Catalyst for purifying exhaust gas of natural gas engine and preparation method thereof

The invention discloses a catalyst for purifying exhaust gas of a natural gas engine and a preparation method thereof. The catalyst consists of a carrier, a coating coated on the carrier and catalytic active components loaded on the coating, wherein the carrier of the catalyst is made of a honeycomb cordierite ceramic material, the coating is a mixture of activated alumina, a ceria-zirconia solid solution, a rare-earth oxide, an alkaline-earth metal oxide and a caking agent, and the catalytic active components include a platinum group metal and at least one transition metal composite oxide or one transition metal-rare earth composite oxide. Since the transition metal composite oxide or the transition metal-rare earth composite oxide has high oxidative activity for hydrocarbon, and the rare-earth and alkaline-earth metal oxide in the coating has good stabilization effect on the coating and the active components, therefore, the catalyst disclosed by the invention has high catalytic activity and stability for hydrocarbon compounds, the dosage of precious metal is greatly reduced, and the cost of the catalyst is lowered. Moreover, the catalyst can be used for purifying the exhaust gas of the natural gas engine, and besides, the catalyst can be also used for purifying the exhaust gas of automotive vehicles which take gasoline or liquefied petroleum gas as fuel.