Fluorine tin oxide-supported copper nanofilms as effective and selective de-nitration electrocatalysts

Abstract

• Copper nanofilms are electrodeposited directly on FTO/Glass. • Catalyst can re-designed and scaled-up for continuous-flow rate water de-nitration. • Cu@FTO is more efficient and nitrogen-selective than Cu or FTO. • Cu@FTO lowers nitrate to acceptable levels. Due to widespread water pollution with nitrate ion, methods to remove or lower the nitrate concentrations in water are needed. A novel route to reproducibly electro-deposit copper nano-films, with no need for additional treatments or additives, from acidic media onto fluorine-doped tin oxide/glass (Cu@FTO) is described. The films involve elemental copper nanoparticles inside copper agglomerates of larger sizes. Within 2 h, at ambient potential (−1.8 V), the Cu@FTO electrode reduces aqueous nitrate ions (∼40%) more effectively than the benchmark bare Cu metal sheet (∼11%). The Cu@FTO is also more selective to N 2 production (∼30%) compared to bare Cu sheet with only (∼1.1%). Furthermore, the Cu@FTO effectively functions for 7 h and continues to bring down the nitrate ion concentration from 200 ppm to acceptable levels (less than 60 ppm), reproducibly in 5 attempts. The results are promising for future water de-nitration processes using easy-to-prepare Cu@FTO electrodes, aiming at producing electrodes for continuous flow reactors at larger scale.