Morphology control enriches active surfaces in metal oxides

Base transition-metal oxides are not sufficiently active at ambient temperature and are also severely deactivated by moisture presented in the feed stream when they are used for catalyzing low-temperature oxidation of CO, which is widely applied in cleaning air and lowering automotive emissions. The conventional spherical nanoparticles of metal oxides are usually constructed by truncated octahedron, surrounded by less active {111} and {001} planes that do not favor the presence of catalytically active sites for the oxidation reactions. Therefore, the active sites are often the surface defects located in the corners and edges of the spherical particles in heterogeneous catalysts. It is generally acknowledged that only the atoms on the sub-layers are easily exposed in these defects and thus contribute considerably to the catalysis.