Graphite intercalation compounds (GICs) have been extensively studied; however, their visual appearance has not been systematically documented. The appearance of GICs plays a crucial role in understanding their properties and potential applications. In this study, alkali metal GICs (Li-, Na-, K-, Rb-, and Cs-GICs), known for their vivid gold and blue colors, were synthesized using a common host graphite under standardized conditions. Photographs were taken under controlled settings to capture their visual appearance, and reflectance spectra were measured to provide objective optical data, contributing to a standardized color sample compilation. Additionally, their structures and electrical conductivities were evaluated. Furthermore, the relationship between the crystallinity of the host graphite and the perceived appearance of the GICs is discussed. This study provides a comprehensive reference dataset on GIC appearance and is expected to support future research on intercalation compounds.

Hydrothermal treatment and carbonization of various residues from the extraction of beverages, namely coffee grounds and tea leaves, were performed to investigate the morphological properties and the potential for ethene adsorption of the resulting carbons. Hydrothermal treatment promoted the pore development of the carbons. Removal of crystalline fatty acid produced by hydrothermal treatment with ethanol washing before carbonization significantly increased the BET specific surface area, especially in coffee grounds. The carbonization process contributed to the development of ultra-micropores due to the pyrolysis of the cellulose components in as-received residues. Such narrower pores in the carbons functioned effectively for ethene adsorption.

We evaluated the effect of the molecular structure of lithium naphthalenide derivatives on the lithium doping depth, for a simple pre-doping method for natural graphite electrodes by immersing in 2-methyltetrahydrofuran (2-MeTHF) solution of lithium naphthalenide derivatives. To increase the reducing ability of lithium naphthalenide, multiple kinds of naphthalene derivatives having electron-donating substituents on the aromatic ring were examined. As a result, it was found that when a radical anion solution prepared from a 1 mol kg^-1 solution of 1,5-dimethylnaphthalene in 2-MeTHF and an excess amount of lithium metal was used, the doping depth of 88 mAh g^-1 could be achieved by immersion for 1 hour at room temperature. This method may be potentially applied as a pre-doping method for the negative electrodes for electrochemical energy storage devices.

Iron phthalocyanine (FePc)—a molecular catalyst—has attracted attention for the oxygen reduction reaction (ORR) in fuel cells and other applications. Supporting FePc on carbon materials enhances the ORR activity. However, factors influencing its ORR activity remain unclear owing to limited data on carbon supports. To further improve the ORR catalytic performance of the Fe–N₄ structure, this study systematically investigated the structural parameters of carbon supports that influence the ORR activity of FePc. Compared to bulk FePc powder, the ORR activity was higher for all the carbon-supported FePc catalysts. The ORR current correlated with the amount of electrochemically responsible FePc, determined by cyclic voltammetry, rather than with the total loaded FePc. The amount of electrochemically responsible FePc also increased with carbon layer size. Furthermore, the onset potential for the ORR varied with carbon support, with Ketjenblack (KB) showcasing the highest value. Transmission electron microscopy and small-angle X-ray scattering measurements revealed a hollow spherical structure for KB (the average diameter = 44.8 nm). X-ray absorption fine structure analysis showed that the KB-supported FePc was curved. Thus, our study provides insights into the key influencing factors of carbon support that enhance the ORR activity of FePc.

This report presents a simple, low-cost thermal chemical vapor deposition method using alcohol as a carbon source for producing micron-sized carbon nanowalls (CNWs) on spherical carbon particles. The obtained CNWs have structural disorder and defects, as indicated by a low I_G/I_D (the ratio of the D-band peak to the G-band peak) ratio in the Raman spectrum. It is worth noting that the height and width of the CNWs reach approximately 10 µm, making them larger than previously reported CNWs. CNWs are produced at 730°C when using a tungsten mesh heater, while submicron-sized amorphous carbon grains are produced with a tungsten plate heater. However, CNWs are not produced at 800°C, even with a tungsten mesh heater. The reason why CNWs are not produced at 800°C remains unclear; however, their growth at 730°C is attributed to the preferential production of sp² carbon.