Premium
Molecular Crowding Effect in Aqueous Electrolytes to Suppress Hydrogen Reduction Reaction and Enhance Electrochemical Nitrogen Reduction
Author(s) -
Guo Ying,
Gu Jinxing,
Zhang Rong,
Zhang Shaoce,
Li Zhen,
Zhao Yuwei,
Huang Zhaodong,
Fan Jun,
Chen Zhongfang,
Zhi Chunyi
Publication year - 2021
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202101699
Subject(s) - electrolyte , electrochemistry , aqueous solution , inorganic chemistry , redox , catalysis , chemistry , kinetics , yield (engineering) , materials science , electrode , organic chemistry , physics , quantum mechanics , metallurgy
The H 2 evolution reaction (HER), one of the most intractable issues for the electrochemical N 2 reduction reaction (NRR), seriously hinders NH 3 production selectivity and yield rate. Considering that hydrogenation reactions are essential to the aqueous NRR process, acidic electrolytes would be an optimum choice for NRR as long as the proton content and the HER kinetics can be well balanced. However, there is a striking lack of strategies available for electrolyte optimization, i.e ., rationally regulating electrolytes to suppress HER and promote NRR, to achieve impressive NRR activity. Herein, a HER‐suppressing electrolytes are developed using hydrophilic poly(ethylene glycol) (PEG) as the electrolyte additive by taking advantage of its molecular crowding effect, which promotes the NRR by retarding HER kinetics. On a TiO 2 nanoarray electrode, a significantly improved NRR activity with NH 3 Faraday efficiency (FE) of 32.13% and yield of 1.07 µmol·cm −2 ·h −1 is achieved in the PEG‐containing acidic electrolytes, 9.4‐times and 3.5‐times higher than those delivered in the pure acidic electrolytes. Similar enhancements are achieved with Pd/C and Ru/C catalysts, as well as in an alkaline electrolyte, demonstrating a universally positive effect of molecular crowding in the NRR. This work casts new light on aqueous electrolyte design in retarding HER kinetics and expediting the NRR.