Bondue Christoph J, Liang Zhiqin, Koper Marc T M
Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
J Phys Chem C Nanomater Interfaces. 2021 Apr 1;125(12):6643-6649. doi: 10.1021/acs.jpcc.0c11360. Epub 2021 Mar 18.
In this article, we investigate the poisoning reaction that occurs at platinum electrodes during the electrocatalytic hydrogenation of acetone. A better understanding of this poisoning reaction is important to develop electrocatalysts that are both active for the hydrogenation of carbonyl compounds and resilient against poisoning side reactions. We adsorb acetone to Pt(331), Pt(911), Pt(510), and Pt(533) (i.e., Pt[2(111) × (110)], Pt[5(100) × (111)], [5(100) × (110)], and Pt[4(111) × (100), respectively])) as well as Pt(100) single-crystal electrodes and perform reductive and oxidative stripping experiments after electrolyte exchange. We found that acetone adsorbs molecularly intact on all sites apart from Pt(100) terrace sites and can be stripped reductively from the electrode surface at a potential positive of hydrogen evolution. However, at Pt(100) terraces, acetone adsorbs dissociatively as carbon monoxide, which remains attached to the electrode surface and leads to its poisoning. Strikingly, dissociative adsorption does not occur on step sites with (100) geometry, which suggests that the dissociative adsorption of acetone is limited to Pt(100) terraces featuring a certain minimum "ensemble" number of freely available Pt atoms.
在本文中，我们研究了丙酮电催化氢化过程中铂电极上发生的中毒反应。深入了解这种中毒反应对于开发对羰基化合物氢化具有活性且能抵抗中毒副反应的电催化剂至关重要。我们将丙酮吸附到Pt(331)、Pt(911)、Pt(510)和Pt(533)（即分别为Pt[2(111)×(110)]、Pt[5(100)×(111)]、[5(100)×(110)]和Pt[4(111)×(100)]）以及Pt(100)单晶电极上，并在电解液交换后进行还原和氧化脱附实验。我们发现，除了Pt(100)台阶位点外，丙酮在所有位点上均以分子形式完整吸附，并且在析氢电位正向时可从电极表面被还原脱附。然而，在Pt(100)台阶上，丙酮以一氧化碳形式解离吸附，一氧化碳会一直附着在电极表面并导致其中毒。引人注目的是，在具有(100)几何形状的台阶位点上不会发生解离吸附，这表明丙酮的解离吸附仅限于具有一定最小“原子簇”数量自由可用铂原子的Pt(100)台阶。
