The catalytic conversion of carbon dioxide to synthetic fuels and
other valuable chemicals is an issue of global environmental and economic impact.
In this report we show by means of X-ray photoelectron spectroscopy in the millibar
range that, on a Ni surface, the reduction of carbon dioxide is indirectly governed by
the CO chemistry. While the growth of graphene and the carbide-graphene
conversion can be controlled by selecting the reaction temperature, oxygen is mainly
removed by CO, since oxygen reduction by hydrogen is a slow process on Ni. Even
though there is still a consistent pressure gap with respect to industrial reaction
conditions, the observed phenomena provide a plausible interpretation of the
behavior of Ni/Cu based catalysts for CO2 conversion and account for a possible
role of CO in the methanol synthesis process.
