Photocatalytic Use of Porphyrin Based Functional Materials

Abstract

Porphyrin-containing materials have been often used in photocatalysis for chemical transformations such as hydrogen evolution, CO2 reduction, purification, sterilization, and photoelectrochemical conversion. Reactive oxygen species (ROS) including free radicals/electrons and singlet oxygen (1O2) generated by photosensitizers are known to undergo secondary reactions such as multiple organic transformations and degradation of a wide variety of contaminants. Specially, they are often used for decomposition of chemical warfare agents (CWAs) such as sulfur mustard gas, which is one of the most notorious and effective chemical weapons. Various photocatalysts have been developed with successful use of ROS in photooxidation reactions. For example, in photodegradation of 2-chloroethyl ethyl sulfide (2-CEES), a sulfur mustard simulant, and demonstrated a selective decomposition to 2-chloroethyl ethyl sulfoxide (2-CEESO). Note that overoxidation of 2-CEESO generates 2-chloroethyl ethyl sulfone (2-CEESO2, fully oxidized product) and becomes a highly toxic material. Therefore, selective oxidation of 2-CEES without generating 2-CEESO2 is considered an important process in the detoxification of sulfur mustard gas.In this presentation, photocatalytic application of porphyrin based materials including PIM, silica, MOF and nanofiber will be demonstrated. Although porphyrins are well-known photosensitizers for effective photocatalytic reactions, they often suffer from self-degradation. Incorporation of porphyrins into nano materials may prevent self-degradation, resulting in effective systems with a long lifetime.