Construction of surface charge-controlled reduced graphene oxide-loaded FeO and Pt nanohybrid for peroxidase mimic with enhanced catalytic activity.

Hybrid nanomaterials with synergistic effect are highly potential for developing advanced nanozymes. Herein, we designed a nanozyme assembled by polyethylenimine (PEI)-protected reduced graphene oxide anchoring iron oxide (PRGI) and Pt nanoparticle using electrostatic interaction, PRGI/Pt nanohybrid. The different ratio of PRGI nanocomposite and Pt nanoparticle could control PRGI/Pt nanohybrid's surface charge and stability, which determined PRGI/Pt nanohybrid's catalytic activity. At the mass ratio of 0.8, the as-obtained PRGI/Pt nanohybrid showed the highest catalytic ability, and was better than Pt nanoparticle at different pH and temperature, although the PRGI/Pt nanohybrid showed lower affinity for TMB than Pt nanoparticle, which maybe attributed to the fact that PRGI/Pt nanohybrid possessed better product desorption ability or larger contact area. Furthermore, PRGI/Pt nanohybrid showed much higher catalytic activity than the sum of PRGI nanocomposite and Pt nanoparticle, indicating the strong cooperation between PRGI nanocomposite and Pt nanoparticle. Our study also provided a new way to conveniently construct nanozyme based on hybrid nanomaterials.