Denitration catalyst comprising a porous coating and process for producing them

a. Denitration catalyst comprising a porous coating and process for producing them. b. Producing a denitration catalyst comprising a porous coating by immersing a porous metal catalyst base in a coating bath containing silica, drying the catalyst base to form a support comprising a porous silica coating, immersion carrier in a solution containing an active component and drying the resulting support for fixing the active component on the support. c. Purifying the exhaust gas.