Heterojunction interface editing in Co/NiCoP nanospheres by oxygen atoms decoration for synergistic accelerating hydrogen and oxygen evolution electrocatalysis

Controllable designing of well-defined heterojunction nanostructures provides an insightful strategy for accelerating the kinetics of the hydrogen and oxygen evolution reactions (HER/OER), but such task is still challenging. Herein, we proposed a protocol of heterojunction interface editing (HIE) strategy by oxygen atoms decoration for synergistic boosting electrocatalytic HER and OER performances. A novel Co/NiCoP nanospheres (NSs) heterojunction was synthesized by crystal seed template transformation method with Ni₅P₄ microspheres as seeds. The effective oxygen atoms interface editing increased the oxidation state of Co atoms and prolonged the Co–P bond length of Co/NiCoP NSs heterojunction, thus the electron localization on P sites was enhanced, leading to the dramatically elevated HER and OER performances simultaneously. The as-constructed O-Co/NiCoP NSs show excellent electrocatalytic activity with 361 and 430 mV vs. reversible hydrogen electrode (RHE) to arrive high current density of 300 mA·cm⁻² for HER and OER in 1 M KOH as well as good stability. The proposed HIE concept could provide a new perspective on the catalyst design for energy conversion systems.