Rapid microwave assisted sol-gel synthesis of CeO2 and CexSm1-xO2 nanoparticle catalysts for CO oxidation

Polychronopoulou, Kyriaki; Zedan, Abdallah F.; Katsiotis, Marios S.; Baker, Mark; AlKhoori, Ayesha A.; AlQaradawi, Siham Y.; Hinder, Steven J.; Alhassan, Saeed M.

doi:10.1016/j.molcata.2016.11.039

Cited by 66 publications

(37 citation statements)

References 66 publications

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“…The apparent activation energy (E a ) of selected catalysts were determined from the Arrhenius plots (ln (r CO ) vs. 1/T) using reaction rate data obtained in the linear region of <20% CO conversion [3,57,58]. Figure 9a-c compares the plots of the CO fractional conversion (X CO ) vs. W/F CO at different temperatures in the range of 60-125 • C for the three selected catalysts.…”

Section: Kinetic Studiesmentioning

confidence: 99%

“…The heterogeneous catalytic oxidation of carbon monoxide (CO) is an important reaction for CO removal in many environmental and industrial applications such as air purification, closed-cycle CO 2 lasers, the purification of hydrogen from CO traces in polymer electrolyte membrane fuel cell systems [1], and the removal of toxic CO from flue and exhaust gas emissions [2,3]. Precious noble metals such as Ru, Pt, Au, and Pd supported on reducible metal oxides are known for their high catalytic activity for CO oxidation.…”

Section: Introductionmentioning

confidence: 99%

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A Study of Low-Temperature CO Oxidation over Mesoporous CuO-TiO2 Nanotube Catalysts

2017

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Supported copper oxide nanoparticles have attracted considerable attention as active and non-precious catalysts for many catalytic oxidation reactions. Herein, mesoporous xCuO-TiO 2 nanotube catalysts were fabricated, and their activity and kinetics toward CO oxidation were studied. The morphology and structure of the prepared catalysts were systematically studied using SEM, TEM, EDS, EDX, XRD, TGA, BET, XPS, H 2 -TPR, and Raman techniques. The BET surface area study revealed the effect of the large surface area of the mesoporous TiO 2 nanotubes on promoting the catalytic activity of prepared catalysts. The results also revealed the existence of strong metal-support interactions in the CuO-TiO 2 nanotube catalyst, as indicated by the up-shift of the E 2g vibrational mode of TiO 2 from 144 cm −1 to 145 cm −1 and the down-shift of the binding energy (BE) of Ti 2p 3/2 from 458.3 eV to 458.1 eV. The active phase of the catalyst consists of fine CuO nanoparticles dispersed on a mesoporous anatase TiO 2 nanotube support. The 50-CuO-TiO 2 nanotube catalyst demonstrated the highest catalytic activity with 100% CO conversion at T 100 = 155 • C and a reaction rate of 36 µmole s −1 g −1 . Furthermore, the catalyst demonstrated excellent long-term stability with complete CO conversion that was stable for 60 h under a continuous stream. The enhanced catalytic activity is attributed to the interplay at the interface between the active CuO phase and the TiO 2 nanotubes support.

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Section: Kinetic Studiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Study of Low-Temperature CO Oxidation over Mesoporous CuO-TiO2 Nanotube Catalysts

2017

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“…Pure and mixed rare-earth and transition metal oxides can be synthesized by several physical and wet-chemical methods, such as sonochemical [33], mechanical mixing [25], chemical precipitation [42], freeze-drying [34], conventional hydrothermal synthesis [35], microwave-assisted synthesis [38], sol-gel preparation [43] and solution combustion synthesis [36]. Solution combustion synthesis (SCS) has received a great deal of interest because of its ability to yield high-surface area materials, with ease of scalability, minimal preparation steps and almost no post-synthesis treatment is needed, significantly reducing the time needed for preparation and processing, allowing a simple and rapid obtainment of solid products [44,45,46].…”

Section: Resultsmentioning

confidence: 99%

Combustion Synthesis of Non-Precious CuO-CeO2 Nanocrystalline Catalysts with Enhanced Catalytic Activity for Methane Oxidation

Zedan

Aljaber

2019

Materials

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In this study, xCuO-CeO2 mixed oxide catalysts (Cu weight ratio x = 1.5, 3, 4.5, 6 and 15 wt.%) were prepared using solution combustion synthesis (SCS) and their catalytic activities towards the methane (CH4) oxidation reaction were studied. The combustion synthesis of the pure CeO2 and the CuO-CeO2 solid solution catalysts was performed using copper and/or cerium nitrate salt as an oxidizer and citric acid as a fuel. A variety of standard techniques, including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were employed to reveal the microstructural, crystal, thermal and electronic properties that may affect the performance of CH4 oxidation. The CuO subphase was detected in the prepared solid solution and confirmed with XRD and Raman spectroscopy, as indicated by the XRD peaks at diffraction angles of 35.3° and 38.5° and the Ag Raman mode at 289 cm−1, which are characteristics of tenorite CuO. A profound influence of Cu content was evident, not only affecting the structural and electronic properties of the catalysts, but also the performance of catalysts in the CH4 oxidation. The presence of Cu in the CeO2 lattice obviously promoted its catalytic activity for CH4 catalytic oxidation. Among the prepared catalysts, the 6% CuO-CeO2 catalyst demonstrated the highest performance, with T50 = 502 °C and T80 = 556 °C, an activity that is associated with the availability of a fine porous structure and the enhanced surface area of this catalyst. The results demonstrate that nanocrystalline copper-ceria mixed oxide catalysts could serve as an inexpensive and active material for CH4 combustion.

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“…Cerium oxide, although thermally unstable [65], is known to possess high oxygen storage capacity (OSC) and redox properties (Ce 4+ /Ce 3+ ) that help to improve the dispersion of the active sites and decrease carbon deposition on the catalyst surface by promoting carbon oxidation reactions. Moreover, CeO 2 can help to achieve strong interaction with the supported metal (improving the stability of the active phase against sintering), and also increase basicity, which leads to the adsorption and activation of CO 2 on the support sites [66][67][68][69][70].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Noble Metal (M: Ir, Pt, Pd) on M/Ce2O3-γ-Al2O3 Catalysts for Hydrogen Production via the Steam Reforming of Glycerol

et al. 2020

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A promising route for the energetic valorisation of the main by-product of the biodiesel industry is the steam reforming of glycerol, as it can theoretically produce seven moles of H2 for every mole of C3H8O3. In the work presented herein, CeO2–Al2O3 was used as supporting material for Ir, Pd and Pt catalysts, which were prepared using the incipient wetness impregnation technique and characterized by employing N2 adsorption–desorption, X-Ray Diffraction (XRD), Temperature Programmed Reduction (TPR), Temperature Programmed Desorption (TPD), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The catalytic experiments aimed at identifying the effect of temperature on the total conversion of glycerol, on the conversion of glycerol to gaseous products, the selectivity towards the gaseous products (H2, CO2, CO, CH4) and the determination of the H2/CO and CO/CO2 molar ratios. The main liquid effluents produced during the reaction were quantified. The results revealed that the Pt/CeAl catalyst was more selective towards H2, which can be related to its increased number of Brønsted acid sites, which improved the hydrogenolysis and dehydrogenation–dehydration of condensable intermediates. The time-on-stream experiments, undertaken at low Water Glycerol Feed Ratios (WGFR), showed gradual deactivation for all catalysts. This is likely due to the dehydration reaction, which leads to the formation of unsaturated hydrocarbon species and eventually to carbon deposition. The weak metal–support interaction shown for the Ir/CeAl catalyst also led to pronounced sintering of the metallic particles.

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Rapid microwave assisted sol-gel synthesis of CeO2 and CexSm1-xO2 nanoparticle catalysts for CO oxidation

Cited by 66 publications

References 66 publications

A Study of Low-Temperature CO Oxidation over Mesoporous CuO-TiO2 Nanotube Catalysts

A Study of Low-Temperature CO Oxidation over Mesoporous CuO-TiO2 Nanotube Catalysts

Combustion Synthesis of Non-Precious CuO-CeO2 Nanocrystalline Catalysts with Enhanced Catalytic Activity for Methane Oxidation

The Effect of Noble Metal (M: Ir, Pt, Pd) on M/Ce2O3-γ-Al2O3 Catalysts for Hydrogen Production via the Steam Reforming of Glycerol

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