The key role of reduction process in enhancing the properties and catalytic performance of nanoscale copper particles anchored on three-dimensional macroporous graphene

Abstract

Abstract Optimization of the synthesis process and promotion of the catalytic efficiency are crucial to develop low-cost and effective catalysts for the removal of antibiotics from wastewater. In our previous work, a kind of hybrid material of nanoscale copper particles anchored on three-dimensional macroporous graphene (3D-GN@Cu) has been proved to be a satisfying Fenton-like catalyst. Herein, the self-assembly methods of 3D-GN@Cu preparation by a facile liquid-phase reduction was further investigated with field emission scanning electron microscopy, nitrogen adsorption/desorption isotherms, Raman spectrum analysis, X-ray diffraction, X-ray photoelectron spectroscopy and cyclic voltammograms measurements. The effects of various reduction methods, reduction time and reducing agent dosage on the physicochemical properties and catalytic performances of 3D-GN@Cu were investigated, and the preparation process was optimized. It was found that 3D-GN@Cu prepared by method A with 1.0 M KBH4 for 24 h had the largest surface area, the more defects and the best catalytic properties for the removal of metronidazole. In the combination of experimental results and density functional theory (DFT) calculations, the assembly and optimization law for preparing 3D-GN@Cu and the corresponding mechanisms were illustrated. This provides the theoretical basis and new insights for the preparation of graphene-encapsulated nanometals and related composites, which have a promising application potential in the fields of catalysis, electronics, sensors, bioapplications and environmental pollution control.