs) show the excellent OER performance with a lowest onset potential (∼1.35 V vs. RHE) and a greatest magnetic enhancement (∼118%) among bulk materials, single agglomerations and NPs. Furthermore, we explore the utility of theoretical investigation by density functional theory (DFT) calculations for studying OER process on NiZnFeOx surfaces without and with spin alignment, indicating monodispersed NiZnFeOx NPs with totally spin alignment facilitates the OER process under the external magnetic field. It is found that the well-dispersion of NiZnFeOx NPs would increase the electrical conductivity and the surface spin state, resulting in promoting their OER activities. This work provides a test for uncovering the essential roles of NPs assembly to a significant promotion of their magnet-assisted OER.