Heterogeneous catalytic system
One of our researching interests is to involve exploratory synthetic, structure, and reactivity studies on heterogeneous catalytic system with an ultimate goal of developing practical catalysts for specific chemical transformations.
1. Skeleton isomerization of n-alkane:
Under the worldwide trend for safer and cleaner process, the conventional catalysts such as corrosive liquid acids and metal halides have to be replaced by the more environmental friendly halide-free solid acid catalysts. Zirconia based solid acids, sulfated zirconia and tungstated zirconia , have thus received increasing attentions and great potential application. Recently, our group has found that the addition of an optimum amount of main group metals, such as Al or Ga, onto the sulfated zirconia or tungstated zirconia, in various morphologies, give rise to a catalyst which is much more activate at relatively milder temperatures than the corresponding unpromoted one. To obtain further information, a variety of spectroscopic instruments had been used to optimize synthetic conditions, to measure reaction mechanism, and to invent new catalysts.
2. CO oxidation:
Supported gold catalysts have been extensively investigated for CO oxidation. It has been found that the catalytic activity of gold is remarkably sensitive to the size of the gold particles and the nature of its support. Generally knowing, the electron transfer form metal to O 2 is a key factor for the chemisorption of oxygen on a metal surface. Unfortunately, electron transfer is difficult on a gold surface, since the gold surface has a high work function. Relative to gold, copper and silver have a larger electron-donating ability. On the other hand, both gold and copper are able to adsorb CO, but silver is not. Thus, in our recent work we combined gold with silver and prepared a series of Au-Ag alloy catalysts supported on MCM-41. The mesoporous support helps the dispersion of nanoparticles of Au-Ag alloy, and facilitates the transport of molecules. We demonstrated a novel efficient catalyst Au-Ag alloy catalyst with exceptionally high activity for CO oxidation at low temperature.