Saxena Apurv, Kapila Shubhender, Medvedeva Julia E, Nath Manashi
Department of Chemistry, Missouri University of Science & Technology, Rolla, Missouri 65409, United States.
Department of Physics, Missouri University of Science & Technology, Rolla, Missouri 65409, United States.
ACS Appl Mater Interfaces. 2023 Mar 9. doi: 10.1021/acsami.3c00488.
Copper cobalt selenide, CuCoSe, has been identified as an efficient catalyst for electrocatalytic CO reduction, exhibiting high selectivity for carbon-rich and value-added products. Achieving product selectivity is one of the primary challenges for CO reduction reactions, and the catalyst surface plays a pivotal role in determining the reaction pathway and, more importantly, the intermediate adsorption kinetics leading to C1- or C2+-based products. In this research, the catalyst surface was designed to optimize the adsorption of the intermediate CO (carbonyl) group on the catalytic site such that its dwell time on the surface was long enough for further reduction to carbon-rich products but not strong enough for surface passivation and poisoning. CuCoSe was synthesized through hydrothermal method, and the assembled electrode showed the electrocatalytic reduction of CO at various applied potentials ranging from -0.1 to -0.9 V vs RHE. More importantly, it was observed that the CuCoSe-modified electrode could produce exclusive C2 products such as acetic acid and ethanol with 100% faradaic efficiency at a lower applied potential (-0.1 to -0.3 V), while C1 products such as formic acid and methanol were obtained at higher applied potentials (-0.9 V). Such high selectivity and preference for acetic acid and ethanol formation highlight the novelty of this catalyst. The catalyst surface was also probed through density functional theory (DFT) calculations, and the high selectivity for C2 product formation could be attributed to the optimal CO adsorption energy on the catalytic site. It was further estimated that the Cu site showed a better catalytic activity than Co; however, the presence of neighboring Co atoms with the residual magnetic moment on the surface and subsurface layers influenced the charge density redistribution on the catalytic site after intermediate CO adsorption. In addition to CO reduction, this catalytic site was also active for alcohol oxidation producing formic or acetic acid from methanol or ethanol, respectively, in the anodic chamber. This report not only illustrates the highly efficient catalytic activity of CuCoSe for CO reduction with high product selectivity but also offers a proper insight of the catalyst surface design and how to obtain such high selectivity, thereby providing knowledge that can be transformative for the field.
硒化铜钴（CuCoSe）已被确定为一种用于电催化CO还原的高效催化剂，对富含碳且具有高附加值的产物表现出高选择性。实现产物选择性是CO还原反应的主要挑战之一，催化剂表面在决定反应路径方面起着关键作用，更重要的是，决定导致基于C1或C2 +产物的中间吸附动力学。在本研究中，对催化剂表面进行了设计，以优化中间CO（羰基）基团在催化位点上的吸附，使其在表面的停留时间足够长，以便进一步还原为富含碳的产物，但又不至于强到导致表面钝化和中毒。通过水热法合成了CuCoSe，组装电极在相对于可逆氢电极（RHE）为-0.1至-0.9 V的各种施加电位下均显示出CO的电催化还原。更重要的是，观察到CuCoSe修饰电极在较低的施加电位（-0.1至-0.3 V）下能够以100%的法拉第效率产生独家的C2产物，如乙酸和乙醇，而在较高的施加电位（-0.9 V）下则获得得到得到甲酸和甲醇等C1产物。对乙酸和乙醇形成的这种高选择性和偏好突出了这种催化剂的新颖性。还通过密度泛函理论（DFT）计算对催化剂表面进行了探究，C2产物形成的高选择性可归因于催化位点上最佳的CO吸附能。进一步估计，Cu位点显示出比Co更好的催化活性；然而，表面和次表面层上具有剩余磁矩的相邻Co原子的存在影响了中间CO吸附后催化位点上的电荷密度重新分布。除了CO还原外，该催化位点在阳极室中对于分别由甲醇或乙醇产生甲酸或乙酸的醇氧化反应也具有活性。本报告不仅说明了CuCoSe在CO还原方面具有高效催化活性且产物选择性高，还提供了对催化剂表面设计以及如何获得这种高选择性的恰当见解，从而为该领域提供了具有变革性的知识。
