A NiCo alloy particle-decorated TiO2 nanoarray as an efficient electrocatalyst for nitrite reduction to ammonia

Abstract

Electrocatalytic nitrite (NO₂⁻) reduction (NO₂⁻RR) is a potential environmentally friendly method for producing NH₃ efficiently. Herein, a hybrid catalyst with NiCo alloy particles uniformly decorated on a TiO₂ nanograss array (NiCo–TiO₂) is reported to display excellent NO₂⁻RR performance. In alkaline media, NiCo–TiO₂ possesses a large NH₃ yield of 18 736.2 μg h⁻¹ cm⁻² at −0.4 V vs. RHE and a maximum FE of 97.5%. Utilizing NiCo–TiO₂ as the cathode of a Zn–NO₂⁻ battery, it exhibits remarkable peak power density (6.49 mW cm⁻²) and a large NH₃ yield (1911.4 g h⁻¹ cm⁻² at 20 mA cm⁻²). This work highlights the potential of catalysts based on alloy-metallic oxide hybrids for the electrochemical conversion of the NO₂⁻ pollutant into NH₃.