Therefore, it is vital to determine the structure-activity relationships that control the product selectivity as well as the reasons for the high overpotentials, so that enhanced catalysts can be rationally designed. In this talk, I will show a reaction mechanism obtained with DFT calculations for CO electroreduction to C2H4, CH3CHO, and CH3CH2OH on Cu(100) electrodes (3, 4). The mechanism proceeds via a (hydrogenated) CO dimer intermediate which can be observed experimentally (5). Based on the structure-activity relationships for Cu catalysts, I will explain the conspicuous preference of (100) terraces towards the production of C2 species such as C2H4 and CH3CH2OH. Importantly, such preference stems from the breaking of adsorption-energy scaling relations on Cu(100) (6).
Furthermore, the proposed mechanism predicts that the late stages of the electroreduction of CO to CH3CH2OH correspond to CH3CHO reduction (3, 4). Evaluating experimentally and theoretically the structure-activity relationships of CH3CHO reduction on various single-crystal Cu electrodes suggests that the selectivity of Cu catalysts towards CH3CH2OH or C2H4 can be tweaked by introducing certain undercoordinated sites (7).
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2. R. Kortlever, J. Shen, K. J. P. Schouten, F. Calle-Vallejo and M. T. M. Koper, The Journal of Physical Chemistry Letters, 6, 4073 (2015).
3. F. Calle-Vallejo and M. T. M. Koper, Angewandte Chemie International Edition, 52, 7282 (2013).
4. K. J. P. Schouten, F. Calle-Vallejo and M. T. M. Koper, Angewandte Chemie International Edition, 53, 10858 (2014).
5. E. Pérez-Gallent, M. C. Figueiredo, F. Calle-Vallejo and M. T. M. Koper, Angewandte Chemie, 129, 3675 (2017).
6. H. Li, Y. Li, M. T. M. Koper and F. Calle-Vallejo, Journal of the American Chemical Society, 136, 15694 (2014).
7. I. Ledezma-Yanez, E. P. Gallent, M. T. M. Koper and F. Calle-Vallejo, Catalysis Today, 262, 90 (2016).