Surface aging behaviour of Fe-based amorphous alloys as catalysts during heterogeneous photo Fenton-like process for water treatment

Two novel, multifunctional Fe-based amorphous alloys with the nomihal components of Fe78Si9B13 and Fe73.5Si13.5B9Cu1 Nb-3 exhibit advanced catalytic capability when degrading methyl blue (MB) and methyl orange (MO) dyes. The production rate of hydroxyl radicals (center dot OH) in this work is 5-10 times faster than other Fe-based catalysts. The surface aging behaviour on Fe78Si9B13 and Fe73.5Si13.5B9Cu1Nb3 ribbons shows a significant effect on the dye degradation efficiency and reusability of the catalyst. Results reveal that crystallized alpha-Fe, iron oxide and SiO2 are gradually precipitated on the surface of the reused Fe78Si9B13 ribbon which ultimately becomes corroded through with holes. However, the inclusion of Nb atoms in the Fe73.5Si13.5B9Cu1Nb3 alloy causes the formation of niobium oxides which overlay the ribbon surface, and tend to reduce the contact area between the Fe and H2O2, thereby decreasing the generation of (OH)-O-center dot and further reducing the dye degradation efficiency. Tert-butanol is employed for quenching hydroxyl radicals ((OH)-O-center dot), causing a dramatic reduction in the amount available for degrading the MB and MO molecules. The MB and MO dye degradation and mineralization under UV-vis light are also fully investigated. The findings of this critically important work should form the basis of new research opportunities into the study of amorphous alloy catalysis. (C) 2016 Elsevier B.V. All rights reserved.