The present invention relates to a compressed natural gas combustion and exhaust system comprising: (i) a natural gas combustion engine; and (ii) an exhaust treatment system, the exhaust treatment system comprising a intake for receiving an exhaust gas from the combustion engine and a catalyst article arranged to receive and treat the exhaust gas, wherein the catalyst article comprises: a substrate having at least first and second coatings, the first coating being free from platinum-group-metals and comprising a copper-containing zeolite having the CHA framework-type and the second coating comprising a palladium-containing zeolite, wherein the first coating is arranged to contact the exhaust gas before the second coating. The present invention further relates to a method and a use.

Disclosed in certain embodiments is a sulfur tolerant catalytic system that includes a catalytic material coated onto a substrate. Certain embodiments are directed to a method of preparing a sulfur-tolerant catalyst.

Disclosed in certain embodiments is a sulfur tolerant catalytic system that includes a catalytic material coated onto a substrate.

Disclosed in certain embodiments is a sulfur tolerant catalytic system that includes a catalytic material coated onto a substrate. Certain embodiments are directed to a method of preparing a sulfur-tolerant catalyst.

Disclosed in certain embodiments is a catalytic material comprising: an active precious metal component comprising platinum; a sulfur-tolerant support material comprising silica on zirconia; and a substrate having the catalytic material coated thereon.

Disclosed in certain embodiments is a catalytic material comprising: an active precious metal component comprising platinum; a sulfur-tolerant support material comprising silica on zirconia; and a substrate having the catalytic material coated thereon.

Disclosed in certain embodiments is a sulfur tolerant catalytic system that includes a catalytic material coated onto a substrate.