Review the x-ray technique in the  ” In-situ X-ray Absorption Spectroscopy of Supported Ru Catalysts in the aqueous phases’ Many of the techniques used to characterize catalysts in the presence of vapor-phase molecules are not appropriate for liquid water. Because X-ray absorption spectroscopy and H2 chemisorption are specific probes of the active transition metal, we used X-ray diffraction (XRD) and N2 physisoprtion to probe the stability of the supports. In this paper, we applied X-ray absorption spectroscopy (XAS) to evaluate in-situ the oxidation state and particle size of supported Ru catalysts in the aqueous phase at elevated pressure and temperature. In this paper, we did these work and found the following information 1. X-ray absorption near edge spectra (XANES) the XANES for the catalysts prior to and following reduction by H2 saturated water at 473K.Because the XANES of catalysts in air are similar to that of RuO2 powder, which means that supported Ru samples completely oxidized upon exposure to air. Conclusion: The treatments by H2 (g) and H2-saturated water solution at 473 K were both sufficient to reduce the oxide to Ru metal. 2. Extended X-ray absorption fine structure (EXAFS), we found for Ru/Al2O3 and Ru/SiO2, the first shell Ru-Ru coordination number increased significantly, but for Ru/C nd Ru/TiO2 samples have slight changes.Conclusion: for Ru/Al2O3 and Ru/SiO2,the observed particle agglomeration is resulting from hydrolysis of the support, which strongly suggests that both ç-alumina and silica are not suitable supports for the aqueous phase catalytic conversion of biomass. 3. X-ray Absorption Spectroscopy (XAS), to investigate if the stability of the Ru/C could be generalized for other carbon-supported materials, we also use the in situ XAS technique to investigate a Pt/C catalyst. Pt dispersion decreased significantly when treated under aqueous conditions at elevated pH. Conclusion: Carbon supports cannot be assumed to be proper carries for transition metals under reducing conditions. 4. X-ray diffraction (XRD), XRD results from both Ru/C and Ru/SiO2, indicating that no diffraction peaks (except for a small graphitic peak in the C sample), which did not change following the aqueous treatments. The XRD results from the Ru/Al2O3, which indicates significant structural changes after the various aqueous treatments. When t=0, the Al is present in the gamma phase. Aqueous treatment at 473 K resulted in formation of boehmite with some gamma-Al still remaining. Upon treatment with the NaOH solution, the gamma-Al peaks disappeared, the intensities of the boethmite peaks increased .And there are similar results for Si. The XRD results from the Ti, which has a a mixture of anatase (80%) and rutile (20%) in agreement with the manufacturer’s specifications and remained unchanged throughout all of the treatments. Conclusion: the Al2O3 and SiO2 supports were significantly altered by the aqueous treatment. Conclusion: Ru/C and Ru/TiO2 revealed the highest degree of particle stability, but the Ru/Al2O3 and Ru/SiO2 samples exhibited significant particle agglomeration upon aqueous-phase treatment. XAS The storage ring operated at 2.8 GeV with a ring current of 150-300 mA. Data were collected on beamlines X-10C and X-18B operating in transmission mode at the Ru K-edge (21.118 keV) with a beam spot size of 0.5 mm×10 mm and at the Pt LIII-edge (11.564 keV) with a spot size of 1 mm×10 mm. XRD using a Scintag 2000 powder X-ray diffractometer. The diffractometer operated with Cu K radiation at 40 kV, 35 mA, and scan rate of 1min-1. EXAFS The Ru reference sample was treated as having the bulk crystallographic values of the Ru hcp structure with a first-shell coordination number (CN) of 12 and nearest neighbor distance of 2.68.