Yasuhiro Ikuta

Mesoporous Ferrihydrite‐Based Iron Oxide Nanoparticles as Highly Promising Materials for Ozone Removal

Gaseous ozone (O3) in the troposphere is considered to be one of the most harmful air pollutants in view of its high reactivity and immediate action to the surroundings, which causes both shortand long-term adverse health effect and also disrupts plant growth. Materials explored for eliminating O3 in several applications include activated carbon or carbon-promoted oxide materials, noble-metal-supported catalysts, and various transition-metal oxides. These materials have diverse drawbacks: they must often be deposited on high-surface-area metal oxides or mixed with organic additives to enhance their performance, they use expensive metal components, they are not very environmentally friendly, and they are not flexible enough to use as a common choice in a wide range of sectors. Herein, we report for the first time that the two-line ferrihydrite (2LFh) with accessible mesopores can be used as a potential candidate for O3 removal. The following aspects prompted us to consider mesoporous 2LFh (M2LFh) a judicial choice for O3 removal: 1) it possesses high surface area and, being in the ferrihydrite (Fh) phase, a much higher percentage of iron sites are at or near the surface than in the bulk; 2) with accessible mesopores, Fh nanoparticles have the potential for high adsorption owing to an increased rate of mass transfer to the reactive iron sites, such as we recently reported for their high efficiency in rapidly removing organic contaminants in the air; and 3) as an oxyhydroxide of iron, Fh is environmentally friendly and can be applied in various sectors. We also show herein that the presence of Fh nanoparticles in disordered mesostructured iron oxide has a significant effect on the bulk and surface structure of the material and on the activity. Our findings can contribute toward designing Fh-based materials as new potential catalysts for rapid removal of O3 and its decomposition. M2LFh was prepared according to a reported procedure by assembly of Fh nanoparticles in 1-propanol in the presence of polyoxyethylene (20) cetyl ether template. Additionally, a mesostructured semicrystalline iron oxide composed of amorphous Fh nanoparticles and crystalline g-Fe2O3 phase (MSIO) and a crystalline iron oxide with no welldefined mesopores (CIO) were prepared for comparison. MSIO was prepared through a sol–gel process in which iron nitrate, oleic acid, a triblock polymer template (F127), and 1propanol were mixed, with subsequent ageing and calcination. CIO was prepared by assembly of iron oxyhydroxide in a water/ethylene glycol mixture in the presence of cetyltrimethylammonium bromide. Details of MSIO and CIO synthesis are given in the Supporting Information. The wide-angle XRD pattern of M2LFh (Figure 1a,A) shows two broad reflections of the 2LFh phase. Although the amorphous Fh-phase reflections in the XRD pattern of MSIO

New semi-empirical computational analysis of catalytic reactions for automobile

Reaction profiles of diatomic molecules,

Apparatus for controlling the ignition timing of an internal combustion engine having a turbocharger

\hbox {O}_2, \hbox {N}_2

Mesoporous ferrihydrite with incorporated manganese for rapid removal of organic contaminants in air.

O2,N2, and NO, on a transition

Power control system for a turbocharged internal combustion engine

d

Air by-pass system in an internal combustion engine with a supercharger

d-metal surface were semi-empirically calculated using a new approach based on a bond-energy bond-order (BEBO) model. The BEBO model could be a useful relation for describing reaction configurations. In this work, we introduce a new semi-empirical model which combines density functional theory (DFT)-based interaction parameters with the empirical Miyazaki BEBO model and demonstrate that our model could also be used successfully in previous DFT calculation results. The predictions calculated using this model, such as adsorption energies and adsorption geometries of incoming gas molecules, are close to previous experimental and theoretical results. In particular, the most remarkable point is that previous DFT calculation results and experimental results are available to our procedure. In other words, our model could be extremely simple but powerful.