Nanorods assembly of mesoporous boehmite film on glass: an efficient catalyst for permanganate reduction to MnO2 nanoparticles

Nanorods assembly of mesoporous boehmite (gamma-AlOOH) films of thickness similar to 2 mm with a preferential crystallographic growth along < 020 > have been synthesized. The films have been deposited on glass substrates by dip-coating using aluminium tri-sec-butoxide derived AlOOH sols in presence of CTAB. CTAB allows assembly of colloidal particles (Al-O polynuclear species) into a rod shape and can be removed at 300 degrees C. TEM study of the heat-treated (300 degrees C) films reveals that the rod like (diameter 2.5 +/- 0.5 nm) boehmite nanocrystals are assembled in a disorder manner. BET analysis shows that the film has a surface area of 162 m(2) g(-1) with an average pore size of 3.3 nm. The average pore size of the film is also measured by SAXS and found to be 2.9 nm. These films show excellent catalytic activities in the reduction of KMnO4 to MnO2 nanoparticles (30-40 nm) in aqueous solution (pH similar to 7.0) at room temperature.