Research on Urea Oxidation Coupled with Electrolysis of Water to Produce Hydrogen Based on (NiFe)₂P Catalyst

Abstract

Hydrogen production at low potential was realized by urea oxidation coupled water electrolysis. Transition metal phosphides ((NiFe)2P) were prepared by regulating polyvinylpyrrolidone (PVP) addition during the materials preparation, and their electrocatalytic performance for urea oxidation coupled hydrogen production was investigated. It was found that the material prepared with the PVP addition of 300 mg shows the best catalytic activity. The potential required to reach 100 mA cm-2 in KOH+urea solution is only 1.433 V with an impedance value of 4.128 Ω, which is 103 mV lower than that in KOH solution. Hydrogen evolution in KOH solution required 414 mV to reach -100 mA cm-2 with an impedance value of 48.75 Ω, while the potential required to reach the same current density in KOH+urea solution is only 343 mA with an impedance value of 5.65 Ω. As a result, the energy barrier and electron transfer resistance of electrocatalytic reaction can be significantly reduced by urea oxidation, and it provides a strategy for large-scale application of water electrolysis.