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

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.