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Liu Y.,Inner Mongolia University | Liu B.,Inner Mongolia University | Wang Q.,Inner Mongolia University | Hu W.,Inner Mongolia University | And 5 more authors.
Applied Catalysis B: Environmental | Year: 2013

Three-dimensionally ordered macro- and meso-porous (3DOM) M/CeO2 (M=Pt, Au and Pt-Au) catalysts supported with different noble metal nanoparticles of Pt, Au and Pt-Au alloy were synthesized by thermal decomposition of cerium nitrate precursor using the close packed structures of PS colloidal crystals as templates. The obtained 3DOM M/CeO2 catalysts possess well-defined 3DOM skeletons composed of ultrafine CeO2 nanoparticles. The macroporous CeO2 skeletons contain the mesoporous walls possessing the nanopores of ~3-4nm and the noble metal nanoparticles of Pt, Au, and Pt-Au alloy with the grain sizes of ~5.0nm homogenously dispersed. The catalytic performance of CO preferential oxidation (PROX) in H2-rich gases on 3DOM Pt/CeO2, Au/CeO2, and Pt-Au/CeO2 catalysts were systematically studied. The superior catalytic performance with 90% CO conversion and 83% CO2 selectivity are realized on 3DOM 1wt.% Pt1Au1/CeO2 catalyst at 80°C under the weight hourly space velocity of 30,000mLg-1h-1. Moreover, the 3DOM 1wt.% Pt1Au1/CeO2 catalyst exhibits excellent catalytic stability maintaining 90% CO conversion and 56% CO2 selectivity even after the test period of 260h under the same flow rate. The three-dimensionally ordered macro- and meso-porous skeletons, the synergistic effect due to the formation of Pt-Au alloy, and the strong interaction of Pt-Au alloy nanoparticles with CeO2 supports are identified to be beneficial to the improvement of catalytic activity and stability of CO PROX. The obtained 3DOM Pt-Au/CeO2 catalysts may be potential candidates with the improved catalytic performance of CO PROX reaction in H2-rich gases for polymer electrolyte membrane fuel cells (PEMFCs) applications. © 2013 Elsevier B.V. Source


Liu Y.,Inner Mongolia University | Liu B.,Inner Mongolia University | Wang Q.,Inner Mongolia University | Li C.,Inner Mongolia University | And 5 more authors.
RSC Advances | Year: 2014

Three dimensionally ordered macroporous (3DOM) Au/CeO2 catalysts were synthesized via a thermal decomposition-assisted colloidal crystal templating method following different synthetic procedures using citric acid and oxalic acid as chelating ligands and CeCl3 and Ce(NO 3)3 as cerium salt precursors. All 3DOM Au/CeO2 catalysts possess well-defined 3DOM skeletons composed of well-crystallized CeO2 nanoparticles, based on the different synthetic procedures, the 3DOM Au/CeO2 catalysts show variations in surface elemental compositions, particle sizes of CeO2, macroporous and mesoporous structures, and valence states of Au. The mesoporous walls with nanopores ∼3-4 nm on 3DOM Au/CeO2 skeletons can be created when using Ce(NO3)3 as precursor. The catalytic performance of 3DOM Au/CeO2 catalysts for CO preferential oxidation in H2-rich gases was systematically investigated. The catalytic performance is closely correlated to surface elemental compositions, particle sizes of CeO2, macroporous and mesoporous structures, and valence states of Au due to the different synthetic procedures. The 3DOM Au/CeO2 catalysts prepared using oxalic acid as chelating ligand and Ce(NO3)3 as cerium salt precursor show the highest catalytic activity for CO preferential oxidation in H2-rich gases with 90.1% CO conversion and 59.9% CO 2 selectivity at 50 °C, and 88.3% CO conversion and 59.3% CO 2 selectivity at 80 °C, respectively. The obtained 3DOM Au/CeO2 catalysts may be of importance for guiding the design of efficient catalysts with desired porous structures that are potentially applicable in polymer electrolyte membrane fuel cells. © 2014 The Royal Society of Chemistry. Source


Hu W.,Inner Mongolia University | Liu B.,Inner Mongolia University | Wang Q.,Inner Mongolia University | Liu Y.,Inner Mongolia University | And 5 more authors.
Chemical Communications | Year: 2013

A novel magnetic double-shell Fe3O4@TiO 2/Au@Pd@TiO2 microsphere composed of a Fe 3O4 core and double TiO2 shells with Au and Pd nanoparticles encapsulated is created. The microsphere can be used as a highly efficient reusable catalyst with superior catalytic activity and stability and magnetic separable capability in reduction of 4-nitrophenol. This journal is © The Royal Society of Chemistry. Source


Gao Y.,Inner Mongolia University | Zhang X.,Inner Mongolia University | Sun W.,Inner Mongolia University | Liu Z.,Inner Mongolia University | Liu Z.,Inner Mongolia Key Laboratory of Nanoscience and Nanotechnology
Dalton Transactions | Year: 2014

An extremely thermostable magnesium metal-organic framework (Mg-MOF) is reported for use as a highly selective and sensitive, instantaneous and colorimetric sensor for Eu3+ ions. There has been extensive interest in the recognition and sensing of ions because of their important roles in biological and environmental systems. However, only a few of these systems have been explored for specific rare earth ion detection. A robust microporous Mg-MOF for the recognition and sensing of Eu3+ ions with high selectivity at low concentrations in aqueous solutions has been synthesized. This stable metal-organic framework (MOF) contains nanoscale holes and non-coordinating nitrogen atoms inside the walls of the holes, which makes it a potential host for foreign metal ions. Based on the energy level matching and efficient energy transfer between the host and the guest, the Mg-MOF sensor is both highly selective and sensitive as well as instantaneous; thus, it is a promising approach for the development of luminescent probing materials with unprecedented applications and its use as an Eu3+ ion sensor. This journal is © The Royal Society of Chemistry 2015. Source


Gao Y.,Inner Mongolia University | Cao J.,Inner Mongolia University | Song Y.,Inner Mongolia University | Zhang G.,Inner Mongolia University | And 3 more authors.
CrystEngComm | Year: 2013

Two series of lanthanide-based coordination polymers, [Ln(HCPOB)(CPOB) (H2O)2]n [Ln = Eu(a1), Gd(a2), Tb(a3), Dy(a4), Ho(a5), Er(a6)] and [Ln(HCPOB)(CPOB)]n [Ln = Eu(b1), Gd(b2), Tb(b3), Dy(b4), Ho(b5), Er(b6)], have been synthesized using an asymmetric semi-rigid V-shape multicarboxylate ligand [H4CPOB = 2-(4-carboxyphenoxy)benzoic acid] by a hydrothermal method at different temperatures. Series a were obtained at 130 °C and have one-dimensional (1D) chain architectures, while series b were synthesized at 180 °C and exhibit three-dimensional (3D) structures. Interestingly, temperature-dependent XRD patterns for 1D compounds indicate that the 1D structure changes to form the 3D coordination polymers on heating the crystals. Single crystals of series a can transform into crystals of series b without any significant change in crystal quality. The variations from 1D to 3D coordination structures are attributed to variable coordination modes of multicarboxylate ligand H2CPOB. In addition, we have studied the luminescent properties of Eu3+, Tb3+, and Dy3+ compounds of series a and series b, and found that series a give very weak luminescence because of coordinated water molecules existing in the complexes. Due to the "antenna effect" or "luminescence sensitization", series b exhibit much stronger fluorescent intensity than that of series a. © 2013 The Royal Society of Chemistry. Source

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