Calcined Cu10-Al shows two reductio

Calcined Cu10-Al shows two reduction peaks at 130 and 180
C. These two components are shifted towards lower temperature with respect to pure bulk CuO, which exhibits two reduction peaks centred at 240 and 315
C (data not reported). In the case of pure bulk Cu2O, a single component is present at 350
C (data not reported). The TPR profile of the calcined Cu10-Al indicates the absence of Cu2O, consistently with the XRD data. No appreciable effect of the thermal oxidative treatments on the reduction of the Cu was detected. Cu species appear to interact with the support more weakly than Ni species. New broad peaks (400–900
C temperature range) are observed in the TPR spectra only after the re-oxidation at 900
C. These new features can be attributed either to CuOx crystallites with different dimensions, or to the CuOx species which interact differently with the support: the stronger the interaction, the higher the reduction temperature.