2024/04/14 by Weixing Zhang, Yancai Yao, Ziyue Chen +3 · 4 citations
Chemical Engineering · Computer Science · #Ammonia Synthesis and Nitrogen Reduction #Opportunistic and Delay-Tolerant Networks #Caching and Content Delivery
paper · pdf · doi:10.1021/acs.est.4c00151
Electrocatalytic nitrate reduction to ammonia (NITRR) offers an attractive solution for alleviating environmental concerns, yet in neutral media, it is challenging as a result of the reliance on the atomic hydrogen (H*) supply by breaking the stubborn HO–H bond (∼492 kJ/mol) of H 2 O. Herein, we demonstrate that fluorine modification on a Cu electrode (F-NFs/CF) favors the formation of an O–H···F hydrogen bond at the Cu–H 2 O interface, remarkably stretching the O–H bond of H 2 O from 0.98 to 1.01 Å and lowering the energy barrier of water dissociation into H* from 0.64 to 0.35 eV at neutral pH. As a benefit from these advantages, F-NFs/CF could rapidly reduce NO 3 – to NH 3 with a rate constant of 0.055 min –1 and a NH 3 selectivity of ∼100%, far higher than those (0.004 min –1 and 9.2%) of the Cu counterpart. More importantly, we constructed a flow-through coupled device consisting of a NITRR electrolyzer and a NH 3 recovery unit, realizing 98.1% of total nitrogen removal with 99.3% of NH 3 recovery and reducing the denitrification cost to 5.1/kg of N. This study offers an effective strategy to manipulate the generation of H* from water dissociation for efficient NO 3 – -to-NH 3 conversion and sheds light on the importance of surface modification on a Cu electrode toward electrochemical reactions.