Polarized Active Pairs at Grain Boundary Boost CO 2 Chemical Fixation.

The chemical fixation of CO 2 as a C1 feedstock is considered one of the most promising ways to obtain long-chain chemicals, but its efficiency was limited by the ineffective activation of CO 2 . Herein, we propose a grain boundary engineering strategy to construct polarized active pairs with electron poor-rich character for effective CO 2 activation. By taking CeO 2 as a model system, we illustrate that the polarized "Ce 4+ -Ce 3+ -Ce 4+ " pairs at the grain boundary can simultaneously accept and donate electrons to coordinate with O and C, respectively, in CO 2 . By the combination of synchrotron radiation in situ technique and density functional theory calculations, the mechanism of the catalytic reaction has been systematically investigated. As a result, the CeO 2 nanosheets with a rich grain boundary show a high DMC yield of 60.3 mmol/g cat with 100% atomic economy. This study provides a practical way for the chemical fixation of CO 2 to high-value-added chemicals via grain boundary engineering.