Fe(TCNQ)2 nanorod arrays: an efficient electrocatalyst for electrochemical ammonia synthesis via the nitrate reduction reaction

Abstract

The electrochemical reduction of nitrate to ammonia (NO₃RR) catalyzed by metal organic frameworks (MOFs) is a promising and efficient method for reducing nitrate pollution in water while simultaneously producing a valuable product, ammonia. Herein, we report the 3D nanoarray architecture of the metal organic complex Fe-(tetracyanoquinodimethane)₂ Fe(TCNQ)₂ as an efficient electrocatalyst that exhibits a high ammonia yield rate of 11 351.6 μg h⁻¹ cm⁻² and faradaic efficiency (FE) of 85.2% at −1.1 V vs. RHE and excellent catalytic stability up to 2 days. The excellent catalytic performance is evaluated by ATR-FTIR spectroscopy and a series of control experiments. Density functional-based theoretical calculations are carried out to identify Fe–N₄ active sites in metal–organic network structures. This study showcases the advancement of transition metal-based organic frameworks as very effective electrocatalysts for the reduction of nitrate to ammonia (NH₃).