Figure 9
DRIFTS spectra of the Cu K edge of the sample (1%Cu/SiO2) during reduction under CO. (a) Selected spectra at different temperatures, showing the three steps of the evolution of copper carbonyl, and (b) detail of the evolution of the carbonyl region during reduction. From 25 to 220°C, the intensity increases while the centre moves to higher wavenumbers; from 220 to 300°C, the intensity decreases without any shift in the signal. The IR signal-to-noise ratio is not good since the sample becomes dark during the reduction and SiO2 at room temperature was used as background. |