Catalytic activity of vanadium oxide catalysts prepared by electrodeposition for the selective catalytic reduction of nitrogen oxides with ammonia

A facile synthesis of nanostructured vanadium oxide catalysts grown inside a honeycomb ceramic filter by electrodeposition without heat treatment is reported. The prepared catalysts are investigated for a selective catalytic reduction (SCR) of nitrogen oxide (NO_x) with ammonia (NH₃) in the temperature ranges from 250 to 450 °C. The SCR test results indicate that the NO_x removal efficiency of the as-deposited sample is comparable to that of the sample heat treated at 600 °C as well as that of the sample prepared by conventional wash coating method. The nanostructured catalysts show similar NO_x removal efficiencies after several recycles. Both polycrystalline and amorphous phases co-exist in the electrodeposited V-oxide catalysts confirmed by X-ray diffraction and selective area electron diffraction. The V-oxide catalysts show stronger V=O bond peaks and higher ratio of V⁴⁺/V⁵⁺ and O_α/O_β on their surfaces as characterized by Raman spectroscopy and X-ray photoelectron spectroscopy.