This gold catalyst takes the crown for high activity and selectivity
By Tetsuo Satoh |
Gold catalysts have been shown to have superior activities for oxidation reactions, especially at low temperature, compared to other metal-based catalysts. But the high price of gold makes it necessary to develop Au catalysts with ever-higher activities, reducing the amount of Au needed. A promising step in this direction is a new type of catalyst developed by Professor Naoki Toshima and his research group at the Tokyo University of Science, Yamaguchi (Yamaguchi, Japan; www.ed.yama.tus.ac.jp/toshima), with support from Japans Science and Technology Agency.
The catalyst is a nano-cluster of gold and palladium with a crown-jewel (CJ) structure (CJ-Au/Pd NC). The group has developed a very simple procedure for synthesizing the CJ-Au/Pd NC in which reactive Pd atoms at the corners of the nanocluster are replaced by Au atoms. A nanocluster (1.8-nm dia.) with 135 Pd atoms and 12 Au atoms was produced, and the Au atoms arranged at the special positions that result in extremely high catalyst activities.
As a test reaction, the researchers studied the oxidation of glucose into gluconic acid — a widely used food additive. The CJ-Au/Pd NC was shown to have an activity 3.8 and 3.1 times higher than existing Pd and Au clusters, and the selectivity…