Degradation of methyl orange by dielectric films based on contact-electro-catalysis.

Contact-electro-catalysis (CEC) has been recently proposed for the effective degradation of methyl orange, but the reactivity of catalysts in the CEC process needs further investigation. Here, we have used dielectric films, such as fluorinated ethylene propylene (FEP), modified by inductively coupled plasma (ICP) etching with argon, to replace the previously employed micro-powder due to their potential scalability, facile recycling process, and possible lower generation of secondary pollution. It has been found that ICP creates cone-like micro/nano structures on the surface, and thus changes the contact angle and specific surface area. The value of the contact angle varies non-linearly with etching time and attains a maximum after 60 seconds of etching. Concurrently, an increased electron transfer is observed, as well as an enhanced degradation efficiency, thus suggesting a special role of the surface structure. Finally, KPFM measurements show a lower electron affinity at the summit of the nanocones. This observation suggests that the structures are endowed with higher charge transfer ability. In addition, this film-based CEC has been observed in several polymer materials, such as PET, PTFE, and PVC. We view this work as a stepping stone to develop CEC into scalable applications, based on film technologies.