Photo-Fenton mineralization of aquatic organic pollutants in visible-light-driven photocatalysis: Revisiting Fe3+ reduction and noble metal necessity

Abstract

The photo-Fenton process is an advanced oxidation technique that utilizes electrons photogenerated from a photocatalyst to activate hydrogen peroxide (H2O2), forming highly reactive hydroxyl radicals (center dot OH) capable of rapidly degrading organic pollutants. While noble metal co-catalysts are often introduced to facilitate charge separation and promote H2O2 activation, their use can increase the cost and complexity. In this study, hierarchically porous tungsten oxide (WO3) demonstrated enhanced photo-Fenton performance without the need for noble metals owing to its larger surface area and strong ferric ion (Fe3+) adsorption capacity. This facilitated efficient electron transfer from WO3 to Fe3+, promoting rapid ferrous ion (Fe2+) formation and subsequent center dot OH generation. Compared to commercial and unstructured WO3, porous WO3 achieved faster and more complete mineralization of isopropanol, a model organic pollutant. The system also exhibited broad reactivity toward various phenolic and non-phenolic contaminants, confirming its non-selective degradation capability. These findings highlight the importance of catalyst surface properties over noble metal loading in photo-Fenton re-actions and present a promising strategy for coupling electrochemically produced H2O2 for sustainable water treatment applications.