ACS Catalysis
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2016
·
IF 9.307
Shanhui Zhu,Yanfeng Xue,Jing Guo,Youliang Cen,Jianguo Wang,Weibin Fan
The high-yield synthesis of the biofuel γ-valerolactone (GVL) is a challenging task, which currently stems from the depolymerization of cellulose to levulinic acid, followed by its hydrogenation. We have developed a novel integrated process for the production of GVL from hemicellulose without using liquid acids and external hydrogen. The hemicellulose feed underwent hydrolysis and consecutive dehydration to produce furfural over ZSM-5 catalyst. Subsequently, the formed furfural with 2-propanol performed tandem conversion to GVL over Au/ZrO2 catalyst combined with ZSM-5. This process gave a high yield of GVL under mild conditions: up to 61.5% based on hemicellulose. The outstanding performance was mainly ascribed to the strong interface interaction of Au with ZrO2 species, large amounts of medium-strength acid sites over ZSM-5, and efficient synergy between active metal and acid sites.
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Journal of Physical Chemistry C
·
2019
·
IF 4.309
Bo Yu,Bo Han,Xinrui Jiang,Chenggang Zhou,Kaisheng Xia,Qiang Gao,Jinping Wu
Catalytic hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) is widely recognized as one of the most effective solutions to deal with the water-related environmental issues, where catalysts with high activity and long cycle life are always pursued. In this paper, oxygen-rich boron nitride (BNO)-supported Au nanoparticles (Au/BNO) were proposed to serve as catalysts for 4-NP hydrogenation. Our results show that the Au nanoparticles are well dispersed on the highly porous BNO substrate with a small particle size of 2.2 nm. Under the optimal reaction conditions, the 4-NP molecules could be completely reduced to 4-AP in 2.5 min over Au/BNO with a relatively high conversion rate constant of 2.25 min–1. Moreover, the as-synthesized Au/BNO is also highly stable with no visible efficiency decay after been reused for several times. The excellent durability of the catalyst could be ascribed to the strong anchoring strength between the Au nanoparticles and BNO substrate, leading to a negligible metal loss or particle agglomeration upon cycling. The role of O heteroatoms in promoting the activity and durability of the Au/BNO catalyst was further confirmed by first-principles calculations. Our simulation results indicate that the high activity of Au/BNO could be attributed to the strong π–π attraction between BNO and 4-NP, which facilitates the fast diffusion of 4-NP molecules to the surface of Au/BNO. The long cycle life of Au/BNO is correlated to the partially destroyed electronic conjugation of the substrate, leading to a relatively strong coordination interaction between BNO and the Au atom to stabilize the metal nanoparticles.
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Materials Science and Engineering B-Advanced Functional Solid-State Materials
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2015
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IF 2.169
Jian Zhu,Fan Zhang,Bei-Bei Chen,Jian-Jun Li,Jun-Wu Zhao
The temperature dependent synthesis and plasmonic optical properties of Ag coated Au nanocubes have been investigated experimentally. It has been found that the Au nanocubes with more uniform morphology and higher yield could be obtained by decreasing the growth temperature. Because of the non-spherical symmetry of the particles shape and the plasmon coupling between Au–Ag interface and outer Ag surface, four absorption peaks at most have been observed. As the Ag coating thickness is increased, the absorbance intensity of these plasmon peaks gets intense greatly, and the absorption peak at longest wavelength blue shifts firstly and then red shifts. The non-monotonous plasmonic shift has been attributed to the competition between the increase of Ag composition and the enlargement of the particle size. What's more, the wavelength region of both blue shift and red shift could also be enhanced by decreasing the temperature.
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ACS Catalysis
·
2017
·
IF 10.614
Fanpeng Kong,Chunyu Du,Jinyu Ye,Guangyu Chen,Lei Du,Geping Yin
Heterogeneous nanostructures hold substantial promise in many fields including energy conversion and catalysis, and their functionality is largely determined by the interactive surface features of respective architectural components. Herein, we report the facile preparation of a Pt–Au heterogeneous nanostructure, which as a model exhibits not only the enhanced electrocatalysis for oxygen reduction reaction (ORR) and ethanol oxidation reaction (EOR), but also an unprecedented activity for formic acid oxidation (FAO). Further, selective under-potential deposition coupled with CO adsorption is employed to probe the electrocatalytic mechanism of the Pt–Au heterogeneous nanostructure. The electronic effect is clarified for the ORR and EOR mechanisms on the Pt–Au nanostructure. A synergetic mechanism in that Pt ruptures the C–H bond of HCOOH and Au converts the resulted −COOH into CO2 is revealed for FAO. This strategy provides a versatile and powerful tool for the selective surface engineering and in-depth analysis of the functionalizing mechanism of heterogeneous nanostructures.
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ECS Journal of Solid State Science and Technology
·
2018
·Vol. 7
·期 12
·M201
·
IF 1.808
Yuehuan Yuan,Feifei Zhang,Haiyan Wang,Linna Gao,Zonghua Wang
A carbon nitride/graphene composite is synthesized in one step by calcining graphene oxide and melamine. Given that the surface of the carbon nitride is rich in amino groups, the composite material formed by its combination with graphene considerably increases the active sites and enhances the electrical conductivity. Au nanoparticles are ultrasonically added to a carbonitride/graphene composite to form Au NPs/carbon nitride/graphene composites (Au/C3N4/GN) with three-dimensional nanostructures. The introduction of Au nanoparticles makes the Au/C3N4/GN composites more sensitive and accurate for the detection of small molecules. To test the electrochemical properties of the composites, chloramphenicol and ciprofloxacin were detected by Au NPs/carbon nitride/graphene-modified electrodes (Au/C3N4/GN/GCE), and satisfactory results were obtained. Under optimized experimental conditions, the detection limits of Au/C3N4/GN/GCE for chloramphenicol and ciprofloxacin were 2.7 × 10−8 M and 4.2 × 10−7 M, and the linear ranges of detection were 0.7–120 μM and 0.6–120 μM respectively. In addition, the electrochemical sensor was successfully used for quantitative determination of chloramphenicol and ciprofloxacin in milk samples, which clearly revealed its practical feasibility in food analysis.
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ChemCatChem
·
2020
·Vol. 12
·期 10
·2752-2759
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IF 4.853
Xiangjian Meng,Wandi Kuang,Weiliang Qi,Zhixing Cheng,Tiju Thomas,Siqi Liu,Chun Yang,Minghui Yang
Graphical Just a bit of gold : The Ni 3 N−Au c −TiO 2 catalyst exhibits a better hydrogen evolution rate under full band light irradiation as compared to those of binary Ni 3 N−TiO 2 and Au c −TiO 2 . The amount of Au c is ultralow (0.00025 wt%) with Ni 3 N in the optimum photocatalyst Ni 3 N−Au c −TiO 2 , which shows the loading of noble metal is reduced by 99.95 wt% compared with the optimal load of Pt (0.5 wt%). Platinum (Pt) is a widely used co-catalyst with excellent performance for photocatalytic hydrogen evolution. However, it is not suitable for industrial production because of its prohibitive cost. Currently, there are two means to overcome this challenge. One is to, find alternative cocatalysts for Pt. The other is to develop ultrasmall of noble metal clusters, which reduces the amount of noble metal loading required. This reduces the loading amount of noble metals and improves their atomic efficiency. In this work, we have integrated both these approaches to generate a non-noble metal co-catalyst nickel nitride (Ni 3 N) and Au clusters (Au c ). The composite cocatalyst (Ni 3 N−Au c ) thus obtained promotes photocatalytic hydrogen production of TiO 2 . The (Ni 3 N−Au c −TiO 2 ) composite with an ultralow amount of Au c (0.00025 wt%) shows photocatalytic hydrogen production rates that are even higher than that of Pt−TiO 2 . The loading requirement of noble metal is reduced by 99.95 wt% compared to the optimal load of Pt; further indicating the cost efficiency possible through this method.
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JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2024
·
IF 11.2
Huanmin Liu,Chao Wu,Kangle Lv,Dingguo Tang,Qin Li
Photogenerated charge separation is a challenging step in semiconductor-based photosynthesis. Though numerous efforts have been devoted to developing multi-component photocatalyst heterostructures for improving charge separation efficiency, the short distance between electrons and holes-aggregated regions still leads to undesirable charge recombination. Herein, a facile and commercial in-situ synthesis method was designed to directly prepare a three-component Au–carbon–TiO 2 photocatalyst from Ti 3 C 2 MXene , air, CO 2 , and HAuCl 4 , in which the carbon layer bridged Au and TiO 2 nanoparticles for stable and efficient photocatalytic hydrogen production. Kelvin probe measurements and density functional theory (DFT) calculations demonstrated that a multi-interfacial charge transmission network was successfully constructed to achieve a directional and long-distance spatial charge separation/transfer channel between TiO 2 and Au through carbon layer, desirably inhibiting the recombination of photogenerated charge carriers. The hydrogen production rate of the formed three-component Au/C–TiO 2 (CTA) photocatalyst was demonstrated to be 27 times higher than that of Au–TiO 2 , which also surpassed many reported Ti 3 C 2 MXene-derived carbon–TiO 2 photocatalysts. This work sheds light on the ingenious use of 2D MXene to form a well-behaved TiO 2 -based photocatalytic system and helps to propose future design principles in accelerating charge transfer.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2020
·Vol. 325
·期 2
·453-462
·
IF 1.137
Lu Shichao,Chang Shuquan,Li Zheng,Zhang Xiaohong,Hu Xiaodan,Zhang Haiqian
Magnetic Au/Fe 3 O 4 /poly(styrene-sodium styrene sulphonate) composite microspheres (Au/Fe 3 O 4 /P(St-NaSS) CMs) were successfully prepared via a gamma-radiation method. Au and Fe 3 O 4 were formed at the same time under irradiation and well dispersed on uniform P(St-NaSS) microspheres. The as-prepared CMs exhibit good catalytic properties and recyclable performances for the catalytic reduction of 4-nitrophenol (4-NP). The kinetic rate constants are 8.75 × 10 −3 s −1 and 7.71 × 10 −3 s −1 for two samples, respectively. The conversion rate of 4-NP can keep about 95% with catalysts after five cycles. They exhibit good magnetic behavior and have saturation magnetization value of about 9 emu g −1 , which can be easily separated from the solution under external magnetic field. This strategy is efficient and facile, which can be extended to fabricate other CMs.
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ANALYST
·
2018
·Vol. 143
·期 21
·5145-5150
·
IF 3.864
Yunxiao Jia,Tianxia Sun,Yingnan Jiang,Weiyi Sun,Yu Zhao,Jingwei Xin,Yiting Hou,Wensheng Yang
Gold nanoclusters have attracted widespread attention because of their unique optical and physical properties. However, traditional synthesis methods are complicated and require additional reducing agents, while the yield is often very low. Such resource and time-consuming synthesis processes limit their further application. Herein, a rapid sonochemical route is used to synthesize fluorescent Au nanoclusters in large quantities using glutathione (GSH) both as a capping and reducing agent. These Au nanoclusters are synthesized quickly (∼40 min) due to the presence of ultrasonic waves, and show orange red photoluminescence (Em = 598 nm), small size (∼2 nm) and good dispersion in aqueous solution. Moreover, GSH, as a protecting agent on the surface of resultant Au nanoclusters, has many functional groups including carboxyl and amino groups because of which the nanoclusters show high photo-, storage-, metal- and pH-stability. A stable Au nanoclusters-based nano-sensor is designed for highly sensitive and selective label-free detection of Cu2+ with a low limit of detection of 7 ppb (based on S/N = 3). The fluorescent probe can be used in versatile nanothermometry devices, because their photoluminescence intensity correlates strongly with temperature and varies considerably over a wide temperature range (20–80 °C). Therefore, the novel fluorescent sensing probe has great application prospects in Cu2+ detection and temperature sensing.
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Journal of the Taiwan Institute of Chemical Engineers
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2017
·
IF 4.217
Likang Fu,Libo Zhang,Shixing Wang,Bing Zhang,Jinhui Peng
A new adsorbent was synthesized via functionalizing nano-silica with poly(methacryloxyethyltrimethyl ammonium chloride) (PDMC) for selective recovery of Au(III) from aqueous solutions. The adsorbent was characterized by FT-IR, TGA, XPS and TEM. A batch adsorption experiment was conducted to evaluate the adsorption capacity, reusability and selectivity. The maximum adsorption capacity of Au(III) was 127.3 mg/g at room temperature and the optimum pH 3.0. The adsorption equilibrium was achieved within 20 min. The adsorption process followed preferably the pseudo-second order kinetics and the Langmuir isotherm model. Ion exchange between gold ions and amines/chlorine groups played an important role in the adsorption process. The adsorption desorption cycles indicated that the adsorbent had a stable adsorption performance and retained high adsorption efficiency. Moreover, the adsorbent can selectively adsorb Au(III) from coexisting ions in aqueous solution. Therefore, nano-silica modified with PDMC could be of great potential in recovering Au(III) from industrial effluents and waste e-products.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Sen Sun,Yan Wang,Li'na Wang,Tong Guo,Xiaorong Yuan,Dongxia Zhang,Zhonghua Xue,Xibin Zhou,Xiaoquan Lu
Here, a unique triple-layered core-shell structure (Au@N-CQDs@Pt) with an Au metal core, nitrogen-doped carbon quantum dots interlayer, and metal Pt outside shell was obtained by chemical reduction of HAuCl 4 and H 2 PtCl 6 in the presence of N-CQDs. The remarkable advantage of the method reported here is no any stabilizer or surfactant agent involved. The results of transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS) reveal that the as-prepared nanocomposites exhibit the nanostructured dendritic Pt and the quantity of Pt shell can be easily changed through controlling the synthesis time. Specifically, Au@N-CQDs@Pt displays excellent catalytic activity toward methanol oxidation reaction in alkaline condition than Au-Pt without N-CQDs, which indicate the useful application of CQDs in designing new catalysts to be used in direct methanol fuel cells.
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ELECTROANALYSIS
·
2024
·Vol. 36
·期 10
·e202400028
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IF 2.7
Suning Man,Junying Zheng,Yi Zhang,Lei Huang,Xiaoping Wu
Given the high solubility and mobility of hexavalent chromium in the environment and edible plants, the development of a suitable method for the screening and quantification of Cr(VI) is highly desirable. Herein, a selective and sensitive sensing method for detecting Cr(VI) in food grains was established, using an electrodeposited gold-palladium bimetallic nanoparticles (BNPs) based electrochemical sensor and a microwave digestion procedure for chromium dissolution. The sensor interface was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and cyclic voltammetry. The results indicate that the fabricated sensor has a larger active surface area and an enhanced electrocatalytic effect compared to the monometallic modification, leading to a significant increase in the electrochemical reduction current of Cr(VI) as a consequence of synergistic effects. Using square wave anodic stripping voltammetry, the sensor demonstrates a wide linear range (5–3000 μg L −1 ) and a low detection limit of 2.7 μg L −1 for Cr(VI), as well as considerable repeatability and stability. Satisfactory selectivity towards Cr(VI) was also demonstrated, even in the presence of 500-fold Cr(III) and 100-fold common heavy metal ions like Cd(II), Pb(II), and Hg(II). The proposed sensing method offers a promising alternative for rapidly identifying toxic Cr(VI) in water and food grains.
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