Envirox™ CatCoat (Nano-Catalyst treatment for coating CDPF)
Envirox™ CatCoat is a unique, water-based formulation containing cerium oxide nanoparticles. The high surface area of the nanoparticles produces a highly active coating that rapidly oxidises soot in Catalysed Diesel Particulate Filters (CDPFs). The nano-catalyst particles in Envirox™ CatCoat are only 5-10nm wide. This creates an extremely large surface area where activity is maximised by its action as an ‘oxygen sponge’ – absorbing and releasing active oxygen species to react with soot. Envirox™ CatCoat is readily absorbed so it can be applied using normal manufacturing processes for coating automotive catalyst substrates.
DPFs work by trapping soot particles in tiny micron sized pores in the channel walls whilst the exhaust gases pass through. It is important for DPFs to be highly porous to be effective, so any pore blockage will damage performance and risk damage. Cerium oxide used in traditional washcoat catalyst systems for DOC and TWC is supplied in the form of micron size powders, which are then applied as slurries. The size of the cerium oxide particles in these powders makes them unsuitable for use in CDPF applications because they are too large and will block the pores in the channel walls. Pore blockage can lead to cracking and premature failure of the CDPF.
Using nanotechnology, scientists at Energenics have developed a breakthrough solution to this problem: Envirox™ CatCoat. This unique water based formulation provides nanoscale cerium oxide particles, synthesised to be small enough to coat the internal walls of a DPF without blocking pores. And because they are nanoscale the particles have a very high surface area available for catalytic activity.
Traditionally only precious metals such as Platinum and Palladium have been available to manufacturers wishing to apply catalytic coatings to soot filters. The cost of precious metals often limits the quantity that can be used in CDPFs which in turn limits the oxidation performance. Envirox™ CatCoat introduces the new cost-effective option of cerium oxide as a component of a catalyst coating for DPFs, allowing manufacturers to achieve higher performance within cost constraints.
Workshop treatment – Envirox™ CatCoat may also be applied as a treatment for DPFs in-service. It can ‘top up’ existing catalytic coatings which may have degraded and extend DPF lifetime. It can be included as part of a DPF cleaning process as a ‘Final Stage’ catalyst treatment which will provide protection against future soot blocking when the vehicle is returned to service.