Xinhe Bao

Xiamen University, Amoy, Fujian, China

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Publications (416)2068.64 Total impact

  • Xuejun Xu · Qiang Fu · Xinhe Bao
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    ABSTRACT: Pt-Mo/SiO2 catalysts were prepared using impregnation-reduction methods. Mo-promoted Pt catalysts exhibit much higher water gas shift reaction activity at low temperatures than Pt/SiO2 catalysts. Various characterization methods including inductive coupled plasma atomic emission spectrometry, X-ray diffraction, transmission electron microscopy, X-ray absorption near edge spectrum, and X-ray photoelectron spectroscopy were applied to investigate the composition, structure and chemical state of the Pt-Mo/SiO2 catalysts. Our results indicate that the added Mo species effectively improves the dispersion of Pt nanoparticles and the synergistic effect between the Pt nanoparticles and surface MoOx species enhances the catalytic performance for the water gas shift reaction. Pt nanoparticles decorated with highly dispersed MoOx patches are found to be the active architecture.
    Chinese Journal of Catalysis 12/2015; 36(5):750-756. DOI:10.1016/S1872-2067(14)60294-1 · 1.96 Impact Factor
  • The Journal of Physical Chemistry C 09/2015; 119(36):21219-21226. DOI:10.1021/acs.jpcc.5b06344 · 4.77 Impact Factor
  • Yanhong Zhang · Mingming Wei · Qiang Fu · Xinhe Bao
    09/2015; DOI:10.1007/s11434-015-0875-z
  • Jinjing Li · Xiulian Pan · Xinhe Bao
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    ABSTRACT: Direct conversion of syngas into hydrocarbons with high selectivity remains a challenge. Herein, we report the synthesis of a core–shell-structured catalyst constituting Cr-Zn oxide as the core and SAPO-34 as the shell for the conversion of syngas into hydrocarbons with high selectivity. A SiO2 layer was sandwiched between the core and the shell to prevent damage to the core during shell synthesis. Furthermore, the intermediate SiO2 layer acted as a Si source for the formation of the shell. The prepared catalyst displayed considerably higher selectivity toward the production of C2–C4 hydrocarbons (66.9%) than that of methanol and methane. The findings show the potential of the prepared core–shell-structured catalyst in the one-step production of hydrocarbons, such as liquefied petroleum gas, from syngas. However, further optimization of the catalyst is necessary to achieve higher performance.
    Chinese Journal of Catalysis 07/2015; 36(7). DOI:10.1016/S1872-2067(14)60297-7 · 1.96 Impact Factor
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    ABSTRACT: Long-term stability test of Mo/HZSM-5-N catalysts (HZSM-5-N stands for nano-sized HZSM-5) in methane dehydroaromatization (MDA) reaction has been performed with periodic CH4-H2 switch at 1033–1073 K for more than 1000 h. During this test, methane conversion ranges from 13% to 16%, and mean yield to aromatics (i.e. benzene and naphthalene) exceeds 10%. N2-physisorption, XRD, NMR and TPO measurements were performed for the used Mo/HZSM-5 catalysts and coke deposition, and the results revealed that the periodic hydrogenation can effectively suppress coke deposition by removing the inert aromatic-type coke, thus ensuring Mo/HZSM-5 partly maintained its activity even in the presence of large amount of coke deposition. The effect of zeolite particle size on the catalytic activity was also explored, and the results showed that the nano-sized zeolite with low diffusion resistance performed better. It is recognized that the size effect was enhanced by reaction time, and it became more remarkable in a long-term MDA reaction even at a low space velocity.
    Journal of Energy Chemistry 05/2015; 24(3). DOI:10.1016/S2095-4956(15)60309-6 · 2.35 Impact Factor
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    ABSTRACT: Nickel carbide and graphene overlayers were grown on Ni(111), which were in-situ monitored by near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and low energy electron microscopy. CO adsorption and desorption on the formed carbon-modified Ni(111) surfaces were further investigated by NAP-XPS. We found that the carbidic carbon weakens CO adsorption on Ni, resulting in quick CO desorption around room temperature. A full graphene layer on Ni(111) blocks CO adsorption in 10-6 Torr CO while CO intercalates the graphene overlayers in 0.1 Torr CO at room temperature. The major part of intercalated CO molecules desorb extensively around 90 oC from the graphene/Ni interface and the left part get trapped under the graphene. These results suggest that the surface reactivity of a metal catalyst can be strongly modulated by surface carbon structures.
    The Journal of Physical Chemistry C 05/2015; 119(24):150526191240006. DOI:10.1021/acs.jpcc.5b01395 · 4.77 Impact Factor
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    Fan Yang · Dehui Deng · Xiulian Pan · Qiang Fu · Xinhe Bao
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    ABSTRACT: Catalysis, as a key and enabling technology, plays an increasingly important role in fields ranging from energy, environment and agriculture to health care. Rational design and synthesis of highly efficient catalysts has become the ultimate goal of catalysis research. Thanks to the rapid development of nanoscience and nanotechnology, and in particular a theoretical understanding of the tuning of electronic structure in nanoscale systems, this element of design is becoming possible via precise control of nanoparticles’ composition, morphology, structure and electronic states. At the same time, it is important to develop tools for in-situ characterization of nanocatalysts under realistic reaction conditions, and for monitoring the dynamics of catalysis with high spatial, temporal and energy resolution. In this review, we discuss confinement effects in nanocatalysis, a concept that our group has put forward and developed over several years. Taking the confined catalytic systems of carbon nanotubes (CNTs), metal-confined nano-oxides, and two-dimensional (2D) layered nano-catalysts as examples, we summarize and analyze the fundamental concepts, the research methods and some of the key scientific issues involved in nanocatalysis. Moreover, we present a perspective on the challenges and opportunities in future research on nanocatalysis from the aspects of: 1) controlled synthesis of nano-catalysts and rational design of catalytically active centers; 2) in-situ characterization of nanocatalysts and dynamics of catalytic processes; 3) computational chemistry with a complexity approximating that of experiments; and 4) scale-up and commercialization of nanocatalysts.
    05/2015; 2(2). DOI:10.1093/nsr/nwv024
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    ABSTRACT: A series of phosphates is investigated as additives to improve the stability of the electrolyte for vanadium flow battery (VFB). Two selected additives show positive effect on the stability of electrolytes under ex-situ stability tests and in situ flow cell experiments. The effects of additives on electrolyte are studied by Nuclear magnetic resonance (NMR), X-ray diffraction (XRD), Raman spectroscopy, Cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS) and charge–discharge test. The results show that a VFB using the electrolyte with NH4H2PO4additive demonstrates significantly improved redox reaction reversibility and activity, and higher energy efficiency. In addition, the cell employing the electrolyte with NH4H2PO4 exhibits a charge capacity fading rate much slower than the cell without additives during the cycling at high temperature. These results indicate that the phosphate additives are highly beneficial to improving the stability and reliability of VFB.
    Electrochimica Acta 05/2015; 164. DOI:10.1016/j.electacta.2015.02.187 · 4.50 Impact Factor
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    ABSTRACT: Silica-supported catalysts for the conversion of ethanol to 1,3-butadiene were investigated. The combination of Hf(IV) and Zn(II) resulted in a stable, active, and selective catalyst in which the Zn(II) effectively suppressed the dehydration activity of Hf(IV); the catalyst preparation method plays a crucial role. Using the crystalline Zn-silicate hemimorphite as an alternative Zn(II) source proved to be even more successful in suppressing ethanol dehydration.Keywords: 1,3-butadiene; ethanol; zinc silicate; hemimorphite; heterogeneous catalysis; silica impregnation
    ACS Catalysis 04/2015; 5(6):150424100944007. DOI:10.1021/acscatal.5b00376 · 9.31 Impact Factor
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    ABSTRACT: In heterogeneous catalysis molecule-metal interaction is often modulated through structural modifications at the surface or under the surface of the metal catalyst. Here, we suggest an alternative way towards this modulation by placing a two-dimensional (2D) cover on the metal surface. As an illustration, CO adsorption on Pt(111) surface has been studied under 2D hexagonal boron nitride (h-BN) overlayer. Dynamic imaging data from surface electron microscopy and in-situ surface spectroscopic results under near ambient pressure conditions confirm that CO molecules readily intercalate monolayer h-BN sheets on Pt(111) in CO atmosphere but desorb from the h-BN/Pt(111) interface even around room temperature in ultrahigh vacuum. The interaction of CO with Pt has been strongly weakened due to the confinement effect of the h-BN cover, and consequently CO oxidation at the h-BN/Pt(111) interface was enhanced thanks to the alleviated CO poisoning effect.
    Nano Letters 04/2015; 15(5). DOI:10.1021/acs.nanolett.5b01205 · 13.59 Impact Factor
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    ABSTRACT: Supported VOx/TiO2-Rod catalysts were studied by 51V MAS NMR at high field using a sample spinning rate of 55 kHz. The superior spectral resolution allows for the observation of at least five vanadate species. The assignment of these vanadate species was carried out by quantum chemical calculations of 51V NMR chemical shifts of model V-Surface structures. Methanol oxidative dehydrogenation (ODH) was used to establish a correlation between catalytic activity and the various surface V-Sites. It is found that monomeric V-Species are predominant at low vanadium loadings with two 51V NMR peaks observed at about -502 and -529 ppm. V-Dimers with two bridged oxygens result in a peak at about -555 ppm. Vanadate dimers and polyvanadates connected by one bridged oxygen atom between two adjacent V atoms resonate at about -630 ppm. A positive correlation is found between the V-Dimers giving rise to the -555 ppm peak and the ODH rate, and an even better correlation is obtained by including V-monomer contributions. This result suggests that surface V-Dimers related to the -555 ppm peak and monomers are the primary active sites for the methanol ODH reaction. Furthermore, a portion of the V-Species is found to be invisible to NMR and the level of such invisibility increases with decreasing V-Loading levels, suggesting the existence of paramagnetic V-Species at the surface. These paramagnetic V-Species are also fund to be much less active in methanol ODH.
    ACS Catalysis 04/2015; 5(7):150415154110003. DOI:10.1021/acscatal.5b00286 · 9.31 Impact Factor
  • Peng Jiang · Xinhe Bao · Miquel Salmeron
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    ABSTRACT: Heterogeneous catalysis is of great importance for modern society. About 80% of the chemicals are produced by catalytic reactions. Green energy production and utilization as well as environmental protection also need efficient catalysts. Understanding the reaction mechanisms is crucial to improve the existing catalysts and develop new ones with better activity, selectivity, and stability. Three components are involved in one catalytic reaction: reactant, product, and catalyst. The catalytic reaction process consists of a series of elementary steps: adsorption, diffusion, reaction, and desorption. During reaction, the catalyst surface can change at the atomic level, with roughening, sintering, and segregation processes occurring dynamically in response to the reaction conditions. Therefore, it is imperative to obtain atomic-scale information for understanding catalytic reactions.
    Accounts of Chemical Research 04/2015; 48(5). DOI:10.1021/acs.accounts.5b00017 · 22.32 Impact Factor
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    ABSTRACT: The layered silicate COK-5 has been used for an interlayer expansion reaction with dichlorodimethylsilane (DCDMS) at 180 °C to interconnect neighboring layers, yielding a new and crystalline microporous framework. The samples containing the methyl functional groups in the as-made form and having OH groups in the calcined form were designed as COE-5 and calcined COE-5. These samples were characterized with X-ray diffraction (XRD), N2 sorption isotherms, inductively coupled plasma optical emission spectrometry (ICP-OES), infrared spectroscopy (IR), high-resolution transmission electron micrograph (HRTEM), thermogravimetry-differential thermal analysis (TG-DTA), and 29Si and 13C solid-state magic-angle spinning nuclear magnetic resonance (MAS NMR), as well as the contact angle techniques. XRD patterns and HRTEM images suggest that the sample interlayer spacing has been expanded by nearly 0.5 Å. The N2 sorption isotherms of the materials show the BET surface areas are 165 m2/g for COE-5 and 340 m2/g for calcined COE-5. 29Si and 13C MAS NMR as well as IR spectroscopy confirm the insertion of the linker group -Si(CH3)2- connecting neighboring layers. Interestingly, calcined COE-5 shows enhanced catalytic performance in the acetalisation of glycerol with acetone to produce solketal, compared with COK-5.
    Microporous and Mesoporous Materials 04/2015; 214. DOI:10.1016/j.micromeso.2015.04.017 · 3.45 Impact Factor
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    ABSTRACT: Electrocatalytic splitting of water is one of the most efficient technologies for hydrogen production, and two-dimensional (2D) MoS2 has been considered as a potential alternative to Pt-based catalysts in hydrogen evolution reaction (HER). However, the catalytic activity of 2D MoS2 is always contributed from its edge sites, leaving a large number of in-plane domains useless. Herein, we for the first time demonstrated that the catalytic activity of in-plane S atoms of MoS2 can be aroused via single-atom metal doping in HER. The single-Pt atoms doped few-layer MoS2 nanosheets (Pt-MoS2) in experiments showed a significantly enhanced HER activity compared with pure MoS2, which originates from the tuned adsorption behavior of H atoms on the in-plane S sites neighboring to doped Pt atoms according to the density functional theory (DFT) calculations. Furthermore, the HER activity of a number of transition metals doped MoS2 was screened by virtue of DFT calculations and presented a volcano curve along the adsorption free energy of H atoms (ΔGHo), which was further confirmed in experiment by using non-precious metals such as Co and Ni atoms doped 2D MoS2 as the catalysts.
    Energy & Environmental Science 04/2015; DOI:10.1039/C5EE00751H · 20.52 Impact Factor
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    ABSTRACT: Graphene coatings have been widely considered as protection layers on metal surfaces to prevent surface oxidation and corrosion in gaseous atmospheres. Here, using in-situ ambient pressure X-ray photoelectron spectroscopy we demonstrate that oxygen intercalation readily occurs at full monolayer graphene/Ru(0001) interfaces in 0.5 Torr O2 around 150 °C, resulting in decoupling of the graphene overlayer from the Ru surface and oxidation of the metal surface. Moreover, oxygen intercalation has been observed even upon illumination of the graphene/Ru(0001) surface with an infrared lamp in air. These results indicate that the stability of graphene/metal interfaces under ambient conditions should be taken into consideration for future applications.
    Surface Science 04/2015; 634:37-43. DOI:10.1016/j.susc.2014.10.008 · 1.93 Impact Factor
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    ABSTRACT: The electronic interaction of a catalyst and its support is of vital importance to its catalytic performance. However, it is still a great challenge to directly probe the interaction due to the lack of well-defined model and efficient technical means. In this study, we report that pod-like carbon nanotubes with encapsulated iron particles (Pod-Fe) and scanning transmission X-ray microscopy (STXM) can be used as an ideal model and technique to study the electronic interaction between carbon shells and iron particles. The chemical imaging and spectroscopy of a single Pod-Fe by STXM shows that the local electronic structures at C K-edge near edge (π*) of carbon shells can be significantly modified by the encapsulated iron particles, which promotes the adsorption of oxygen-containing species, and thereby further modifies the electronic structure (π* and σ*) of carbon shells. Moreover, computed X-ray absorption near edge structure spectra (XANES) confirmed the electronic modifications of carbon shells by the encapsulated iron particles. The present study provides a direct evidence of electronic interactions with simultaneously collected images and spectra, which can promote the understanding towards the nature of active sites and supports.
    Chemical Science 03/2015; DOI:10.1039/C5SC00353A · 9.21 Impact Factor
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    ABSTRACT: Adsorbed hydrogen participates in electrocatalytic reduction of CO2 and competitive hydrogen evolution reaction (HER) simultaneously, and its reaction pathway greatly affects the activity and selectivity of CO2 reduction. In this work, we investigate pH effect on electrocatalytic reduction of CO2 over Pd and Pt nanoparticles (NPs) with a similar size in a pH range from 1.5 to 4.2. Pt NPs completely contributes to HER in the pH range. Over Pd NPs, Faradaic efficiency for CO production at -1.19 V (vs. reversible hydrogen electrode) varies from 3.2% at pH of 1.5 to 93.2% at pH of 4.2, and current density for CO production reaches maximum at pH of 2.2. The significant enhancement of Faradaic efficiency and current density for CO production over Pd NPs at high pH values is attributed to decreased kinetics of hydrogen evolution reaction by increasing hydrogen binding energy and lowered adsorption affinity of CO-like intermediate compared to Pt.
    Electrochemistry Communications 03/2015; 55. DOI:10.1016/j.elecom.2015.03.008 · 4.85 Impact Factor
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    ABSTRACT: Exploring highly efficient electrocatalysts toward oxygen reduction and evolution reactions are critical for the development of rechargeable zinc–air batteries. As a novel class of electrocatalyst, transition metal nanoparticles encapsulated within nitrogen-doped carbon have been regarded as competitive alternative to replace noble metal electrocatalysts. Herein, we report successful synthesis of high-density iron nanoparticles encapsulated within nitrogen-doped carbon nanoshell (Fe@N–C) by solid-phase precursor׳s pyrolysis of dicyandiamide and ammonium ferric citrate. The resulting Fe@N–C material shows excellent bifunctionality for ORR and OER in alkaline medium compared to state-of-the-art commercial Pt/C and IrO2, which demonstrates high performance and cycling durability in zinc–air battery as efficient oxygen electrocatalyst.
    Nano Energy 03/2015; 13. DOI:10.1016/j.nanoen.2015.02.025 · 10.33 Impact Factor
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    ABSTRACT: Rhenium (Re), a high-performance engineering material with a hexagonal close-packed (hcp) structure, remains stable even under pressures of up to 250 GPa and at temperatures up to its melting point (3453 K). We observed here that Re atoms self-assembled, within the confined space of carbon nanotubes (CNTs) with a diameter of <1.5 nm, into ultrathin nanowires stacking with an unusual face-centered cubic (fcc) structure along the CNTs. In contrast, only Re nanoparticles of hcp structure formed on an open surface of graphite and carbon black. Aberration-corrected electron microscopy unambiguously showed the atomic arrangements of the Re nanowires and their confinement within the CNTs, ∼80% exhibiting a four-atom and 15% a nine-atom configuration. Density functional theory calculations confirmed that the formation of unusual fcc-stacking Re nanowires is largely facilitated by the strong interaction between Re atoms and CNTs and the spatial restriction within the CNTs. The use of CNTs as nanoscale reactors to create novel structures not only is fundamentally interesting but also may find unique applications in catalysis, sensing, and nanoelectronics.
    Chemistry of Materials 03/2015; 27(5):1569-1573. DOI:10.1021/cm504012h · 8.35 Impact Factor
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    ABSTRACT: Size effect has been regularly utilized to tune the catalytic activity and selectivity of metal nanoparticle (NPs). Yet, there has been a lack of understanding on size effect in the electrocatalytic reduction of CO2, an important reaction coupling with intermittent renewable energy storage and carbon cycle utilization. We report here a prominent size-dependent activity/selectivity in the electrocatalytic reduction of CO2 over differently-sized Pd NPs, ranging from 2.4 nm to 10.3 nm. The Faradaic efficiency for CO production varies from 5.8% at -0.89 V (vs. reversible hydrogen electrode) over 10.3 nm NPs to 91.2% over 3.7 nm NPs, along with an 18.4 fold increase in current density. Based on the Gibbs free energy diagrams from density functional theory calculations, the adsorption of CO2 and the formation of key reaction intermediate COOH* are much easier on edge and corner sites than on terrace one of Pd NPs. In contrast, the formation of H* for competitive hydrogen evolution reaction is similar on all three sites. A volcano-like curve of the turnover frequency for CO production within the size range suggests that CO2 adsorption, COOH* formation and CO* removal during CO2 reduction can be tuned by varying the size of Pd NPs due to the changing ratio of corner, edge and terrace sites.
    Journal of the American Chemical Society 03/2015; 137(13). DOI:10.1021/jacs.5b00046 · 12.11 Impact Factor

Publication Stats

8k Citations
2,068.64 Total Impact Points


  • 2015
    • Xiamen University
      Amoy, Fujian, China
  • 1998–2015
    • Dalian Institute of Chemical Physics
      Lü-ta-shih, Liaoning, China
  • 2013
    • Peking University
      • College of Chemistry and Molecular Engineering
      Peping, Beijing, China
  • 1998–2013
    • Chinese Academy of Sciences
      • • State Key Laboratory of Catalysis
      • • Dalian Institute of Chemical Physics
      Peping, Beijing, China
  • 2008–2011
    • State Key Laboratory of Medical Genetics of China
      Ch’ang-sha-shih, Hunan, China
  • 2010
    • Northeast Normal University
      Hsin-ching, Jilin Sheng, China
  • 2001–2005
    • Dalian University of Technology
      • School of Chemical Engineering
      Lü-ta-shih, Liaoning, China
  • 2002
    • The Hong Kong University of Science and Technology
      Chiu-lung, Kowloon City, Hong Kong
    • University of Science and Technology of China
      • Department of Chemical Physics
      Luchow, Anhui Sheng, China
  • 1993–1996
    • Max Planck Society
      München, Bavaria, Germany
  • 1992–1995
    • Fritz Haber Institute of the Max Planck Society
      • Department of Inorganic Chemistry
      Berlín, Berlin, Germany