Effect of noble metal on oxidative steam reforming of methanol over CuO/ZnO/Al2O3 catalysts

Noble metals of Pd, Pt, Ru and Rh were introduced into the CuO/ZnO/Al2O3(30/60/10) catalyst via incipient impregnation and co-precipitation methods to examine their effects on the oxidative steam reforming of methanol (OSRM). No obvious effect of Pd and even a negative effect of Pt were observed by incipient impregnation method. With co-precipitation, noble metals were homogeneously dispersed in CuO/ZnO/Al2O3(30/60/10) and interacted with CuO and ZnO. They improved the reducibility of the catalysts and enhanced the dissociative adsorption of methanol. Introducing Pd, Rh or Ru promoted the conversion of methanol, but enhanced the formation of CO. Depositing platinum exhibited a high conversion of methanol and a low selectivity of CO in the OSRM reaction. The promoting effect of noble metals involved facilitating the split and adsorption of H atoms during the dehydrogenation of the intermediates in OSRM.

► The reducibility of CuO/ZnO/Al2O3(30/60/10) catalysts was promoted by noble metals.
► Noble metals enhanced the dissociative adsorption of methanol on the catalysts.
► Noble metals promoted the split of H atoms of the intermediates in the OSRM.
► Pd, Rh or Ru promoted the conversion of methanol but increased the CO selectivity.
► Pt was the best dopant with a high methanol conversion and a low CO selectivity.