Masaaki Kitano

Novel approaches to efficient ammonia synthesis at an ambient pressure are actively sought out so as to reduce the cost of ammonia production and to allow for compact production facilities. It is accepted that the key is the development of a high-performance catalyst that significantly enhances dissociation of the nitrogen-nitrogen triple bond, which is generally considered a rate-determining step. Here we examine kinetics of nitrogen and hydrogen isotope exchange and hydrogen adsorption/desorpt

The reaction mechanism of the hydrolysis of cellulose by a carbon-based solid acid, amorphous carbon containing graphene sheets bearing SO(3)H, COOH, and phenolic OH groups, has been investigated in detail through the hydrolysis of water-soluble beta-1,4-glucan. Whereas a range of solid strong Brønsted acid catalysts (inorganic oxides with acidic OH groups, SO(3)H-bearing resins, and the carbon-based solid acid) can hydrolyze the beta-1,4-glycosidic bonds in cellobiose (the shortest water-solubl

Nitrogen-substituted TiO2 (N-TiO2) thin film photocatalysts have been prepared by a radio frequency magnetron sputtering (RF-MS) deposition method using a N2/Ar mixture sputtering gas. The effect of the concentration of substituted nitrogen on the characteristics of the N-TiO2 thin films was investigated by UV-vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses. The absorption band of the N-TiO2 thin film w

Mixed anionic materials such as oxyhydrides and oxynitrides have recently attracted significant attention due to their unique properties, such as fast hydride ion conduction, enhanced ferroelectrics, and catalytic activity. However, high temperature (≥800 °C) and/or complicated processes are required for the synthesis of these compounds. Here we report that a novel perovskite oxynitride-hydride, BaCeO_3-<i>x</i>N_<i>y</i>H_<i>z</i>, can be directly synthesized by th

Nanostructured titanate materials with different morphologies, including layered materials, nanosheets, and nanotubes, were examined as solid acid catalysts to elucidate the relationship between the structure and the catalytic properties. The titanate nanotube consists of a scroll-like layered structure derived from lamellar titanate nanosheets that exhibits excellent catalytic performance for the Friedel–Crafts alkylation of toluene with benzyl chloride near room temperature, exceeding the acti

Protonated titanate nanotubes are demonstrated to function as a highly active solid Lewis acid catalyst even near room temperature. The high catalytic activity for the reaction can be attributed to the unique nanotube structure, which contains both Brønsted and Lewis acid sites.

Nickel has been studied as an alternative catalyst to ruthenium for ammonia decomposition. However, high reaction temperatures are generally required to achieve good ammonia conversion because the weak interactions between nitrogen and the Ni surface reduce the frequency of the dehydrogenation reaction of ammonia. Here, we report Ni-supported CaNH as a highly efficient catalyst for ammonia decomposition through an NH2– vacancy-mediated Mars–van Krevelen mechanism. Ni/CaNH exhibited much greater

CO₂ hydrogenation to methanol is one of the most promising routes to CO₂ utilization. However, difficulty in CO₂ activation at low temperature, catalyst stability, catalyst preparation, and product separation are obstacles to the realization of a practical hydrogenation process under mild conditions. Here, we report a PdMo intermetallic catalyst for low-temperature CO₂ hydrogenation. This catalyst can be synthesized by the facile ammonolysis of an oxid