Natural carbon nanodots assisted development of size-tunable metal (Pd, Ag) nanoparticles grafted on bionic dendritic α-Fe2O3 for cooperative catalytic applications

In this work, we fabricated size-tunable metal (Pd, Ag) nanoparticles grafted on bionic dendritic alpha-Fe2O3 (M@Fe2O3) through an in situ growth method by using carbon nanodots as a reducing agent followed by a hydrothermal reaction. The size of the supported noble metal nanoparticles can be directly controlled on the surface of dendritic alpha-Fe2O3 by adjusting the added amount of noble metal salts. The catalytic performances of the resulting M@Fe2O3 hybrid composites were firstly evaluated by reduction of p-nitrophenol. The results indicated that the size of the noble metal nanoparticles had a crucial influence on the catalytic behaviors of the M@Fe2O3. In addition, the dendritic M@Fe2O3 also showed improved photocatalytic efficiencies for visible-light-driven MB degradation due to synergic effects between dendritic alpha-Fe2O3 and noble metal nanoparticles, including optical properties, unique structure, good dispersion, good charge separation and the SPR effect. The M@Fe2O3 composites have good reproducibility and are highly stable for p-nitrophenol reduction/degradation of MB. Our strategy can be extended to a general strategy for the formation of other novel composites consisting of a 3D hierarchical metal oxide and noble metal nanoparticles with tailorable size (e.g., Pt@TiO2, Pd@MnO2, Au@ZnO and Ag@Cu2O) for broad applications in water treatment.