Electrocatalytic Self-Supported-Electrode Based on CoxNi1-xP/TiC0.5N0.5 for Enhancing pH-Universal Hydrogen Evolution Electrocatalysis

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 (TiC 0.5 N 0.5 ) 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 Co x Ni 1- x P active layer is in situ formed by a hydrothermal technique and phosphorization to achieve integrated Co x Ni 1- x P/TiC 0.5 N 0.5 self-supported ceramic electrodes. Electrochemical tests reveal that the optimized Co 0.9 Ni 0.1 P/TiC 0.5 N 0.5 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 H 2 SO 4 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 Co 0.9 Ni 0.1 P/TiC 0.5 N 0.5 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 |Δ G H* | among the Co x Ni 1- x P catalysts. Compared with other CoP or NiP-based electrodes, the Co 0.9 Ni 0.1 P/TiC 0.5 N 0.5 electrode benefits from high strength, unique pore structure, tight and compatible bonding, and high hydrophilicity.