Carbon Dioxide and Water Activation by Niobium Trioxide Anions in the Gas Phase

Abstract

Transition metals are important in various industrial applications including catalysis. Due to the current concentration of CO2 in the atmosphere, various ways for its capture and utilization are investigated. Here, we study the activation of CO2 and H2O at [NbO3]− in the gas phase using a combination of infrared multiple photon dissociation spectroscopy and density functional theory calculations. In the experiments, Fourier-transform ion cyclotron resonance mass spectrometry is combined with tunable IR laser light provided by the intracavity free-electron laser FELICE or optical parametric oscillator-based table-top laser systems. We present spectra of [NbO3]−, [NbO2(OH)2]−, [NbO2(OH)2]−(H2O) and [NbO(OH)2(CO3)]− in the 240-4000 cm-1 range. The measured spectra and observed dissociation channels together with quantum chemical calculations confirm that upon interaction with a water molecule, [NbO3]− is transformed to [NbO2(OH)2]− via a barrierless reaction. Reaction of this product with CO2 leads to [NbO(OH)2(CO3)]− with the formation of a [CO3] moiety.