SPring-8, the large synchrotron radiation facility

Inquiry number

SOL-0000001208

Beamline

BL01B1 (XAFS I)

Scientific keywords

A. Sample category	inorganic material
B. Sample category (detail)	amorphous, glass
C. Technique	absorption and its secondary process
D. Technique (detail)	XAFS, EXAFS, XANES
E. Particular condition	polarization (linear), room temperature
F. Photon energy	X-ray (4-40 keV)
G. Target information	chemical state, chemical bonding, local structure, function and structure, function

Industrial keywords

level 1---Application area	Chemical product, industrial material, others
level 2---Target	catalysis, health care（shampoo, cosmetics,dental paste）
level 3---Target (detail)
level 4---Obtainable information	local structure, chemical state
level 5---Technique	XAFS

Classification

A80.34 catalysis, M40.10 XAFS

Body text

In this solution, fluorescence EXAFS method at Pd K-edge was applied to hydroxyapatites (HAP)-bound Pd (0.16 wt%) catalysis (PdHAP). For dilute samples, the fluorescence EXAFS method is a powerful technique to study local structure (distance, coordination number, species of neighbor atoms) of selected elements both in crystalline states and in non-crystalline states. The PdHAP have demonstrated different catalytic activities, such as aerobic alcohol oxidation and Heck reaction, only by controlling the ratio of Ca:P in the parent HAP. EXAFS analysis revealed that local structure of PdHAP strongly depends on composition of HAP and causes heterogeneous catalytic activities as shown in the figure.

Fig. Model structure of PdHAP catalysts for aerobic alcohol oxidation (a) and Heck reaction (b).
[Journal of the American Chemical Society 124, 11572-11573 (2002), Fig. 1(b), ©2002 The American Chemical Society.]

[ K. Mori, K. Yamaguchi, T. Hara, T. Mizugaki, K. Ebitani and K. Kaneda, Journal of the American Chemical Society 124, 11572-11573 (2002), Fig. 1（ｂ）,
©2002 American Chemical Society ]

Source of the figure

Original paper/Journal article

Journal title

K. Mori et al., J. American Chem. Soc., 124, (2002) 11572-11573

Figure No.

1（ｂ）

Technique

XAFS spectra of dilute samples are taken by fluorescence XAFS method. This method is performed by measuring fluorescence from excited atoms as a function of x-ray energy around an absorption edge of a selected element. A 19-element Ge detector is used for measurement of 1-1000 ppm samples. Acquisition time per XAFS spectrum is 1-1.5 hr in this solution.

Source of the figure

No figure

Required time for experimental setup

4 hour(s)

Instruments

Instrument	Purpose	Performance
XAFS Measurement System	Measurement of XAFS spectra	3.8-113 keV
19 Ge Detector	Measurement of XAFS spectra of dilute sample and thin film	concentration: 1-1000　ppm, thickness > 0.1 nm

References

Document name
K. Mori et al., J. American Chem. Soc., 124, (2002) 11572

Related experimental techniques

Questionnaire

This solution is an application of a main instrument of the beamline.

Ease of measurement

With a great skill

Ease of analysis

Middle

How many shifts were needed for taking whole data in the figure?

Less than one shift