In situ XANES study of methanol decomposition and partial oxidation to syn-gas over supported Pt catalyst on SrTiO 3 nanocubes

•In situ XANES is used to study methanol decomposition and partial oxidation on a supported Pt catalyst.•The catalyst is made by ALD of Pt on a single crystal of SrTiO3 nanocube with Pt (111) nanoparticles on the surface.•The as-received catalyst and the reduced or oxidized catalyst all have activity but show different selectivity for H2, CO and CO2.•In situ XANES observed CO on Pt the only surface adsorption species during the reactions.•The study confirms that the mechanism only includes the breakage of C–H and O–H bonds.