Synergistic effect of various elements in Fe41Co7Cr15Mo14C15B6Y2 amorphous alloy hollow ball on catalytic degradation of methylene blue

Abstract

Metallic glasses have recently attracted great attention in terms of degrading dyes and other organic pollutants as an environmentally friendly material for wastewater remediation. Herein, we report a new type of amorphous catalyst Fe41Co7Cr15Mo14C15B6Y2 hollow balls. Results demonstrate that the catalyst can still completely decolorize the 20 mg/L methylene blue (MB) solution after reused for 50 times under conditions of pH = 5, catalyst content 0.5 g/L, and temperature 80 °C. The catalyst is easily broken during degradation, so the inner surface also provides additional active sites. The Fe41Co7Cr15Mo14C15B6Y2 amorphous alloy hollow balls were characterized by energy dispersive X-ray specroscopy (EDS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The elements in the catalytic system have a synergistic catalytic effect. Redox cycle Fe2+/Fe3+, Co2+/Co3+ and Mo4+/Mo6+ promote mutual conversion and accelerate the catalytic process of their reaction with H2O2, forming a self-stable redox cycle process. Among them, Fe2+ promotes the conversion of Co3+ to Co2+, and Mo4+ promotes the conversion of Fe3+ to Fe2+, mainly Fe2+ and Co2+ react with H2O2 to generate •OH. Mo and Cr elements form MoO2 and Cr2O3 plasma compounds on the surface, which act as a protective film to make the catalyst more stable and be repeated used more frequently.