Highly Selective Electrooxidation of Urea to Nitrogen on Copper/Nickel Boride Interface under Alkaline Condition

Abstract

Urea electrooxidation reaction (UOR) plays an important role in environmental protection and energy regeneration. The extensively studied nickel-based catalysts exhibit good activity for UOR, but urea is more prone to be overelectrooxidized to another pollutant NO x – (x = 2, 3). Herein, the Cu/Ni-B interface catalyst is presented. The introduction of Cu significantly enhances the Faradaic efficiency of N2 (nearly 70% at 1.70 V versus RHE). Electrochemical tests and in situ Raman spectroscopy results show that the introduction of Cu significantly affects the density of OH* species on the catalyst in the UOR process. It is proposed that with a moderate decrease in OH* density, the catalyst can provide enough sites for urea molecules to allow simultaneous adsorption of the two N atoms, facilitating the process of N-N coupling to form N2. This work is also instructive for the design of electrocatalysts for other nucleophile electrooxidation reactions.

New Insights into Urea Electro-Oxidation: Complete Mass-Balances and Proof of Concept with Real-Matrix Effluent

“…To overcome this issue, several attempts are very recently made to orient the mechanism towards N , 2 for example by electrode material functionalization. 14,22 The production of H 2 estimated from Eq. 5 is reported in Fig.…”