Production of hydrogen by steam reforming of methanol over copper-based catalysts: The effect of cesium doping

Abstract The catalytic production of hydrogen by steam reforming of methanol was investigated using samples of copper oxide supported on alumina (Cu/Al 2 O 3 ) and promoted with cesium (Cu-Cs/Al 2 O 3 ). The effects of cesium content and reaction temperature on the catalytic activity were investigated. The Cu-Cs/Al 2 O 3 catalysts exhibited higher activity and stability as compared to the undoped ones. The catalyst containing 2 wt% of cesium was the most active and at 300 °C the methanol conversion reached 94 mol% and the hydrogen selectivity 97 mol% with no detectable formation of CO. After an ageing treatment at 400 °C, methanol conversion was still close to 100% with the cesium-doped catalyst, while the undoped catalyst drastically deactivated. X-ray powder diffraction (XRD) and XPS measurements indicate that cesium prevents the reduction of copper oxide into metallic Cu, by the hydrogen produced, and inhibits the formation of CuAl 2 O 4 spinel upon thermal treatment.