Patent ID: 8221693

Claim:
A two stage carbon monoxide preferential oxidation article, comprising a container, the container comprising: an article inlet for an inlet gas stream; an article outlet; an upstream chamber comprising a substrate having a plurality of channels that extend from the substrate inlet to the substrate outlet, wherein each of the channels is enclosed by the channel walls of the substrate; and the plurality of channels comprise a first group of channels which form a first upstream zone and a second group of channels which form a second upstream zone, wherein the channel walls of the first group of channels have an upstream Prox catalyst, and the channel walls of the second group of channels are substantially free of Prox catalyst; and wherein a first portion of the inlet gas stream passes through the first upstream zone as a first inlet gas stream and a second portion of the inlet gas stream passes through the second upstream zone as a second inlet gas stream; a single injection chamber having an O 2 injector for injecting an O 2 -containing gas to adjust the O 2 concentration of the inlet gas stream, wherein the single injection chamber is in fluid communication with the article inlet and the upstream chamber, wherein the injection chamber is the sole location for O 2 -containing gas injection; a downstream chamber comprising a downstream Prox catalyst, wherein the downstream chamber is in fluid communication with the article outlet; and a mixing chamber between the upstream and downstream chambers, wherein the mixing chamber is in fluid communication with the upstream and downstream chambers, and wherein the first inlet gas stream and the second inlet gas stream combine in the mixing chamber to form an intermediate gas stream.