Surface Science

1. CO₂ activation on ultrathin ZrO₂ film by H₂O co-adsorption: In situ NAP-XPS and IRAS studies

   Publication date: January 2019

   Source: Surface Science, Volume 679

   Author(s): Hao Li, Christoph Rameshan, Andrey V. Bukhtiyarov, Igor P. Prosvirin, Valerii I. Bukhtiyarov, Günther Rupprechter

   Abstract

   Utilizing CO₂ as sustainable carbon source requires its activation by catalytically active oxides on which CO₂ can form different surface bound carbonaceous species. This may be promoted or even enabled by surface hydroxyl groups. We have investigated the interaction of CO₂ with a ZrO₂ model surface, i.e. a O-Zr-O trilayer grown on Pt₃Zr(0001), in the absence and presence of H₂O, employing in situ near ambient (atmospheric) pressure X-ray photoemission spectroscopy (NAP-XPS) and infrared reflection absorption spectroscopy (IRAS). Whereas room temperature exposure to pure CO₂ up to 3 × 10⁻² mbar did not induce any interaction with the ZrO₂ model surface, co-adsorption of CO₂ + H₂O resulted in the formation of various carbonaceous surface species. Apparently, in the presence of humidity (surface hydroxylation) CO₂ was activated on ZrO₂ at near ambient pressures. Combining NAP-XPS and IRAS allowed identifying the surface species, which were formate, dioxymethylene, formaldehyde and carbon. These species may be intermediates of upconverting CO₂ to methanol and highlight the ability of ZrO₂ as active support.

   Graphical abstract