Structure Effect Of Rh-based Catalyst On The Synthesis Of C₂ Oxygenates From Syngas

By using microemulsion technique, a series of mono- and bi- components catalysts with the same loading but different particle sizes was synthesized. Particle size effect and Mn effect on CO hydrogenation to produce C₂ oxygenates were studied. It is observed that the catalysts prepared by microemulsion have a core-shell structure; and CO conversion and the selectivity to C₂ oxygenates increase with the particle size decrease when the Rh particle size is more than 3 nm, when particle size is less than 3 nm, both decreased along with the particle sizes.Over SiO₂ and MCM-41 supports with different pore sizes, a series of monometallic catalysts were prepared by traditional impregnation method with the same metal loading. Studies of support pore effect on rhodium particle sizes and morphology were carried out, as well as the Rh particle size effect on CO hydrogenation. It is found that Rh particles were limited inside the support pore and the size increases along with the pore sizes. CO activity, the selectivity to C₂ oxygenates and C₂ oxygenates yields all increase along with the particle sizes.