Chelating agent effects in the synthesis of supported Ni nanoparticles as catalysts for hydrogen production

Abstract

A series of Ni supported over MgAl2O4–CeO2 catalysts have been prepared by the wet impregnation method as catalysts for steam ethanol reforming. The synthesis was performed using nitrilotriacetic acid (NTA) or citric acid (CA) as chelating agents (L) with different L/Ni molar ratios. The features of catalytic solids were determined by DR–UV–Vis–NIR, FTIR, BET, TGA, XRD, H2–TPR, XPS, Raman, HRTEM and SEM. Changes in the crystallite size of NiO and CeO2 were evidenced with the use of NTA, while the addition of CA allowed to reduce the crystallite size of NiO and Ni with a slight effect in CeO2 size. The use of chelating agents induced changes in the Ni-CeO2 interactions and an increase in the Ce/Ni0 surface ratio. Catalytic systems prepared using an L/Ni ratio leading to the most stable complex formation (NTA/Ni=1 and CA/Ni=2) exhibited the best performances in the reforming reaction under the operation conditions studied.