Control of Carbon Monoxide (CO) from Automobile Exhaust by a Dealuminated Zeolite Supported Regenerative MnCo₂O₄ Catalyst

We synthesized MnCo₂O₄ catalyst with very high porosity on the surface of dealuminated zeolite molecular sieves (DAZMS) for CO oxidation under actual automobile conditions. The MnCo₂O₄ catalyst was selected on the basis of preliminary DFT study using the software ADF BAND. The MnCo₂O₄ catalyst had comparatively higher CO adsorption energy and very low oxygen vacancy formation energy. The synthesized MnCo₂O₄/DAZMS catalyst was characterized by XRD, XRF, BET, SEM, and Confocal Microscopy. The Confocal microscopic analysis revealed that porosity of the dealuminated zeolite surface was significantly enhanced after the catalyst loading process. The completely precious metal free and DAZMS-supported catalyst exhibited excellent CO oxidation ability with renewed activity for seven months under actual automobile conditions with reference to normal and cold start conditions. The synthesized MnCo₂O₄/DAZMS not only exhibited surprisingly high catalytic activity for CO oxidation at a temperature resembling a cold start period but was also sufficiently stable/active under actual automobile conditions and ambient conditions containing large amounts of CO,H₂O,CO₂, and NO_x at 155–715 °C. These significant results revealed the flexible use of the present catalyst system for a wide variety of automobiles from a small gasoline-fuelled vehicle to a large diesel-fuelled vehicle that may produce high CO-content exhaust.