Copper and nickel-based oxides delicately tailored via galvanic reaction as electrocatalyst for solid-state direct urea fuel cell

The sluggish kinetics of urea oxidation reaction (UOR) critically restrict the prevalence of direct urea fuel cell (DUFC), utilizing electrolyte containing urea/urine. In this work, the copper and nickel-based composite oxides are prepared by meticulously controlling the galvanic reaction of copper ion to metallic nickel and the high-temperature oxidation process. Based on a systematic electrochemical characterization of the catalyst, the asfabricated nano-architectures are optimized toward UOR performance, showing a low potential of 1.39 V vs. RHE to drive 100 mA cm-2 in alkaline solution. The button-like DUFCs configuration of as-developed catalysts exhibits a maximum power density of 1.19 mW cm-2. Furthermore, the DUFCs assembled with bio-urine, including men, dogs, cats, and rats as electrolytes without further purification, show a similar voltage. These findings open up a direction to convert bio-waste into treasure.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The sluggish kinetics of urea oxidation reaction (UOR) in direct urea fuel cells (DUFC) can be improved by utilizing copper and nickel-based composite oxides as catalysts. Through meticulous control of galvanic reaction and high-temperature oxidation, the nano-architectures of the catalysts are optimized to achieve low potential and high performance. Moreover, DUFCs assembled with bio-urine without further purification show similar voltage, indicating the possibility of converting bio-waste into valuable energy sources.