Platinum Metals Rev., 1995, 39, (1), 13
Nanocatalysis Uses Platinum-Rhodium Tip
Studying the atomic structures involved in catalysis under catalytic conditions is possible using the recently developed scanning tunnelling microscope (STM) that operates inside a reactor cell. This equipment has enabled the STM tip to pattern a surface and manipulate atoms. Researchers at the University of California, Berkeley, have suggested that the tip can be made to act catalytically to produce investigable surface reactions (B. J. Mclntyre, M. Salmeron and G. A. Somorjai, Science, 1994, 265, (5177), 1415-1418).
With a platinum-rhodium STM tip in a reactor cell and a propylene atmosphere ordered propylidyne structures were formed on the platinum surface. Carbon monoxide and propylene-hydrogen mixtures were introduced into the cell to observe the reaction, and characteristic clusters were seen after activation of the tip by short electric pulses. The catalytic action caused by the tip may be atomisation of hydrogen from the gas phase and hydrogenation of the carbon bonds of the clusters under it.
This method provides possible insights into atomic-scale structures and the kinetics of local catalytic activity, which presendy is only studied in an average way by more conventional tools.