(626d) Understanding the Role of Fe in Bi-Metallic Ni-Fe Dry Reforming Catalysts: A Combined in-Situ XAS-XRD Study | AIChE

(626d) Understanding the Role of Fe in Bi-Metallic Ni-Fe Dry Reforming Catalysts: A Combined in-Situ XAS-XRD Study

One major drawback of Ni-based dry reforming (CH4 + CO2 â?? 2CO + 2H2) catalysts is coke formation.1,2 In order to overcome this limitation, bi-metallic Ni-Fe catalysts have been developed, synthesized via a hydrotalcite-based precursor. Here, Ni and Fe are embedded in a thermally stable MgxAlyOz matrix. The formation of alloyed Ni-Fe nanoparticles was confirmed via TEM-EDX, XRD and XAS measurements. The catalytic performance of monometallic Ni and Fe as well as the Ni-Fe bimetallic catalysts was evaluated at 650 °C. It was found that the bi-metallic catalysts, in particular, Ni4Fe1 (2.6 h-1 of TOFCH4) have a high activity and stability, whereas fast deactivation and a low catalytic activity was observed for monometallic Ni (1.8 h-1 of TOFCH4) and Fe (0.4 h-1 of TOFCH4) catalysts, respectively. In-situ XAS and XRD analysis in combination with Raman, TEM, TGA and TPO allowed us to elucidate the underlying reason for the high activity and stability of the bimetallic Ni-Fe catalyst. The formation of FeO was observed in bimetallic Ni-Fe catalysts via in-situ XAS measurement, whereas metallic Ni0 was maintained in both Ni and Ni-Fe catalysts. Furthermore, using combined in-situ XAS and XRD experiments, we could demonstrate that FeO removes the carbon deposited via a redox mechanism (C + FeO â?? CO + Fe).

References

  1. V.C.H. Kroll, H.M. Swaan, S. Lacombe, C. Mirodatos, J. Catal.,1996, 2, 387-398
  2. E. Ruckenstein and Y.H. Hu, J. Catal.,1996, 2, 230-238
  3. S. A. Theofanidis, V. V. Galvita, H. Poelman, G. B. Marin, ACS Catal., 2015, 5, 3028-3039.