Inverse opal catalysts

Chem.Mater.http://doi.org/pwp(2013)

Semiconductor oxides with inverse opal morphologies are of potential interest for catalytic applications because they exhibit advantageous structural characteristics such as ordered porosity and high surface areas. The porous structure can be used for metal nanoparticle immobilization, but controlling nanoparticle size and dispersion for heterogeneous catalysis has proved difficult. Now Colm O'Dwyer and co-workers report the preparation of three dimensionally ordered, porous tin dioxide (SnO₂) inverse opals using a simple synthesis approach that involves tin acetate precursors. The hierarchical structure of SnO₂ is porous on multiple length scales and can be functionalized with immobilized Pd nanoparticle assemblies. The dispersion of the nanoparticles is governed by weak ligand–metal and strong metal–oxide interactions. These SnO₂–Pd inverse opals show strong electrocatalytic activity for formic acid oxidation and improved catalytic performance for liquid phase synthesis via Susuki cross-coupling reactions. The enhanced catalytic performance is due to the porosity, which allows easier access to the catalytically active sites.