Standalone Ni-Free Electrode for Direct Urea/Urine Real Fuel Cell Operation

Abstract

Developing cost-effective, durable anode electrodes is essential for commercializing direct urea fuel cells (FCs). In the current study, standalone copper hydroxide nanograss was grown on the surface of the copper foam at room temperature. The surface morphology, elemental analysis, and crystalline structure were investigated. The prepared materials demonstrated a high activity towards urea electro-oxidation that increased with increasing urea concentration and slightly decreased at 4 M. The generated current using the modified electrodes is almost twice that obtained using the bare copper foam. The electrodes effectively operated for a prolonged current discharge (15 hr) using 3 M urea with outstanding stability. The morphology of the nanograss was retained even after such a very long time of operation. Moreover, the prepared materials are effectively used for the current generation from real urine with and without pH adjustment. Finally, real FC operation using urine was verified, showing an open circuit voltage of 1 V. The cell was operated for a long time, demonstrating the potential of the prepared electrodes for commercialization to realize simultaneous wastewater treatment and electricity generation from urine and other urea-contaminated wastewater.