The water gas shift reaction over Pt–CeO₂ nanoparticles confined within mesoporous SBA-16

Abstract

Novel nanocomposite catalysts for the single step Water Gas Shift Reaction (WGSR) were prepared by deposition–precipitation and impregnation of Pt–CeO2 nanophases onto an ordered mesoporous silica support featuring a cubic arrangement of mesopores (SBA-16 type). The highly interconnected porosity of the SBA-16 developed in three dimensions (3D) provides a scaffold which is easily accessible to reactants and products by diffusion. The textural and morphological properties of the final catalyst were affected by the procedure utilized for dispersion of the nanophases onto SBA-16. The catalysts prepared by deposition–precipitation present highly dispersed nanocrystalline CeO2 on the surface of SBA-16 and retain a high surface area, high thermal stability and high Pt accessibility. The catalysts prepared by impregnation show improved Pt–CeO2 interaction but a more significant decrease of surface area compared to pure SBA-16, due to the confinement of the CeO2 crystallites within the mesoporous matrix. As a result, the catalysts prepared by deposition–precipitation are effective for the WGSR under working conditions in the high temperature range (around 300–350 °C), whereas the catalysts prepared by impregnation are suitable for the process operating at low temperature. Our results point out that these catalyst preparation procedures can be used to optimise the performance of heterogenous catalysts, by controlling the CeO2 crystallite size and optimizing the Pt–CeO2 contact by embedding. Improved thermal and chemical stabilities were achieved using a mesoporous scaffold

Elucidation of metal and support effects during ethanol steam reforming over Ni and Rh based catalysts supported on (CeO2)-ZrO2-La2O3

“…The combined promotional effects of metal and support are further demonstrated by the observed COx selectivities. CO2 selectivity (Figure 2b) over both the Ni and Rh catalysts supported on CeO2-ZrO2-La2O3 is much higher to that obtained over the ZrO2-La2O3 catalysts, especially at the lower temperatures, in very good agreement with the well-recognised high activity of ceria in the water gas shift reaction [51][52][53]. ZrO2, on the contrary, as also evidenced from the TPR profiles, has insignificant reducibility.…”

Determining the maximum lanthanum incorporation in the fluorite structure of La-doped ceria nanocubes for enhanced redox ability

“…Ceria nanomaterials have attracted much attention due to their extraordinary reactivity, stemming from the capacity to store and release oxygen ions depending on the oxygen partial pressure of the environment. [1][2][3][4][5][6] This reactivity originates from the labile and reversible redox cycle between Ce 4+ and Ce 3+ , which is enhanced at the nanoscale and generates the equilibrium given in eqn (1), using the Kröger-Vink notation:…”

Cu/CeO2 Catalyst for Water‐Gas Shift Reaction: Effect of CeO2 Pretreatment

“…The CO can be utilized for the production of H 2 through the WGS reaction, for which Fe−Cr and CuO/ZnO/Al 2 O 3 catalysts are commercially used. Unfortunately, high reaction temperature is needed for the former, while the latter is pyrophoric and susceptible to chemical poisoning . Therefore, there are ongoing researches on the development of novel WGS catalysts…”