LAUSR

Abstract Iron (hydr)oxides were deposited on different carbonaceous materials carriers and their Fenton-like performance was critically evaluated. The solid carbon substrate significantly affected the crystal structure of the iron-containing phase. In particular, a layer of α-FeOOH was formed on the surface of hydrochar microsphere at pH = 6 and T = 60 °C without any additives for the synthesis conditions applied. Among the other obtained samples, the latter exhibited the highest catalytic activity, expressed either per gram of Fe metal or per total surface area basis, and the highest stability as well towards degradation of Orange II in the presence of H2O2. This is suggested to be due to the core@shell structure of hydrochar microsphere@α-FeOOH and its favorable catalytic mechanism and kinetics as compared to previously reported FeOOH Fenton catalysts. H2O2 mainly reacted with photo-generated holes rather than Fe(II)/(III) and photo-generated electrons to produce superoxide radicals.