Capturing metal-support interactions in situ during the reduction of a Re promoted Co/γ-Al₂O₃ catalyst

The reduction of a Re promoted Co/γ-Al₂O₃ catalyst was monitored in situ by synchrotron X-ray powder diffraction (XRPD) under H₂ environment. Whole powder pattern analysis revealed a non-linear expansion of the unit cell of γ-Al₂O₃ during the reduction process, suggesting the diffusion of Co cations into the structure of the support. The non-linear cell expansion coincided with the formation of a CoO phase. In addition, space resolved diffraction at the inlet and the outlet of the reactor evidenced a negative effect of the partial pressure of indigenous H₂O_(g) on the reduction process.