Methane Dry Reforming over Rh and Ru Based Pyrochlore

Dry reforming of methane was studied over LSZ pyrochlore catalysts containing Rh and Ru. The 1%LSRZ and 1%LSRuZ catalysts were synthesized using a variation of Pechini method. Both the catalysts have a Lanthanum Strontium Zirconate support with Rhodium or Ruthenium substitution. The catalysts were characterized by TPR, XRD, and ICP. Five cycles of TPR's were carried out for each catalyst with intermediate TPO’s. The results showed an increase in reducibility for both the catalysts from one cycle to another. The catalysts were tested for their dry-reforming activities at different temperatures. Long time (90 hrs) testing of the catalysts were carried out at a reference temperature of 700 °C. The results showed that the Ru-substituted catalyst deactivated quickly, whereas the Rh-substituted catalyst showed practically no deactivation with time-on-stream. Post-reaction TPO for the catalysts showed carbon deposition in various forms – amorphous, polymeric, and graphitic. Even though 1%LSRuZ shows deactivation with time-on-stream, the catalyst exhibited lesser carbon deposition on the surface. This work clearly shows the effect of metal on the progress of the reaction and Rh metal was thus identified to be a better active metal for the dry reforming reaction.