Functionalization of oxides with chemical groups such as �NH2, -CN, -COOH, is an interesting route to prepared metal-supported catalysts since it favors a firmly attachment of the metal species and improvement of metal loading and dispersion. In this work we explore the functionalization of CeO-2- nanorods (~11 x 70 nm2) with 3-aminopropyltrimethoxysilane (APTMS) to address its impact on catalytic activity of Cu/CeO2 catalysts under water-gas shift reaction (WGS). The WGS refers to the conversion of CO with steam producing CO2 and H2 and copper catalysts are usually under low temperature regime, below 230 oC. Interestingly, the studies revealed a negative effect of the functionalization, decreasing by half the CO conversion under the same conditions. A set of characterization techniques were used to address this result. We found that the functionalization decreased the surface area (from 96 to 53 m2/g) and truncated the length of the CeO2 nanorods (from ~70 to 40 nm), but did not affect the mean nanorod diameter. The APTMS totally covers the CeO2 surface and after calcination created a thin silica layer, detected by nuclear magnetic resonance. Cu2+ was well dispersed on the CeO2 nanorod surfaces, and we did not find a significant improvement due to the functionalization. A minor population of large Cu nanoparticles (~13 nm) was detected by X ray diffraction but it was similar to bare and functionalized nanorods. The results suggest that the thin silica layer formed between metallic copper and CeO2 nanorod hinders the Cu-CeOx interaction that favors H2O activation, decreasing the catalyst performance.

Negative impact of functionalization of Cu/CeO<sub>2</sub> catalysts for hydrogen production

247th National Meeting (2014)

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Negative impact of functionalization of Cu/CeO2 catalysts for hydrogen production

Negative impact of functionalization of Cu/CeO₂ catalysts for hydrogen production