Hierarchical MoP/NiFeP hybrid hollow spheres as highly efficient bifunctional electrocatalysts for overall water splitting

Abstract

Although some progress on exploring non-noble-metal based materials with remarkable activity for the electrocatalytic hydrogen or oxygen evolution reactions has been made, it still remains a critical challenge especially for overall water splitting. Herein, we report a facile synthesis of novel hierarchical MoP/NiFeP hybrid hollow spheres (MoP/NiFeP HSs) as an electrocatalyst for the first time. The obtained MoP/NiFeP HSs enable not only abundant accessible sites, but also facilitated electron transfer through the heterointerfaces and synergistically promoted kinetics. The optimal MoP/NiFeP HSs present efficient bifunctional electrocatalytic performance with low overpotentials of 73 and 256 mV to achieve 10 mA cm⁻² for the HER and OER in 1 M KOH, respectively. More importantly, when employed as electrocatalysts in a two-electrode device, low cell voltage of 1.51 V at 10 mA cm⁻² with long term durability can be achieved, comparable to the Ir/C-Pt/C couple and exceeding those of the recently reported typical bifunctional electrocatalysts. This work might inspire the design and preparation of highly active and low-cost hybrid materials with hierarchical structures for water splitting applications.