Co-reporter:Xiao Wang, Dapeng Liu, Junqi Li, Jiangman Zhen, Fan Wang and Hongjie Zhang
Chemical Science 2015 vol. 6(Issue 5) pp:2877-2884
Publication Date(Web):27 Feb 2015
DOI:10.1039/C4SC03854A
In this paper, we have successfully demonstrated the clean synthesis of high-quality Pd@CeO2 core@shell nanospheres with tunable Pd core sizes in water, and furthermore loaded the as-obtained Pd@CeO2 products on commercial γ-Al2O3via electrostatic interaction. KBr here plays two key roles in inducing the growth and self-assembly of Pd@CeO2 core@shell nanospheres. First, Br− ions can retard the reduction of Pd2+ ions via the formation of the more stable complex of [PdBr4]2− so as to tune the size of Pd cores. Second, it greatly decreases the colloidal stability, and hence the surface polarity-weakened Pd and CeO2 NPs have to spontaneously self-assemble into more stable and ordered structures. Among different-sized Pd samples, the as-obtained 8 nm-Pd@CeO2/Al2O3 one exhibits the best performance in catalytic CO oxidation, which can catalyze 100% CO conversion into CO2 at 95 °C, which is much lower than the previously reported CeO2-encapsulated Pd samples.
Co-reporter:Xiao Wang, Dapeng Liu, Junqi Li, Jiangman Zhen and Hongjie Zhang
NPG Asia Materials 2015 7(1) pp:e158
Publication Date(Web):2015-01-01
DOI:10.1038/am.2014.128
The fabrication of multi-component hybrid nanostructures is of vital importance because their two-phase interface could provide a rich environment for redox reactions, which are beneficial for enhancing catalytic performance. Inspired by the above consideration, strongly coupled Cu2O@CeO2 core@shell nanostructures have been successfully prepared via a non-organic and clean aqueous route without using any organic additive. In this process, an auto-catalytic redox reaction occurred on the two-phase interface, followed by a triggered self-assembly process. Additionally, the size, morphology and composition of the as-obtained nanostructures can be tuned well by varying the reaction temperature, as well as the species and the amount of Cu precursors. The catalytic tests for peroxidase-like activity and CO oxidation have been conducted in detail, and the results confirm a strong synergistic effect at the interface sites between the CeO2 and Cu2O components.
Co-reporter:Jiangman Zhen, Dapeng Liu, Xiao Wang, Junqi Li, Fan Wang, Yinghui Wang and Hongjie Zhang
Dalton Transactions 2015 vol. 44(Issue 5) pp:2425-2430
Publication Date(Web):15 Dec 2014
DOI:10.1039/C4DT03141E
A fast and facile self-assembly method has been developed to deposit 3–5 nm sized PdxPt1−x (0 ≤ x ≤ 1) nanoparticles (NPs) on Ni(OH)2 nanosheets. The biomolecule L-lysine has been used here as the linker to hybridize PdxPt1−x NPs and Ni(OH)2 nanosheets together. The catalytic properties of the obtained PdxPt1−x/Ni(OH)2 hybrids were evaluated by employing the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 as a model reaction. The results reveal that the stability, activity and recyclability of PdxPt1−x NPs have been remarkably enhanced after being supported on Ni(OH)2 nanosheets. Moreover, the influence of the composition of noble metals on the catalytic properties has been studied in depth and Pd0.5Pt0.5/Ni(OH)2 hybrids show the optimal catalytic properties.
Co-reporter:Yinghui Wang;Shuyan Song;Jianhua Liu; Hongjie Zhang
Angewandte Chemie 2015 Volume 127( Issue 2) pp:546-550
Publication Date(Web):
DOI:10.1002/ange.201409519
Abstract
Limited therapeutic efficiency and severe side effects in patients are two major issues existing in current chemotherapy of cancers in clinic. To design a proper theranostic platform seems thus quite needed to target cancer cells accurately by bioimaging and simultaneously release drugs on demand without premature leakage. A novel ZnO-functionalized upconverting nanotheranostic platform has been fabricated for clear multi-modality bioimaging (upconversion luminescence (UCL), computed tomography (CT), and magnetic resonance imaging (MRI)) and specific pH-triggered on-demand drug release. In our theranostic platform multi-modality imaging provides much more detailed and exact information for cancer diagnosis than single-modality imaging. In addition, ZnO can play the role of a “gatekeeper” to efficiently block the drug in the mesopores of the as-prepared agents until it is dissolved in the acidic environment around tumors to realize sustained release of the drug. More importantly, the biodegradable ZnO, which is non-toxic against normal tissues, endows the as-prepared agents with high therapeutic effectiveness but very low side effects. These findings are of great interests and will inspire us much to develop novel effective imaging-guided on-demand chemotherapies in cancer treatment.
Co-reporter:Yinghui Wang;Shuyan Song;Jianhua Liu; Hongjie Zhang
Angewandte Chemie International Edition 2015 Volume 54( Issue 2) pp:536-540
Publication Date(Web):
DOI:10.1002/anie.201409519
Abstract
Limited therapeutic efficiency and severe side effects in patients are two major issues existing in current chemotherapy of cancers in clinic. To design a proper theranostic platform seems thus quite needed to target cancer cells accurately by bioimaging and simultaneously release drugs on demand without premature leakage. A novel ZnO-functionalized upconverting nanotheranostic platform has been fabricated for clear multi-modality bioimaging (upconversion luminescence (UCL), computed tomography (CT), and magnetic resonance imaging (MRI)) and specific pH-triggered on-demand drug release. In our theranostic platform multi-modality imaging provides much more detailed and exact information for cancer diagnosis than single-modality imaging. In addition, ZnO can play the role of a “gatekeeper” to efficiently block the drug in the mesopores of the as-prepared agents until it is dissolved in the acidic environment around tumors to realize sustained release of the drug. More importantly, the biodegradable ZnO, which is non-toxic against normal tissues, endows the as-prepared agents with high therapeutic effectiveness but very low side effects. These findings are of great interests and will inspire us much to develop novel effective imaging-guided on-demand chemotherapies in cancer treatment.
Co-reporter:Dr. Xiao Wang;Dr. Dapeng Liu;Fan Wang;Junqi Li;Jiangman Zhen ; Hongjie Zhang
ChemPlusChem 2015 Volume 80( Issue 8) pp:1241-1244
Publication Date(Web):
DOI:10.1002/cplu.201500189
Abstract
The nonstoichiometric metal oxide Ni0.3Co2.7O4 served as a support for small-sized Pt nanoparticles. The whole synthesis of the hybrid material can be kinetically controlled and no further surface-modification treatment was required. More importantly, the as-obtained strongly coupled PtNi0.3Co2.7O4 hybrid nanoflowers exhibit remarkably enhanced catalytic activities compared with PtNiO and PtCo3O4 hybrid samples. This result indicates that it is possible to optimize the catalytic performance of noble metals by using a nonstoichiometric metal oxides as a support instead of a stoichiometric metal oxide.
Co-reporter:Jiangman Zhen;Xiao Wang;Zhuo Wang;Junqi Li;Fan Wang
Nano Research 2015 Volume 8( Issue 6) pp:1944-1955
Publication Date(Web):2015 June
DOI:10.1007/s12274-015-0704-3
In this study, Co3O4@CeO2 core@shell nanowires were successfully prepared via thermal decomposition of Co(CO3)0.5(OH)·0.11H2O@CeO2 core@shell nanowire precursors. As a CO oxidation catalyst, Co3O4@CeO2 shows remarkably enhanced catalytic performance compared to Co3O4 nanowires and CeO2 nanoparticles (NPs), indicating obvious synergistic effects between the two components. It also suggests that the CeO2 shell coating can effectively prevent Co3O4 nanowires from agglomerating, hence effecting a substantial improvement in the structural stability of the Co3O4 catalyst. Furthermore, the fabrication of the well-dispersed core@shell structure results in a maximized interface area between Co3O4 and CeO2, as well as a reduced Co3O4 size, which may be responsible for the enhanced catalytic activity of Co3O4@CeO2. Further examination revealed that CO oxidation may occur at the interface of Co3O4 and CeO2. The influence of calcination temperatures and the component ratio between Co3O4 and CeO2 were then investigated in detail to determine the catalytic performance of Co3O4@CeO2 core@shell nanowires, the best of which was obtained by calcination at 250 °C for 3 h with a Ce molar concentration of about 38.5%. This sample achieved 100% CO conversion at a reduced temperature of 160 °C. More importantly, more than 2.5 g of the Co3O4@CeO2 core@shell nanowires were produced in one pot by this simple process, which may be beneficial for practical applications as automobile-exhaust gas-treatment catalysts.
Co-reporter:Fan Wang, Xiao Wang, Dapeng Liu, Jiangman Zhen, Junqi Li, Yinghui Wang, and Hongjie Zhang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 24) pp:22216
Publication Date(Web):November 21, 2014
DOI:10.1021/am505853p
In this paper, we report a self-assembly method to synthesize high-quality ZnCo2O4@CeO2 core@shell microspheres with tunable CeO2 thickness. ZnCo2O4 spheres were first synthesized as the core, followed by a controlled CeO2 shell coating process. The thickness of CeO2 shell could be easily tuned by varying the feeding molar ratio of Ce/Co. Transmission electron microscope (TEM) images and scanning transmission electron microscope (STEM) image have identified the core@shell structure of these samples. In CO oxidation tests these ZnCo2O4@CeO2 core@shell microspheres exhibited promising catalytic performance, and the catalytic activity of the best sample is even close to the traditional noble metal-CeO2 system, attaining 100% CO conversion at a relatively low temperature of 200 °C. Cycling tests confirm their good stability of these core@shell microspheres besides activity. Their high catalytic performance should be attributed to the core@shell structure formation, and moreover further H2–temperature-programmed reduction (TPR) results revealed the possible synergistic effects between the two components of ZnCo2O4 and CeO2.Keywords: CeO2; CO oxidation; core@shell; microspheres; ZnCo2O4
Co-reporter:Xiao Wang, Dapeng Liu, Junqi Li, Jiangman Zhen, Fan Wang and Hongjie Zhang
Chemical Science (2010-Present) 2015 - vol. 6(Issue 5) pp:NaN2884-2884
Publication Date(Web):2015/02/27
DOI:10.1039/C4SC03854A
In this paper, we have successfully demonstrated the clean synthesis of high-quality Pd@CeO2 core@shell nanospheres with tunable Pd core sizes in water, and furthermore loaded the as-obtained Pd@CeO2 products on commercial γ-Al2O3via electrostatic interaction. KBr here plays two key roles in inducing the growth and self-assembly of Pd@CeO2 core@shell nanospheres. First, Br− ions can retard the reduction of Pd2+ ions via the formation of the more stable complex of [PdBr4]2− so as to tune the size of Pd cores. Second, it greatly decreases the colloidal stability, and hence the surface polarity-weakened Pd and CeO2 NPs have to spontaneously self-assemble into more stable and ordered structures. Among different-sized Pd samples, the as-obtained 8 nm-Pd@CeO2/Al2O3 one exhibits the best performance in catalytic CO oxidation, which can catalyze 100% CO conversion into CO2 at 95 °C, which is much lower than the previously reported CeO2-encapsulated Pd samples.
Co-reporter:Jiangman Zhen, Dapeng Liu, Xiao Wang, Junqi Li, Fan Wang, Yinghui Wang and Hongjie Zhang
Dalton Transactions 2015 - vol. 44(Issue 5) pp:NaN2430-2430
Publication Date(Web):2014/12/15
DOI:10.1039/C4DT03141E
A fast and facile self-assembly method has been developed to deposit 3–5 nm sized PdxPt1−x (0 ≤ x ≤ 1) nanoparticles (NPs) on Ni(OH)2 nanosheets. The biomolecule L-lysine has been used here as the linker to hybridize PdxPt1−x NPs and Ni(OH)2 nanosheets together. The catalytic properties of the obtained PdxPt1−x/Ni(OH)2 hybrids were evaluated by employing the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 as a model reaction. The results reveal that the stability, activity and recyclability of PdxPt1−x NPs have been remarkably enhanced after being supported on Ni(OH)2 nanosheets. Moreover, the influence of the composition of noble metals on the catalytic properties has been studied in depth and Pd0.5Pt0.5/Ni(OH)2 hybrids show the optimal catalytic properties.
