Structural and electronic modulation of (Fe,Ni)2P@Ni2P heterostructure for efficient overall water splitting at high current density
Yaxin Li, Xin Yu, Juan Gao, Yurong Ma
Abstract
To meet the demand of practical applications, it is pivotal to obtain electrocatalysts with high performance and cost-effective at high current density in water splitting. Herein, (Fe, Ni) 2 P@Ni 2 P was obtained through precise modulation of their morphological and electronic properties. The fusion of (Fe, Ni) 2 P and Ni 2 P makes (Fe, Ni) 2 P@Ni 2 P have good structural stability. The unique porous structure can expose more active sites. Meanwhile, electrons transfer from electron-rich Ni 2 P to electron-negative (Fe, Ni) 2 P resulting in a low schottky barriers that promotes charge transfer efficiency. The unique morphological and electronic characteristics as well as the synergistic effect of (Fe, Ni) 2 P and Ni 2 P endow (Fe, Ni) 2 P@Ni 2 P with excellent catalytical performance. Ultra-low overpotentials of 331 and 255 mV are required to reach current density of 1000 mA cm −2 in oxygen evolution reaction and hydrogen evolution reaction, respectively. In overall water splitting, potentials of 1.702, 1.838 and 1.933 V are needed to achieve current densities of 100, 500 and 1000 mA cm − 2 , respectively. It also owns excellent fast response ability and a splendid long-term stability, with a continuously stable current density of 1000 mA cm −2 for up to 120 h. This work provides a new idea for the design of dual-function electrocatalysts for large-scale industrial hydrogen production.