Bottom-up preparation of gold nanoparticle-mesoporous silica composite nanotubes as a catalyst for the reduction of 4-nitrophenol

Gold (Au) nanoparticle (NP)-mesoporous silica (SiO 2 ) composite nanotubes were prepared by a bottom-up approach, in which Au NPs were anchored to the inner wall of mesoporous SiO 2 tubular shells. In this composite, the agglomeration, exfoliation, and grain growth of Au NPs were restricted, and the loading and size of the catalyst NPs were easily tuned. The mesoporous shell, open ends, and one-dimensional passage of the SiO 2 nanotubes all promote the diffusion of reactants, which enhanced the catalytic efficiency of this composite in the reduction of 4-nitrophenol. The Au NP-mesoporous SiO 2 composite nanotubes also demonstrated good reusability, and no leaching or agglomeration of the Au NPs was observed during the catalytic reaction .