Boosting electrocatalysis by heteroatom doping and oxygen vacancies in hierarchical Ni-Co based nitride phosphide hybrid

Abstract

Designing highly active and low-cost electrocatalysts towards oxygen evolution reaction has ignited much interest in recent years. Thereby, rational design of those catalysts is an urgent topic that must be addressed. Herein, an effective strategy is demonstrated to be beneficial to the formation of hierarchical nitride phosphide hybrid with abundant oxygen vacancies. This hybrid catalyst exhibits an excellent OER catalytic performance, as demonstrated by an ultralow Tafel slope of 41 mV·dec−1 and an overpotential of 290 mV at 10 mA cm−2 in 1.0 M KOH solution, which is superior to those of the pure nitride, phosphide, and the commercial IrO2 catalysts. The outstanding catalytic performance can be attributed to the specific heterojunction structure, accessible active sites, and abundant oxygen vacancies, which can facilitate the charge transport and the release of the O2 bubbles. This study not only provides a facile strategy for constructing surface oxygen vacancies onto phosphide/nitride hybrid, but also exhibits an insight into the nature of hierarchical electrocatalyst with multiple active sites.