Size and symmetry dependent CO2 activation on Tin [n = 4, 8, 13] cluster: an insight from first principle

This study presents a comprehensive analysis of four titanium (Tiₙ) clusters investigating their potential for CO₂ activation and conversion into valuable products such as formate, methanol, and methane. When the CO2 molecule adsorbed on bare Tin clusters it undergoes noticeable structural distortion, characterized by C–O bond elongation and O–C–O angle bending and charge transfer from the Tin clusters to the CO2 molecule is observed. Furthermore, a systematic analysis of adsorption energies, natural population analysis (NPA), projected density of states (PDOS), electrostatic potential (ESP) and free energy profiles was performed to elucidate the electronic interactions and thermodynamic feasibility of the process, These results demonstrates that all four clusters are suitable for the adsorption and activation of CO2, indicating their potential suitability as catalytic candidates for CO₂ conversion. Among these clusters, Ti₄-td exhibits the highest CO₂ adsorption energy, while Ti₄-planar (Ti₄-p) shows the lowest. Notably, the larger Ti₁₃ cluster exhibits a thermodynamic preference for methane formation, highlighting the role of cluster size in determining product selectivity. Their reactivity is governed primarily by structural symmetry and cluster size. These findings provide valuable insights for the developing an effective titanium-based cluster-catalysts for CO₂ reduction. The ability to selectively generate methane and methanol from CO₂ offers promising pathways for sustainable fuel production, addressing critical aspects of the global energy crisis and supporting the transition to cleaner energy solutions.