[in Japanese]

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[in Japanese]

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 Recent trends of synchrotron radiation spectroscopy, especially X-ray absorption spectroscopy for industrial applications are introduced based on our latest results for energy efficient devices such as magnetic RAM, LSI and organic FET, power generation devices such as fuel cells, and energy storage devices such as Li ion batteries. Furthermore, future prospects of spectroscopy with higher energy resolution, higher spatial resolution, higher temporal resolution and operando spectroscopy taking advantage of much brighter synchrotron radiation beam at low emittance SR rings are discussed from the view point of practical applications.

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 The redox reactions of supported metal species have been investigated by means of in-situ and time-resolved XAFS technique for the Co, Ni, and Cu catalysts supported on silica. The in-situ XAFS experiments revealed the chemical state conversions of supported metal species during the temperature-programmed reduction and oxidation processes. The small metal particles tend to be oxidized at lower temperature and reduced at higher temperature than the corresponding larger particles for the Co and Ni catalysts. The temperature shift is ascribed by the strong interaction of the divalent metal oxide with silica. The time-resolved XAFS measurements revealed the detail dynamic processes of redox reactions for the supported metal specie. The chemical state conversions of the supported Ni species under the mixed gas environment of CO and NO were studied by means of the time-resolved XAFS technique at 873 K. The faster oxidation of metallic Ni than the reduction of NiO were directly demonstrated, and the dynamic conversion of the Ni species thus indicated that the oxidation of CO and the reduction of NO were simultaneously achieved on the supported Ni particles.

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 Recent technical developments of X-ray absorption spectroscopy (XAS) enable us to measure in situ/operando transmission spectra of liquid samples in the soft X-ray region. We have discussed how various inter-molecular interactions around the core-excited atom are analyzed from the chemical shifts in XAS for the chemical state analysis of interacting molecular systems. We have newly developed liquid flow cells for XAS in transmission mode, where liquid samples are sandwiched between two 100 nm thick Si₃N₄ (or SiC) membranes in vacuum or in helium atmosphere. In order to get reliable XAS spectra, our XAS system makes it possible to optimize the absorbance by simply controlling the liquid sample thickness from 20 nm to 2000 nm, and also makes it possible to find the region of uniform thickness by scanning the beam position on sandwiched liquid samples.

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 In this paper, we present our recent results of 2D or 3D imaging of heterogeneous solid catalysts by spatially-resolved X-ray absorption fine structure (XAFS) techniques. These state-of-art XAFS imaging techniques show heterogeneous behaviors of solid catalysts. XAFS imaging of an automobile exhausting catalyst and electrocatalyst for polymer electrolyte fuel cell was presented.

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