30.05.2025 - 12:41:59

Neue Publikation in Materials Horizons

Relevanz von weniger stabilen Reaktionsintermediaten für die elektrochemische CO2-Reduktion

New concepts
The present manuscript focuses on resolving selectivity trends for the CO2RR over Ti3C2Tx MXene with different terminal groups, Tx, including *OH and *F adsorbates, using electronic structure theory calculations. The traditional approach in the community to understand selectivity in the CO2RR involves constructing thermodynamic free-energy diagrams for the different reaction channels, where only the most stable intermediate states are considered in the mechanistic analysis. In the case of the CO2RR over Ti3C2Tx MXene, this framework does not reproduce the experimentally observed selectivity trends. We demonstrate that less-stable intermediates and coadsorbates, which also lead to less-stable configurations, must be included in the analysis to determine selectivity trends that are consistent with experimental data. The inclusion of these new configurations, even if they are energetically less favorable, opens new reaction channels that are energetically more favorable and thus can change the activity and selectivity trends compared to the traditional approach. The presented concept of factoring less-stable intermediate states and coadsorbates into the mechanistic analysis based on adsorption free energies is not limited to the CO 2 RR or MXene systems, and we believe that the proposed framework will guide the design of improved materials for energy conversion and storage processes using computational methods.

Mehr:
https://pubs.rsc.org/en/content/articlepdf/2025/MH/D5MH00168D