Converting CO 2 to formic acid by tuning quantum states in metal chalcogenide clusters.

The catalytic conversion of CO 2 into valuable chemicals is an effective strategy for reducing its adverse impact on the environment. In this work, the formation of formic acid via CO 2 hydrogenation on bare and ligated Ti 6 Se 8 clusters is investigated with gradient-corrected density functional theory. It is shown that attaching suitable ligands (i.e., PMe 3 , CO) to a metal-chalcogenide cluster transforms it into an effective donor/acceptor enabling it to serve as an efficient catalyst. Furthermore, by controlling the ratio of the attached donor/acceptor ligands, it is possible to predictably alter the barrier heights of the CO 2 hydrogenation reaction and, thereby, the rate of CO 2 conversion. Our calculation further reveals that by using this strategy, the barrier heights of CO 2 hydrogenation can be reduced to ~0.12 eV or possibly even lower, providing unique opportunities to control the reaction rates by using different combinations of donor/acceptor ligands.