Programmed electrochemical reconstruction of NiCoxMo4-xN5 for making Core-Shell shaped Schottky junction electrocatalyst

Abstract

Electrochemical reconstruction (ECR) sets natural limit to exploring reactivity of pristine catalysts in the electrocatalytic reactions. The ECR phenomena need to be regulated to unveil intrinsic property of pristine catalysts. Herein, we introduced ‘sacrificial cation optimization’ method to control element-leaching phenomenon at NiMo4N5 surface during the ECR. Partial substitution of sacrificial Mo with Co enabled timely cessation of the ECR of NiCoxMo4-xN5 with forming stable oxyhydroxide outer shell. This controlled ECR generated classic Schottky junction (SJ) at the core–shell interface of NiCoxMo4-xN5 | Ni1-yCoyOOH. The in situ formed SJ remarkably enhanced electron transfer with nullifying the poor conductance of front-line oxyhydroxides. As a result, the core–shell SJ yielded the current density of 10 mA/cm2 at a low overpotential of 126 mV (without iR compensation). The in situ formation of core–shell SJ proposed a breakthrough in the research to regulate ECR process as well as produced a new type of electrode beyond the oxyhydroxides. © 2024 Elsevier B.V.