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

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 NH(3)via 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 mu mol 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.