Pt coupled ZnFe2O4 nanocrystals as a breakthrough photocatalyst for Fenton-like processes - photodegradation treatments from hours to seconds

A stable magnetically recyclable extraordinary photocatalyst for Fenton-like processes, Pt coupled ZnFe2O4 nanocrystals (Pt/ZnFe2O4), was developed, which makes possible the shortening of photodegradation treatment times from hours to seconds. Pt/ZnFe2O4 nanocrystals (NCs) were prepared by simply mixing ZnFe2O4 NCs with Pt NCs, produced by a carrier solvent assisted interfacial reaction process and a polyol process, respectively. The extraordinary organic pollutant degradation efficiency of the Pt/ZnFe2O4 NCs was demonstrated with rhodamine B (RhB) degradation in a Fenton-like process under illumination of simulated sunlight at 100 mW cm(-2). The apparent reaction rate constant can reach as high as 9.31 min(-1), almost three orders of magnitude higher than 0.01 min(-1) typically achieved by photocatalysts reported in the literature. The excellent magnetic recyclability and cycling stability of the Pt/ZnFe2O4 NCs toward RhB degradation were also demonstrated. A degradation mechanism was proposed to show how the coupling of Pt enhances the charge separation of ZnFe2O4 NCs and generation of HO2 center dot and HO center dot, all significant factors to boost the RhB degradation efficiency. The Pt/ZnFe2O4 NCs prove to be an extremely efficient and promising catalyst for Fenton-like processes for the removal of recalcitrant organic pollutants and greatly increase the competitiveness and practicality of photocatalytic degradation in pollutant control.