SSITKA-DRIFTS

Assessing Formates as Potential Intermediates over Pt/Zr02 and Na-Doped Pt/Zr02 Catalysts Employing the SSITKA-DRIFTS Technique... 

In this contribution, the steady-state isotopic transient kinetic analysis-diffuse reflectance Fourier transform spectroscopy (SSITKA-DRIFTS) method provides further support to the conclusion that not only are infrared active formates likely intermediates in the water-gas shift (WGS) reaction, in agreement with the mechanism proposed by Shido and Iwasawa for Rh/ceria, but designing catalysts based on formate C-H bond weakening can lead to significantly higher... 

Jacobs, G., and Davis, B.H. 2007. Low temperature water-gas shift Applications of a modified SSITKA-DRIFTS method under conditions of H2 co-feeding over metal/ ceria and related oxides. Appl. Catal. A Gen. 333 192-201. 

Tibiletti, Meunier, Goguet, Burch, and coworkers—application of SSITKA-DRIFTS technique to elucidate intermediates during RWGS/WGS—dependency on catalyst type and feed conditions of the reactivity of formates/carbonates. 

The chemical structure of the active adsorbed NO species participating in the reaction path of the NO/H2/O2 lean de-NO reaction was determined by performing SSITKA-DRIFTS experiments. Initially, DRIFT spectra were recorded after 30 min of reaction in N0/H2/02 at 140 °C. The reaction feed stream was then switched to the equivalent isotopic N0/H2/02 gas mixture, and DRIFT spectra were recorded after 30 min of continuous reaction. After appropriate IR band deconvolution, it was found that only two IR bands provided the red isotopic shift (shift to lower by 30-50 cm ) and which were assigned to two different in structure NO species [21]. The first one is the nitrosyl species (NO -s) formed on the support (IR band at 2220 cm Figure 26.7a) and the second one is the bidentate nitrate also formed on the support (IR band at 1540 cm . Figure 26.7a, inset). In the case of Pt/Si02, the two active NO species correspond to nitrosyls and unidentate nitrates on Pt [21]. 

Transient isotopic techniques (e.g., SSITKA-DRIFTS, SSITKA-MS, 2, NO, and N 0-pulsing) were used only to a small extent toward a better understanding of important but complex mechanistic issues of lean-burn deNO catalytic systems. The need of use of such techniques shoidd be enhanced as illustrated in the present case of H2-SCR for stationary sources. 

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