Chemical Bond Changes and Automobile Pollution Control: The Mechanism of Bond Breaking and New Bond Formation in Catalytic Converters

This paper systematically reviews the mechanisms and technological advancements of catalytic converters designed to achieve the efficient conversion of automotive exhaust pollutants through targeted chemical bond cleavage and formation. Studies indicate that the breaking of NO bonds and subsequent formation of NN bonds at catalyst surfaces represent the core reaction pathways for nitrogen oxides (NOx) reduction. Conversely, the cleavage of CO bonds followed by the formation of O=C=O primarily governs carbon monoxide (CO) oxidation processes. Recently developed materials, including single-atom catalysts (SACs) and layered double hydroxides (LDHs), have significantly improved catalytic performance at lower temperatures and reduced dependence on noble metals through optimized bond activation pathways. Notably, Ru-CeO catalysts achieve complete NOCO conversion at 150C, while atomically dispersed Rh catalysts realize full NOx conversion at just 120C. Nonetheless, insufficient low-temperature catalytic activity and undesirable byproduct generation, particularly NO, remain significant technical challenges. Future research should integrate surface science and computational materials science to advance non-noble metal alternatives and develop intelligent control systems, thus enabling simultaneous progress in pollutant removal efficiency and carbon neutrality objectives.