Turbostratic graphene is a multilayer graphene, which has exotic electrical properties similar to those of monolayer graphene due to the low interlayer interaction. Additionally, the stacking structure of the turbostratic multilayer graphene can decrease the effect of attachment of charge impurities and surface roughness. This paper explores the growth of high-purity and high-quality turbostratic graphene with different interlayer spacings by calcining ferric chloride and sucrose at 1000 °C for 1 h under an argon atmosphere. X-ray diffraction patterns and Raman results imply that the turbostratic graphene contains two different interlayer spacings: 3.435 and 3.55 Å. The 3.55 Å turbostratic graphene is on top of the 3.435 Å turbostratic graphene, and there is an AB stacking pattern between the topmost graphene layer of 3.435 Å turbostratic graphene and the first graphene layer of the 3.55 Å turbostratic graphene, with an interlayer spacing of 3.35 Å. The two different interlayer spacings of turbostratic graphene arise from different cooling rates between the higher temperature ranges (>700 °C) and lower temperatures (<700 °C).

Lithium iron phosphate (LFP) is widely used as an active material in a cathode electrode for lithium-ion batteries (LIBs). LFP has many remarkable properties such as high working voltage and excellent thermal stability. However, it suffers with slow ion diffusion and low electrical conductivity. Graphene foam has many outstanding properties such as large surface area and great electrical conductivity. These properties are suitable for improving the cathode electrode. In this work, the graphene foam was synthesized by chemical vapor deposition. The cathode electrode was prepared by dropping the LFP on the graphene foam. We found that the specific capacity of battery which contained the LFP between the anode and the graphene foam (LFP/GF) was 23.1 mAh⸳g-1 at 3C, while the specific capacity of battery which contained the graphene foam between the anode and the LFP (GF/LFP) was 112.6 mAh⸳g-1 at 3C. The diffusion coefficients of Li+ of GF/LFP was 9.1 times higher than that of LFP/GF. The specific capacity of GF/LFP was higher than that of LFP/GF at high current density due to the high ion transfer rate which arises from the graphene foam.

Graphene quantum dots (GQDs) have attracted attention from researchers owing to their outstanding properties, such as chemical inertness, stable photoluminescence (PL), biocompatibility, and low toxicity, which make them suitable for bioimaging, optoelectronic device, sensor, and others. At present, there are several studies that report the effect of the size of GQDs on their properties; however, but there is only a few studies that report the effect of the thickness of GQDs on their properties. It may be attributed to the difficulty to obtain the accurate information on the thickness of GQDs. In this study, we demonstrate the facile and one-step hydrothermal synthesis of monolayer and bilayer n-doped graphene quantum dots (NGQDs) using sucrose as a carbon source. UV-visible and PL spectra show the quantum yield of the NGQDs is 4.9 times higher than that of the GQDs. Besides, the NGQDs exhibit sensitive PL for Ag⁺ ions. In addition, the thickness distribution and interlayer spacing of NGQDs are revealed by X-ray diffraction (XRD) curve fitting, which is calculated using a simple and accurate equation. The information on the structure of the NGQDs from the XRD curve fitting is in a good agreement with the Raman results. This accurate estimation of the structure of GQDs by XRD curve fitting using the simple equation may extend the limits of GDQ study.

Monolayer graphene has excellent electrical properties especially a linear dispersion in the band structure at the K-point in the Brillouin zone. However, its electronic transport properties can be degraded by surface roughness and attachment of charge impurities. Although multilayer graphene can reduce the surface roughness and attachment of charge impurities, the increase in the number of graphene layers can degrade the electronic transport properties due to interlayer interactions. Turbostratic graphene can significantly reduce the effect of interlayer interaction of multilayer graphene resulting in electrical properties similar to those of monolayer graphene. In this report, we have demonstrated the growth of turbostratic stacked graphene using waste ferric chloride solution as a feedstock by vaporization and calcination at 700 °C for 6 hours under an argon atmosphere. SEM images and EDX elemental distribution maps showed graphene can be grown on iron and nickel catalysts. XRD results and Raman spectra confirmed the presence of turbostratic stacked graphene with the interlayer spacing in the range of 3.41 Å to 3.44 Å. The Raman spectra in all samples also displayed a weak intensity peak of iTALO⁻ and a well-fitted 2D band by a single Lorentzian peak indicating the presence of turbostratic stacked graphene. In addition, XPS spectra reveal the growth mechanism of the turbostratic stacked graphene. This synthesis process of turbostratic stacked graphene is not only simple, low-cost, and suitable for large-scale production but also decreases the environmental issues from releasing waste ferric chloride solution with improper disposal.