Tracing SO 2 Heterogeneous Oxidation Dual-Pathway via Hydrogen-Bond-Enriched Interfacial Radical Chemiluminescence

Le résumé fourni par la source

Elucidating the SO 2 heterogeneous oxidation mechanism at the gas–liquid interface is critical for understanding haze formation. However, the dominant pathways and the oxidant’s relative contributions remain ambiguous. This study developed a methodology that coupled a radical interfacial enrichment strategy with chemiluminescence (CL) detection, establishing a CL system capable of discriminating between the dissolved oxygen (DO) pathway and the non-DO oxidation pathway. By anchoring sorbic acid (SA)-functionalized Cr 3+ -doped ZnGa 2 O 4 nanoparticles (ZGC NPs) at the interface of SO 2 microbubbles, we constructed a highly efficient CL reaction interface with nanoscale characteristics. This design facilitated hydrogen-bond-driven spatial enrichment of SO 2 and its radical intermediates at the gas–liquid interface. The radical-enriched interface induced a highly sensitive CL signal from the ZGC-SA-SO 2 system, which displayed composite characteristics from both pathways. Deciphering the signals revealed that the heterogeneous oxidation mechanism of SO 2 evolved dynamically with concentration. The dependence on the DO pathway decreased as the concentration increased. Additionally, the proposed method has been successfully implemented in the monitoring of automotive exhaust SO 2 and the rapid assessment of food freshness. The generality of this approach was further demonstrated by the observable interfacial CL signals across various ZGC-type NPs-unsaturated fatty acid-SO 2 systems. This work not only deciphers the dynamic, oxidant-dependent mechanism of SO 2 oxidation but also establishes a universal platform for SO 2 gas detection under mild conditions.

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