In adding steam to benzene, or C6H6, to generate hydrogen, the step that determines the reaction’s speed is not the benzene’s absorption onto the catalyst, but rather the first benzene bond that breaks, according to scientists at Pacific Northwest National Laboratory. The team further explored increasing the speed of the hydrogen-producing reaction by evaluating rhodium and iridium catalysts on a magnesium aluminum spinel support. Through experimental and computational studies, they found that small rhodium particles had a higher turnover efficiency than either larger rhodium particles or iridium. This research graced the cover of ACS Catalysis.
Read more: http://www.laboratoryequipment.com/news/2013/06/hydrogen-release-depends-bond-scission-not-absorption