High-efficiency electrosynthesis of ammonia with selective reduction of nitrite over an Ag nanoparticle-decorated TiO2 nanoribbon array

Abstract

Electrochemical nitrite (NO₂⁻) reduction can yield value-added ammonia (NH₃) while removing NO₂⁻ as an environmental pollutant in wastewater; however, it involves a six-electron transfer process and requires highly efficient and selective electrocatalysts. In this study, we report high-efficiency electrosynthesis of NH₃via NO₂⁻ reduction enabled by an Ag nanoparticle-decorated TiO₂ nanoribbon array on a titanium plate (Ag@TiO₂/TP). When tested in 0.1 M NaOH containing 0.1 M NO₂⁻, such Ag@TiO₂/TP shows a large NH₃ yield of 514.3 μmol h⁻¹ cm⁻² and a high faradaic efficiency of 96.4% at −0.5 V vs. a reversible hydrogen electrode. Significantly, it also demonstrates excellent durability for 12 h electrolysis.