Experimental evidence for the influence of charge on the adsorption capacity of carbon dioxide on charged fullerenes

Abstract

We show, both experimentally and theoretically, that the adsorption of CO₂ is sensitive to charge on a capturing model carbonaceous surface. In the experiment we doped superfluid helium droplets with C₆₀ and CO₂ and exposed them to ionising free electrons. Both positively and negatively charged C₆₀(CO₂)_n^+/− cluster ion distributions are observed using a high-resolution mass spectrometer and they show remarkable and reproducible anomalies in intensities that are strongly dependent on the charge. The highest adsorption capacity is seen with C₆₀⁺. Complementary density functional theory calculations and molecular dynamics simulations provided insight into the nature of the interaction of charged C₆₀ with CO₂ as well as trends in the packing of C₆₀⁺ and C₆₀⁻. The quadrupole moment of CO₂ itself was found to be decisive in determining the charge dependence of the observed adsorption features. Our findings are expected to be applied for the adsorption of CO₂ on charged surfaces in general.