Facile Synthesis of Chitosan-Mediated Hematite Clusters as an Efficient Photocatalyst

摘要

This paper reports a facile synthesis of chitosan-mediated Fe2O3 (Fe2O3@chitosan) composites and their photocatalytic activity for the degradation of organic pollutant. The Fe2O3@chitosan composites were prepared through the thermal calcination of chitosan-linked Fe3O4 (1-5 ml of chitosan, 0.02 M) under N-2 flow (0.5 l/min) at 700 degrees C for 2 h. The resulting Fe2O3@chitosan composites exhibited rough surface morphology that consisted of small Fe2O3 particles, while the bare Fe2O3 consisted of relatively large particles because of the sintering effects of the calcination process. Compared to the fair magnetism of the bare Fe2O3, the Fe2O3@chitosan composites exhibited negligible magnetism because of the magnetite-to-hematite (Fe3O4-to-alpha-Fe2O3) phase transformation that occurs at high temperature. All of the Fe2O3@chitosan composites exhibited enhanced photocatalytic activity in comparison to that of the bare Fe2O3 when applied to the photodegradation of methylene blue (5 ppm). The Fe2O3@chitosan composites (2 ml of chitosan) exhibited the highest photocatalytic activity among all the Fe2O3@chitosan samples, highlighting the importance of optimal nanostructure of hematite clusters with high surface area.