Theoretical Investigation of CO₂ Adsorption and Dissociation on Low Index Surfaces of Transition Metals

Abstract

Adsorption and dissociation processes of gas molecules on bulk materials and nanomaterials are essential for catalytic conversion of carbon dioxide (CO2). In this work, we systematically investigated the CO2 adsorption and dissociation on low index surfaces of different transition metals by Density Functional Theory (DFT) calculations. A comparison study demonstrates that the open surfaces (Fe(100), Ni(100), Ni(110), Rh(100), and Ir(100)) have stronger interactions with CO2 molecules than the close-packed surfaces. The order of energy barriers for CO2 dissociation is Fe(110), Ir(100) < Ru(0001), Rh(100), Co(0001), Ni(100) < Os(0001), Ni(111) < Ir(111), Rh(111), Ni(110) < Fe(100), Pt(111) < Cu(100), Pd(111) < Cu(111). The interaction order between the dissociative CO*, O* species and the surfaces is Fe(100) > Fe(110) > Ru(0001) > Os(0001) > Ir(100), Rh(100) > Ni(110) > Co(0001) > Rh(111), Ir(111) > Ni(100), Ni(111) > Cu(100) > Pt(111) > Cu(111), Pd(111). In addition, we found that the change trend of adsorption energy is consistent with that of charge transfer amounts from the low index surfaces to CO2. The Brønsted–Evans–Polanyi relation showed that the electronic effects of Ni(111) and Ni(110), Cu(111) and Cu(100) and the geometric effects of Fe(110) and Fe(100), Ir(111) and Ir(100) have great influence on the CO2 dissociation, which is closely related to cleavage of C–O in transition states. Our results may provide an insight into the design of highly efficient nanocatalysts for CO2-involved reactions.