Traditionally, gold was considered a purely noble metal and of little value in the field of catalysts. It was only used to dilute other metals to lower their activity. However, at the end of the 20^th century, it was discovered that gold nanoparticles had a completely different behavior from bulk gold metal and could be used for a variety of catalytic conversions with remarkably high activity.

One of these catalytic conversions for which gold turned out to be very suitable is the direct epoxidation of propene. Propene oxide is currently produced via complex multi-step processes, with economic or environmental problems. Gold nanoparticles on a titanium containing support, however, can directly epoxidize propene in a single step. Unique in this oxidation reaction, is that the presence of hydrogen is essential. The common idea is that this is a bifunctional catalyst, with gold producing in-situ hydrogen peroxide and titanium using this to do the epoxidation.

Before this catalyst system can be used industrially, a number of problems need to be solved, like catalyst activity, stability and hydrogen efficiency. This presentation will give an introduction on gold catalysis, detail on the unique activity of gold in this epoxidation reaction system and present a mechanistic and kinetic study. The kinetic and mechanistic information will be used to present an approach on how this interesting reaction system can be develop further to become industrially feasible.

 

Xander Nijhuis is working as an associate professor in Catalysis Engineering in the Chemical Reactor Engineering group headed by Prof Jaap Schouten at Eindhoven University. He obtained PhD in 1997 and did a post-doctoral fellowship for five years afterwards in the group of prof. Jacob Moulijn at Delft University of Technology, where he worked on transient catalysis and structured catalysts.  From 2002 until 2006 he worked as an assistant professor in spectroscopy engineering in the group of prof Bert Weckhuysen  at Utrecht University. At the end of 2006, Xander moved to Eindhoven University.

Xander Nijhuis works on the interface between reactor engineering and catalysis. He currently has his own research group, consisting of 2 post-doctoral fellows, 8 PhD students and several M.Sc. students. Topics include microreactor technology, structured reactors, and novel catalyst development. One of the research focal points is gold catalysis for the direct epoxidation of propene. Currently he has over 80 papers published in international refereed journal, including 4 highly cited papers (>100 citations).