A completely automated temperature-programmed reaction (TPR) system for carrying out gas-solid catalytic reactions under atmospheric flow conditions is fabricated to study CO and hydrocarbon oxidation, and NO reduction. The system consists of an all-stainless steel UHV system, quadrupole mass spectrometer SX200 (VG Scientific), a tubular furnace and micro-reactor, a temperature controller, a versatile gas handling system, and a data acquisition and analysis system. The performance of the system has been tested under standard e_xperimental conditions for CO oxidation over well-characterized Ce_1−−x−y Pt_x(La/Y)_yO_2-δ catalysts. Testing of 3-way catalysis with CO, NO and C₂H₂ to convert to CO₂, N₂ and H₂O is done with this catalyst which shows complete removal of pollutants below 325°C. Fixed oxide-ion defects in Pt substituted Ce_1−y(La/Y)_yO_2−y/2 show higher catalytic activity than Pt ion-substituted CeO₂.