Xylitol raw powder exhibits strong aggregation during storage, making it difficult to form fluidized bed and low compressibility. In this study, fluidized bed could be formed by co-milled with xylitol and fumed silica, and tabletability could also be improved by granulation with hydroxypropyl cellulose (HPC-L). To further improve the compressibility of xylitol, cellulose nanofiber (CN) was applied as a binder. As methods for adding CN, we investigated 1-step granulation method in which CN were added to the HPC-L binder solution and 2-step granulation method in which cellulose nanofibers are sprayed onto xylitol granules. In the 1-Step method, there was an optimum amount of CN. Addition of excess CN caused troubles during granulation and decreased the compressibility. In the 2-step method, the surfaces of xylitol granules were coated with CN. As a result, compressibility of the xylitol granules could be improved by only slight addition (13 ppm in xylitol) of CN.

This review article evaluates the powder flowability of nine different samples, focusing on differences in particle diameter distribution. Because the proportion of fine particles that can reduce flowability varies depending on the sample preparation conditions, the use of the median diameter as the representative value for each sample is inappropriate. Instead, we proposed a method to use the particle diameter that maximizes the coefficient of determination obtained by regression analysis between the powder flowability and the particle diameter. The test results showed that the particle diameter at a cumulative ratio of 10% was appropriate as the representative value.

The realization of a carbon-neutral (decarbonized) society requires a shift to a hydrogen society that uses renewable energy on a large scale. The necessary technologies to realize a sustainable hydrogen society include water electrolysis, which produces hydrogen using renewable energy, and fuel cells, which generate electricity from hydrogen. To establish fuel cells and water electrolysis as widespread technologies, issues related to efficiency, cost, and durability must be resolved. A key component of fuel cell and water electrolysis cell systems is the membrane–electrode assembly, which is composed of several materials: catalyst, ionomer, and electrolyte membrane. Therefore, in order to achieve optimal device performance, it is necessary to develop materials in a multi-scale hierarchy from each material to the membrane–electrode assembly. This paper outlines nanostructured catalysts for fuel cells and water electrolysis, focusing on connected nanoparticle catalysts that have been systematically designed and developed considering the entire cell systems.