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

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.