Applied Surface Science, Vol.258, No.1, 448-455, 2011
Sol-gel based alumina powders with catalytic applications
The sol-gel process provides a new approach to the preparation of oxide materials and offers many advantages for making catalysts. Since homogeneous mixing can be achieved at the molecular scale, the chemical reactivity of the oxide surface can be greatly enhanced; thus powders with high surface area and optimized pore size distribution can be obtained at low temperatures. In the present work NiO/Al(2)O(3) sol-gel catalysts were obtained by simultaneous gelation of aluminium isopropoxide and nickel nitrate. A comparative study with pure sol-gel alumina was also realized. By physical-structural studies the changes induced by the introduction of the Ni precursor, before and after aluminium alkoxide hydrolysis were highlighted. The introduction of Ni at the beginning of the reaction favors gamma-Al(2)O(3) crystallization. When Ni is added at the end of reaction, it delays the alumina crystallization and induces the disorder of the lattice. The obtained Ni doped sol-gel derived alumina has been used as catalyst in the finished form for glycerol reforming to generate H(2) for fuel cell applications. Some evaluation results of Ni-doped alumina combined with TiO(2) in photocatalytic glycerol reforming reaction have been included. (C) 2011 Elsevier B. V. All rights reserved.
Keywords:NiO/Al(2)O(3) nanopowders;Sol-gel process;Structural study;Catalytic activity;Glycerol reforming