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The chemical exfoliation of graphite to produce graphene and its oxide is undoubtedly an economical method for scalable production. Carbon researchers have dedicated significant resources to developing new exfoliation methods leads to graphene oxides with high quality. However, only a few studies have been dedicated to the effect of the starting graphite material on the resulting GO. Herein, we have prepared two different GOs through chemical exfoliation of graphite materials having different textural and structural characteristics. All samples have been subjected to structural investigations and comprehensive characterizations using Raman, X-ray diffraction, scanning electron microscopy, TGA, N2 physisorption, and FTIR spectroscopy. Our results provide direct evidence of how the crystallite size of the raw graphite affects the oxidation degree, surface functionality, and sheet size of the resulting GO. Building on these significant understandings, the optimized GO achieves a highly specific capacitance of 191 F·g−1 at the specific current of 0.25 A·g−1 in an aqueous electrolyte. This superior electrochemical performance was attributed to several factors, among which the specific surface area was accessible to the electrolyte ions and oxygenated functional groups on the surface, which can significantly modify the electronic structure of graphene and further enhance the surface energy.

The purpose of the study was to investigate the synthesis of economic calcium phosphate powders from recycled oyster shells, using a ball milling method. The oyster shell powder and a calcium pyrophosphate powder were used as starting materials and ball milled, then heat treated at 1,050°C for 5 h to produce calcium phosphate powders through a solid-state reaction. Electrochemically synthesized mesoporous silicon microparticles were then added to the prepared phosphate powders by mechanical mixer. The final powders were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy to analyze their chemical composition and determine the most suitable process conditions. The biocompatibility of the produced powders was also tested in vitro using murine cells and the results showed good biocompatibility.