Design and synthesis of dispersed Ni2P/Co nano heterojunction as bifunctional electrocatalysis for boosting overall water splitting.

The design of multi-components nanostructure with interface heterojunction is the cutting-edge research in recent years because the catalytic activity, stability, and durability of catalysts are highly affected by the strong electronic effects, geometric effects, and synergistic effects occurring at the interface. Based on this, an efficient bifunctional electrocatalyst embedding highly dispersed Ni 2 P/Co nano heterojunction at the porous hollow-out carbon shell is developed for overall water splitting through evenly epitaxial growth of ultrathin Ni 2 P nanosheets on Co-based ZIF-67. The distinct electron interaction between the interfacial Ni 2 P (300) and Co (100) effectively lowers the overpotential of OER (316 mV vs. RHE) and HER (149 mV vs. RHE) at the current density of 10 mA cm−2. Density functional theory (DFT) calculation further identifies that the Ni 2 P and Co heterojunctions optimize the adsorption energy of intermediate products and lower the energy barrier of the rate-determining step of OER significantly. This work provides a rational design of a well-defined interface toward overall water splitting electrocatalysts and offers a scientific basis for an in-depth understanding of the mechanism of the catalysts with nano heterojunction. • Synthesis a highly dispersed Ni 2 P/Co nano heterojunction catalyst at the porous hollow-out carbon shell. • The nano heterojunction is composed of Ni 2 P (300) and Co (100) crystal face. • Low overpotential of 316 mV and 149 mV are required at 10 mA/cm2 for OER and HER in 1 M KOH respectively. • Present a low cell voltage of 1.56 V at 10 mA/cm2 for overall water splitting. [ABSTRACT FROM AUTHOR]