ACS Applied Materials & Interfaces
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2015
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IF 6.723
Tao Yang,Guojian Cao,Qingli Huang,Yanxia Ma,Sheng Wan,Hong Zhao,Na Li,Xia Sun,Fujun Yin
Exploring superior catalysts with high catalytic activity and durability is of significant for the development of an electrochemical device involving the oxygen reduction reaction. This work describes the synthesis of Pt-on-Pd bimetallic heterogeneous nanostructures, and their high electrocatalytic activity toward the oxygen reduction reaction (ORR). Pt nanoclusters with a size of 1–2 nm were generated on Pd nanorods (NRs) through a modified Cu underpotential deposition (UPD) process free of potential control and a subsequent surface-limited redox reaction. The Pt nanocluster decorated Pd nanostructure with a ultralow Pt content of 1.5 wt % exhibited a mass activity of 105.3 mA mg–1 (Pt–Pd) toward ORR, comparable to that of the commercial Pt/C catalyst but 4 times higher than that of carbon supported Pd NRs. More importantly, the carbon supported Pt-on-Pd catalyst displays relatively small losses of 16% in electrochemical surface area (ECSA) and 32% in mass activity after 10 000 potential sweeps, in contrast to respective losses of 46 and 64% for the commercial Pt/C catalyst counterpart. The results demonstrated that Pt decoration might be an efficient way to improve the electrocatalytic activity of Pd and in turn allow Pd to be a promising substitution for commercial Pt catalyst.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2013
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IF 3.548
Wenyu Liu,Haokun Cai,Ping Lu,Qiumei Xu,Yafeng Zhongfu,Jian Dong
Catalyzed sodium borohydride hydrolysis is a highly valuable method to produce clean hydrogen energy for portable applications. This study provides a new and fast route to preparation of reusable hybrid materials composed of nickel-boron based nanoclusters dispersed in nanoporous poly(acrylamide) hydrogels for catalyzed hydrogen production . Palladium was added to the Ni–B catalysts during chemical reduction under the protection of poly(N-vinylpyrrolidone). The resulting nanoclusters immobilized in the hydrogels were essentially alloy particles with uni-modal size distributions and average diameters ranging from ca . 4–8 nm. Pd exerted significant promoting effects on the activities of the Ni–B catalysts. The highest activity was achieved for Pd–Ni–B nanoclusters with a charge ratio of Pd/Ni = 1/20 in moles, which exhibited activity nearly twice that of a Ni–B catalyst and good recyclability for consecutive uses. The hydrogen production rates also increased with the decreasing particle sizes. The activation energy , enthalpy and entropy for the reaction were determined to be 31.10 kJ mol −1 , 28.39 kJ mol −1 and -45.22 J mol −1 K −1 , respectively. The activation energy is lower than that of previously reported polymer-stabilized Co(0), Fe(0), or Ni(0) nanoparticle catalysts.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2013
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IF 5.257
Peng Liao,Songhu Yuan,Mingjie Chen,Man Tong,Wenjing Xie,Peng Zhang
A novel Pd-based electro-Fenton (E-Fenton) process has recently been developed to transform organic contaminants in groundwater. However, it only produces H2O2 and requires addition of Fe2+. In this study, an innovative approach is developed to effectively regulate the generation of Fe2+ from an iron cathode in a three-electrode system in addition to H2O2 production. The Fe2+ is then used for the Pd-catalytic transformation of methyl tert-butyl ether (MTBE) in groundwater. Results from batch experiments suggest Fe2+ accumulation follows pseudo-first-order kinetics with rate quantitatively regulated by current and pH, and MTBE can be completely transformed. In a specially configured three-electrode column using iron as the first cathode, the localized acidic conditions develop automatically in the iron cathode and Pd zone by partitioning the current between the two cathodes, leading to controllable generation of Fe2+ and H2O2. Effects of electrolyte concentrations and types as well as humic acid on MTBE transformation are slight. The stable transformation (∼70%) in a long-term study (20 days) suggests this improved Pd-based E-Fenton process is sustainable to produce Fe2+, H2O2, and appropriate pH conditions simultaneously for transforming organic contaminants. This study presents a new concept of generating Fe2+ from an iron cathode for the processes requiring Fe2+.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2013
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IF 3.554
Jun Yan,Shi Liu,Zhenqin Zhang,Guangwu He,Ping Zhou,Haiying Liang,Lulu Tian,Xuemin Zhou,Huijun Jiang
Pd–Pt bimetallic nanoparticles anchored on functionalized reduced graphene oxide (RGO) nanomaterials were synthesized via a one-step in situ reduction process, in which Pt and Pd ions were first attached to poly(diallyldimethylammonium chloride) (PDDA) functionalized graphene oxide (GO) sheets, and then the encased metal ions and GO were subjected to simultaneous reduction by ethylene glycol. The as-prepared Pd 3 Pt 1 /PDDA-RGO nanocomposites were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and electrochemical methods. In addition, an electrochemical sensor based on the graphene nanocomposites was fabricated for the simultaneous detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA) in their ternary mixture. Three well-separated voltammetric peaks along with remarkable increasing electro-oxidation currents were obtained in differential pulse voltammetry (DPV) measurements. Under the optimized conditions, there were linear relationships between the peak currents and the concentrations in the range of 40–1200 μM for AA, 4–200 μM for DA and 4–400 μM for UA, with the limit of detection (LOD) (based on S/N = 3) of 0.61, 0.04 and 0.10 μM for AA, DA and UA, respectively. This improved electrochemical performance can be attributed to the synergistic effect of metallic nanoparticles and RGO and the combination of the bimetallic nanoparticles. Furthermore, the practical electroanalytical utility of the sensor was demonstrated by the determination of AA, DA and together with UA in human urine and blood serum samples with satisfactory results.
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RSC Advances
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2015
·Vol. 5
·期 124
·102811-102817
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IF 3.84
Fengwei Zhang,Shuai Chen,Huan Li,Xian-Ming Zhang,Hengquan Yang
A multi-component mesoporous core–shell structured nanocatalyst was prepared via encapsulation of a hydrophobic mesoporous carbon with amino-functionalized mesoporous silica, followed by coordination of palladium precursors and then reduction with a NaBH4 reagent. The resulting Pd/MCN@MS-NH2 catalyst could be well-dispersed in an aqueous medium owing to the inherent hydrophilic properties of the mesoporous silica shell. The experimental results indicated that the Pd/MCN@MS-NH2 catalyst had high catalytic activity and selectivity for the hydrogenation of phenol to cyclohexanone under 1 atm of H2 at 80 °C for 3 h in pure water (conversion > 99% and selectivity 99%). Furthermore, the catalyst can be easily recovered and reused six times without significant loss of catalytic activity.
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RSC Advances
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2014
·Vol. 4
·期 58
·30914-30922
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IF 3.708
Mingxi Chen,Zhe Zhang,Lingzhi Li,Yu Liu,Wei Wang,Jianping Gao
Ultrafine Ag–Pd bimetallic nanoparticles homogeneously distributed on reduced graphene oxide (rGO) were prepared by redox reactions between Pd2+, Ag+ and GO. This method is simple, and the use of rGO as a support facilitated the separation and reuse of the Ag–Pd@rGO catalyst. The Ag–Pd@rGO bimetallic nanoparticles were characterized by ultraviolet-visible spectroscopy, Raman spectroscopy, thermogravimetric analysis, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The microstructure of the Ag–Pd@rGO was investigated with scanning electron microscopy and transmission electron microscopy. The Ag–Pd@rGO catalyst exhibited high catalytic activities in the Suzuki-Miyaura carbon coupling reaction and the Sonogashira carbon coupling (SCC) reaction. These reactions used mild, efficient, ligand-free and heterogeneous conditions. Interestingly, the presence or absence of oxygen in the SCC catalytic system resulted in two different products, in which oxygen can be used as “switch” to control different products.
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GREEN CHEMISTRY
·
2017
·Vol. 19
·期 21
·5103-5113
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IF 9.125
Ying Duan,Min Zheng,Dongmi Li,Dongsheng Deng,Lu-Fang Ma,Yanliang Yang
The catalytic conversion of HMF to 2-hydroxy-3-methyl-2-cyclopenten-1-one (MCP), which is a valuable edible essence that has traditionally been obtained from adipic acid, was achieved with an isolated yield of 58%. This procedure comprised two steps: the hydrogenation of 5-hydroxymethylfurfural (HMF) to 1-hydroxy-2,5-hexanedione (HHD) in water on Pd/Nb2O5 catalysts and then the isomerization of HHD to MCP in the presence of a base. The Nb2O5 supports, which were acidic, were characterized by FTIR, XRD and NH3-TPD. The supported Pd/Nb2O5 catalysts, in which Pd was highly dispersed, were synthesized employing cyclohexene as a reductant and were characterized by XRD, TEM, ICP-AES, XPS, EDX and CO pulse chemisorption. The high conversion of HMF was attributed to the high dispersion of Pd, and the acidity of the supports led to high selectivity for HHD. The conversion of HHD to MCP was an intramolecular aldol condensation reaction, and the protonic solvent favored this reaction. Ca–Al was proved to be an effective solid base for the conversion of HHD to MCP in water.
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Journal of Physical Chemistry C
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2016
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IF 4.509
Kunpeng Song,Zhijuan Zou,Deli Wang,Bien Tan,Jingyu Wang,Jian Chen,Tao Li
The usage of noble metal catalysts for oxygen reduction reaction (ORR) can be minimized by supporting them on porous carbon. Herein, a simple and industrially scalable approach for preparation of porous carbon supports is developed by directly pyrolyzing microporous organic polymers (MOPs). The rigid aromatic building blocks in MOPs function as self-templates to retain the high surface area and regular pore distribution during carbonization to the formation of high quality microporous carbon framework. The electrochemical performance of Pd catalysts supporting on MOPs-derived carbons is evaluated and compared with commercial products, indicating the superiority of MOPs as carbon precursor. Significant difference in ORR activity is observed among three types of MOPs due to the impact of framework and heteroatom. The highest performance of Pd/CKN catalyst is attributed to heteroatom-induced altering of electronic structures besides the stable skeleton.
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CRYSTENGCOMM
·
2017
·Vol. 19
·期 37
·5686-5691
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IF 3.474
Zhao Huang,Kai Cai,Huan Zhang,Zilan Hong,Zhaodong Yuan,Heyou Han
A facile method for the synthesis of Au-pearl/Pd-wire heterostructured nanonecklaces (APHNs) was developed for the first time, in which regular Au pearls with controllable size and interval distance were interlinked into a string by an ultrathin and ultralong Pd nanowire. The distribution density of Au nanopearls was regulated by the concentration of the reducing agent, while their size was controlled by the amount of the Au precursor. In the study of degradation of 4-nitrophenol (4-NP), the catalytic properties of several typical APHNs are proved to be inherently related to their morphology. By comparison with other nanostructures and commercial Pd/C, the APHNs show superior catalytic activities and better stability in general. The study demonstrated that novel heterostructures have superior catalytic properties in the degradation of 4-NP. Moreover, the nanostructures have the potential to be used as a high-efficiency catalyst in other catalytic reactions.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2016
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IF 3.652
Qiang Lu,Zhi-bo Zhang,Xiao-ning Ye,Wen-tao Li,Bin Hu,Chang-qing Dong,Yong-ping Yang
A new technique was proposed to selectively produce 4-ethyl guaiacol (4-EG), a valuable phenolic compound, via low-temperature catalytic fast pyrolysis of softwood biomass using the Pd/SBA-15 catalyst. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to compare 4-EG production from three biomass materials with different lignin types (pine wood, poplar wood and bagasse) and two catalytic patterns (in-situ and ex-situ). Further experiments were performed to reveal 4-EG formation affected by the pyrolysis temperature, catalyst-to-biomass ratio and Pd content of the Pd/SBA-15 catalyst. The results indicated that 4-EG could be selectively produced from pine wood by the in-situ catalytic pattern. 4-EG was a very minor pyrolytic product in the non-catalytic process, while it could be selectively produced in the catalytic process, via the decomposition and hydrogenation of lignin. Our results suggested that several holocellulose-derived pyrolytic products could serve as the hydrogen-donors (H-donors) for the formation of 4-EG, without any extra H-donors. The highest 4-EG yield of 18.44 mg/g from pine wood was obtained at the temperature of 350 °C and catalyst-to-biomass ratio of 2, and the corresponding peak area% (calculated by GC/MS) was 38.34%.
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BIOSENSORS & BIOELECTRONICS
·
2017
·
IF 7.78
Zengqiang Gao,Yueyun Li,Xiaobo Zhang,Jinhui Feng,Ling Kong,Ping Wang,Zhiwei Chen,Yunhui Dong,Qin Wei
A sensitive sandwich-type electrochemical immunosensor for the detection of hepatitis B e antigen (HBeAg) was successfully developed based on the gold@palladium nanoparticles (Au@Pd NPs) loaded by molybdenum disulfide functionalized multiwalled carbon nanotubes (Au@Pd/MoS 2 @MWCNTs). The resultant nanocomposites not only possessed high specific surface area and good biocompatibility , but also exhibited excellent electro-catalytical property. Au NPs functionalized porous graphene oxide (p-GO@Au) were used as sensing platforms and primary antibodies carriers, which can accelerate the electron transfer and improve the load capacity of primary antibodies (Ab 1 ), improving the sensitivity of the immunosensor. Under optimal conditions, the designed immunosensor could detect target HBeAg concentration in the range from 0.1pg/mL to 500 pg/mL, with a low detection limit of 26 fg/mL (S/N = 3) for HBeAg. Additionally, the designed immunosensor showed excellent specificity, good reproducibility and acceptable stability. The satisfactory results in analysis of human serum samples indicated that it had potential application in clinical monitoring of tumor markers.
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JOURNAL OF MATERIALS SCIENCE
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2017
·Vol. 52
·期 13
·8016-8026
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IF 2.599
Yang Hongyu,Wen Chengwei,Tang Zhenghua,Wang Likai,Wang Qiannan,Yan Wei,Wu Wen,Chen Shaowei
Bio-inspired metal nanomaterials are receiving increasing research attentions in catalytic field recently, while peptide-based method represents new revenues to fabricate stable and reactive catalyst under mild and environmental friendly conditions. Among all kinds of noble metals, peptide-based palladium nanomaterials have demonstrated excellent catalytic capabilities in a variety of organic reactions. However, their electrocatalytic properties have not been systematically studied. Herein, R5-templated Pd nanomaterials have been fabricated and employed as potent catalysts for oxygen reduction reaction (ORR). The shape and morphology of these Pd nanomaterials were manipulated by tuning the metal-to-R5 ratio. The as-prepared Pd nanomaterials demonstrated excellent ORR activity in alkaline media. R5-Pd-90 exhibited the best activity which is superior than commercial Pt/C, in terms of onset potential, diffusion-limited current density as well as long-term stability. The correlation between the shape and/or morphology of the peptide-templated Pd nanomaterials and their ORR activity has been successfully established.
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