Intersting idea, adding air to the exhaust to improve cat function. I assume a pump is required as ambient air would probably cool the cat too much and reduce its efficiency. By pressurizing it the air gets heated. Any good articles regarding this tech? Found one.
http://www.12v.org/engine/index.php?section=hw&sm=2nd
http://www.12v.org/engine/index.php?section=hw&sm=2nd