In the fine chemical industry catalysts based on precious metals on activated carbon supports are frequently used because such systems exhibit interesting features with regard to their application. Activated carbons are stable in both acidic and basic media, which is not true for alumina or silica. Alumina as well as silica are dissolved at high pH and the former is also attacked at very low pH.

A very important point for the economic use of precious metal catalysts, especially highly loaded ones, is recovery, refining and recycling of the metal. This procedure is simplified by the use of carbon as support, for this material can be burnt off, leading to highly concentrated ashes that permit an economical recovery of the precious metal. This technology is also very effective from an ecological standpoint, for it does not produce large amounts of solid waste that need to be landfilled.

SEM picture of a wood based activated carbon.

To date, three forms of carbon are used as supports for precious metal catalyst manufacture to provide optimum properties and performance in the multitude of different applications exercised by the chemical industry. The most important carbon support material is activated carbon, followed by carbon black and graphite or graphitised materials. However, compared to the main stream applications of these carbons such as water and gas treatment, rubber production or refractories, their use as catalyst supports is almost negligible.