Producing Catalysts by Ion Implantation
A catalyst is a substance for which its presence changes the rate of a chemical reaction. These have been very useful in modern material science and chemistry as a way of creating and speeding up favorable reactions. A liquid or gas catalyst in a liquid or gas mixture can simply be mixed into the substance to obtain the desired effect. However, for a solid substrate, the catalyst must be either present in the lattice (structure) of the solid or coated on its surface. Generally, to add a catalyst to a lattice it must either be adding during the forming of a solid or chemically or mechanically applied to the surface. Coating and controlling the concentration of the catalyst on the surface of the base material may be difficult. Traditionally, adding the catalyst during the manufacturing stage or chemically applying it is the current cost effective and efficient way catalysts are attached to the surface of solids.
The problems faced with this approach are that by mixing in the catalytic material in the lattice there is an even amount of catalyst throughout the mixture. This means to get a set dosage at the surface the same concentration is required throughout the material. This in turn means that a great amount of catalytic material is completely wasted doing nothing on the inside of the solid. With chemical deposition, there may be waste and potentially more environmental risk since caustic and dangerous chemicals are often required. If, however, there were a way of adding an exact dosage of catalytic material to the surface of solid after it was manufactured without the use of chemicals there could be a great decrease in the production cost especially for costly catalyst materials.
Surface Engineering Technologies LLC has established the world’s first production scale Heavy Metal Ion Implanter, a device which can ionize and then accelerate metal atoms with enough energy to cause them to imbed permanently within the surface of a material. This allows the implanted metal to modify the properties of the base substrate, including catalytic properties, in a highly controlled process. While this will only open the door to metallic catalyst production, the potential applications for this technology are tremendous.
One example is in the production of fuel cell catalysts. Fuel cell technology may be improved by Metal Ion Implantation in two ways, efficiency of power generation and lowering the cost of production. There are three parts of a fuel cell which can be implanted to produce the necessary catalysts. The anode catalyst, which splits the hydrogen into ions and electrons, the cathode catalyst which turns the ions into waste material such as water and oxygen, and the membrane catalyst which allows for only positive ions to pass through. The membrane can also use a catalyst to help keep it hydrated. Ion implantation can lower the cost of the anode catalyst, platinum, by implanting only the necessary amount into the surface with low cost. It can lower the cost of the cathode catalyst, nickel, in the same way. The membrane could be implanted with platinum as well to lower the cost of production. It could also be implanted with silicon to keep the membrane hydrated to prevent cracking and deterioration of the polymer. The U.S Department of Energy estimates that fuel cell manufacturers will need to lower the amount of platinum by a factor of 4 to become more cost effective than the internal combustion engine. With ion implantation that should be possible.
Another use of catalysts by ion implantation is in the production of hydrogen itself. The Honda-Fujishima effect is a process in which UV sunlight is absorbed by a TiO2 plate tied to a platinum plate which when submerged in water spontaneously splits water into hydrogen and oxygen separately and it can be collected. The problems with this process are one, the cost of platinum in the catalyst and two the efficiency of the process only absorbing UV light. By implanting the platinum rather than using a pure piece we should be able to lower the cost greatly. Implanting in other metals may enable the TiO2 plate to readily absorb visible and IR sunlight. The effect of this could be a low cost and more efficient way of making hydrogen.
Catalytic converters for combustion engines currently contain about $30 worth of platinum. To get the same effective catalyst reaction by ion implanting in these elements we may be able lower this cost by a factor of 5-10, making the platinum cost for producing a catalytic converter $3-$6. Assuming every new car built contains this new catalytic converter, the estimated savings could be hundreds of millions of dollars per year for US automakers alone.
Metal ion implantation represents the latest technology in the field of nano-metallurgy and may provide a way of efficiently and effectively adding metallic catalysts to substrates for a much reduced cost. It represents billions of dollars in the way of savings and profits in just the fields mentioned above and for the catalysts discussed. There are very many uses for heavy metal implantation and as Surface Engineering Technologies LLC continues to develop its technology, we expect dramatic improvements in cost and function for many materials and mechanisms used in everyday life, and for the processes used to make them.
Director of Surface Engineering/R&D