The fabrication of hollow ZrO2nanoreactors encapsulating Au–Fe2O3dumbbell nanoparticles for CO oxidation

Yang, Fan; Wu, Chunzheng; Yu, Hongbo; Wang, Shiwei; Li, Tong; Yan, Bo; Yin, Hongfeng

doi:10.1039/d1nr00173f

Cited by 6 publications

(4 citation statements)

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“… 21 , 22 The fitting peaks with binding energies of approximately 718.7 and 732.3 eV corresponded to satellite peaks. 23 An XPS quantitative analysis showed that the ratio of Fe 2+ to Fe 3+ on the sample surface was approximately 0.526, very close to that (0.5) in Fe 3 O 4 , 5 proving again that these NPs consisted of Fe 3 O 4 . According to peak fitting of the O 1s XPS fine spectra, the peak with binding energy ∼529.6 eV corresponded to lattice oxygen O 2– , 24 the peak with binding energy ∼530.9 eV corresponded to surface OH – , and the peak with binding energy ∼533.4 eV corresponded to H 2 O adsorbed on the surface.…”

Section: Resultsmentioning

confidence: 83%

“…Figure c,d shows the XPS fine spectra of Fe and O of Fe 3 O 4 magnetic NPs, respectively. The peak fitting of Fe showed that the fitting peaks with binding energies of approximately 710 eV (Fe 2p 3/2 ) and 723.5 eV (Fe 2p 1/2 ) corresponded to Fe 2+ , and those with binding energies of approximately 711.5 eV (Fe 2p 3/2 ) and 725.5 eV (Fe 2p 1/2 ) corresponded to Fe 3+ . , The fitting peaks with binding energies of approximately 718.7 and 732.3 eV corresponded to satellite peaks . An XPS quantitative analysis showed that the ratio of Fe 2+ to Fe 3+ on the sample surface was approximately 0.526, very close to that (0.5) in Fe 3 O 4 , proving again that these NPs consisted of Fe 3 O 4 .…”

Section: Resultsmentioning

confidence: 98%

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Concurrent Dual-Contrast Enhancement Using Fe₃O₄ Nanoparticles to Achieve a CEST Signal Controllability

Wang

et al. 2023

ACS Omega

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Traditional T 2 magnetic resonance imaging (MRI) contrast agents have defects inherent to negative contrast agents, while chemical exchange saturation transfer (CEST) contrast agents can quantify substances at trace concentrations. After reaching a certain concentration, iron-based contrast agents can "shut down" CEST signals. The application range of T 2 contrast agents can be widened through a combination of CEST and T 2 contrast agents, which has promising application prospects. The purpose of this study is to develop a T 2 MRI negative contrast agent with a controllable size and to explore the feasibility of dual contrast enhancement by combining T 2 with CEST contrast agents. The study was carried out in vitro with HCT-116 human colon cancer cells. A GE SIGNA Pioneer 3.0 T medical MRI scanner was used to acquire CEST images with different saturation radiofrequency powers (1.25/2.5/3.75/5 μT) by 2D spin echo−echo planar imaging (SE-EPI). Magnetic resonance image compilation (MAGiC) was acquired by a multidynamic multiecho 2D fast spin−echo sequence. The feasibility of this dual-contrast enhancement method was assessed by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, dynamic light scattering, ζ potential analysis, inductively coupled plasma, X-ray photoelectron spectroscopy, X-ray powder diffraction, vibrating-sample magnetometry, MRI, and a Cell Counting Kit-8 assay. The association between the transverse relaxation rate r 2 and the pH of the iron-based contrast agents was analyzed by linear fitting, and the linear relationship between the CEST effect in different B 1 fields and pH was analyzed by the ratio method. Fe 3 O 4 nanoparticles (NPs) with a mean particle size of 82.6 ± 22.4 nm were prepared by a classical process, and their surface was successfully modified with −OH active functional groups. They exhibited self-aggregation in an acidic environment. The CEST effect was enhanced as the B 1 field increased, and an in vitro pH map was successfully plotted using the ratio method. Fe 3 O 4 NPs could stably serve as reference agents at different pH values. At a concentration of 30 μg/mL, Fe 3 O 4 NPs "shut down" the CEST signals, but when the concentration of Fe 3 O 4 NPs was less than 10 μg/mL, the two contrast agents coexisted. The prepared Fe 3 O 4 NPs had almost no toxicity, and when their concentration rose to 200 μg/mL at pH 6.5 or 7.4, they did not reach the halfmaximum inhibitory concentration (IC 50 ). Fe 3 O 4 magnetic NPs with a controllable size and no toxicity were successfully synthesized. By combining Fe 3 O 4 NPs with a CEST contrast agent, the two contrast agents could be imaged simultaneously; at higher concentrations, the iron-based contrast agent "shut down" the CEST signal. An in vitro pH map was successfully plotted by the ratio method. CEST signal inhibition can be used to realize the pH mapping of solid tumors and the identification of tumor active components, thus providing a new imaging method for tumor efficacy evaluation.

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Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 98%

Concurrent Dual-Contrast Enhancement Using Fe₃O₄ Nanoparticles to Achieve a CEST Signal Controllability

Wang

et al. 2023

ACS Omega

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“…Micro/nanoreactors exhibit excellent electrochemical properties arising from the ion accumulation within confined geometry of the pores, 12,13 such as prolonging an intermediates lifetime and shortening the diffusion distance of both reactants and products. 14,15 Recently, our group reported the COFs as micro-reactors to improve the intensity and stability of the Ru(bpy) 3 2+ /TPA binary ECL system by providing a considerably confined and independent reaction environment for the electrochemical oxidation of TPrA and the survival of TPrA˙. 16 From this foundation, we designed an integrated ternary strategy by preparing pyrenecarboxaldehyde (Pyc) encapsulated porous titania (pTiO 2 ) nanospheres (Pyc@pTiO 2 ) as ECL nanoreactors.…”

Section: Introductionmentioning

confidence: 99%

Pyrenecarboxaldehyde encapsulated porous TiO₂ nanoreactors for monitoring cellular GSH levels

Sun

Lei

et al. 2022

Nanoscale

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“…or carbon to form core–shell or yolk–shell nanoreactors. − The porous shells not only protect the active metal cores from migration and agglomeration but also allow the reactants to diffuse freely across the shells. In some cases, the void of the hollow nanoreactors can even concentrate the reactant molecules. , For example, Li et al observed an evident improvement in the hydrodechlorination of 4-chlorophenol when confining Pd NPs into mesoporous hollow silica spheres, compared to the supported one. Besides, they found that core–shell nanoreactors displayed excellent structural stability after five recycling experiments while a significant loss of catalytic activity was observed on supported Pd/SiO 2 .…”

Section: Introductionmentioning

confidence: 99%

RhCu Bimetallic Nanoparticles in Hollow Carbon Spheres for Catalytic Halonitrobenzene Chemoselective Hydrogenation

Yang

et al. 2022

ACS Appl. Nano Mater.

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Supported Rh nanoparticles (NPs) exhibit excellent activity for the chemoselective hydrogenation of halonitrobenzenes (HNBs), but their selectivity to aromatic amines is not satisfactory due to the side reaction on the carbon−halogen bonds, and their recycling stability is limited due to the aggregation and the leaching of active component during the long-term usage. Herein, we design a yolk−shell-structured catalyst that consists of RhCu alloy cores and hollow/microporous carbon shells (HCS) to overcome these problems. The obtained RhCu@HCS catalyst with a Rh/Cu ratio of 1:1 showed good activity, selectivity, and stability in the hydrogenation of p-CNB (p-chloronitrobenzene) to produce p-CAN (p-chloroaniline) due to the synergistic effect between Rh and Cu. The protective carbon shells not only prevented the aggregation of metal NPs but also allowed the reactants to diffuse freely across the shells. Therefore, our research provides a general strategy to design highly efficient and stable hydrogenation catalysts.

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The fabrication of hollow ZrO₂nanoreactors encapsulating Au–Fe₂O₃dumbbell nanoparticles for CO oxidation

Abstract: Nanosized Au catalysts suffer from serious sintering problems during the synthesis or catalytic reactions at high temperatures. In this work, we integrate dumbbell shaped Au-Fe3O4 heterostructures into hollow ZrO2 nanocages...

Cited by 6 publications

References 60 publications

Concurrent Dual-Contrast Enhancement Using Fe₃O₄ Nanoparticles to Achieve a CEST Signal Controllability

Concurrent Dual-Contrast Enhancement Using Fe₃O₄ Nanoparticles to Achieve a CEST Signal Controllability

Pyrenecarboxaldehyde encapsulated porous TiO₂ nanoreactors for monitoring cellular GSH levels

RhCu Bimetallic Nanoparticles in Hollow Carbon Spheres for Catalytic Halonitrobenzene Chemoselective Hydrogenation

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The fabrication of hollow ZrO2nanoreactors encapsulating Au–Fe2O3dumbbell nanoparticles for CO oxidation

Abstract: Nanosized Au catalysts suffer from serious sintering problems during the synthesis or catalytic reactions at high temperatures. In this work, we integrate dumbbell shaped Au-Fe3O4 heterostructures into hollow ZrO2 nanocages...

Cited by 6 publications

References 60 publications

Concurrent Dual-Contrast Enhancement Using Fe3O4 Nanoparticles to Achieve a CEST Signal Controllability

Concurrent Dual-Contrast Enhancement Using Fe3O4 Nanoparticles to Achieve a CEST Signal Controllability

Pyrenecarboxaldehyde encapsulated porous TiO2 nanoreactors for monitoring cellular GSH levels

RhCu Bimetallic Nanoparticles in Hollow Carbon Spheres for Catalytic Halonitrobenzene Chemoselective Hydrogenation

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Product

Resources

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The fabrication of hollow ZrO₂nanoreactors encapsulating Au–Fe₂O₃dumbbell nanoparticles for CO oxidation

Concurrent Dual-Contrast Enhancement Using Fe₃O₄ Nanoparticles to Achieve a CEST Signal Controllability

Concurrent Dual-Contrast Enhancement Using Fe₃O₄ Nanoparticles to Achieve a CEST Signal Controllability

Pyrenecarboxaldehyde encapsulated porous TiO₂ nanoreactors for monitoring cellular GSH levels