Nickel-cobalt alloy nanosheet-decorated three-dimensional titanium dioxide nanobelts electrodeposited on titanium...

Electrocatalytic nitrate reduction reaction presents a promising avenue for environmentally friendly ammonia (NH₃) synthesis and wastewater treatment. An essential aspect to consider is the meticulous design of electrocatalysts. This study explores the utilization of a Ni-Co alloy nanosheet-decorated three-dimensional titanium dioxide (3D-TiO₂) nanobelts electrodeposited on titanium meshes (Ni_xCo_y@TiO₂/TM) for efficient electrocatalytic NH₃ production. The optimized Ni₁Co₃@TiO₂/TM electrode achieves a significant NH₃ yield of 676.3 ± 27.1 umol h^-1 cm^-2 with an impressive Faradaic efficiency (FE) of 95.1 % ± 2.1 % in a 0.1 M KOH solution containing 0.1 M NO₃^- at -0.4 V versus the reversible hydrogen electrode. Additionally, the electrode demonstrates exceptional electrochemical activity for NH₃ synthesis in simulated wastewater, delivering an outstanding NH₃ yield of 751.6 ± 44.3 umol h^-1 cm^-2 with a FE of 96.8 % ± 0.4 % at the same potential of -0.4 V. Moreover, the electrode exhibits minimal variation in current density, NH₃ yields and FEs throughout the 24-h stability test and the 20-cycle test, demonstrating its excellent stability and durability. This study offers a straightforward electrodeposited approach for the development of 3D-nanostructured alloys as catalysts for NH₃ electrosynthesis from nitrates at room temperature.