PHOSPHORIC ACID COMPOSITION, ITS PRODUCTION AND CATALYST FOR REDUCTION DECOMPOSITION OF NOX USING THE SAME

摘要

PURPOSE:To obtain a compsn. suitable for a catalyst for reduction decomposition of NOx by adding an aq. soln. of phosphorus-contg. compd. to an aq. mixture of a Cu-contg. compd. and a Zr-contg compd. and controlling the mixture liquid to specified pH to precipitate a specified crystal phase. CONSTITUTION:A water-soluble Cu-contg. compd. [e.g. Cu(NO3)2] and a Zr-contg. compd. [e.g. ZrO(3)2.8H2O] are dissolved in water. Then, an aq. soln. of a phosphorus-contg. compd. (e.g. NH4H2PO4) is added to the mixture soln. and controlled to pH6+ or -0.5 to precipitate a specified crystal phase. This precipitate is heat-treated at 650-1050 deg.C for >=10 hours to obtain the catalyst for reduction decomposition of NOx having >=10m<2>/g BET specific surface area.