Modulating the Electrode-Electrolyte Interface with Cationic Surfactants in Carbon Dioxide Reduction
Modulating the Electrode-Electrolyte Interface with Cationic Surfactants in Carbon Dioxide Reduction
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DOI：
10.1021/acscatal.9b00449
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发表时间：
2019-06-01
期刊：
影响因子：
12.9
通讯作者：
Thoi, V. Sara
中科院分区：
文献类型：
--
作者：
Banerjee, Soumyodip;Han, Xu;Thoi, V. Sara
铜是研究最多的用于CO2转化的电催化剂之一，因为其显著的形成高阶碳产物的能力。然而，导致高碳产品选择性的控制因素仍然是基础科学理解的主要障碍。在这项工作中，我们研究了阳离子表面活性剂的效用，以修改在电催化CO2还原（CO2 RR）的铜箔的选择性。我们表明，十六烷基三甲基溴化铵（CTAB）显着抑制析氢反应（HER），竞争性的平行反应CO2 RR此外，高表面活性剂浓度和长的烷基链长度提高选择性CO2 RR在NaHCO 3溶液。重要的是，电化学阻抗谱用于监测在不同的实验条件下，在CTAB的存在下的电极-电解质界面的演变。在我们广泛的电化学表征的基础上，我们提出阳离子表面活性剂在电化学双电层中积累，并有效地降低了HER的可用质子源。我们的方法提供了一种简便的策略来修改金属电极的表面反应性，对电催化具有广泛的影响。
Copper is among the most studied electrocatalyst for CO2 conversion due to its remarkable ability to form high-order carbon products. However, controlling factors that lead to high carbon product selectivity remains a major hurdle to fundamental scientific understanding. In this work, we investigate the utility of cationic surfactants to modify the selectivity of Cu foil in electrocatalytic CO2 reduction (CO2RR). We demonstrate that cetyltrimethylammonium bromide (CTAB) significantly suppresses the hydrogen evolution reaction (HER), a competitive parallel reaction to CO2RR In addition, high surfactant concentrations and long alkyl chain lengths enhance the selectivity for CO2RR in NaHCO3 solutions. Importantly, electrochemical impedance spectroscopy is used to monitor the evolution of the electrode-electrolyte interface in the presence of CTAB under varying experimental conditions. On the basis of our extensive electrochemical characterization, we propose that cationic surfactants accumulate in the electrochemical double layer and effectively lower the available proton sources for HER Our approach provides a facile strategy to modify the surface reactivity of metal electrodes with broad implications for electrocatalysis.