Superior catalysts for selective catalytic reduction of nitric oxide. Quarterly technical progress report, 1 April--30 June 1994

Abstract

In the last Quarterly Technical Progress Report the authors reported the synthesis and (partial characterization) and SCR (Selective Catalytic Reduction of NO) activity for a delaminated Fe{sub 2}O{sub 3}-pillared clay (Fe{sub 2}O{sub 3}-PILC). The SCR activity for this PILC was substantially higher than that of the commercial-type V{sub 2}O{sub 5} + WO{sub 3}/TiO{sub 2} catalyst. During the past quarter, the authors first completed the characterization of the delaminated Fe{sub 2}O{sub 3}-PILC catalyst. Both physical characterization (micropore probing by adsorption and Moessbauer spectroscopy) and chemical characterization (by IR spectroscopy) were performed. Since the synthesis of this PILC sample was undertaken under a specific set of conditions and it is known that the PILC properties depend strongly on the synthesis conditions, they then proceeded to examine in a systematic manner the dependence of the catalytic properties of the PILC on its synthesis conditions. Four parameters in the synthesis were studied: Fe precursors, pH of the pillaring solution, concentration of the pillaring solution, and the starting clay. Finally, the effect of the Cr{sub 2}O{sub 3} promoter on the SCR activity of the pillar clay was studied. Results are reported.