Determination of the Non-stoichiometric Value of Oxygen in the Compound Metal Oxide Ce_xZr_1-xO_2-δ

The compound metal oxide of CexZr1-xO2-δ was prepared by adding aq.ammonia to a mixed solution containing ceric nitrate and zirconium nitrate with polyacrylamide as dispersing agent.The precipitate was filtered by suction,dried at 110 ℃ and calcined for 2 h in air at 600 ℃.The powdery solid sample was dissolved in 3 mol·L-1 H2SO4,a definite and known amount of Fe2+ ion (in form of standard solution of Fe(NH4)2(SO4)2 solution) to reduce Ce4+ ion,and the excess amount of Fe2+ ion in the solution was titrated with standard K2Cr2O7 solution.The non-stoichiometric value of oxygen (δ) was calculated by the formula given.Value of RSD′s (n=6) found was 1.0%.Results found by this method were in conformity with those obtained by the thermogravimetry.