Results in Engineering (Dec 2024)
NiMnO nanoparticle-activated carbon anodes for efficient urea oxidation and energy production in wastewater-driven direct urea fuel cells
Abstract
The growing concern over urea-containing wastewater from industrial sources necessitates innovative treatment solutions that also offer sustainable energy production. In this study, a novel anode material is developed by decorating activated carbon with NiMnO nanoparticles through thermal treatment under an inert atmosphere. The resulting NiMnO NPs-decorated activated carbon was evaluated for its electrocatalytic performance in the electrooxidation of urea and its application in a direct urea fuel cell (DUFC). X-ray diffraction patterns confirmed the formation of nickel metal and Mn(II) oxide, with activated carbon showing representative peaks. Scanning electron microscopy images revealed well-dispersed nanoparticles on the activated carbon surface, corroborated by uniform elemental distribution from mapping results. Electrochemical measurements using cyclic voltammetry demonstrated that the 30 wt% MnAc sample exhibited the highest electrocatalytic activity among the tested samples (0, 5, 10, 20, 30, 40 and 50 wt% MnAc) with a maximum current density of 123 mA/cm2 at 3.0 M urea concentration and an onset potential of −0.02 V versus Ag/AgCl. Linear sweep voltammetry of the assembled DUFC showed promising open circuit potentials of 0.82 V and maximum power densities reaching 4.9 W/m2, achieved using industrial wastewater from the Egyptian Chemical Industries Company (KIMA) in Aswan, Egypt. The results highlight the efficacy of NiMnO NPs-decorated activated carbon in both urea oxidation and electrical energy generation. This study not only provides a viable method for treating urea-rich industrial wastewater but also presents a sustainable approach to energy production. The findings underscore the potential of this material for future applications in DUFCs, offering significant environmental and economic benefits.
