Cr3C2 nanoparticles decorated carbon nanofibers for efficient nitrate reduction to ammonia at ambient conditions

Electrochemical nitrate (NO 3 − ) reduction is a promising approach to relieve nitrate pollution and produce value-added ammonia (NH 3 ), but efficient and durable catalysts are required due to the large bond dissociation energy of nitrate and low selectivity . Herein, we propose chromium carbide (Cr 3 C 2 ) nanoparticles loaded carbon nanofibers (Cr 3 C 2 @CNFs) as electrocatalysts to convert nitrate to ammonia. In phosphate buffer saline containing 0.1 mol L −1 NaNO 3 , such catalyst achieves a large NH 3 yield of 25.64 mg h −1 mg −1 cat. and a high faradaic efficiency of 90.08% at −1.1 V vs the reversible hydrogen electrode, which also shows excellent electrochemical durability and structural stability. Theoretical calculations reveal the adsorption energy for nitrate at Cr 3 C 2 surfaces reaches −1.92 eV and the potential determining step (*NO→*N) for Cr 3 C 2 hits a low energy increase of 0.38 eV.