Exhaust gas cleaner and method of cleaning exhaust gas catalyst for cleaning exhaust gas

An exhaust gas cleaner comprising a heat-resistant, porous body and a catalyst supported by said body for cleaning an exhaust gas containing substantially no fine carbonaceous particles which is equivalent to an oxidizing atmosphere, said catalyst being a mixture consisting essentially of:

• (a) 10-80% by weight of one or more alkali metal elements selected from the group consisting of Na, K, Cs, Rb and Fr;
• (b) 10-80% by weight of copper;
• and
• (c) 10-80% by weight of one or more rare earth elements.

An exhaust gas cleaner comprising a heat-resistant, porous body, a first catalyst supported by said body on the inlet side, and a second catalyst supported by said body on the outlet side, for cleaning an exhaust gas containing substantially no fine carbonaceous particles, which is regarded as an oxidizing atmosphere, said first catalyst consisting essentially of:

• (a) one or more alkali metal elements;
• (b) one or more transition metal elements in Group IB, Group IIB, Group VB, Group VIB, Group VIIB, and Group VIII of the Periodic Table, excluding platinum-group elements, and Sn;
• and
• (c) one or more rare earth elements;
• and said second catalyst consisting essentially of at least one platinum-group element.

A catalyst for cleaning an exhaust gas containing substantially no fine carbonaceous particles, which is capable of removing nitrogen oxides from said exhaust gas regarded as an oxidizing atmosphere by utilizing unburned hydrocarbons contained in said exhaust gas as agents for reducing said nitrogen oxides, said catalyst being a mixture consisting essentially of:

• (a) 25-50% by weight of one or more alkali metal elements selected from the group consisting of Li, Na, K and Cs;
• (b) 25-50% by weight of one or more transition metal elements in Group IB, Group IIB, Group VB, Group VIB, Group VIIB and Group VIII of the Periodic Table, excluding platinum-group elements, and Sn;
• and
• (c) 25-50% by weight of one or more rare earth elements.

An exhaust gas cleaner comprising a heat-resistant, porous body, a first catalyst supported by said body on the inlet side and a second catalyst supported on the outlet side for cleaning an exhaust gas containing substantially no fine carbonaceous particles, which is equivalent to an oxidizing atmosphere, said catalyst being a mixture consisting essentially of:

• (a) 25-50% by weight of one or more alkali metal elements;
• (b) 25-50% by weight of one of more transition metal elements in Group IB, Group IIB, Group VB, Group VIB, Group VIIB, and Group VIII of the Periodic Table, excluding platinum-group elements, and Sn;
• and
• (c) 25-50% by weight of one or more rare earth elements;
• and said second catalyst consisting essentially of at least one platinum-group element.