US Patent 7837953 Simplified article for carbon monoxide removal

Provided are improved carbon monoxide removal articles and processes for treating hydrogen gas streams to achieve very low threshold levels of carbon monoxide. The articles have a substrate with an inlet end, an outlet end, a length extending between the inlet end to the outlet end, wall elements and a plurality of cells defined by the wall elements. A first layer is deposited on the wall elements from the inlet end and extending at least partially toward the outlet end. The first layer has a preferential carbon monoxide oxidation catalyst. A second layer contains a methanation catalyst, and is deposited on at least part of the first layer from the outlet end. The second layer has a length that is about 10-70% of the substrate length.