A catalyst having a mixture of Ru and RuOx, wherein x is greater than 0 and equal to or less than 2, supported by a suitable metal oxide support material is suitable for the heterogeneous catalytic gas phase direct methane production from hydrogen and carbon dioxide at mild temperatures as low as 25 DEG C. and atmospheric pressure. Photo-methanation using such catalysts having photoexcitable support materials significantly increases the rate of methane production and the methane yield, yielding almost stoichiometrically quantitative amounts of methane according to the Sabatier reaction.