Structural catalyst bodies are described herein which, in some embodiments, can be used in the treatment of nitrogen oxides present in exhaust or flue gases from stationary or mobile combustion sources. In some embodiments, a structural catalyst body described herein comprises an outer peripheral wall and a plurality of inner partition walls having an average thickness less than about 0.5 mm, the outer peripheral wall and the inner partition walls having dispersed throughout a chemical composition comprising 50-99.9% by weight an inorganic oxide composition, less than 3% by weight an inorganic extrusion aid and at least 0.1% by weight a catalytically active metal functional group comprising vanadium, the structural catalyst body having a crystalline vanadium pentoxide content less than 0.1 weight percent.