Carbon monoxide is oxidized to carbon dioxide in automobile catalytic converters. One proposed gas-phase pathway in the converter begins with a trace amount of NO2(g) already present in the exhaust stream.
Proposed mechanism at 600 K:
(a) Identify the species that functions as a catalyst in the mechanism above. Cite specific evidence from the sequence of elementary steps to support your identification.
(b) Using the mechanism, explain in detail how the catalyst is simultaneously consumed and regenerated so that its bulk concentration remains nearly constant despite participating in multiple elementary steps.
(c) Experimental rate studies at 600 K give the rate law rate = k[NO2][CO]. Explain why the catalyst concentration does not appear explicitly in this experimentally determined rate law even though the catalyst is essential for the observed rate enhancement.