Probing the Surface Reactivity of Pyrogenic Carbonaceous Material (PCM) through Synthesis of PCM-Like Conjugated...

Pyrogenic carbonaceous matter (PCM) is redox-active and promotes both abiotic and biotic reactions in the environment, possibly as a result of its conductivity and phenolic/quinone functional groups. However, due to the complexity of PCM, the contribution of conductivity or phenolic/quinone functional groups to its redox activity is poorly understood, which hinders its potential engineering applications. Here, we synthesized tunable conjugated microporous polymers (CMPs) that possess key properties of PCM, which can be used as PCM analogues to provide insights to PCM reactivity. Specifically, controlled incorporation of phenolic moieties into CMPs during polymer synthesis affected electron-donating capacity, while carbonization of CMPs at various temperatures altered conductivity. Both properties were then correlated with PCM reactivity measured by the decay kinetics of a model pollutant trichloronitromethane. We demonstrate that some of the prepared CMPs enabled transformation of trichloronitromethane, while no decay was observed in the absence of CMPs. Results of further investigation suggest that trichloronitromethane decay occurs by reductive dechlorination, suggesting that CMPs are electron donors and the first dissociative electron transfer from CMPs was likely to be the rate-limiting step. Conductivity but not electron-donating capacity was positively correlated with CMP-mediated trichloronitromethane decay kinetics, suggesting an important role of the electron transfer kinetics at the interface for PCM-mediated transformation of environmental pollutants.