Precious metal catalyst supported on a silicate; its use for selective oxidation of carbon monoxide and for hydrogen refining

摘要

Disclosed is a selective carbon monoxide oxidizing catalyst capable of selectively oxidizing CO contained in a gaseous mixture containing H2, CO and an oxidizing agent of O2, comprising a carrier and an active metal (2) consisting of at least one kind of metal selected from the group consisting of Pt, Pd, Ru, Rh and Ir and supported on the carrier, the carrier being a crystalline silicate (1) having the highest to the fifth highest peaks in the powder X-ray diffraction using CuKα ray in the lattice spacing of 3.65±0.1Å, 3.75±0.1Å, 3.85±0.1Å 10.0±0.3Å, and 11.2±0.3Å, and having the composition represented by formula (1) under a dehydrated state:

        (1±0.8)R2O · [aM2O3 · bNO · cAl2O3] · ySiO2     (1)


where R denotes at least one element selected from the group consisting of an alkali metal and H, M denotes at least one element selected from the group consisting of VIII group elements, rare earth elements, Ti, V, Cr, Nb, Sb and Ga, N denotes at least one element selected from the group consisting of Mg, Ca, Sr, and Ba, and the molar ratios a, b, c and y are: 0 ≦ a, 0 ≦ b ≦ 20, a+c=1, and 11 ≦ y ≦ 3000.