whereνis the C-O stretch frequency. Figure4eillustrates the variation of the computed Stark tuning rates against the dipole moments of Au, Cu, Pd, and Pt surfaces. We find that the computed Stark tuning rates are in the range of 0–20 cm−1/V, in line with the previous work66,6...
A sensible chemical effect of the alloying on the CO stretching frequency has been put in evidence when Pt surface segregation occurs. The red-shift of the band compared with that of pure Pt indicates that in the alloy the Pt atoms make a bond with CO with a higher backdonation character....
For Pt nanoparticles supported on a-Al2O3, CO stretching frequencies below 2,100 cm À 1 have been rigorously assigned to metallic adsorption sites on nanoparticle surfaces at either well-coordinated (B2,090 cm À 1) or undercoordinated (B2,070 cm À 1) Pt sites41, but CO adsorbed ...
RAIRS results show that carbon monoxide on β-Mo 2 C at 100 K is characterized by a single CO vibrational stretching frequency, typical of on-top adsorption, which increases from 2057 to 2072 cm 1 as a function of increasing coverage. Preadsorption of oxygen leads to a broadening to ...
The frequency shift is attributed to an ion-dipole interaction between adsorbed CO and support cations. The ion-dipole interaction is screened by the adsorbed water leading to a smaller red shift in the CO stretching frequency. 展开 关键词: Infrared spectroscopy DRIFT FT-IR CO adsorption Pt/K-...
For cations inside the main channels of the zeolite, the C-O stretching frequencies increase continuously from 2155 cm(-1) for Cs+ up to 2188 cm(-1) for Li+. Cations located at the bottom of the side pockets were found to induce a smaller shift from the frequency corresponding to the ...
The results show that this band cannot be attributed to a C−O stretching frequency of the CO from the gas-phase incorporated into a CO−O surface complex, such as that identified as the transition state in recent density-functional theory (DFT) calculations of the Pt{111}/CO + O2 ...
The C–O stretching frequency at saturation coverages observed by IRRAS represents these structural differences clearly. For 1–4 ML thick fcc Fe films C–O stretch is located at 2000 cm−1 and the 6–8 ML thick films yield two C–O stretch bands at 2000 and 2032 cm−1, the latter...
The 1H signals at 4.9 ppm and 4.13–4.33 pm correspond to the methine (Hc) and methylene (Hd) carbon linked to carbonate unit (when X=CO3) indicates the presence of carbonate linkage (Supplementary Figure 9a) and further it was supported by the IR which shows a stretching frequency ...
We collected IRAS spectra for the prepared samples before and after exposure to 13CO to observe the peak corresponding to the 13CO stretching mode. This method, known as the CO probe method, is commonly used to investigate the chemical states of Pt16,17,18,19. It should be noted that at...