Supported porphyrins for the photocatalytic degradation of organic contaminants in water: a review

Porphyrins are differentiated pi-conjugated compounds with unique photochemical and redox properties. The tetrapyrrole macrocycle core of porphyrins is extremely favorable for the complexation of metal ions, resulting in hybrid metal-organic molecules with good photocatalytic properties. Over the years, porphyrins have been extensively tested as photocatalysts in advanced oxidative processes for the degradation of various organic contaminants in water. Recently, the use of porphyrins supported on solid materials is viewed as one of the most effective strategies to obtain photocatalytic systems with superior properties and applicability. Supported porphyrins can form highly organized hybrid materials, with high electron conductivity and great photoreaction properties. Here we review concepts, development, and application of supported porphyrins/metalloporphyrins. The first sections present an overview of the water contamination problem, the fundamentals of the photocatalytic treatment of water, and the main properties of porphyrins. The following sections focus on the application of supported porphyrins in the photodegradation of common organic contaminants in water. The last two sections discuss the main mechanisms and limitations.