Computational Investigation on Adsorption Facilitated Activation of CO2 on Fe2-7 Clusters.

In this article, we report a comprehensive computational investigation on the adsorption and activation of carbon dioxide (CO2) on the surface of small iron clusters, Fen (n = 2-7). The adsorption process in each system was investigated following a two-dimensional potential energy surface (2D-PES) scans. The calculated adsorption energies range between -57 and -112 kJ mol-1, indicating a strong and favorable binding. The most stable adsorption products were characterized with a bicoordinated bend CO2 moiety with two Fe-C bonds on the edge of the clusters. All Fen clusters have shown a barrierless CO2 adsorption process. The adsorption of CO2 on the Fe2-7 clusters resulted (a) ∼0.09 Å elongation of the CO bond lengths, (b) bending of the OCO bond angles ∼47°, (c) red-shifted νCO stretching frequencies ∼700 cm-1 and (d) significant reduction of CO bond strength and order. The strong adsorption and high activation of CO2 were attributed to charge transfer from the electron-rich iron clusters to the CO2. The results revealed the applications of small metal clusters for barrierless adsorption and efficient activation of CO2. These findings hold significance in the pursuit of efficient and economical catalytic processes for capturing and recycling CO2, thereby contributing to a sustainable future.