ITO@TiO2 nanoarray: An efficient and robust nitrite reduction reaction electrocatalyst toward NH3 production under ambient conditions

Ambient electrochemical nitrite ( NO 2 - ) reduction is viewed as an effective and sustainable approach for simultaneously removing NO 2 - and producing ammonia (NH 3 ). However, the complex multi-electron transfer steps involved in the NO 2 - reduction reaction ( NO 2 - RR ) lead to sluggish kinetics and low product selectivity toward NH 3 , underscoring the need for NH 3 synthesis electrocatalysts with high activity and durability. Herein, we report amorphous indium–tin oxide sputtered on a TiO 2 nanobelt array on a Ti plate (ITO@TiO 2 /TP) as a 3D NH 3 -producing catalyst for the NO 2 - . In 0.5 ​M LiClO 4 with 0.1 ​M NO 2 - , it shows greatly boosted NO 2 - RR activity toward NH 3 production, with excellent selectivity, achieving a large NH 3 yield of 411.3 ​μmol ​h −1 ​cm −2 and a high Faradaic efficiency of 82.6%. It also shows high durability for continuous electrolysis. A Zn ‐ NO 2 - battery with ITO@TiO 2 /TP cathode offers an NH 3 yield of 23.1 ​μmol ​h −1 ​cm −2 and a peak power density of 1.22 ​mW ​cm −2 .