CoO nanoparticle decorated N-doped carbon nanotubes: a high-efficiency catalyst for nitrate reduction to ammonia

Abstract

Ambient electrochemical NO₃⁻ reduction is emerging as an appealing approach toward eliminating NO₃⁻ contaminants and generating NH₃ simultaneously, but its efficiency is challenged by a lack of active and selective electrocatalysts. In this work, we report CoO nanoparticle decorated N-doped carbon nanotubes as an efficient catalyst for highly selective hydrogenation of NO₃⁻ to NH₃. In 0.1 M NaOH electrolyte with 0.1 M NO₃⁻, this catalyst is capable of achieving a large NH₃ yield of up to 9041.6 ± 370.7 μg h⁻¹ cm⁻² and a high faradaic efficiency of 93.8 ± 1.5%, with excellent durability. Theoretical calculations reveal the catalytic mechanisms.