In situ synthesized rGO–Fe3O4 nanocomposites as enzyme immobilization support for achieving high activity recovery and easy recycling

Herein, the reduced graphene oxide–Fe 3 O 4 (rGO–Fe 3 O 4 ) nanocomposites are synthesized by the simultaneous reduction of graphene oxide (GO) and in situ deposition of Fe 3 O 4 nanoparticles ( ca. 20   nm) enabled by Fe 2+ ions. The rGO–Fe 3 O 4 nanocomposites integrate the magnetic property of Fe 3 O 4 nanoparticles and the large specific surface area of rGO nanosheets. Catalase (CAT), as a commonly used enzyme, can be efficiently immobilized on the rGO–Fe 3 O 4 nanocomposites through physical adsorption. The CAT loading capacity is as high as 312.5   ±   12.6   mg   g −1 , while the activity recovery of CAT can be high up to nearly 98%. The strong magnetic response of immobilized CAT ensures its easy separation from the reaction system when an external magnetic field is applied. Owing to the hydrophobic and hydrogen bonding interactions between enzyme and the support, the immobilized CAT exhibits zero leaching, desirable stability and excellent reusability.