Screening of TiO2-supported catalysts for selective NOx reduction with ammonia

In the present study, the catalytic activities of several TiO2-supported metal and metal oxide catalysts have been tested simultaneously for the selective catalytic redn. of nitrogen oxides with ammonia (NH3-SCR) using high-throughput-screening equipment. Two different series of various catalyst samples were evaluated for different feed gas compns., both with and without water, and before and after SO2 exposure. The first series of samples consisted of catalysts contg. a single metal or metal oxide (Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Rh, Ag, W, Ir, or Pt), including a com. SCR catalyst sample for comparison. Of the metals investigated in the first series, Cr, Mn, Fe, and Rh were found to have the most interesting catalytic properties, regarding activity and selectivity at high or low temps. A second series of samples were prepd. contg. combinations of the selected metals, and the results from the catalytic tests show a general trend of increased SCR activity at lower temps. when Rh is added to the multiple-metal samples. The results further indicate that it is possible to widen the active temp. window by combining different metals in the catalyst formulation