Gold supported on Gd-doped CeO2 nanorods applied as water-gas shift catalyst under H2 rich stream

Abstract

In this work, we report the synthesis of catalysts based on ceria nanorods (CeO2NRs) doped with 3% and 5% mol gadolinium. The supports were obtained from cation co-precipitation hydrothermal synthesis over which gold nanoparticles (AuNPs) were deposited by the deposition-precipitation (DP) methodology, allowing the Au nanoparticles size control at around 3 nm. The catalysts were evaluated in water gas shift reaction and showed high activity under a H2 rich stream (7%CO/7%CO2/14%N2/42%H2/30%H2O) with steam/process gas molar ratio (S/G) of 0.3 at 300 and 250 °C. The results revealed that Gd-doping increased the oxygen vacancies concentration due to the insertion of a trivalent cation in ceria lattice. In addition, the synergistic effect between AuNPs and Gd-doped CeO2 provided the increase of reducibility and oxygen storage capacity (OSC). These properties were associated with the catalytic activity in water gas shift reaction. The nanostructured materials decreased the CO concentration under conditions of H2 rich stream, indicating the catalysts potential for industrial applications after further studies. The catalyst doped with 5% mol Gd was the most active and achieved 24% of CO conversion at 300 °C.