Fe3O4 nanoclusters highly dispersed on a porous graphene support as an additive for improving the hydrogen storage properties of LiBH4

Fe3O4 nanoclusters anchored on porous reduced graphene oxide (Fe3O4@rGO) have been synthesized by a one-step hydrothermal route, and then ball milled with LiBH4 to prepare a hydrogen storage composite with a low onset dehydrogenation temperature, and improved dehydrogenation kinetics and rehydrogenation reversibility. The LiBH4-20 wt% Fe3O4@rGO composite begins to release hydrogen at 74 °C, which is 250 °C lower than for ball-milled pure LiBH4. Moreover, the composite can release 3.36 wt% hydrogen at 400 °C within 1000 s, which is 2.52 times as high as that of pure LiBH4. Importantly, it can uptake 5.74 wt% hydrogen at 400 °C under 5 MPa H2, and its hydrogen absorption capacity still reaches 3.73 wt% after 5 de/rehydrogenation cycles. The activation energy (E a) of the hydrogen desorption of the composite is decreased by 79.78 kJ mol-1 when 20 wt% Fe3O4@rGO is introduced into LiBH4 as a destabilizer and catalyst precursor, showing enhanced thermodynamic properties. It could be claimed that not only the destabilization of Fe3O4, but also the active Li3BO3 species formed in situ, as well as the wrapping effect of the graphene, synergistically improve the hydrogen storage properties of LiBH4. This work provides insight into developing non-noble metals supported on functional graphene as additives to improve the hydrogen storage properties of LiBH4.

Magnetically recoverable graphene-based nanocomposite material as an efficient catalyst for the synthesis of propargylamines via A3 coupling reaction

The magnetically separable Au NPs–Fe₃O₄–rGO catalyst provides a robust and efficient route for the A³ coupling reaction of secondary amines, terminal alkynes and aldehyde with tolerance of diverse functional groups for the synthesis of propargylamine in high yields.

Electrocatalytic oxidation behavior of NADH at Pt/Fe3O4/reduced-graphene oxide nanohybrids modified glassy carbon electrode and its determination

We have developed Pt/Fe3O4/reduced-graphene oxide nanohybrids modified glassy carbon (Pt/Fe3O4/RGO/GC) electrode as a novel system for the preparation of electrochemical sensing platform. Characterization of as-made composite was determined using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM) and energy-dispersive analysis of X-ray (EDAX) where the Pt, Fe, Si, O and C elements were observed. The Pt/Fe3O4/RGO/GC electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Due to the synergistic effect between Pt, Fe3O4 and RGO, the nanohybrid exhibited excellent performance toward dihydronicotinamide adenine dinucleotide (NADH) oxidation in 0.1M phosphate buffer solution, pH7.0, with a low detection limit of 5nM.

Highly efficient removal of pathogenic bacteria with magnetic graphene composite

Magnetic Fe3O4/graphene composite (abbreviated as G-Fe3O4) was synthesized successfully by solvothermal method to effectively remove both bacteriophage and bacteria in water, which was tested by HRTEM, XRD, BET, XPS, FTIR, CV, magnetic property and zeta-potential measurements. Based on the result of HRTEM, the single-sheet structure of graphene oxide and the monodisperse Fe3O4 nanoparticles on the surface of graphene can be observed obviously. The G-Fe3O4 composite were attractive for removing a wide range of pathogens including not only bacteriophage ms2, but also various bacteria such as S. aureus, E. coli, Salmonella, E. Faecium, E. faecalis, and Shigella. The removal efficiency of E. coli for G-Fe3O4 composite can achieve 93.09%, whereas it is only 54.97% with pure Fe3O4 nanoparticles. Moreover, a detailed verification test of real water samples was conducted and the removal efficiency of bacteria in real water samples with G-Fe3O4 composite can also reach 94.8%.