Rational Construction of Heterostructured Cu3 P@TiO2 Nanoarray for High-Efficiency Electrochemical Nitrite Reduction to Ammonia

Abstract

Electroreduction of nitrite (NO₂ ^- ) to valuable ammonia (NH₃ ) offers a sustainable and green approach for NH₃ synthesis. Here, a Cu₃ P@TiO₂ heterostructure is rationally constructed as an active catalyst for selective NO₂ ^- -to-NH₃ electroreduction, with rich nanosized Cu₃ P anchored on a TiO₂ nanoribbon array on Ti plate (Cu₃ P@TiO₂ /TP). When performed in the 0.1 m NaOH with 0.1 m NaNO₂ , the Cu₃ P@TiO₂ /TP electrode obtains a large NH₃ yield of 1583.4 µmol h^-1 cm^-2 and a high Faradaic efficiency of 97.1%. More importantly, Cu₃ P@TiO₂ /TP also delivers remarkable long-term stability for 50 h electrolysis. Theoretical calculations indicate that intermediate adsorption/conversion processes on Cu₃ P@TiO₂ interfaces are synergistically optimized, substantially facilitating the conversion of NO₂ ^- -to-NH₃ .

Keywords: Cu3P@TiO2 nanoarrays; ammonia synthesis; electrochemical nitrite reduction; heterostructures; theoretical calculations.