Most urban air pollution is caused by automobiles, accounting for two-third of the pollution that harms individuals. The catalytic converter is most widely used for lowering engine exhaust emissions. The current study investigates the effect of metal oxide catalysts on the performance of modified catalytic converter. Wash coat slurry is prepared using metal oxide catalysts such as Al2O3(at a dosage of 50 g), and ZrO2(10, 20, 30, and 40 dosage levels) with ethanol alcohol at a ratio of 1:1, employing ultrasonication technique. The modified catalytic converter is tested on a 4-stroke, single-cylinder, diesel engine. The test results disclosed that the tailpipe emissions such as HC, CO, NOx, and Smoke are reduced by 60, 63.63. 56.95, and 58.27%, respectively, when compared to those without catalytic converter at full load conditions for A50Z40-E90 blend. From the above study, the modified catalytic converter is found to have the potential to reduce the diesel engine exhaust gases.