Promoting effect of Pt, Pd and Rh noble metals to the Ni0.03Mg0.97O solid solution catalysts for the reforming of CH4 with CO2 Original Research Article

Reforming of CH4 with CO2 to produce synthesis gas was studied over Ni0.03Mg0.97O solid solution catalyst and its bimetallic derivative catalysts which contained small amounts of Pt, Pd and Rh, respectively (the atomic ratio of M/(Ni+Mg) was varied from 0.007 to 0.032%, M=Pt, Pd or Rh). It was found that there was a significant promotion in both activity and stability due to the addition of noble metals. The optimum loadings of these noble metals were observed at the atomic ratio of M/(Ni+Mg) ≈0.021%. Temperature programmed hydrogenation (TPH) of carbonaceous species formed during the catalytic reaction indicated that the good resistance of Ni0.03Mg0.97O solid solution to carbon deposition was retained on the bimetallic catalysts. Furthermore, we obtained a clear evidence showing the formation of Pt—Ni alloy particles by means of TEM and EDS observation. The kinetic study and temperature programmed reaction (TPR) of CH4 suggest that CH4 decomposition as the rate-determining step on the Ni0.03Mg0.97O is accelerated by the alloy formation. The improved stability was attributed to the promotion in catalyst reducibility.