dipping the catalyst substrate in the slurry with intermediate drying by holding at 200 u00b0 c for 30 minutes step 100 finally when a suitable catalyst loading is achieved the catalyst substrate and its perovskite coating are calcined for 5 hours at 700 u00b0 c again under an air flow of 100 sccm as indicated at step 110 however in this prior art method the catalytic activity of the perovskite on the catalyst support is decreased relative to the catalytic activity of the perovskite as first formed at step 60 while such theory is not relied upon it is speculated that some of the porosity inherent in the as formed perovskite is rendered ineffective by the washcoating process with consequent reduction in catalytic activity for example the addition of hno 3 at step 80 to promote adhesion of the washcoat may detrimentally affect catalytic performance thus it is desired to develop alternate simpler approaches to applying the perovskite to the catalyst support which maintain its high as formed catalytic activity practice of this invention illustrated in the flow diagram of fig3 is an improved approach to wash coating catalyst substrates for fabrication of perovskite catalysts this invention also exploits the beneficial attributes of the citrate process and steps 10 20.