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.