Nitrogen-doped carbon-decorated yolk-shell CoP@FeCoP micro-polyhedra derived from MOF for efficient overall water splitting

Abstract Designing efficient non-precious electrocatalysts to facilitate overall water splitting is crucial and highly desirable but remains challenging. In this study, we synthesized nitrogen-doped carbon-decorated CoP@FeCoP yolk-shelled micro-polyhedras (denoted as CoP@FeCoP/NC YSMPs) via the phosphorization of ZIF-67@Co-Fe Prussian blue analogues YSMPs. The yolk-shelled construction and nitrogen-doped carbon matrix can effectively reduce the degree of CoP agglomeration, which is beneficial for increasing the specific surface area and active sites of the catalysts. The synergistic effect of yolk-shelled structure and nigtrogen-doped carbon matrix also optimizes the electronic structure and enhances the electrocatalytic activity of CoP@FeCoP/NC YSMPs. In an alkaline electrolyte, the overpotentials of hydrogen evolution reaction and oxygen evolution reaction only need 141 and 238 mV, respectively, to drive the current density of 10 mA cm−2. When a two-electrode water splitting device was conducted with the as-prepared catalyst, it required only a low cell voltage of 1.68 V to achieve a current density of 10 mA cm−2 and displayed outstanding stability over 20 h. This work offers insights into the facile, controllable synthesis strategy of various non-precious metal nanomaterials for high-efficiency water splitting electrocatalysis.