text: The following reactions describe the methanation of carbon monoxide and carbon dioxide respectively:
  :  -206 kJ/mol
  :  -164 kJ/mol
  The methanation reactions are classified as exothermic and their energy of formations are listed.
  There is disagreement on whether the CO methanation occurs by first associatively adsorbing an adatom hydrogen  and forming oxygen intermediates before hydrogenation or dissociating and forming a carbonyl before being hydrogenated. CO is believed to be methanated through a dissociative mechanism where the carbon-oxygen bond is broken before hydrogenation with an associative mechanism only being observed at high H concentrations.
  Methanation reaction over different carried metal catalysts including Ni, Ru and Rh has been widely investigated for the production of CH from syngas and other power to gas initiatives. Nickel is the most widely used catalyst due to its high selectivity and low cost.