Hierarchically pores carbon-covered alumina/TiO2 catalysts from particle stabilized foams

To develop a more efficient support for free titania nanoparticles, the processing of particle-stabilized wet foams into macroporous carbon-covered alumina (CCA) supports was investigated in this study. The prepared supports had hierarchical pore structures consisting of pores with average cell sizes less than 2 μm uniformly distributed on the walls of the macropores (>150 μm). Furthermore, the carbon coverage and thus the pore size could be effectively controlled by tuning the sucrose content in the precursor. In particular, the cell diameter of the CCA foams decreased from 500 to 150 μm with increasing sucrose content in the initial suspension from 10 wt.% to 40 wt.%. The hierarchical pore structures led to a strong adsorption capacity for organic dyes. Thus, the macroporous CCA/TiO2 catalysts showed about 16% higher photocatalytic degradation rates toward rhodamine B under ultraviolet light irradiation than do commercial free titania nanocatalysts.