We completed a kinetic study of Pd supported on different metal oxides. The kinetic measurements were carried out at 280°C, 1 bar, 7% CO, 22% H2O, 8% CO2, 37% H2, and balance Ar. The gas composition represents a typical outlet concentration of a methane steam reformer. At these conditions the TOR normalized by the exposed Pd surface area increased as a function of the support (Al2O3 (2.6 x 10-3 s-1) < SiO2 (6.6 x 10-3 s-1) < Nb2O5 (7.4 x 10-3 s-1) < Cr2O3 (7.9 x 10-3 s-1) < La2O3 (2.6 x 10-2 s-1) < TiO2 (2.7 x 10-2 s-1) < ZrO2 (4.9 x 10-2 s-1) < CeO2 (6.7 x 10-2 s-1)). In the case of La2O3, TiO2, ZrO2 and CeO2, the TOR changed by less than a factor of 3 suggesting that support reducibility did not have a strong effect on the TOR under the conditions studied. However, catalysts supported on silica and alumina showed a TOR about 10 times lower than on these four supports suggesting that alumina and silica have a deleterious effect on the rates. In general, the WGS rate could be described by the power rate law expression rate ~ [CO]0.5 [H2O]0.5 [H2O] -0.5. With the exception of La2O3, a decrease in electronegativity of the metal M in the metal oxide support MxOy corresponded to an increase in rate. There was also a compensation effect between the measured apparent activation energies and pre-exponential factors. For Pd on Al2O3 there was no dependence of particle size (4-14 nm) on the TOR. The selectivity towards the formation of methane (CO + 3H2 → CH4 + H2O) was affected by two factors, namely support and particle size. First, at similar particle size and temperatures, supports that had high WGS TOR showed no methanation activity under the conditions studied compared to supports with low WGS TOR. Second, larger particle sizes meant higher methanation TOR. For Pd/Al2O3 the methanation TOR increased by a factor of 8 when the particle size grew from 4 to 14 nm. It was found that by tuning the particle size, it is possible to decrease (increase) the CH4 selectivity on supports with low (high) WGS TORs. Thus, 12 nm Pd particles on TiO2 showed methanation TOR (8.3 x 10-4 s-1) as high as Pd (14nm) on Al2O3, while 3 nm Pd particles on SiO2 showed no methanation activity.