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 (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-x/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 vertical bar Delta G(H)vertical bar 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.

Automated summary

A porous titanium carbonitride ceramic substrate with finger-like holes was prepared, and CoxNi1-xP was in situ formed on it to achieve self-supported ceramic electrodes. The Co0.9Ni0.1P/TiC0.5N0.5 electrode exhibited low overpotentials, high long-term stability, and better performance than Pt/C at high current density in neutral media.