Yanhui Yang

Xiamen University, Amoy, Fujian, China

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Publications (151)817.89 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Bimetallic AuAg/SBA-15 catalysts were disclosed to efficiently catalyze vapor-phase chemoselective hydrogenation of crotonaldehyde (CRAL) with improved hydrogenation rate and selectivity to crotonyl alcohol (CROL). The CRAL hydrogenation rate and product distribution were remarkably influenced by reaction parameters such as the reaction pressure and CRAL/hydrogen ratio. Ag decoration on Au/SBA-15 effectively stabilized bimetallic AuAg nano-alloy particles in small size and promoted the catalytic stability. In situ FT-IR investigation revealed that unusual C2M2 di-σ bonded CRAL surface species with reinforced symmetric δ(CH3) IR band under the “metal-surface selection rule” (MSSR) were formed on bimetallic AuAg/SBA-15. The stronger CRAL chemisorption on bimetallic AuAg/SBA-15 surfaces than on monometallic Au/SBA-15 was possibly due to the relatively strong ligating of CO bond on Ag active sites and the enhancement of the co-adsorption of the conjugated double bonds of CRAL. Synergistic interaction between Au and Ag active sites for the activation of HH, CC and CO bond may be the origin of positive effect of Ag decoration on Au/SBA-15.
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    ABSTRACT: Titania nanowires (NW) supported gold–copper (Au–Cu) bimetallic nanoparticles were synthesized and pretreated in hydrogen and air at 300, 500 and 700 • C, for the one-pot conversion of cellobiose to glu-conic acid. Catalyst samples were characterized by temperature-programmed desorption of NH 3 , Fourier transform infrared spectroscopy (FT-IR), Energy-dispersive X-ray spectroscopy, Field emission scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD), Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The structure and activity of Au–Cu/TiO 2 NW were highly affected by the pretreatment conditions. Catalyst samples reduced in H 2 and at higher temperatures resulted better catalytic performance as compared with those calcinated in air at the same temperature. The influence of support, calcination temperature and atmosphere as well as gold content on the catalytic performance of Au–Cu/TiO 2 NWs are investigated. The characterization results suggested high hydrogen reduction temperature created oxygen vacant sites on the titania NW support. This is consequently associated with the stabilization of highly reactive oxygen species at the periphery of the metal–support interface. Interactions between the metals and the titania NWs support and between the promoter and the active metal enhanced the formation of gluconic acid.
    Applied Catalysis A: General 09/2015; 505:16-27. DOI:10.1016/j.apcata.2015.07.027 · 3.94 Impact Factor
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    Jun Zhao · Chunmei Zhou · Chao He · Yihu Dai · Xinli Jia · Yanhui Yang ·
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    ABSTRACT: A carbon-based solid acid catalyst was prepared via hydrothermal method using glucose as carbon precursors and aqueous solution of H2SO4 as sulfonation agent. The as-synthesized solid acid catalyst was attempted in the catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF). The effects of acid site density, reaction time, solvents, catalyst amount, temperature and mole ratio of catalyst to substrate were investigated. Under the optimum reaction conditions, the HMF yield of 90% was achieved in dimethylsulfoxide (DMSO) solvent at 160 °C after 1.5 h reaction time duration. The solid acid catalyst can be separated from the reaction mixture after reaction and reused without substantial loss in catalytic activity.
    Catalysis Today 08/2015; DOI:10.1016/j.cattod.2015.07.005 · 3.89 Impact Factor
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    ABSTRACT: Biodiesels produced from renewable sources exhibit superior fuel properties and renewability and they are more environmentally friendly than petroleum-based fuels. In this paper, a three-step transesterification, catalyzed by a pyridinium-based Brønsted acidic ionic liquid (BAIL), for biodiesel production was investigated using density functional theory (DFT) calculations at the B3LYP/6-311++G(d) level. The DFT results elucidate the detailed catalytic cycle, which involves the formation of a covalent reactant–BAIL–(methanol)n (n = 1/3) intermediate and two transition states. Hydrogen bond interactions were found to exist throughout the process of the catalytic cycle, which are of special importance for stabilizing the intermediate and transition states. Thus, a mechanism involving cooperative hydrogen bonding for BAIL-catalyzed biodiesel production was established. The Gibbs free energy profile based on the above mechanism was validated by the subsequent kinetic study. The trend of activation energy from kinetic mathematical models was reasonably consistent with that obtained from the DFT calculations.
    Green Chemistry 08/2015; 17(8). DOI:10.1039/C5GC00976F · 8.02 Impact Factor
  • Yibo Yan · Xinli Jia · Yanhui Yang ·

    Catalysis Today 08/2015; DOI:10.1016/j.cattod.2015.07.021 · 3.89 Impact Factor
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    ABSTRACT: The aerobic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) is one of the most attractive reactions to establish biomass-based sustainable chemical processes. Supported Au and Pt catalysts have mainly been reported for this reaction, but excess amounts of base additives are generally required, which makes the process less green. Here, we demonstrate that Pt nanoparticles loaded on functionalized carbon nanotubes (CNTs) can catalyze the aerobic oxidation of HMF to FDCA in water without any base additives. Kinetic studies suggest a tandem reaction mechanism via 2,5-diformylfuran and 5-formylfurancarboxylic acid intermediates. It has been clarified that the oxygen-containing functional groups, in particular carbonyl/quinone and/or phenol groups, on CNT surfaces play crucial roles in FDCA formation. These functional groups could enhance the adsorption of HMF as well as the reaction intermediates from water and might facilitate hydrogen transfer.
    ChemCatChem 07/2015; 7(18). DOI:10.1002/cctc.201500352 · 4.56 Impact Factor
  • Chunmei Zhou · Zhen Guo · Yihu Dai · Xinli Jia · Hao Yu · Yanhui Yang ·
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    ABSTRACT: PtBi/CNT catalyst was synthesized by a one-step polyol reduction method assisted by microwave radiation, and its catalytic performance was investigated in aerobic oxidation of benzyl alcohol in the aqueous phase. Pt and BiOx species uniformly dispersed on the CNT surfaces and strong synergic interaction between them occurred, which confirmed by the comprehensive analysis of TEM, XRD, XPS and electrochemical characterizations. Further investigations revealed that the synergic effect effectively promoted the activation of both molecular oxygen and benzyl alcohol substrate; also protected Pt active sites from over-oxidization. The advantage of such synergic effect was reflected in the increased yield for the desired product benzaldehyde: PtBi/CNT catalyst exhibited about 3.5 times higher yield toward benzaldehyde compared to Pt/CNT catalyst. Furthermore, owing to the positive effect of Bi avoiding Pt from oxidizing, the deactivation of PtBi/CNT (with 2% selectivity and 9% conversion decrease) is much slower than that of Pt/CNT (with 8% selectivity and 39% conversion decrease) after six reaction cycles. PtBi/CNT catalyst was proved as a remarkably effective catalyst with high stability for the aerobic oxidation of benzyl alcohol.
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    ABSTRACT: An integrated experimental and computational investigation reveals that surface lattice oxygen of copper oxide (CuO) nanoleaves activates the formyl CH bond in glucose and incorporates itself into the glucose molecule to oxidize it to gluconic acid. The reduced CuO catalyst regains its structure, morphology, and activity upon reoxidation. The activity of lattice oxygen is shown to be superior to that of the chemisorbed oxygen on the metal surface and the hydrogen abstraction ability of the catalyst is correlated with the adsorption energy. Based on the present investigation, it is suggested that surface lattice oxygen is critical for the oxidation of glucose to gluconic acid, without further breaking down the glucose molecule into smaller fragments, because of CC cleavage. Using CuO nanoleaves as catalyst, an excellent yield of gluconic acid is also obtained for the direct oxidation of cellobiose and polymeric cellulose, as biomass substrates. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Angewandte Chemie International Edition 06/2015; DOI:10.1002/anie.201503916 · 11.26 Impact Factor
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    ABSTRACT: Anatase interim layer-stabilized rutile@CrxOy core–shell nanorod arrays as photoanodes of photoelectrochemical water splitting cell can output a four-fold enhanced and stabilized visible-light photocurrent, as reported on p. 1352 by J. L. long, X. X. Wang, B. Liu et al.
    ChemPhysChem 05/2015; 16(7):1318-1318. DOI:10.1002/cphc.201590035 · 3.42 Impact Factor
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    ABSTRACT: In order to reduce considerable emissions of N-containing pollutants from combustion of sewage sludge derived solid fuel, an integrated system of hydrothermal deamination and air stripping was developed to effectively remove and recover nitrogen from dewatered sewage sludge (DSS). Three characteristic hydrothermal regimes contributing to deamination were identified. Initial hydrolysis of inorganic-N and labile protein-N was responsible for ammonium (NH+ 4-N) released below 300 oC/9.3 MPa, whereas deamination of pyridine-N dominated when being raised to 340 oC/15.5 MPa. At 380 oC and 22.0 MPa, remarkable deamination of stable protein-N occurred, which was accompanied by formation of more heterocyclic-N compounds and resulted in 76.9% N removal from DSS and 7980 mg/L NH+ 4-N solution. As a result of catalytic hydrolysis and cracking, calcium oxide additive not only accelerated deamination of stable protein-N, pyrrole-N, and pyridine-N but also favored transformations of protein-N and quaternary-N to nitrile-N and pyridine-N, respectively, leading to 86.4% total N removal efficiency. The nitrogen transformation reactions and conversion pathways during hydrothermal deamination were proposed and elaborated in detail. Moreover, an efficient air stripping process was coupled to remove and recover ammonia from liquid fraction via ammonium sulfate. Consequently, this system achieved an overall N recovery rate of 62%.
    Environmental Science & Technology 05/2015; 49(11):6872–6880. DOI:10.1021/acs.est.5b00652 · 5.33 Impact Factor
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    ABSTRACT: Carbon nanotubes are promising materials for various applications. In recent years, progress in manufacturing and functionalizing carbon nanotubes has been made to achieve the control of bulk and surface properties including the wettability, acid-base properties, adsorption, electric conductivity and capacitance. In order to gain the optimal benefit of carbon nanotubes, comprehensive understanding on manufacturing and functionalizing carbon nanotubes ought to be systematically developed. This review summarizes methodologies of manufacturing carbon nanotubes via arc discharge, laser ablation and chemical vapor deposition and functionalizing carbon nanotubes through surface oxidation and activation, doping of heteroatoms, halogenation, sulfonation, grafting, polymer coating, noncovalent functionalization and nanoparticle attachment. The characterization techniques detecting the bulk nature and surface properties as well as the effects of various functionalization approaches on modifying the surface properties for specific applications in catalysis including heterogeneous catalysis, photocatalysis, photoelectrocatalysis and electrocatalysis are highlighted.
    Chemical Society Reviews 04/2015; 44(10). DOI:10.1039/c4cs00492b · 33.38 Impact Factor
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    Chao He · Ke Wang · Apostolos Giannis · Yanhui Yang · Jing-Yuan Wang ·
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    ABSTRACT: In the present study, hydrothermal conversion (HTC) of dewatered sewage sludge (DSS) under sub- and near-critical water has been performed to investigate effects of reaction temperature and pressure, moisture content of DSS, and calcium oxide (CaO) additive on evolution profile and characteristics of gas, solid, and liquid products. Although energy recovery rate decreased with increasing temperature and pressure, significant decarboxylation and dehydration reactions led to hydrochars with best fuel quality at 320 °C. High moisture content favored decarboxylation reaction but reduced H2 and CH4 yields. Compared to that in the absence of additive, H2 yield increased almost 6-fold at 380 °C and Ca/C molar ratio of 0.2, resulting in 58% H2 and 26% CH4 in final fuel gas. The results suggested that mineralization of heteroatomic compounds and dissolution of metals or mineral elements occurred during HTC. Under higher temperature and pressure, heavy metals or mineral elements were prone to be immobilized whereas dehalogenation became more distinct. CaO additive not only facilitated hydrolysis and deamination of organic compounds but also accelerated further fixation of inorganic elements and anions.
    International Journal of Hydrogen Energy 04/2015; 40(17):5776–5787. DOI:10.1016/j.ijhydene.2015.03.006 · 3.31 Impact Factor
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    ABSTRACT: Mesoporous-metal-organic frameworks (meso-MOFs) with size-, shape-, and space-distribution-controlled mesopores are obtained by a facile encapsulation and selective etching strategy of metal nanoparticles. Hierarchical or functionalized meso-MOFs are achieved by the above strategy. Interestingly, the functional meso-MOFs display higher catalytic activity originating from the mesopores existing in the MOFs, as well as good selectivity due to protection of the micro-porous frameworks. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Advanced Materials 03/2015; 27(18). DOI:10.1002/adma.201405752 · 17.49 Impact Factor
  • Hong Chen · Xinli Jia · Yongdan Li · Changjun Liu · Yanhui Yang ·
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    ABSTRACT: The catalytic activity of gold supported on ZSM5 (Au/ZSM5) was investigated for the selective oxidation of ethanol in the presence of excess oxygen. Au/ZSM5 catalyst pretreated by nonthermal O2 plasma method showed the best oxidative activity compared to low-temperature calcination in air and high-temperature reduction in hydrogen atmosphere. Results from microscopy and X-ray diffraction characterizations proved that plasma pretreatment afforded a small Au particle size and a uniform dispersion of Au nanoparticles on ZSM5 surfaces. Characterization results further demonstrated that the residual ammonia adsorbed on ZSM5 surfaces during the precipitation can be oxidized to nitrate ions by nonthermal O2 plasma treatment, while it converted to NO+ by low-temperature oxygen calcination and was completely removed by high-temperature hydrogen reduction. Dissimilar surface/interface properties caused the tremendously different interaction between gold nanoparticles and zeolite support, and consequently the catalytic performances in ethanol oxidation. In particular, under the nonthermal O2 plasma pretreatment, the formed NO3− species lowered the acidity of ZSM5 surfaces as well as anchored the Au nanoparticles, resulting in nearly 100% selectivity toward selective oxidation instead of acid-catalyzed reactions even under high reaction temperature.
    Catalysis Today 02/2015; DOI:10.1016/j.cattod.2015.01.020 · 3.89 Impact Factor
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    ABSTRACT: Ternary core–shell heterostructured rutile@anatase@Crx Oy nanorod arrays were elaborately designed as photoanodes for efficient photoelectrochemical water splitting under visible‐light illumination. The four‐fold enhanced and stabilized visible‐light photocurrent highlights the unique role of the interim anatase layer in accelerating the interfacial charge transfer from the Crx Oy chromophore to rutile nanorods. Driving light: Ternary core–shell heterostructured rutile@anatase@Crx Oy nanorod arrays are elaborately designed as photoanodes for photoelectrochemical water splitting under visible‐light irradiation. Thus, affording a novel strategy to extend the photoresponse of oxide array materials, and showing the promising application of rutile@anatase@Crx Oy photoanodes in the domain of photoelectrochemistry.
    ChemPhysChem 02/2015; 16(7). DOI:10.1002/cphc.201402905 · 3.42 Impact Factor
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    Linlu Bai · Lin Yao · Yanhui Yang · Jong-Min Lee ·
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    ABSTRACT: A novel microspherical composite with an Au@SiO2 core and mesoporous aluminosilica shell is synthesized and used as the heterogeneous catalyst in the aerobic epoxidation of cis-cyclooctene, exhibiting great catalytic activity and stability.
    Chemical Communications 02/2015; 51(20). DOI:10.1039/c4cc09570g · 6.83 Impact Factor
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    Chao He · Jianwei Zheng · Ke Wang · Haiqiang Lin · Jing-Yuan Wang · Yanhui Yang ·
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    ABSTRACT: In this study, multi-walled carbon nanotubes supported Pt and Pt-based bimetallic catalysts were prepared and their catalytic activities were investigated to screen effective and economical catalyst for H2 production in catalytic aqueous phase reforming (CAPR) of glycerol. Nickel promoted Pt catalyst with optimized Ni:Pt molar ratio afforded highest glycerol conversion rate (81.21%) and carbon conversion to gas (15.3%) although hydrogen gasification ratio (7.2%) was poorer than that of noble metals promoted Pt-based bimetallic catalysts. Adding CaO significantly enhanced the fraction and selectivity of H2 over Pt-Ni catalyst and those of CH4 were reduced to a negligible level, which was possibly attributed to the facilitated water-gas shift reaction and inhibited methanation through in-situ CO2 sorption via carbonation. Results suggested that Pt-Ni bimetallic catalysts improved dehydrogenation–decarboxylation and dehydration–hydrogenation reactions, leading to high glycerol conversions. Introducing CaO further favored C–C bond cleavage towards high H2 yield. The catalytic performance can be completely recovered after regenerating the catalyst and adding sacrificial CaO. In terms of reduced consumption of precious metal catalyst, excellent catalyst performance and hydrothermal stability, combination of Pt-Ni bimetallic catalyst and CaO additive was identified as an effective catalytic system for H2 production in CAPR of glycerol.
    Applied Catalysis B Environmental 01/2015; 162:401–411. DOI:10.1016/j.apcatb.2014.07.012 · 7.44 Impact Factor
  • Zhihong Yang · Zhengwen Li · Yanhui Yang · Zhichuan J Xu ·
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    ABSTRACT: We report here the composition optimization of ZnxFe3-xO4 hollow nanospheres for enhancing microwave attenuation. ZnxFe3-xO4 hollow nanospheres were synthesized through a simple solvothermal process. The maximum magnetization moment of 91.9 emu/g can be obtained at x=0.6. The composite filled with Zn0.6Fe2.4O4 exhibited the bandwidth of 3.21~8.33 GHz for RL< -10 dB and a maximum relative bandwidth (Wp,max) of 88.6% at optimized thickness t0=0.34 cm. The enhancement should be attributed to the enhanced permeability resonance at high frequency. This optimized hollow material is very promising to be used as a mass efficient and broadband microwave attenuation material.
    ACS Applied Materials & Interfaces 12/2014; 6(24). DOI:10.1021/am5075612 · 6.72 Impact Factor
  • Prince Amaniampong · Bo Wang · Armando Borgna · Yanhui Yang ·
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    ABSTRACT: A series of bimetallic catalysts Au-M (M = Cu, Co, Ru, Pd and Ni) were supported on TiO2 via deposition-precipitation (DP) method using urea as precipitating agent. The resulting catalysts were used in the catalytic oxidation of cellobiose into gluconic acid. The interactions between the metals in the bimetallic catalysts were carefully investigated in order to unravel the effect of the second metal on the chemical and electronic properties of the active sites and their impact on the catalytic performance. Cu and Ruwere found to be promising promoters for the oxidation of cellobiose into gluconic acid, promoting oxygen activation in gold-catalyzed oxidation reactions, while Co and Pd were found to enhance the retro-aldol condensation of fructose into glycolic acid. In this case, the catalytic activity is dominated by the second metal added to Au. Hence, Au behaves more like a promoter of the second metal, preventing over oxidation and poisoning by the reaction intermediates and products. Ni specifically promoted the C-C scission, yielding a mixture of lower carbon-containing compounds and glycolic acid as the main products. The major reaction products obtained were gluconic acid, glycolic acid, ethylene glycol and erythritol. The catalytic activity of the catalysts followed the order: Au-Cu/TiO2 > Au-Pd/TiO2 > Au-Ru/TiO2 > Au-Co/TiO2 > Au/TiO2 > Au-Ni/TiO2. Upon comparison, Au-Ru/TiO2 was found to be an active and selective catalyst towards the formation of gluconic acid. The nature of the metal interactions in the bimetallic systems greatly influenced the product distribution.
    14 AIChE Annual Meeting; 11/2014
  • Yihu Dai · Ye Wang · Bin Liu · Yanhui Yang ·
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    ABSTRACT: Rapidly growing research interests surround heterogeneous nanocatalysis, in which metal nanoparticles (NPs) play a pivotal role as structure-sensitive active centers. With advances in nanotechnology, the morphology of metal NPs can be precisely controlled, which can provide well-defined models of nanocatalysts for understanding and optimizing the structure–reactivity correlations and the catalytic mechanisms. Benefiting from this, further credible evidence can be acquired on well-defined nanocatalysts rather than common multiphase systems, which is of great significance for the design and practical application of active metal nanocatalysts. Numerous studies demonstrate that enhanced structure-sensitive catalytic activity and selectivity are dependent not only on an increased surface-to-volume ratio and special surface atom arrangements, but also on tailored metal–metal and metal–organic–ligand interfaces, which is ascribed to the size, shape, composition, and ligand effects. Size–reactivity relationships and underlying size-dependent metal–oxide interactions are observed in many reactions. For bimetallic nanocatalysts, the composition and nanostructure play critical roles in regulating reactivities. Crystal facets favor individual catalytic selectivity and rates via distinct reaction pathways occurring on diverse atomic arrangements, both to low-index and high-index facets. High-index facets exhibit superior reactivities owing to their high-energy active sites, which facilitate rapid bond-breaking and new bond generation. Additionally, organic ligands may enhance the catalytic activity and selectivity of metal nanocatalysts via changing the adsorption energies of reactants and/or reaction energy barriers. Furthermore, atomically dispersed metals, especially single-atom metallic catalysts, have emerged recently, which can achieve better specific catalytic activity compared to conventional nanostructured metallic catalysts due to the low-coordination environment, stronger interaction with supports, and maximum service efficiency. Here, recent progress in shaped metallic nanocatalysts is examined and several parameters are discussed, as well as finally highlighting single-atom metallic catalysts and some perspectives on nanocatalysis. The integration of nanotechnology and nanocatalysis has been shaping up and, no doubt, the combination of sensitive characterization techniques and quantum calculations will play more important roles in such processes.
    Small 10/2014; 11(3). DOI:10.1002/smll.201400847 · 8.37 Impact Factor

Publication Stats

4k Citations
817.89 Total Impact Points


  • 2014-2015
    • Xiamen University
      • • Department of Chemistry
      • • College of Chemistry and Chemical Engineering
      Amoy, Fujian, China
  • 2006-2015
    • Nanyang Technological University
      • School of Chemical and Biomedical Engineering
      Tumasik, Singapore
  • 2004-2007
    • Yale University
      • • Department of Biomedical Engineering
      • • Department of Chemical & Environmental Engineering
      New Haven, Connecticut, United States