Physical insight into the enhanced urea electrooxidation using Ni and Fe-based LDH, LDO, and hydroxides under different dissolved gas saturation conditions in electrolyte

Abstract

The production of green hydrogen is one of the most demanding and challenging for modern technology. A promising and an effective approach is electrocatalytic anodic urea oxidation reaction to generate hydrogen at cathode under alkaline electrolysis condition. However, it remains crucial for the development of active and stable electrocatalysts for efficient urea oxidation. In this study, we employed the hydrothermal synthesis route for NiFe LDH, NiFe LDO, and Ni(OH)2. The superior performance of NiFe LDH compared to other catalysts is observed due to easy charge transfer facilitated by Fe ions. Moreover, Fe incorporation prevents surface poisoning of the electrocatalyst, resulting in increased activity and stability for electrocatalytic urea oxidation reaction. The influence of different electrolyte environments on the performance of urea-based electrolyzers for sustainable hydrogen production and management of urea-rich wastewater has been measured for the first time by varying oxygen saturation and nitrogen purging conditions. In cyclic voltammetry studies, O2-saturated and purging conditions outperformed N2 gas saturation or purging. The findings of this study provide valuable insight into the design of practical and environmentally friendly urea electrooxidation systems.