Guozhu Chen

University of Jinan (Jinan, China), Chi-nan-shih, Shandong Sheng, China

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Publications (28)113.36 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: CeO2-CuO nanorods with mesoporous structure were synthesized by a facile and mild strategy, which involves an interfacial reaction between Ce2(SO4)3 precursor and NaOH ethanol solution at room temperature to obtain mesoporous CeO2 nanorods, followed by a solvothermal treatment of as-prepared CeO2 and Cu(CH3COO)2. Upon solvothermal treatment, CuO species is highly dispersed onto CeO2 nanorod surface to form CeO2-CuO composites, which still maintain the mesoporous feature. A preliminary CO catalytic oxidation study demonstrated that the CeO2-CuO samples exhibited strikingly high catalytic activity, and a high CO conversion rate was observed without obvious loss in activity even after thermal treatment at a high temperature of 500 oC. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and hydrogen temperature-programmed reduction (H2-TPR) analysis revealed that there is a strong interaction between CeO2 and CuO. Moreover, it was found that the introduction of CuO species into CeO2 generates oxygen vacancies, which is highly likely to be responsible for high catalytic activity toward CO oxidation of the mesoporous CeO2-CuO nanorods.
    ACS Applied Materials & Interfaces 10/2015; DOI:10.1021/acsami.5b06495 · 6.72 Impact Factor
  • Guozhu Chen · Federico Rosei · Dongling Ma ·
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    ABSTRACT: Hollow ceria-based composites, which consist of noble metal nanoparticles or metal oxides as a secondary component, are being studied extensively for potential applications in heterogeneous catalysis. This is due to their unique features, which exhibit the advantages of hollow structure (e.g. high surface area and low weight), and also integrate properties of ceria and noble metals/metal oxides. More importantly, the synergistic effect between constituents in hollow ceria-based composites has been demonstrated in various catalytic reactions. In this feature article, we summarize the state-of-the-art in the synthesis of hollow ceria-based composites, including traditional hard-template and more recently, sacrificial-template engaged strategies, highlighting the key role of selected templates in the formation of hollow composites. In addition, the catalytic applications of hollow ceria-based composites are briefly surveyed. Finally, challenges and perspectives on future advances of hollow ceria-based composites are outlined.
    Nanoscale 02/2015; 7(13). DOI:10.1039/C4NR07674E · 7.39 Impact Factor
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    Guozhu Chen · Qihui Xu · Yong Wang · Guolong Song · Weiliu Fan ·
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    ABSTRACT: Unlike the conventional calcination of cerium precursors at elevated temperature, hierarchically porous ceria was successfully synthesized via an interfacial reaction between water-soluble cerium sulfate (Ce2(SO4)3) precursor and NaOH in ethanol at room temperature. Neither additional surfactant molecules nor calcination was employed during the whole preparation process. It was found that the as-prepared ceria inherited well the shape and dimensions of the hierarchically flowerlike Ce2(SO4)3 precursor after interfacial reaction. The concentration of sulfuric acid was demonstrated to play a great role in controlling the precursor’s morphology. Compared with ceria derived from direct calcination of the same Ce2(SO4)3 precursor, the one obtained from interfacial reaction was far more reactive in CO oxidation due to its well-kept hierarchically porous morphology and high surface area. This work is expected to open a new, simple avenue for the synthesis of hollow nanomaterials from water-soluble precursors.
    02/2015; 3(13). DOI:10.1039/C5TA00664C
  • Mee Rahn Kim · Zhenhe Xu · Guozhu Chen · Dongling Ma ·
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    ABSTRACT: Nano-heterostructures have attracted great attention due to their extraordinary properties beyond those of their single-component counterparts. This review focuses on a specific type of hybrid structures: core-shell structures. In particular, we present and discuss the recent wet-chemical synthesis approaches for semiconductor and metallic core-shell nanostructures, and their relevant properties and potential applications in photovoltaics and catalysis, respectively. Hybrid nanomaterials, such as core-shell nanoparticles, have attracted great attention due to their extraordinary properties beyond those of their single-component counterparts. This review focuses on recent advances in the synthesis of semiconductor and metallic core-shell nanostructures and their potential applications in photovoltaics and catalysis, respectively.
    Chemistry - A European Journal 12/2014; 20(36). DOI:10.1002/chem.201402277 · 5.73 Impact Factor

  • ChemInform 07/2014; 45(26). DOI:10.1002/chin.201426227
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    ABSTRACT: The catalytic properties of ruthenium (Ru) are fairly well known. Nevertheless its shape-controlled synthesis (especially as compared to other noble metals) is still elusive. In this review, we present recent advances in the synthesis of Ru nanomaterials, in particular, spherical nanoparticles, one dimensional nanostructures, nanoplates and hollow structures, as well as other examples. In addition, the catalytic applications of Ru materials are selectively surveyed. Finally, the challenges and perspectives on the controlled synthesis of Ru-based nanomaterials and their catalytic applications are described.
    New Journal of Chemistry 04/2014; 38(5). DOI:10.1039/C3NJ01155K · 3.09 Impact Factor
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    ABSTRACT: Fluorescent semiconductor quantum dots (QDs) and magnetic nanoparticles are recognized as the most promising nanomaterials for applications in biology and biomedicine. Fluorescent QDs are attracting increased interest mainly as fluorescent platforms that carry multiple diagnostic probes, providing both structural and metabolic information from diseased sites and thus leading to significantly improved imaging for the detection of a variety of human cancers or other diseased states. Magnetic nanoparticles can serve both as magnetic resonance imaging (MRI) agents for the diagnosis of cancers and as vehicles for carrying therapeutic payloads (anticancer drugs, siRNA, etc.) and efficiently delivering them to cancer sites in a target-specific manner. The further combination of QDs and magnetic nanoparticles into a single nanoarchitecture will undoubtedly lead to a new range of potential applications in biological systems. With both fluorescence and superparamagnetic features, these multifunctional nanoparticles can act as multi-dimensional tools in biological applications and are promising to be used in cell sorting, separation, tracking, imaging and drug delivery, which in principle can be easily controlled using magnetic force and monitored with a fluorescent microscope. This review mainly introduces recent developments on the synthesis and surface modification of these fluorescent-magnetic multifunctional nanoparticles, and their potential applications in fluorescence imaging, MRI and drug delivery.
    12/2013; 2(5). DOI:10.1166/rnn.2013.1038
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    ABSTRACT: To enhance the catalytic activity of gold nanoparticles (AuNPs) for the hydrogenation of nitro-aromatic chemicals, Pt was introduced into AuNPs to form "bare" PtAu alloy NPs using a physical approach, pulsed laser ablation in liquid (PLAL), on single metal-mixture targets. These PLAL-NPs are deemed to favor catalysis due to the absence of any surfactant molecules on their unique "bare and clean" surface. The PLAL-NPs were facilely assembled onto CeO2 nanotubes (NTs) by simply mixing them without conducting any surface functionalization, representing another advantage of these NPs. Their catalytic activity was assessed in 4-nitrophenol (4-NP) hydrogenation. The reaction catalyzed by alloy-NP/CeO2-NT catalysts demonstrates a remarkably higher reaction rate in comparison with that catalyzed by pure Au and Pt NPs, and other similar Au and Pt containing catalysts reported recently. A "volcano-like" catalytic activity dependence of the alloy NPs on their chemical composition suggests a strong synergistic effect between Au and Pt in the 4-NP reduction, far beyond the simple sum of their individual contributions. It leads to the significantly enhanced catalytic activity of Pt30Au70 and Pt50Au50 alloy NPs, outperforming not only each single constituent, but also their physical mixtures and most recently reported AuNP based nanocatalysts. The favorable d-band center shift of Pt after alloying, and co-operative actions between Pt clusters and nearby Au (or mixed PtAu) sites were proposed as possible mechanisms to explain such a strong synergistic effect on catalysis.
    Nanoscale 11/2013; 6(4). DOI:10.1039/c3nr04715f · 7.39 Impact Factor
  • Guozhu Chen · Haiguang Zhao · Federico Rosei · Dongling Ma ·
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    ABSTRACT: The luminescence switching behavior of CePO4:Tb has been widely studied upon an interfacial oxidation–reduction reaction where KMnO4 and ascorbic acid act as an oxidant and a reductant, respectively. However, the transformation of Mn-involved species derived from KMnO4 during the oxidation–reduction cycle and their effect on the luminescence properties of CePO4:Tb have not been explored so far. Here, we further study this interfacial reaction between CePO4:Tb and KMnO4 through various characterization techniques, such as X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. We find that an amorphous manganese oxide layer forms on the CePO4:Tb surface along with the partial oxidation of Ce(III) upon addition of KMnO4. In the subsequent reduction, the ascorbic acid not only reduces Ce(IV) to Ce(III) but also dissolves the formed manganese oxide. If manganese oxide is kept on the CePO4:Tb surface during the reduction treatment, the photoluminescence of Tb(III), due to the energy transfer from Ce(III) to Tb(III), would be restrained even if Ce(IV) ions were efficiently reduced. Although the degree of surface oxidation/reduction (Ce(III)/Ce(IV)) was considered to be a key factor for the luminescence quenching/recovery behavior in previous studies, there is a strong indication that the reaction product, e.g. manganese oxide, and associated surface defects generated from the oxidation–reduction reaction can disturb the photoluminescence of Tb(III) when they are not removed.
    The Journal of Physical Chemistry C 05/2013; 117(19):10031–10038. DOI:10.1021/jp402309f · 4.77 Impact Factor
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    ABSTRACT: We report the preparation and catalytic properties of a new nanostructured catalyst, made of small (∼5 nm in diameter) and uniform gold nanoparticles (AuNPs) and ceria nanotubes (CeO2 NTs). “Surfactant-free” AuNPs fabricated by pulsed laser ablation in liquid (PLAL) on a bulk Au target are efficiently assembled onto the surface of CeO2 NTs without performing any surface functionalization of either component to promote their coupling, thanks to the presence of OH on the PLAL-AuNPs. The reduction reaction of 4-nitrophenol into 4-aminophenol catalyzed by our PLAL-AuNP/CeO2-NT catalyst exhibits remarkably higher reaction rate in comparison to that catalyzed by similar catalysts composed of chemically prepared AuNPs (Chem-AuNPs) as an active phase and/or commercially available CeO2 powder as support. Their superior catalytic activity is found to be due to the unique, relatively “bare” surface of the PLAL-AuNPs as well as oxidized Au species induced by the strong interaction between the “barrier-free” surface of PLAL-AuNPs and surface defects (oxygen vacancies) of CeO2 NTs. The important role of unique surface chemistry of PLAL-AuNPs in catalysis was further demonstrated in CO oxidation reaction in gas phase. Our results suggest that the use of PLAL-AuNPs enables easy and efficient attachment of AuNPs onto the surface of the CeO2 NTs and their unique combination leads to the development of highly efficient catalysts. Our design and fabrication of the nanocatalysts take full advantage of the unique features of the PLAL-AuNPs and potentially constitute a general and efficient route to prepare other metal-NP/metal-oxide-support catalysts, which can therefore largely expand the applications of PLAL-noble metal NPs in catalysis.
    Applied Catalysis B Environmental 03/2013; s 132–133:107–115. DOI:10.1016/j.apcatb.2012.11.030 · 7.44 Impact Factor
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    Fenfen Zhu · Guozhu Chen · Sixiu Sun · Xuan Sun ·
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    ABSTRACT: Core–shell (CS) nanoparticles (NPs) have many applications in areas such as catalysis and sensing. The utilization of hollow nanostructured materials as the supports, such as nanotubes (NT), is a growing interest to anchor NPs. Generally, several steps are necessary to prepare CS NP–NT nanocomposites, including: (i) the synthesis of CS NPs; (ii) the preparation of NTs; and (iii) the combination of CS NPs and NTs. Moreover, surface modifications with organic ligands are often involved during the synthesis of CS NPs and/or the step combining CS NPs and supports. Here we report a facile method for in situ growth of Au@CeO2 CS NPs and CeO2 NTs by mixing HAuCl4 and Ce(OH)CO3 nanorods under mild conditions. The formation of Au–CeO2 nanocomposite is due to the interfacial oxidation–reduction reaction between HAuCl4 and Ce(OH)CO3, where Au(III) in HAuCl4 is reduced to Au(0) by Ce(III) in Ce(OH)CO3, while Ce(III) is oxidized into Ce(IV), followed by hydrolysis to generate CeO2. The slow hydrolysis rate of Ce(IV) leads to the coverage of CeO2 on the Au NPs, and on the residual Ce(OH)CO3 surface, developing into Au@CeO2 and Ce(OH)CO3@CeO2 CS structures. Further depletion/dissolution of Ce(OH)CO3 results in Au@CeO2 CS NP–CeO2 NT nanocomposite eventually. The advantages of our synthetic strategy are independent of foreign reducing agents and additional surface modification. And, such CS NP–NT nanocomposite can be obtained in one step, simplifying the synthesis procedures greatly. This method based on interfacial oxidation–reduction may be employed as a unique entry to other nanocomposites.
    12/2012; 1(2):288-294. DOI:10.1039/C2TA00293K
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    ABSTRACT: Ligand-free Ru nanoclusters supported on carbon black have been synthesized in situ for the first time from the reduction of RuCl3 by ammonia-borane concomitantly with its hydrolysis process at room temperature, and their catalytic activity has been investigated. Well dispersed Ru nanoclusters (∼1.7 nm) are stabilized and immobilized by carbon black. Due to the small size and the absence of ligands on the surface, the Ru catalysts exhibit high catalytic activity, which is partly retained after 5 reaction cycles. A kinetic study shows that the catalytic hydrolysis of ammonia-borane is first order with respect to Ru catalyst concentration; the turnover frequency is 429.5 mol H2 min−1 mol−1 Ru. The activation energy for the hydrolysis of ammonia-borane in the presence of Ru/C catalysts has been measured to be 34.81 ± 0.12 kJ mol−1, which is smaller than most of the values reported for other catalysts, including those based on Ru, for the same reaction.
    International Journal of Hydrogen Energy 12/2012; 37(23):17921–17927. DOI:10.1016/j.ijhydene.2012.09.026 · 3.31 Impact Factor
  • Guozhu Chen · Federico Rosei · Dongling Ma ·
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    ABSTRACT: Interfacial oxidation–reduction reaction is herein developed to prepare hollow binary oxide nanostructures. Ce–Mn nanotubes are fabricated by treating Ce(OH)CO3 templates with KMnO4 aqueous solution, where MnO4− is reduced to manganese oxide and the Ce3+ in Ce(OH)CO3 is simultaneously oxidized to form cerium oxide, followed by selective wash with HNO3. The resulting Ce–Mn binary oxide nanotubes exhibit high catalytic activity towards CO oxidation and show significant adsorption capacity of Congo red. Moreover, guided by the same interfacial-reaction principle, binary oxide hollow nanostructures with different shapes and compositions are synthesized. Specifically, hollow Ce–Mn binary oxide cubes, and Co-Mn and Ce-Fe binary oxide hollow nanostructures are achieved by changing the shape of the Ce(OH)CO3 templates from rods to cubes, by changing the tempates from Ce(OH)CO3 nanorods to Co(CO3)0.35Cl0.20(OH)1.10 nanowires, and by replacing the oxidant of KMnO4 with another strong one, K2FeO4, respectively. This work is expected to open a new, simple avenue for the general synthesis of hollow binary oxide nanostructures.
    Advanced Functional Materials 09/2012; 22(18). DOI:10.1002/adfm.201200900 · 11.81 Impact Factor
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    ABSTRACT: Hollow Ru nanoparticles with ~14 nm diameter and ~2 nm shell thickness are reported for the first time, by removal of Ni from the delicately designed Ni@Ru core@shell NPs. Such hollow Ru NPs exhibit enhanced catalytic activity in the dehydrogenation of ammonia borane with respect to solid ones.
    Chemical Communications 07/2012; 48(64):8009-11. DOI:10.1039/c2cc33396a · 6.83 Impact Factor
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    ABSTRACT: We report the synthesis and characterization of new Ni(x)Ru(1-x) (x = 0.56-0.74) alloy nanoparticles (NPs) and their catalytic activity for hydrogen release in the ammonia borane hydrolysis process. The alloy NPs were obtained by wet-chemistry method using a rapid lithium triethylborohydride reduction of Ni(2+) and Ru(3+) precursors in oleylamine. The nature of each alloy sample was fully characterized by TEM, XRD, energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). We found that the as-prepared Ni-Ru alloy NPs exhibited exceptional catalytic activity for the ammonia borane hydrolysis reaction for hydrogen release. All Ni-Ru alloy NPs, and in particular the Ni(0.74)Ru(0.26) sample, outperform the activity of similar size monometallic Ni and Ru NPs, and even of Ni@Ru core-shell NPs. The hydrolysis activation energy for the Ni(0.74)Ru(0.26) alloy catalyst was measured to be approximately 37 kJ mol(-1). This value is considerably lower than the values measured for monometallic Ni (≈70 kJ mol(-1)) and Ru NPs (≈49 kJ mol(-1)), and for Ni@Ru (≈44 kJ mol(-1)), and is also lower than the values of most noble-metal-containing bimetallic NPs reported in the literature. Thus, a remarkable improvement of catalytic activity of Ru in the dehydrogenation of ammonia borane was obtained by alloying Ru with a Ni, which is a relatively cheap metal.
    Chemistry - A European Journal 06/2012; 18(25):7925-30. DOI:10.1002/chem.201200292 · 5.73 Impact Factor
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    ABSTRACT: Core-shell structured Ni@Ru bimetallic nanoparticles are demonstrated as a bifunctional nanoplatform system for the hydrolysis reaction of ammonia-borane and also for magnetic separation.
    Chemical Communications 06/2011; 47(22):6308-10. DOI:10.1039/c1cc10619h · 6.83 Impact Factor
  • Guozhu Chen · Fenfen Zhu · Xuan Sun · Sixiu Sun · Ruiping Chen ·
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    ABSTRACT: Ceria hollow nanocrystals with single-crystalline-like structure were prepared facilely by solvothermal synthesis free from templates, in which CeCl3 was proposed to hydrolyze with the assistance of poly(vinylpyrrolidone) (PVP) in the water–ethanol mixed solvent. TEM and SEM analyses demonstrated the formation of CeO2 hollow nanocrystals ascribed to a dissolution–recrystallization mechanism. It was found that both the counter ions of the cerium sources (e.g. CeCl3, Ce(NO3)3 or (NH4)2Ce(NO3)6) and the composition of the solvent mixture were critical factors in determining the final morphology of CeO2. The as-prepared CeO2 hollow nanocrystals with high crystallinity exhibited a higher catalytic activity and thermal stability towards COoxidation.
    CrystEngComm 04/2011; 13(8):2904-2908. DOI:10.1039/C0CE00758G · 4.03 Impact Factor
  • Shuling Xu · Sixiu Sun · Guozhu Chen · Ting You · Xinyu Song ·
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    ABSTRACT: Hollow Cu2O nanocubes have been fabricated under solvothermal condition using N,N -dimethylformamide (DMF) as solvent at 120 °C for 12 h. The products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Series of experiment confirmed that the amount of water, the reaction time and temperature played important roles in the morphology evolution of hollow Cu2O nanocubes. DMF is a relatively weak alkali solvent and could release a certain amount of OH– under the given conditions. As the release speed of OH– from DMF became substantially slow, the nucleation and growth of Cu2O nanocubes turned into kinetically controlled process. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
    Crystal Research and Technology 07/2009; 44(7). DOI:10.1002/crat.200900114 · 0.94 Impact Factor
  • Wei Zhao · Xinyu Song · Guozhu Chen · Sixiu Sun ·
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    ABSTRACT: ZnWO4 hollow clusters made up of nanorods were successfully prepared through a tripotassium citrate assisted hydrothermal process at 180 °C. The hollow clusters’ diameter was about 400 nm, and these clusters were made up of nanorods with a diameter of about 10 nm and a length of about 50 nm. X-ray power diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were used to characterize the structure and morphology of the synthesized products. Based on experiments, the growth of these hollow clusters followed an aggregation-Ostwald ripening process. The photocatalytic activities for aqueous Rhodamine B of samples were investigated, and it was seen that ZnWO4 hollow clusters exhibited a strong photocatalytic activity.
    Journal of Materials Science 06/2009; 44(12):3082-3087. DOI:10.1007/s10853-009-3410-2 · 2.37 Impact Factor
  • Shuling Xu · Sixiu Sun · Guozhu Chen · Xinyu Song ·
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    ABSTRACT: A facile, template-free method is reported to prepare Cu2O/Au core–shell nanospheres in aqueous medium at room temperature. In this synthesis, Cu2O nanospheres with definite diameter were first synthesized via the reduction reaction between Cu(NO3)2 and hydrazine (N2H4). Then, the as-prepared Cu2O nanospheres were employed as nucleation centers for deposition of Au shell, resulting in the formation of core–shell nanospheres. The samples obtained at various stages after the addition of the HAuCl4 were studied by TEM observation. These TEM images revealed that the formation hollow interior space between the core and the shell. In addition, UV–vis spectra results indicated that the optical property of the Cu2O/Au core–shell nanospheres was influenced by the size of the hollow interior spaces between the cores and the shells.
    Journal of Crystal Growth 04/2009; 311(9):2742-2745. DOI:10.1016/j.jcrysgro.2009.03.003 · 1.70 Impact Factor

Publication Stats

606 Citations
113.36 Total Impact Points


  • 2015
    • University of Jinan (Jinan, China)
      Chi-nan-shih, Shandong Sheng, China
  • 2011-2014
    • Institut national de la recherche scientifique
      • Institute Armand-Frappier Research Centre
      Québec, Quebec, Canada
  • 2007-2012
    • Shandong University
      • • Department of Chemical Engineering
      • • State Key Laboratory for Crystal Materials
      Chi-nan-shih, Shandong Sheng, China