Electrocatalytic Self‐Supported‐Electrode Based on Co_xNi_1‐xP/TiC_0.5N_0.5 for Enhancing pH‐Universal Hydrogen Evolution Electrocatalysis

Abstract

The industrial application of powder‐based catalytic electrodes is heavily restricted by powder shedding, inhibition of active sites, and poor long‐term stability. Herein, a porous titanium carbonitride (TiC0.5N0.5) ceramic substrate with open straight finger‐like holes is first made by a simple approach of phase‐inversion tape‐casting and pressureless sintering, and then a CoxNi1‐xP active layer is in situ formed by a hydrothermal technique and phosphorization to achieve integrated CoxNi1‐xP/TiC0.5N0.5 self‐supported ceramic electrodes. Electrochemical tests reveal that the optimized Co0.9Ni0.1P/TiC0.5N0.5 electrode exhibits overpotentials of 76.5 and 79.8 mV at 10 mA cm−2, Tafel slopes of 47.3 and 40.5 mV dec−1, in 0.5 m H2SO4 and 1 m KOH, respectively. Furthermore, its superior long‐term stability and resistance to corrosion can be achieved for more than 20 h in both media at 100 mA cm−2. In addition, the Co0.9Ni0.1P/TiC0.5N0.5 electrode has much better performance than Pt/C at high current density in neutral media. Density functional theory calculations confirm that the Ni substitution of 1/10 Co in CoP leads to the more optimal |ΔGH*| among the CoxNi1‐xP catalysts. Compared with other CoP or NiP‐based electrodes, the Co0.9Ni0.1P/TiC0.5N0.5 electrode benefits from high strength, unique pore structure, tight and compatible bonding, and high hydrophilicity.