Enhanced Alkaline Water Electrolysis Using Cr-Doped NiCoP/Ni ₃ S ₂ Hollow Nanowires with Heterointerfaces as Bifunctional Catalysts

For the goal of mitigating energy scarcity via hydrogen production from water electrolysis, the high performance, low cost transition-metal-based catalysts are essential to be designed and manufactured. In this study, we prepare chromium-doped nickel cobalt phosphide/nickel sulfide (Cr-NiCoP/Ni 3 S 2 ) heterostructured hollow nanowires on conductive nickel foam through a two-step hydrothermal method coupled with low temperature phosphorization procedure. Benefiting from the remarkable electron transport capability inherent in transition metal compounds, the large specific surface area afforded by distinctive hollow nanowire architecture, and the interfacial synergistic effect of heterostructure, the as-obtained catalyst delivers low overpotentials of 67 mV for HER and 243 mV for OER at a current density of 10 mA cm –2 in alkaline electrolyte. Additionally, in an electrolytic system where the Cr-NiCoP/Ni 3 S 2 acts as bifunctional anode and cathode materials, the 10 mA cm –2 current density can be achieved at a cell voltage of 1.47 V with good stability. This catalyst demonstrates better performance than the majority of reported transition metal based bifunction substances. The work described in this paper not only develops a new class of catalytic materials integrating application potential and expense advantage but also provides important strategic support for the fabrication and optimization of nonprecious metal electrocatalysts.