Hydrogen Production by Gasification of Cellulose over Ni Catalysts Supported on Zeolites

Hydrogen production by cellulose gasification over Ni catalysts was investigated. The catalytic activity and the species of products were affected by the type of supports. The use of simple metal oxides as supports resulted in the formation of large quantities of dark-colored tar but avoided carbon deposition, whereas the use of zeolites as supports inhibited tar formation but promoted carbon deposition. The loading of Ce on zeolite enhanced the rate of gasification and partially inhibited carbon deposition. On the other hand, in most cases, higher reaction temperatures led to a greater quantity of hydrogen being formed, a higher rate of gasification, and less tar formation or carbon deposition. In this reaction, metallic Ni is likely to be an active site and there is a structure sensitivity of Ni and NiO crystallite: larger Ni crystallite favored hydrogen formation and inhibited tar formation, while larger NiO crystallite inhibited hydrogen formation and tar decomposition. Our results indicate that Ni/Ce/H-ZSM-5 catalyst is a promising candidate for this reaction, despite being slightly less effective than Rh/Ce/SiO2 catalyst, since Ni catalysts are cheaper.