PT/RH/Y-STABILIZED-ZIRCONIA CATALYST FOR THE TREATMENT OF AUTOMOTIVE EXHAUST GAS

THE COST OF PLATINUM AND RHODIUM IN THE THREE-WAY CATALYST ACCOUNTS FOR A MAJOR FRACTION OF THE COST ASSOCIATED WITH TREATMENT OF AUTOMOTIVE EXHAUST. THEREFORE, STRIVING TO ACHIEVE A HIGHER LEVEL OF POLLUTANT REMOVAL BY INCREASING THE PLATINUM AND RHODIUM CONTENTS IN THE THREE-WAY CATALYST IS NOT ECONOMICALLY ATTRACTIVE. IN THIS RESEARCH, AN ALTER-NATIVE METHOD FOR ACHIEVING A HIGHER LEVEL OF POLLUTANT RE- MOVAL IS PROPOSED, IN WHICH BY USING YTTRIA-STABILIZED-ZIR- CONIA (YSZ) AS THE SUPPORT MATERIAL, INSTEAD OF ALUMINA USED AT THE PRESENT TIME, THE ACTIVITY OF THE THREE-WAY CAT-ALYST CAN BE NEARLY DOUBLED. IN PHASE I OF THE PROPOSED STUDY, THE MAGNITUDE OF THE BENEFICIAL EFFECTS OF YSZ AS A SUPPORT MATERIAL WILL BE STUDIED. PHASE II OF THE STUDY BE DEVOTED TO THE DEVELOPMENT OF A CONVERTER IN THE FORM OF A WASHCOATED LAYER OF YSZ ON A CONRDIERITE MONOLITH, WITH THE PLATINUM AND RHODIUM CRYSTALLITES DEPOSITED IN THE YSZ LAYER IT IS ANTICIPATED THAT THIS WORK WILL LEAD TO THE DEVELOP-MENT OF AN IMPROVED THREE-WAY CATALYST FOR THE TREATMENT OF AUTOMOBILE EXHAUST. THE CATALYST WILL ACHIEVE A SUBSTAN- TIALLY HIGHER LEVEL OF POLLUTANT REMOVAL FOR THE SAME CONCENTRATION OF ACTIVE METALS. FURTHER-MORE, THE OXYGEN-ION CON-DUCTING SUPPORT, WHICH IS RESPONSIBLE FOR THE ENHANCED PER- FORMANCE OF THE NEW CATALYST, WILL BE USED ONLY SPARINGLY. CONSEQUENTLY, THE NEW CATALYST WILL COST ESSENTIALLY THE SAME AS THE CURRENTLY-USED THREE-WAY CATALYSTS. HENCE, THE CATALYST IS EXPECTED TO BE READILY MARKETABLE.