Inverse CeO2/CuO catalysts prepared by different precipitants for preferential CO oxidation in hydrogen-rich streams

Abstract

The inverse CeO 2 /CuO catalysts were prepared by different precipitants, and characterized via XRD, ICP, SEM, H 2 -TPR, Raman, TEM and N 2 adsorption-desorption techniques. The study showed that the inverse CeO 2 /CuO configurations were formed and copper is mainly present in the form of bulk CuO in the as-synthesized catalysts.It was found that the length of the contact interface between CeO 2 and CuO was closely associated with the crystal size of CeO 2 and CuO. The CeO 2 /CuO catalysts using urea, NaOH and TMAH (tetramethylammonium hydroxide) as precipitants presented a better catalytic performance for CO oxidation below 185 °C in the hydrogen-rich streams due to some amount of copper-ceria interfacial sites in the catalysts.

X-ray absorption spectroscopy study and photocatalyst application of CuO and Cu0.9Ti0.1O nanoparticles

“…The intermediate complexes of Cu(OH) 2 and Ti(OH) 4 are expected to combine and form Cu 1Àx Ti x O granules in the colloidal medium. During the drying process, at 100 C, the residual water vapors and other chemical gases are expected to eliminate.…”

“…Fourthly; dissimilar to the Cu 2 O, the CuO does not deactivate by the photo-corrosion in the photocatalyst reaction [12]. There are several reports available on the synthesis of CuO NPs using; (i) soft template assisted method (polymers, surfactants and capping agents were used) [13], reverse microemulsion-impregnation method (cyclohexane, triton-X-100 and n-hexanol solutions were used) [2] and solution combustion technique (citric acid, urea and nitric acid were used) [14]. These techniques, however, offer synthesis of CuO NPs but the use of hazardous chemicals and precarious experimental conditions (high operating temperature etc.)…”

Structural features and catalytic performance in CO preferential oxidation of CuO–CeO2 supported on multi-walled carbon nanotubes

“…[51][52][53][54] Carbon nanotubes (CNT) have proved particularly attractive and competitive in catalytic processes owing to the combination of their distinctive morphology and electronic, adsorption, mechanical and thermal properties. 55,56 Recent research interest has been triggered in creating novel composites of CNT-confined or supported metal or oxide nanoparticles and exploring their beneficial effects on the catalytic properties.…”

“…Alternatively, inverse configuration CeO 2 /CuO catalysts were recently developed in order to enhance the selectivity to CO oxidation at a higher reaction temperature due to the decreased reducibility of large size CuO particles. [51][52][53][54] Carbon nanotubes (CNT) have proved to be particularly attractive and competitive in catalytic processes owing to the combination of their distinctive morphology and electronic, adsorption, mechanical and thermal properties. 55,56 Recent research interest has been triggered in creating novel composites of CNT-confined or supported metal or oxide nanoparticles and exploring their beneficial effects on the catalytic properties.…”

Searching for cheaper catalysts with high activity and stability in Ce–M–O systems (M = Fe, Co, Ni)

“…As a quite important rare earth material, CeO 2 has many important applications including gas sensors, 1 solid oxide fuel cells, 2 ceramic additives, 3 heterogeneous catalysts, 4 and so on. Among these application domains, CeO 2 is widely taken as a heterogeneous oxidation catalyst due to its excellent oxygen storage/release capacity (OSC), 5 essential for NO x reduction, [6][7][8] soot oxidation, [9][10][11] CO removal, 10,12 and hydrocarbon/alcohol reforming. [13][14][15][16] Despite these merits, there are still many problems that cannot be ignored: one of which is reducing the catalyst price while maintaining the high catalytic performance.…”