Reduced graphene oxide (rGO) as new support of cobalt/lanthanum oxide for the water gas shift reaction (WGSR)

In this work we prepared Cobalt-Lanthanum oxide supported on reduced graphene oxide (rGO) for the water-gas shift reaction (WGSR). The reduced graphene oxide support was synthesized and then impregnated with cobalt (15% wt.) and lanthanum (10% wt.) nanoparticles using the precipitation-deposition method. The textural and morphologic characterization techniques confirmed that both catalysts presented small and high-dispersed nanoparticles and high surface area. The support structure was also preserved, according to XRD and Raman analyses. XPS results showed that La promotion increased the concentration of Co2+ species, and the reducibility. CO conversions and H2 yields were close to thermodynamic equilibrium values above 400 °C. The WGS catalytic test results ratified that the La promoter improved significantly the H2 yield above 275 °C and inhibited methane formation at low temperatures. Results show that La2O3 react with H2O and subsequently with CO2 increasing H2 formation. [Display omitted] •Co–La supported on reduced graphene oxide (rGO) for the water gas shift reaction.•Catalysts present high dispersed nanoparticles and area; rGO structure preserved.•XPS showed that lanthanum oxide evidenced strong influence on Cobalt reducibility.•LaCo catalysts present high CO conversion and H2 yields at high temperatures.•La-promoted higher CO conversions at low temperatures and inhibits CH4 formation.