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Temperature-programmed diffuse reflectance infrared Fourier transform spectroscopy (TPDRIFTS) is proposed to follow in situ temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) experiments of catalytic systems, as a method for observing relationships between the surface structure and the reducibility of the catalyst under the actual reaction conditions. TPDRIFTS studies of desorption and reduction of a conventional V2O5/TiO2 catalyst have been carried out, showing the presence in both processes of four stages. Both desorption and reduction experiments result in similar DRIFTS spectra for temperatures below 400 °C, accounting for two processes: (1) water desorption and (2) condensation of highly dispersed vanadium species in between V2O5 islands on the anatase surface. V2O5 reduction by H2 takes place between 400 and 680 °C, being characterized by elimination of the first-overtone bands of V= O groups. DRIFTS is shown to be a very powerful tool to characterize both hydrogen-consuming and nonconsuming processes such as O= migration above 725 °C (stage IV). Relationships between the area of V = O overtones bands obtained by TPDRIFTS and the oxidation state of vanadium are proposed as a method to estimate this parameter under actual reaction conditions.

The reactivity of a Lu2O3-promoted Rh/Al2O3 catalyst in the CO/H2 reaction is reported. Methane, heavier hydrocarbons, methanol, and ethanol are obtained. In situ DRIFTS has been employed to record the infrared spectra under the actual reaction conditions. The structure of the observed COads DRIFTS bands has been resolved into its components. The production of oxygenates (methanol and ethanol) has been correlated with the results of the deconvolution calculation. Specific sites for the production of methanol and ethanol in the CO/H2 reaction over a Rh,Lu2O3/Al2O3 catalyst are proposed.

In this work the experimental details and some examples of applications of diffuse reflectance infrared technique are described. Special interest has been devoted to a correct determination of the temperature of the sample, to gas-phase analysis, and to quantitative aspects in a DRIFTS controlled environmental cell. Applications to the analysis of the gas phase during catalytic hydrogenation and to the obtainment of kinetic parameters for the catalytic decomposition of adsorbates are included.

A diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) chamber suitable for in situ and simultaneous analysis of the infrared and electrical response of sensors is tested and described in detail. Experiments on a CdGeON sensor show some results about its reversible/ irreversible behavior in terms of temperature and under N2 atmosphere. A direct relationship between the conductivity and the elimination of DRIFTS peaks at 810,780, and 580 cm−1 is observed. From both DRIFTS spectra and conductivity measurements, an explanation involving the presence and filling of vacancies in the solid framework is proposed.