Magnetically Separable Rice Husk Char-Supported Nickel Ferrite Photocatalyst with High Photoactivity under Visible-Light Irradiation

A specific strategy is presented for the preparation of a NiFe2O4-rice husk char (RHC) nanocatalyst with different RHC contents. The recombination of nano-NiFe2O4 with RHC leads an opposite transformation of the unreactive NiFe2O4 to an upper active photocatalyst, which can be used for the photodegradation of methylene blue in the presence of H2O2 under visible light. In comparison with neat NiFe2O4 as a catalyst, the NiFe2O4-RHC plays a dual function as the photocatalyst for both the electrochemical photodegradation of methylene blue and the producer of the important oxidant hydroxyl radical from the electrochemical dissociation of H2O2 under visible-light irradiation. The photocatalyst displays such excellent stability in the reaction that it can be magnetically separated and recycled for more than five consecutive cycles without any significant loss of activity and degradation.