Search

Herein, a simple, cheap and easily scaled-up procedure to obtain reduced graphene oxide from exfoliated graphene oxide using ferrocene and HNO3 is reported. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) studies show increased number of sp2 domains in the rGO. The rGO shows specific surface area of ∼369 m2 g−1 and is stable till 700 °C. The measured specific capacitance of rGO is 106.5 F/g ensures that the rGO is promising material for electrochemical double layer capacitors. The magnetic hysteresis loop of rGO reveals diamagnetic behavior. The reduction mechanism for the synthesis of rGO using ferrocene and HNO3 has been proposed. We hope this approach might facilitate scalable production of high-quality rGO sheets which could lead to future industrial graphene based devices for various applications.

Structural, magnetic and optical properties of Bi 0.85 Ho 0.15 Fe 1− x Co x O 3 ( x =0.0–0.15) nanoparticles have been studied. X-ray diffraction patterns and Raman spectra demonstrate orthorhombic structure for all samples. Spontaneous magnetization of Ho–Co co-substituted BiFeO 3 nanoparticles increased up to 3.71 emu/g for x =0.15. Electron spin resonance analysis showed that the addition of Co 2+ ions is likely to increase the spin canting angle and reduces anisotropy which favors the enhanced ferromagnetism. Optical studies in the spectral range from 1.1 to 5 eV showed two d–d crystal field transitions and three charge–transfer transitions with band gap variation from 2.60 to 2.38 eV.

Bi1−xDyxFeO3 (x=0.03, 0.05, and 0.10) nanoparticles were synthesized using sol–gel method. X-ray diffraction results show a compositional driven phase transition from a rhombohedral phase for x=0.03 and 0.05 samples to orthorhombic phase for x=0.10 sample. Raman spectroscopy also suggested substitution induced phase transition in Bi1−xDyxFeO3 nanoparticles. A large saturated magnetization of 5.5 emu/g for x=0.10 sample is observed at room temperature, which is ascribed to size reduction of nanoparticles, the distorted spin cycloid and characteristic magnetic activity of Dy3+ ions. UV-visible diffuse reflectance spectroscopy results show strong absorption of light in the range 300–600 nm indicating the optical band gap in the visible region for these samples.