Hydrogen production from the steam reforming of bioethanol over novel supported Ca/Ni-hierarchical Beta zeolite catalysts

Abstract This paper studies the H2 production via the steam reforming of a bioresource-derived ethanol mixture over supported Ca-modified Ni-hierarchical Beta zeolite catalysts. The results showed that the hierarchical Beta zeolite with rich pore structure could be synthesized in one step by using the new quaternary ammonium gemini cationic surfactant. The zeolite had bigger BET area and pore volume than the traditional Beta zeolite. The support plays a key role for the improve of catalytic behavior. The internal structure of the catalyst can be changed by introducing calcium and nickel ions into the synthesized zeolite at the same time through ion exchange. The interaction between active metal and the support would increase, so the dispersion of the active metal can be improved. The intermediate CO2 was efficiently absorbed by Ca in situ, which is an exothermic reaction and also help to provide the heat for the reactor. The adsorption of СО2 in situ transmitting the reversible reforming and water gas shift reactions to the products outside their conventional thermodynamic restrictions, which enhanced H2 production and permits high conversion to be attained. By using the method of gradient distribution of active metal in the support, the repeated catalytic effect similar to that of a hierarchical reactor was constructed, which showed excellent catalytic effect in low and medium high temperature bioethanol reforming to hydrogen. The experimental results show that when the reaction temperature is 350 °C, the 10Ni-MBeta(DI) catalyst maintains stable catalytic efficiency for continuous hydrogen production of 50 h via ESR, high hydrogen production and good stability.