锡气体扩散电极上电化学还原二氧化碳制甲酸性能的稳定性

doi:10.11944/j.issn.1000-0518.2016.10.150467

摘要/Abstract

摘要：

研究了Sn气体扩散电极(SGDE)上电化学还原CO₂制甲酸(ERCF)性能的稳定性。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能量色散谱(EDX)和活性表面积测试等技术手段分别表征SGDE在电化学还原CO₂制甲酸过程前后的物相结构、表面形貌、元素组成和活性表面积。采用生成甲酸的法拉第效率(f_HCOOH)评价SGDE上电化学还原CO₂制甲酸的性能。结果显示,f_HCOOH随电解时间的延长急剧地降低,电解时间12 h的f_HCOOH((36.6±1.6)%)比电解时间0.5 h时的f_HCOOH((78.5±0.1)%)降低了53%。 SGDE在12 h电还原反应后,表面沉积了微量Fe,而且Sn含量(质量分数)减少了66%,活性表面积降低了41%。进一步的研究发现,沉积的微量Fe对电化学还原CO₂制甲酸过程基本没有影响,Sn含量和活性表面积的降低可能是SGDE上电化学还原CO₂制甲酸性能降低的主要原因。

关键词: 电化学还原, 二氧化碳, 甲酸, 锡气体扩散电极, 稳定性

Abstract:

The stability of Sn gas diffusion electrode(SGDE) for electrochemical reduction of CO₂ to formic acid(ERCF) was investigated. The crystal structure, morphology, chemical composition and active surface area of the SGDE were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and active surface area measurement, respectively. The Faraday efficiency of formic acid(f_HCOOH) was measured in order to evaluate the catalytic performance of ERCF over the SGDE. The results show that f_HCOOH decreases sharply with the electrolysis time. The f_HCOOH at the electrolysis time of 12 h((36.6±1.6)%) is 53% lower than that at 0.5 h((78.5±0.1)%). After the electrolysis of 12 h, trace Fe is deposited on the surface of the SGDE. In addition, the Sn content(mass fraction) and active surface area of the SGDE are reduced by 66% and 41%, respectively. Further examinations show that the deposition of trace Fe has no effect on ECRF and the degradation of the SGDE can be attributed to the reduction in the Sn content and active surface area.

Key words: electrochemical reduction, carbon dioxide, tin gas diffusion electrode, formic acid, stability

汪启年, 郑璐, 程庆宇, 梁阿芳, 孙晓文, 孙庆业. 锡气体扩散电极上电化学还原二氧化碳制甲酸性能的稳定性[J]. 应用化学, 2016, 33(10): 1189-1195.

WANG Qinian, ZHENG Lu, CHENG Qingyu, LIANG Afang, SUN Xiaowen, SUN Qingye. Stability of Tin Gas Diffusion Electrode for Electrochemical Reduction of Carbon Dioxide to Formic Acid[J]. Chinese Journal of Applied Chemistry, 2016, 33(10): 1189-1195.

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