Interfacial charge redistribution in interconnected network of Ni2P–Co2P boosting electrocatalytic hydrogen evolution in both acidic and alkaline conditions

In this study, scalable and facile electroless plating accompanied with phosphorization process is explored for preparation of interconnected network of Ni2P–Co2P on carbon clothes (CC) substrate. The binder-free Ni2P–Co2P/CC electrocatalyst with optimized Ni2P:Co2P ratio displays outstanding HER activity in both alkaline and acidic conditions requiring only 93 mV and 172 mV vs. RHE of overpotential to reach 10 mA cm−2 of current density. The superior HER activity of Ni2P–Co2P/CC could be attributed to (i) the abundant interfacial contact and larger electrochemical surface area; (ii) regulated electronic structure and hydrophilic surface of the catalyst, and (iii) interfacial charge redistribution contributing more high-valence Ni active sites, as visualized by off-axis electron holography. Overall, this work directly demonstrates the interfacial charge redistribution in Ni2P–Co2P/CC interconnected network, and suggests a facile strategy for structural design and preparation of highly efficient phosphide electrocatalysts.