Hybrid alkali-acid urea-nitrate fuel cell for degrading nitrogen-rich wastewater

Though direct urea fuel cells (DUFCs) show promising potential for green energy generation, the practical feasibility of its on-site installation is yet encumbered by the sluggish electrokinetics and low-value product (H2O) of oxygen reduction reaction (ORR). We here report the design and synthesis of a bifunctional hybrid electrocatalyst of nitrogen-doped carbon sheets supporting [email protected]@CuO composites ([email protected]@CuO/NCS) via direct calcination of Ni- and Cu-containing metal organic frameworks (MOFs). The as-derived nanohybrid shows impressively high catalytic performance towards urea oxidation reaction (UOR) in alkali and nitrate reduction reaction (NRR) in acidic electrolyte, which inspire us to set up a urea-nitrate fuel cell (UNFC). Owing to the excellent electrochemical characteristics behaviour of prepared nanostructures, the fabricated UNFC simultaneously exhibits improved fuel cell performance of 22.55 ± 2.3 mW cm−2 and degrade the urine and nitrate at the anode and cathode, respectively. The presented innovative electrochemical device may open up a prime step for the development of renewable UNFC for simultaneous green energy generation and N-containing waste removal.