In-situ Raman spectra

Figure 5, In situ Raman spectra for Fe-TsPc adsorbed on Ag(lOO), Ag(lll) and Ag(llO) at 0.2 V vs. SCE in 0.1 M HCIO4 Ar saturated aqueous solutions (15).

In situ Raman spectra studies performed on graphite anodes also seem to reveal a cointercalation occurrence that leads to exfoliation. Huang and Freeh used solutions of LiC104 in EC/EMC and EC/DME as electrolytes and monitored the E2g2 band at 1580 cm in the Raman spectra of the graphite that was cycled between 2.0 and 0.07 Reversible lithium intercalation and deintercalation was indicated by... 

Fig. 8 (a) DRIFTS spectra of catalyst surface in NO flow. Absorbance increases with time, (b) In situ Raman spectra measured while methanol flowing over catalyst. ... 

In situ Raman spectra of 2000 A PPy-GOD film, which was deposited on a GC electrode, were recorded in the 0.05 M PB (pH 7.4) solution. Figure 5 shows Raman spectra of the as-polymerized film and of those recorded at -1.0 V and +0.4 V. In the spectrum for the as-polymerized PPy-GOD film, there are several bands which may be due to the PPy (27, 30, 31) 922, 988, 1044, 1345, and 1552 cm"1. The 1345 cm"1 band could also be due to the GOD (2). However, there has been no clear evidence for the observation of resonance Raman spectrum of GOD itself (2), and the observed Raman spectrum for the as-polymerized PPy-GOD film may be totally due to the PPy. Virdee and Hester (30) have previously observed similar spectrum changes for a PPy-S04 film by applying the redox potentials. At any rate, the above spectroscopic data confirmed that the PPy-GOD film was formed on the GC electrode. Both UV-visible and Raman spectroscopic data were also consistent with the CV data, which indicated the presence of the redox reaction of the PPy in the PPy-GOD film. 

The transition from LDA to HDA Si was observed in the successive experiment by McMillan et al. [264]. In situ Raman spectra and electronic resistance measurements were performed with optical observation. After compression, the LDA form prepared by solid-state metathesis synthesis [10] was found to be transformed to the HDA form at 14 GPa. The electronic resistance exhibited a sharp decrease at 10-14 GPa (Fig. 15), which is consistent with the early experimental findings by Shimomura et al. [260], Optical micrographs show that HDA Si is highly reflective, whereas LDA Si is dark colored and nonreflective. This finding again supports that the LDA-HDA transition of Si is accompanied by a semiconductor-metal transition. Reverse transitions with large hysteresis were also observed LDA Si began to form from HDA Si at 4-6 GPa after decompression from --20 GPa. 

Figure 4-40 In situ Raman spectra of a C6o film taken during rubidium doping (a) superconducting and (b) insulating. (Reproduced with permission from Ref. 58. Copyright 1992 American Chemical Society.)...

Figure 6 In situ Raman spectra of MoOj/Zr02 catalysts at 800 °C top 2wt% middle 5wt% bottom 10wt%... 

In situ Raman spectra of amorphous carbon grains irradiated with 3 keV He+ ions at different fluences are reported in Fig. 5.1 The amorphous carbon grains have been produced by arc discharge between two amorphous carbon electrodes in an inert argon atmosphere. Transmission electron microscopy (TEM) studies... 

Fig. 12.4 In situ Raman spectra of DWCNTs (a) and SWCNTs (b) during nonisothermal oxidation in air. RBMs of DWCNTSs (c) and SWCNTs (d) before and after oxidation. Spectra were recorded using a 633-run excitation wavelength...

Fig. 12.7 (a) Raman spectra and HRTEM images of as-received and vacuum-annealed (graphitized) MWCNTs. As-received nanotubes contain iron particles and amorphous carbon on their surface (inset), (b) Weight loss curves (TGA) of as-received, air-oxidized (0.25 h at 550°C), and graphitized MWCNTs. (c) In situ Raman spectra of nonisothermal oxidation of as-received MWCNTs. All Raman spectra were recorded using 633-nm laser excitation... 

FIG. 2 In situ Raman spectra of a Ceo film taken during potassium (kqiing. a, Initial (pristine) film b. Conducting film c. Insulating film (see text). 

Figure 8.37. In situ Raman spectra of dopamine oxidation in I M HBr at a carbon electrode surface. An IPDA detector was gated for 50 msec time increments ending at the times indicated after initiation of DA oxidation. The band at 1572 cm is from the electrogenerated orthoquinone, that at 1539 cm is from brominated quinone. (Adapted from Reference 33 with permission.)...

Under dehydrated conditions, the adsorbed moisture is removed and the in situ Raman spectra of the surface metal oxides differ markedly showing that the structures of the dehydrated species are very different from those of their hydrated counterparts (see references above in Section 6.2.2). These changes are not surprising since the influence of the net zero surface charge of the oxide support can only be exerted in an aqueous medium. For the dehydrated surface metal oxides, however, essentially the same molecular structures are seen on all the oxide supports for each supported metal oxide. ... 

Figure 2.5 shows the comparison between the ex situ and in situ Raman spectra of two films deposited in the same conditions. A peak at 2100 cm dramatically increases in intensity in the in situ spectrum (we will refer to it as C peak), as shown in Figure 2.5, whereas G and D bands undergo small changes from ex situ to in situ deposition. 

FIGURE 2.6 In situ Raman spectra of cluster assembled carbon films obtained with different excitation wavelengths a frequency-doubled Nd Yag (532nm) and a He-Ne (632.8 nm). In the inset dispersion of polycumulene peak (solid circles) and polyync peak (solid triangles). 

Figure 2. In situ Raman spectra of physical mixture of 4% MoOj/TiOj catalyst pellet during methanol oxidation at 230°C (a) before methanol oxidation, (b) 20 min, (c) 1 h, (d) 3 h, (e) 5 h, (f) after reaction, oxidation of catalyst for 30 min and (g) after reaction, oxidation of catalyst for 1 h.

In situ Raman spectra were recorded with a DILOR OMARS 89 spectrophotometer equipped with an intensified photodiode array detector. The emission line at 514.5 nm from Ar+ ion laser (Spectra Physics, Model 164) was used for excitation. The power of the incident beam on the sample was 36 mW. Before the acquisition of the spectrum the sample was heated up to 400°C (2°C/min) and kept at this temperature for 12h to obtain a complete dehydration of the surface. After cooling down to 300°C the spectra were recorded. The same procedure was used to acquire Raman signals of the pure Ti02 support. The final spectra of the catalysts were obtained by subtracting the Ti02 contribution. 

The molecular structures of the surface vanadium oxide species on the different supports were examined with Raman spectroscopy. The Raman spectrometer system possessed a Spectra-Physics Ar+ laser (model 2020-05) tuned to the exciting line at 514.5 nm. The radiation intensity at the samples was varied from 10 to 70 mW. The scattered radiation was passed through a Spex Triplemate spectrometer (Model 1877) coupled to a Princeton Applied Research OMA III optical multichannel analyzer (Model 1463) with an intensified photo diode array cooled to 233 K. Slit widths ranged from 60 to 550 m. The overall resolution was better than 2 cm l. For the in situ Raman spectra of dehydrated samples, a pressed wafer was placed into a stationary sample holder that was installed in an in situ cell. Spectra were recorded in flowing oxygen at room temperature after the samples were dehydrated in flowing oxygen at 573 K. 

Figure 14.25 In situ Raman spectra of a PANI/Sn02 film polarized in pH 3 solution (a) pristine material (b) after 4300 cycles—> 450 mV (c) after 3000 cycles—> 550 mV Bleaching at —300 mV.

Fig. 5.83. Raman spectra of Co(TMPP) in situ Raman spectra of (FeTMPP)20 in dioxygen-saturated upper trace) and dioxygen-free lower trace) aqueous solution of 0.1 M HCIO4, Aq = 457.9 nm, Pq = 200 mW, Prhe = 400 mV (based on data in [506])...

Because in situ Raman spectra can be recorded, this provides a particularly convenient and useful tool for following the kinetics of gas hydrate formation and decomposition. For example, such studies we e performed during methane hydrate formation. " The evolution of two peaks at 2905 and 2915 cm on hydrate formation from a single peak (at 2911 cm for methane dissolved in water) can be monitored as a function of time/temper-ature/pressure. The effect of adding various chemicals that retard the hydrate formation process was also studied (Refs. [22-24] see Fig. 3). 

Fig. 52 In situ Raman spectra from a hydrogenated Si electrode in a solution of 0.1 mol 1 NaF and a 20 % C2H5OH solution with different pH, respectively. 20 min after detection, in solution of pH = 9. Excitation line 632.8 nm.

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