| abstract |
There is disclosed a honeycomb structure whose outer peripheral portion is plugged, whereby the insulating properties of the structure itself can improve to further improve the insulating properties, and the temperature of an introduced gas can be raised. Furthermore, when a catalyst is loaded, the loaded catalyst can be activated in an early stage. Especially, also during cold start (the cold start of an engine), the temperature of the introduced gas is easily raised, and the loaded catalyst can easily be activated in the early stage. A plasma reactor is also provided which can generate a large amount of hydrogen and which has a high electrode durability. A honeycomb structure 1 includes a cell structural portion having partition walls 4 which connect one end face thereof to the other end face thereof to define a plurality of cells 3 as through channels of a gas, and cells 3 having plugging portions 9 which plug both the end faces of an outer peripheral portion 7 of the cell structural portion, and the cell area of the plugging portions 9 is 10% or more of the whole cell area. |