Study on catalytic properties of Cu-Fe-MgO/AlPO₄-5 for hydrogen production from steam reforming of methanol

Cu-Fe-MgO/AlPO₄-5 catalysts were prepared by impregnation method using AlPO₄-5 molecular sieve as support to produce hydrogen through steam reforming of methanol. The catalysts were characterized by XRD, N₂ adsorption-desorption, H₂-TPR, CO₂-TPD and NH₃-TPD. The reaction results indicated that the addition of Fe could significantly increase the conversion of methanol, but the selectivity of dimethyl ether was also increased. The addition of MgO had obvious effects on the reduction of dimethyl ether formation, but the conversion of methanol could not be improved. The catalyst with Cu, Fe and MgO loadings of 15%, 6% and 1%, respectively showed a higher catalytic activity. Under the reaction conditions of 300℃, 1.1:1 of molar ratio of water to alcohol and 2.51 h^-1 of mass space velocity, the conversion of methanol was 93.08%, the selectivity of carbon dioxide and hydrogen were 95.80% and 96.93% respectively and the selectivity of by-products of carbon monoxide and dimethyl ether were 1.70% and 2.51% respectively. According to the characterization results, Cu-Fe-MgO/AlPO₄-5 contains weak acid and base sites, strong acid and base sites. It can be concluded that appropriate amount of MgO increases the amount of strong basic sites, reduces the strength of weak acidic sites, but had little effects on strong acidic sites.