Consecutive Reduction of Five Carbon Dioxide Molecules by Gas-Phase Niobium Carbide Cluster Anions Nb₃C₄^–: Unusual Mechanism for Enhanced Reactivity by the Carbon Ligands

Abstract

Studying the cleavage of the C�O bond during CO 2 activation at room temperature is highly significant for comprehending the CO 2 conversion processes. Herein, mass spectrometry experiments and density functional theory calculations indicate that the niobium carbide anions Nb 3 C 4 − can continuously convert five CO 2 molecules to CO under thermal collision conditions, while the other clusters with less carbon ligands Nb 3 C 1−3 − reduce fewer CO 2 molecules. Sizedependent reactivity of Nb 3 C 1−4 − cluster anions toward CO 2 is observed. Interestingly, the carbon atoms in Nb 3 C 4 − not only act as highly active adsorption sites for CO 2 but also serve as electron donors to reduce CO 2 . The stored electrons are released through a carbon−carbon coupling process. Our findings on the role of carbon ligands in enhancing transition metal carbide reactivity can offer new insights for designing active sites on catalysts with both high activity and selectivity.

Conversion of Carbon Dioxide into a Series of CBxOy– Compounds Mediated by LaB3,4O2– Anions: Synergy of the Electron Transfer and Lewis Pair Mechanisms to Construct B–C Bonds

“…For example, Nb 2 N 2 – and Nb 2 B – anions can reduce two and three CO 2 molecules, respectively. Both Nb 2 BN 2 – and RhTaC 2 – anions can reduce four CO 2 molecules consecutively, and even five CO 2 molecules are continuously converted into CO by the Nb 3 C 4 – cluster under thermal collision conditions . In addition, several studies involve transforming CO 2 into value-added products at room temperature.…”