High-efficiency electrocatalytic nitrite reduction toward ammonia synthesis on CoP@TiO2 nanoribbon array

Electrochemical reduction of nitrite (NO2-) can satisfy the necessity for NO2- contaminant removal and deliver a sustainable pathway for ammonia (NH3) generation. Its practical application yet requires highly efficient electrocatalysts to boost NH3 yield and Faradaic efficiency (FE). In this study, CoP nanoparticle-decorated TiO2 nanoribbon array on Ti plate (CoP@TiO2/TP) is verified as a high-efficiency electrocatalyst for the selective reduction of NO2- to NH3. When measured in 0.1 M NaOH with NO2-, the freestanding CoP@TiO2/TP electrode delivers a large NH3 yield of 849.57 μmol h-1 cm-2 and a high FE of 97.01% with good stability. Remarkably, the subsequently fabricated Zn-NO2- battery achieves a high power density of 1.24 mW cm-2 while delivering a NH3 yield of 714.40 μg h-1 cm-2.