A three-way catalytic converter is a crucial off-car purification device installed in the vehicle exhaust system. It converts harmful gases like CO, HC, and NOx emitted from the tailpipe into harmless carbon dioxide, water, and nitrogen through oxidation and reduction processes. As the high-temperature exhaust passes through the purification unit, the catalyst in the three-way converter enhances the reactivity of the CO, HC, and NOx gases, prompting them to undergo certain oxidation-reduction chemical reactions. CO is oxidized into colorless, non-toxic carbon dioxide at high temperatures; HC compounds are oxidized into water (H2O) and carbon dioxide; and NOx is reduced to nitrogen and oxygen. The three harmful gases are transformed into harmless gases, thereby purifying the vehicle exhaust.

Three-way catalytic converter, an essential off-vehicle purification device installed in the car exhaust system, converts harmful gases such as CO carbon monoxide, HC hydrocarbons, and NOx nitrogen oxides emitted from the tailpipe into harmless carbon dioxide, water, and nitrogen through oxidation and reduction reactions. As this catalytic converter can simultaneously convert three main harmful substances in the exhaust gas into harmless substances, it is named "three-way."