Ni is known to be a catalyst for the Boudouad reaction
CO+CO ® CO2 + C
This reaction is favoured by high pressure and it thus escaped so far direct investigation under operando conditions. We report here about a Near Ambient Pressure XPS study performed at Soleil (Tempo Beamline).
Exposing bare Ni(111) to CO at a pressure PCO∼2 mbar we observed indeed graphene growth already at 550 K , a temperature significantly lower than the one (670 K) at which growth of graphene by segregation of dissolved carbon occurs.
It was recently shown  that the space between graphene and the substrate can act as a nano-reactor where the activation barrier for CO oxidation is effectively reduced. We show here that this is the case also for the Boudouard reaction.
Exposing single layer Graphene on Ni(111) to CO at 3.7 mbar, CO intercalates under the graphene layer causing its detachment from the substrate. The so obtained high local CO coverage under graphene cover enables the formation of CO2 via the Boudouard reaction catalysed by the Ni(111) surface already at 340 K. The carbon produced by the reaction is used to transform carbide into graphene. Moreover under such conditions a chemisorbed CO species above graphene is observed, thus paving the use of graphene as an active support in catalysis.
- Brief overview about chemistry under graphene cover
- Near Ambient pressure XPS study of the Boudouard reaction
- Growth of graphene by the Boudouard reaction using Ni as catalyst
- Graphene as an active support for catalysis