Wang Suwen, Wu Zhaohui, Xu Cui, Jiang Shuai, Peng Hui-Qing, Zhang Wenjun, Liu Bin, Song Yu-Fei
State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing100029P. R. China.
Center of Super-Diamond and Advanced Films (COSDAF) & Department of Materials Science and Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China.
ACS Appl Mater Interfaces. 2022 Oct 12;14(40):45423-45432. doi: 10.1021/acsami.2c13286. Epub 2022 Oct 3.
The electrocatalytic reduction of CO is deemed to be a promising method to ease environmental and energy issues. However, achieving high efficiency and selectivity of CO electroreduction remains a bottleneck due to huge limitation of CO mass transfer and competition of hydrogen evolution reaction (HER) in aqueous solution. In this work, we propose to utilize triple-phase interface engineering over an InO electrode to enhance its CO reduction reaction (CORR) performance. Notably, distinguishing from other research studies (doping, defect introduction, and heterojunction construction) that regulate the nature of InO-based catalysts themselves, we herein tune interfacial wettability of InO using facile fluoropolymer coating for the first time. In contrast to the hydrophilic InO electrode [Faraday efficiency (FE) ∼ 62.7% and FE ∼ 24.1% at -0.67 V versus RHE], the hydrophobic fluoropolymer (taking polyvinylidene fluoride as an example)-coated InO electrode delivers a significantly enhanced FE of 82.3% and a decreased FE of 5.7% at the same potential. Upon combining contact angle measurements, density functional theory calculation, and ab initio molecular dynamics simulation, the enhanced CORR performance is revealed to be attributed to the rich triple-phase interfaces formed after fluoropolymer coating as an "aerophilic sponge", which increases the local concentration of CO near InO active sites to improve CO reduction and meanwhile reduces the accessible water molecules to suppress competitive HER. This work presents a feasible approach for the enhanced selectivity of HCOOH yield over InO by triple-phase interface engineering, which also provides a convenient and effective method for developing other materials used in gas-consumption reactions.
电催化还原CO被认为是缓解环境和能源问题的一种有前景的方法。然而，由于水溶液中CO传质的巨大限制以及析氢反应（HER）的竞争，实现CO电还原的高效率和选择性仍然是一个瓶颈。在这项工作中，我们提出在InO电极上利用三相界面工程来提高其CO还原反应（CORR）性能。值得注意的是，与其他调节InO基催化剂本身性质的研究（掺杂、引入缺陷和构建异质结）不同，我们在此首次使用简便的含氟聚合物涂层来调节InO的界面润湿性。与亲水性InO电极相比（相对于可逆氢电极，在-0.67 V时法拉第效率（FE）约为62.7%，FE约为24.1%），疏水性含氟聚合物（以聚偏二氟乙烯为例）涂层的InO电极在相同电位下的FE显著提高至82.3%，FE降低至5.7%。结合接触角测量、密度泛函理论计算和从头算分子动力学模拟，结果表明增强的CORR性能归因于含氟聚合物涂层后形成的丰富三相界面，其作为“亲气海绵”，增加了InO活性位点附近CO的局部浓度以促进CO还原，同时减少了可接触的水分子以抑制竞争性HER。这项工作提出了一种通过三相界面工程提高InO上HCOOH产率选择性的可行方法，也为开发用于气体消耗反应的其他材料提供了一种方便有效的方法。
