Ceramic platinum catalyst
This catalyst is best suited if the hydrogen peroxide concentration is above 90%, as silver catalysts may melt at the temperature generated by high concentration peroxide. The catalyst is not poisoned by phosphorous containing stabilizers present in technical grades hydrogen peroxide as is the case with silver catalysts. The activity is also higher, but the durability is not as long as solid silver wire catalysts.
The catalyst is made of a stainless steel wire screen, 12 x 12 mesh. The screen is plasma coated with a quite solid and high strength ceramic coating. The bond between the plasma coating and the steel is very strong.
A porous ceramic wash coating layer is applied on top of the plasma coating and platinum is applied. The wash coating has a strong bond to the plasma coating, but the porous layer still tends to wear off over time at usage. We have varied the wash coating to increase the durability and activity. The platinum content has also been varied in order to find the most optimal content.
The experience so far of the present version of the catalyst is that it is more active than both solid silver catalysts and silver plated nickel screens. It also gives a lower pressure drop.
We have studied the surface of the catalyst under a microscope, and it's obvious that there is a large surface area present, especially under 2,000 times magnification.
Real life experiences
This catalyst is not just a desk product, it is in use by several satisfied customers at this time.
The catalyst is currently used in a rocket belt. The catalyst is switched out already after every 12 to 15 flights (about 6 minutes total), but this is not because the catalyst is deactivated, but the switch is done premature to guarantee the performance at the public shows witnessed by big audiences and media.
The catalyst is also used in our prototype rotor tip rocket system. The cross section load in this application is high because the catalyst package is long with a small diameter. Still, the activity is maintained after about 20 minutes operation, so far. The first 15 % of the cat. pack. length is silver screens. The down stream 85 % is the ceramic Pt catalyst. I believe the silver screens are protecting the ceramic screens from wearing out.
The catalyst is also used in a lunar lander prototype with 2,000 lbs thrust in a combination with silver screens. So far it has been fired up a few times for testing purposes with great success.
The thickness of the screen is 1.4 mm, so fewer screens are needed than when using silver screens. The diameter can also be smaller, thanks to the higher activity and lower pressure drop.
This article was updated on September 12th, 2007