Provided is a catalyst system capable of removing perfluorinated compounds and nitrous oxide. An exhaust gas is heated in two stages through a heat exchange unit and applied to a heater unit. The heater unit generates a flame to heat the exhaust gas to a high temperature. A catalyst unit is directly connected to a heating space of the heater unit so the heated exhaust gas comes into contact with a catalyst, and the perfluorinated compounds and the nitrous oxide are decomposed in the catalyst unit.

Provided is a catalyst apparatus capable of removing perfluorinated compounds or nitrous oxide through a catalyst. A processing gas is introduced into a heat exchange unit, and an exhaust gas having a higher temperature than the processing gas discharged by a heat exchange action is supplied to a heating part. In the heating part, an exhaust gas capable of reacting with the catalyst may be formed through a simple temperature-raising operation, and the perfluorinated compounds or nitrous oxide are effectively removed by the catalyst unit.

A gas decomposition catalyst, a method of decomposing nitrous oxide gas by using the gas decomposition catalyst, and a scrubber system for decomposing nitrous oxide gas by using the gas decomposition catalyst. The gas decomposition catalyst includes a perovskite oxide host material containing a B element and represented by Formula 1, and at least one B element protruding particle derived from some or all of the B element, where the B element protruding particle has a shape in which a portion of the particle is fixed inside the perovskite oxide host material and another portion of the particle protrudes from the surface of the perovskite oxide host material:

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where A, B, B, x and y in Formula 1 are as described in the detailed description.