A structure comprising: a substrate including a first end, a second end, and a porous partition wall defining a plurality of cells extending between the first end and the second end; a first catalyst; and a second catalyst, wherein the plurality of cells include: a first cell opened on the first end and sealed on the second end; and a second cell adjacent to the first cell with the partition wall interposed between the second cell and the first cell, the second cell being sealed on the first end and opened on the second end, wherein the structure includes: a first area between the first end and a first position distant from the first end by a first distance along an extending direction of the plurality of cells; a second area between the first position and a second position distant from the first position by a second distance toward the second end along the extending direction of the plurality of cells; and a third area between the second position and the second end, wherein in the first area, the first catalyst is disposed on a first surface of the partition wall, the first surface facing the first cell, wherein in the second area, the first catalyst is not provided, the second catalyst is disposed in a region including at least a part inside the partition wall, the part facing the first cell, and the partition wall with the second catalyst disposed in the partition wall is permeable to gas, wherein in the third area, any of the first catalyst or the second catalyst is not provided, and the partition wall is permeable to gas, and characterized in that in the first area, the partition wall with the first catalyst disposed on the partition wall is impermeable to gas. a substrate including a first end, a second end, and a porous partition wall defining a plurality of cells extending between the first end and the second end; a first catalyst; and a second catalyst, wherein the plurality of cells include: a first cell opened on the first end and sealed on the second end; and a second cell adjacent to the first cell with the partition wall interposed between the second cell and the first cell, the second cell being sealed on the first end and opened on the second end, a first cell opened on the first end and sealed on the second end; and a second cell adjacent to the first cell with the partition wall interposed between the second cell and the first cell, the second cell being sealed on the first end and opened on the second end, wherein the structure includes: a first area between the first end and a first position distant from the first end by a first distance along an extending direction of the plurality of cells; a second area between the first position and a second position distant from the first position by a second distance toward the second end along the extending direction of the plurality of cells; and a third area between the second position and the second end, a first area between the first end and a first position distant from the first end by a first distance along an extending direction of the plurality of cells; a second area between the first position and a second position distant from the first position by a second distance toward the second end along the extending direction of the plurality of cells; and a third area between the second position and the second end, wherein in the first area, the first catalyst is disposed on a first surface of the partition wall, the first surface facing the first cell, wherein in the second area, the first catalyst is not provided, the second catalyst is disposed in a region including at least a part inside the partition wall, the part facing the first cell, and the partition wall with the second catalyst disposed in the partition wall is permeable to gas, wherein in the third area, any of the first catalyst or the second catalyst is not provided, and the partition wall is permeable to gas, and characterized in that in the first area, the partition wall with the first catalyst disposed on the partition wall is impermeable to gas.