CeO 2 support inhibits CaO sintering, and oxygen vacancy influences CO 2 hydrogenation performance, making CeO 2 widely applied in Integrated CO 2 capture and in-situ conversion technology for reverse water–gas shift (ICCC-RWGS). Oxygen vacancy concentration was dependent on the morphology of CeO 2 , which would affect metal dispersion and CO 2 hydrogenation conversion. However, Very little is known about the morphology effect of CeO 2 on the carbon capture and in-situ hydrogenation performance of DFMs. Here, Cu/CeO 2 with different CeO 2 morphologies was synthesized, and high Cu dispersion was achieved on Cu/CeO 2 -R, exhibiting the best CO 2 hydrogenation performance. Integrated Cu/CeO 2 with CaO by physical mixing method, CaO-Cu/CeO 2 was used to investigate the morphology effects of CeO 2 on the performance of CaO-Cu/CeO 2 for integrated CO 2 capture and conversion to CO. CaO-Cu/CeO 2 -R exhibited the best capture-hydrogenation performance (CO 2 conversion rate of 75 %, CO production rate of 9.72 mmol/g). The CeO 2 -R provided more surface oxygen vacancies, enhancing carbonate hydrogenation. The larger specific surface area and {1 1 0} crystal plane of CeO 2 -rod enhanced Cu dispersion, and the smaller particle size of CeO 2 -R enhanced its interaction with CaO, improving the cyclic stability of CaO-Cu/CeO 2 -R. The hydrogenation performance of CaO-Cu/CeO 2 was dependent on the morphology of CeO 2 , providing insights into the design of high-activity metal catalytic components in ICCC-RWGS.
Jin Yuan,Jinxing Mi,Weitao Zhao,Ke Zheng,Shaoqi Zhou,Jianjun Chen
Although ceria-based catalysts have been proven to be a promising alternative to conventional vanadyl catalysts for the selective catalytic reduction of NOx with NH3 (NH3–SCR), whether the interaction between tungsten (W) and CeO2 could be well established for enhancing SCR performance is still unclear. Herein, W/CeO2 catalysts with different CeO2 morphologies for SCR are fully investigated. Systematic characterization results confirmed that the crystalline WO3 phase was formed on W-loaded CeO2 nanocubes, nanospindles, and nanospheres. Intriguingly, the W/CeO2 nanorods exhibited exclusively polymeric tungstate species. This divergence originates from the distinct W-CeO2 interaction mediated by preferentially exposed {110} lattice planes, endowing the nanorod catalyst with stronger reducibility, more surface-active oxygen species, and acid sites. Consequently, the NH3–SCR activity followed the order W/CeO2 nanorods > W/CeO2 nanospindles > W/CeO2 nanocubes > W/CeO2 nanospheres. This work reveals the significant role of the CeO2 morphology in the dispersion and interaction of W species, which directly influences the NH3–SCR performance. The insight offers a valuable opportunity for the design of a more efficient SCR catalyst.
Li Chi,Zhang Yuanyuan,Li Chunya,Wan Qijin,Ke Qiang,Yang Nianjun
Four CeO 2 nanomaterials with the morphologies of a nanoplate (CeO 2 -p), a nanocube (CeO 2 -c), a porous triangular microplate (CeO 2 -t), and of a porous hierarchical rod-stacked nanobundle (CeO 2 -b) were synthesized using a hydrothermal method. They were characterized by scanning and transmission electron microscopies, X-ray diffraction and X-ray photoelectron spectroscopy. Electrochemical characterizations reveal the tuning of their morphology and the presence of exposed crystal planes of CeO 2 that can be realized by changing the alkali sources. Among these materials, the CeO 2 -b features the largest specific surface and lowest electron transfer resistance towards the redox probe Fe(CN) 6 3-/4- . The best voltammetric response to dopamine and epinephrine is thus achieved by using the Nafion-CeO 2 -b coated electrode. A sensitive and selective method was developed that can voltammetrically detect dopamine (with a peak near 0.13 V vs. SCE), and epinephrine (with a peak near 0.25 V vs. SCE). The detection limits are 2.9 and 0.67 nM, respectively.
Schematic representation of morphology tailoring of CeO 2 and electrochemical sensing of dopamine and epinephrine on these CeO 2 samples with different morphologies
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