电解质
法拉第效率
氧化物
氨生产
电化学
氨
催化作用
材料科学
相(物质)
化学工程
化学
分析化学(期刊)
无机化学
物理化学
电极
有机化学
色谱法
工程类
作者
Shiming Chen,Siglinda Perathoner,Claudio Ampelli,Chalachew Mebrahtu,Dangsheng Su,Gabriele Centi
出处
期刊:ACS Sustainable Chemistry & Engineering
[American Chemical Society]
日期:2017-07-20
卷期号:5 (8): 7393-7400
被引量:160
标识
DOI:10.1021/acssuschemeng.7b01742
摘要
Fe2O3-CNT samples are studied for the room-temperature electrocatalytic synthesis of NH3 from H2O and N2 in a gas–liquid–solid three-phase reactor. A 30 wt % iron-oxide loading was found to be optimal. The performances greatly depend on the cell design, where the possibility of ammonia crossover through the membrane has to be inhibited. The reaction conditions also play a significant role. The effect of electrolyte (type, pH, concentration) was investigated in terms of current density, rate of ammonia formation, and Faradaic efficiency in continuous tests up to 24 h of time on stream. A complex effect of the applied voltage was observed. An excellent stability was found for an applied voltage of −1.0 V vs Ag/AgCl. At higher negative applied voltages, the ammonia formation rate and Faradaic selectivity are higher, but with a change of the catalytic performances, although the current densities remain constant for at least 24 h. This effect is interpreted in terms of reduction of the iron-oxide species above a negative voltage threshold, which enhances the side reaction of H+/e– recombination to generate H2 rather than their use to reduce activated N2 species, possibly located at the interface between iron-oxide and functionalized CNTs.
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