University of Pittsburgh

Todd H Ballinger

John T Yates, Jr

Dilip K Paul

Mohamed I Zaki

A process for chemically converting surface hydroxyl groups present on an uminum oxide supported rhodium catalyst that is suitable for use as an automotive catalyst in controlling automotive exhaust emissions is disclosed. The process includes converting the hydroxyl groups on the aluminum oxide supported catalyst by reacting the aluminum oxide support with an alumina modifier which comprises an inorganic compound containing the cation Y, wherein Y is either an alkali metal or an alkaline earth metal. This process involves replacing the hydroxyl groups on the aluminum oxide support with OY groups to resist the oxidative conversion of supported metallic rhodium Rh.sub.x .sup.(O) to Rh.sup.(I). An associated catalyst suitable for use in automotive catalytic converter technology for environmental protection is provided.

Process for the inorganic chemical modification of rhodium alumina

A process for chemically removing surface hydroxyl groups present on an aluminum oxide supported rhodium catalyst that is suitable for use as an automotive catalyst in controlling automative exhaust emissions is disclosed. The process includes removing the hydroxyl groups from the aluminum oxide supported catalyst by silation at a temperature preferably equal to or greater than about 450 K so that the conversion of active metallic rhodium Rh.sub.x (0) to oxidized rhodium species Rh.sup.(I) cannot substantially occur by reduction of the active hydroxyl groups. The silation is carried out by exposing the aluminum oxide supported rhodium catalyst to a gas phase alkylhalosilane. Subsequent to the silation, evacuation of the alkylhalosilane treated aluminum oxide supported rhodium catalyst is effected to remove substantially all unreacted alkylhalosilane. An associated catalyst suitable for use in automotive catalytic converter technology for environmental protection is also provided.

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Pittsburgh, PA, United States of America

Todd H Ballinger