Reconstruction of Rh nanoparticles in methanol oxidation reaction

Abstract

We have developed a new method based on both kinetic and thermodynamic control to tune the dimensions of Rh nanocubes (varied from 2 nm to 6 nm) and obtained Rh concaves (>10 nm). The prepared Rh nanocubes were loaded on SiO₂ as catalysts for the partial oxidation of methanol. Our results showed that the reaction has an induction period, and the catalyst activity changes with the time on stream, implying the possible change in active sites of the catalysts. A number of characterization methods were used to systematically investigate the catalysts before and after the reaction. It is concluded that the reconstruction of the catalyst surface occurred under reaction atmosphere and the increase in catalytic performance was due to the formation of highly active crystal planes and sites. Our results indicate that facet transformation exists in heterogeneous catalysis reactions, which accounts for some unexpected activity evolution during the reaction.