Boron-doped reduced graphene oxide-based bimetallic Ni/Fe nanohybrids for the rapid dechlorination of trichloroethylene

In this study, a simple chemical reduction method for the synthesis of novel and efficient graphene-based bimetallic Fe/Ni nanoparticles was developed for the rapid and effective dechlorination of trichloroethylene (TCE). Boron-doped reduced graphene oxide (B-rGO) was used as a support for the homogenous dispersion of Fe/Ni nanoparticles between the B-rGO nanosheets. The surface morphological results showed that the particle sizes of the bimetallic Fe/Ni nanoparticles were in the range of 10-50 nm with a mean diameter of 20 nm and the elements, including B, Fe and Ni, were homogenously distributed in the graphitic matrix. The Raman, X-ray photoelectron and electrochemical impedance spectra clearly indicated that the doped boron as well as the immobilized Fe/Ni increased the disordered structure of B-rGO. Conjointly, the interaction between the graphitic backbone and bimetallic nanoparticles resulted in fast and low-resistant electron transport in B-rGO/Fe/Ni for the enhanced dechlorination efficiency and rate of TCE. A rapid and complete hydrodechlorination of TCE by B-rGO/Fe/Ni, which followed the Langmuir-Hinshelwood kinetics, was observed between pH 4 and 7. In addition, the B-rGO-immobilized Fe/Ni could retain the high reactivity after 7 cycles of repeated injection of TCE. The results obtained in this study clearly demonstrate the efficiency, longevity and recyclability of B-rGO-immobilized Fe/Ni nanoparticles, which could pave a new way to prepare novel bimetallic Fe/Ni nanoparticles with high reactivity and long stability for the removal of environmental contaminants in water purification and waste-water treatment.