John Joseph Mooney (April 6, 1930 – June 16, 2020) was an American chemical engineer who was co-inventor of the three-way catalytic converter, which has played a dramatic role in reducing pollution from motor vehicles since their introduction in the mid-1970s.
While serving in the United States Army from 1955 to 1956, Mooney was assigned to a series of nuclear tests in the Pacific Ocean at Enewetak Atoll in the Marshall Islands, which included 17 atom bomb and two hydrogen bomb tests. Mooney was as close as 7½ miles from fission bomb tests.[1]
Mooney came to Engelhard in 1960, after graduate school, as a result of a connection made in an electrochemical engineering course. He worked at the company's Gas Equipment Division. Among his first tasks there were purification of hydrogen, purification and catalysis of ammonia into hydrogen and nitrogen and a process for using a ruthenium catalyst to produce hydrogen from liquid ammonia for the United States Air Force. As a result, the Air Force was able to easily supply hydrogen for weather balloons, since it was more efficient to ship liquid ammonia to distant locations than cylinders of gas.
The 1970 amendments to the Clean Air Act required significant reductions in hydrocarbon, carbon monoxide and nitrogen oxide emissions. The converters available at the time were oxidation catalysts, which could handle hydrocarbon and carbon monoxide, but were ineffective in reducing nitrogen oxides. Car manufacturers and catalyst companies were trying to develop a multiple step process that would address hydrocarbons and carbon monoxide in one process while reducing nitrogen oxides in another.
Chemist Carl D. Keith and Mooney with their team at Engelhard came up with the first production catalytic converter in 1973. The three-way catalyst developed by them allowed all three exhaust pollutants (hydrocarbon, carbon monoxide, and nitrogen oxides) to be remedied using a single catalyst bed. Their solution to addressing the variations in air/fuel mixtures was to combine rare-earth oxides and base metal oxide components in the catalyst together with Platinum and Rhodium in a ceramic honeycomb with tiny passages coated with the catalytic material. This design ensured that the oxygen needed in the reactions was absorbed when it was in excess and released when it was needed, allowing all three pollutants to be removed in a single catalytic component. The three-way catalytic converter reduces nitrogen oxides to nitrogen and oxygen, oxidizes carbon monoxide to carbon dioxide and oxidizes unburnt hydrocarbons to carbon dioxide and water.
