Highly Efficient Urea Oxidation via Nesting Nano-Nickel Oxide in Eggshell Membrane-Derived Carbon

Here, we reported a strategy of using an eggshell membrane to produce hierarchically porous carbon as a low-cost substrate for synthesizing a nano-nickel oxide catalyst (C@NiO), which can effectively turn biowaste-urea-into energy through an electrochemical approach. The interwoven carbon networks within NiO led to highly efficient urea oxidation due to the strong synergistic effect. The as-prepared electrode only needed 1.36 V versus reversible hydrogen electrode to realize a high efficiency of 10 mA cm(-2) in 1.0 M KOH with 0.33 M urea and delivered an even higher current density of 25 mA cm(-2) at 1.46 V, which is smaller than that of the porous carbon and commercial Pt/C catalyst. Benefiting from theoretical calculations, Ni(III) active species and the porous carbon further enabled the electrocatalyst to effectively inhibit the CO2 poisoning of electrocatalysts, as well as ensuring its superior performance for urea oxidation.

Automated summary

The study presented a strategy using eggshell membrane-derived hierarchically porous carbon as a substrate for nano-nickel oxide catalyst to convert biowaste-urea into energy efficiently. The synergetic effect of interwoven carbon networks within NiO led to highly efficient urea oxidation, with the electrode showing superior performance and CO2 poisoning inhibition.