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Interfacial Engineering Promoting Electrosynthesis of Ammonia over Mo/Phosphotungstic Acid with High Performance
Author(s) -
Liao Wanru,
Qi Lu,
Wang Yanlei,
Qin Jingyu,
Liu Guangyong,
Liang Shijing,
He Hongyan,
Jiang Lilong
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202009151
Subject(s) - phosphotungstic acid , electrosynthesis , faraday efficiency , electrocatalyst , ammonia , catalysis , electrochemistry , materials science , carbon nanotube , yield (engineering) , reversible hydrogen electrode , selectivity , adsorption , inorganic chemistry , nitrogen , ammonia production , nuclear chemistry , chemical engineering , electrode , nanotechnology , chemistry , organic chemistry , working electrode , engineering , metallurgy
Abstract Electrochemical nitrogen reduction reaction (eNRR) is recognized as a promising approach for ammonia synthesis, which is, however, impeded by the inert nitrogen and the unavoidable competing hydrogen evolution reaction (HER). Here, a Mo‐PTA@CNT electrocatalyst in which Mo species are anchored on the fourfold hollow sites of phosphotungstic acid (PTA) and closely embedded in multi‐walled carbon nanotubes (CNT) for immobilization is designed and synthesized. Interestingly, the catalyst presents a high ammonia yield rate of 51 ± 1 µg h −1 mg cat. −1 and an excellent Faradaic efficiency of 83 ± 1% at −0.1 V versus RHE under ambient conditions. The concentrations of NH 4 + are also quantitatively calculated by 1 H NMR spectra and ion chromatography. Isotopic labeling identifies that the N atom of the formed NH 3 originates from N 2 . The controlled experiments confirm a strong interaction between Mo‐PTA and N 2 with an adsorption energy of 50.46 kJ mol −1 and activation energy of 21.36 kJ mol −1 . More importantly, due to CNT's gas storage and hydrophobicity properties, there is a fourfold increase in N 2 content. The concentration of H 2 O is reduced by more than half at the interface of the electrode. Thus, the activity of eNRR can be significantly improved with ultrahigh electron selectivity.