Emission norms have become much more stringent to reduce emissions from vehicles. Diesel engines in particular are the predominant contributors to higher emissions. Diesel Oxidation Catalyst (DOC) in diesel engine catalytic converter systems is the crucial component in reducing harmful emissions such as Carbon Monoxide (CO) and unburnt Hydrocarbons (HC). DOCs often rely on expensive noble metals like platinum, palladium, and rhodium as catalyst materials. This significantly raises the cost of emission control units. The proposed idea is to explore MnO2-CeO₂ (Manganese Oxide, Cerium Oxide) as an alternative catalyst to traditional DOC materials. The goal is to deliver effective oxidation performance while reducing overall system cost. MnO2-CeO₂ catalysts are promising because of their good low-temperature activity, oxygen storage capacity, and redox behavior. These features are helpful for diesel engines that operate under various conditions. They improve the oxidation of CO and HC, even during cold starts or at lower exhaust temperatures. The catalyst was successfully synthesized and applied to a honeycomb substrate, resulting in a fabricated catalytic converter prototype. Quantitatively, the fabricated MnO₂–CeO₂ coated prototype demonstrated a 43% reduction in CO, 47% reduction in HC, 27% reduction in NOx, and 41% reduction in PM during low-temperature exhaust testing (150 – 400 °C) during testing on a 1.5 L diesel engine. The results were based on repeated experimental runs using an uncoated substrate as baseline. The work also focuses on material accessibility and environmental sustainability by using non-noble, widely available metal oxides. The hypothesis of this study is that a MnO₂–CeO₂ catalyst synthesized via co-precipitation can deliver meaningful low-temperature oxidation performance at significantly lower cost compared to PGM-based DOCs. Thus, the project contributes a significant step toward developing more accessible and sustainable emission control technologies for the automotive industry.