In Situ Fourier Transform Infrared Spectroscopic Study of CO₂ Reduction on Polycrystalline Platinum in Acid Solutions

The reduction of CO₂ on polycrystalline Pt in 0.1 M HClO₄ has been investigated with in situ Fourier transform infrared reflection absorption spectroscopy and electrochemical techniques. Both methods have provided clear evidence that the reaction proceeds at potentials at which adsorbed hydrogen is also present on the surface. On the basis of the spectroscopic information it has been concluded that linear and bridge-bonded forms of adsorbed CO are the only detectable reduction products with the latter achieving saturation coverage well before the peak associated with linearly bonded CO reaches maximum intensity. Two similar CO bands have also been observed by other authors for CO₂ reduction on Pt in 0.5 MH₂SO₄ using the EMIRS technique. The low energy band, however, was ascribed by these authors to CO bound on 3-fold site.