ELECTROCHIMICA ACTA
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2015
·
IF 4.504
Pei Song,Lei Liu,Ai-Jun Wang,Xi Zhang,Si-Yuan Zhou,Jiu-Ju Feng
In this work, three-dimensional trimetallic Pt–Pd–Co alloyed nanoflowers are fabricated by a facile one-pot solvothermal strategy, with the assistance of oleylamine as the solvent, surfactant, and reducing agents, along with cetylpyridinium chloride (CPC) as the co-surfactant and shape-directing agents. Their morphology and crystal structure were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning transmission electron microscope (STEM), and X-ray photoelectron spectra (XPS) in details. The respective electrochemically active surface area (ECSA) is estimated to be 32.53 m 2 g −1 , and current density is 132.91 mA cm −2 for the electrooxidation of ethylene glycol (EG). These values are much higher than those of PtPdCo nanoparticles, PtPd nanoparticles, commercial Pt black, and Pd black under the identical conditions, showing the improved catalytic activity of Pt–Pd–Co nanoflowers. The excellent performances are attributed to the specific structure and synergistic interactions of the trimetallic alloy. The as-prepared nanoflowers can serve as a promising electrocatalyst in fuel cells.
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Nanoscale
·
2015
·Vol. 7
·期 13
·5699-5705
·
IF 7.394
Jing-Jing Lv,Li-Ping Mei,Xuexiang Weng,Ai-Jun Wang,Li-Li Chen,Xiang-Feng Liu,Jiu-Ju Feng
A facile one-pot solvothermal method was developed for the fabrication of well-defined three-dimensional highly branched Pt–Pd alloyed multipods, using ethylene glycol as a solvent and a reducing agent, along with N-methylimidazole as a structure-directing agent, without any seed, template, or surfactant. The as-prepared nanocrystals exhibited a relatively large electrochemically active surface area, improved electrocatalytic activity and superior stability for ethylene glycol oxidation in alkaline media, compared with commercial Pt black and Pd black, making them promising electrocatalysts in fuel cells.
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高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 10
·5352-5359
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IF 7.443
Li-Li He,Pei Song,Ai-Jun Wang,Jie-Ning Zheng,Li-Ping Mei,Jiu-Ju Feng
In this work, a general strategy was developed for the facile synthesis of bimetallic AuM (M = Pt or Pd) alloyed flowerlike-assembly nanochains (FANs) with the assistance of diprophylline as a structure-directing and stabilizing agent. The morphologies, crystal structures, and compositions of AuPt and AuPd FANs were investigated primarily by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The formation mechanism was discussed in some detail by varying the concentration of diprophylline. The as-prepared AuM FANs displayed improved catalytic activities and better stabilities for oxygen reduction reaction (ORR) compared to commercial E-TEK Pt/C, Pt black and Pd black.
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Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 10
·5321-5327
·
IF 7.443
Pei Song,Li-Li He,Ai-Jun Wang,Li-Ping Mei,Shu-Xian Zhong,Jian-Rong Chen,Jiu-Ju Feng
A simple and facile one-pot wet-chemical co-reduction method was developed for the synthesis of reduced graphene oxide supported porous PtAu alloyed nanoflowers (PtAu-nanoflowers/rGO). p-Aminopyridine was employed as a structure-directing agent and a stabilizing agent. No seed, template, surfactant, or polymer was involved in the synthesis process. It was found that the reaction temperature and the dosage of p-aminopyridine were essential for the final product. Furthermore, the as-prepared nanocomposites showed improved catalytic activity for the reduction of 4-nitrophenol in contrast to monometallic Pt nanocrystals/rGO, Au nanocrystals/rGO, and commercial Pt/C (50 wt%).
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高影响因子
CARBON
·
2014
·
IF 6.16
Dandan Zhu,Liangjun Li,Jinjun Cai,Min Jiang,Jingbo Qi,Xuebo Zhao
A novel pyridine-containing metal-organic framework (MOF), [Zn(bpdc)DMA]·DMF, was first constructed by solvothermal reaction of 2,2′-bipyridine-5,5′-dicarboxylate ( bpdc ) with zinc nitrate, and then it was converted to nitrogen-doped porous carbons (NPCs) by direct carbonization . The as-prepared porous carbon (NPC800) was characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), N 2 sorption isotherms, and X-ray photoelectron spectroscopy. NPC800 was modified onto glassy carbon electrode surface for investigating its electrochemical applications. Cyclic voltammetry (CV) and linear sweep voltammetry were performed to evaluate the electrocatalytic activity of NPC800 for oxygen reduction reaction (ORR) in alkaline solution. NPC800 exhibited better ORR activity than commercial Pt/C. Pt-catalyst supported on NPCs (Pt/NPC800) was prepared by means of electrodeposition and characterized by SEM, Energy dispersive spectrometry and XRD. The electrocatalytic activity and stability of Pt/NPC800 for methanol oxidation reaction (MOR) were estimated in acidic methanol solution by CV and chronoamperometric curves, respectively. Pt/NPC800 showed catalytic role for MOR, and also had better stability than Pt-catalyst supported on commercial Vulcan XC-72.
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CRYSTENGCOMM
·
2017
·Vol. 19
·期 34
·4964-4971
·
IF 3.474
Qi Zhao,Qin Wang,Yiguo Su,Keke Huang,Guangran Xu,Yingjun Li,Jiayin Liu,Baocang Liu,Jun Zhang
Driven by the need of high catalytic performance and low cost Pt-based catalysts for methanol oxidation (MOR) and oxygen reduction (ORR) reactions, we developed a highly active nitrogen species-decorated Pt–Ni–N catalyst with tunable architectures and facets toward high catalytic activity. The synthetic procedure was conducted by Ni2+-assisted morphology and facet transformation from nanoflowers (NFs) (111) to nanoparticles (NPs) (220) and simultaneous optimization of both hierarchical structure and active surface sites. It is found that the adsorption of nitrogen species plays critical roles in determining both facet control of the Pt–Ni–N hierarchical structure and energetic activation of the catalytic reaction. Decoration of surface nitrogen species can effectually improve the relative content and electronic density of Pt0, leading to formation of a hierarchical structure and significantly improved catalytic activity toward both MOR and ORR compared with Pt–Ni and Pt–N, as well as the commercial Pt/C catalysts, indicating a new strategy to obtain highly efficient catalysts. Moreover, the results demonstrate that the catalytic enhancement is mainly due to the synergistic electronic effects among Pt, Ni, and N species.
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Materials
·
2017
·Vol. 10
·期 5
·564
·
IF 2.654
Wensheng Li,Lingtao Sun,Rong Hu,Wenli Liao,Zhongbin Li,Yanrong Li,Chaozhong Guo
The great challenge of boosting the oxygen reduction reaction (ORR) activity of non-noble-metal electrocatalysts is how to achieve effective exposure and full utilization of nitrogen-rich active sites. To realize the goals of high utilization of active sites and fast electron transport, here we report a new strategy for synthesis of an iron and nitrogen co-doped carbon nanolayers-wrapped multi-walled carbon nanotubes as ORR electrocatalyst (N-C@CNT-Fe) via using partially carbonized hemoglobin as a single-source precursor. The onset and half-wave potentials for ORR of N-C@CNT-Fe are only 45 and 54 mV lower than those on a commercial Pt/C (20 wt.% Pt) catalyst, respectively. Besides, this catalyst prepared in this work has been confirmed to follow a four-electron reaction mechanism in ORR process, and also displays ultra-high electrochemical cycling stability in both acidic and alkaline electrolytes. The enhancement of ORR activity can be not only attributed to full exposure and utilization of active site structures, but also can be resulted from the improvement of electrical conductivity owing to the introduction of CNT support. The analysis of X-ray photoelectric spectroscopy shows that both Fe–N and graphitic-N species may be the ORR active site structures of the prepared catalyst. Our study can provide a valuable idea for effective improvement of the electrocatalytic activity of non-noble-metal ORR catalysts.Keywords:oxygen reduction;electrocatalyst;active site;carbon nanotube;hemoglobin
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高影响因子
Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 24
·12513-12519
·
IF 8.867
Jinxing Zhang,Weifeng Yao,Cunping Huang,Penghui Shi,Qunjie Xu
Research and development of high efficiency non-noble metal cocatalysts for solar photocatalytic hydrogen production have been aiming at a long-term goal of a renewable hydrogen economy. This research reports an active and stable tungsten phosphide (WP) cocatalyst as a potential replacement for Pt and Pd noble metal cocatalysts. WP nanoparticles are synthesized via a simple wet chemical process using less expensive and earth abundant materials. The synthesized WP cocatalyst nanoparticles are ball-milled and loaded onto the surface of a CdS photocatalyst, forming a WP/CdS composite. During visible light photocatalytic hydrogen production via the photocatalytic oxidation of an aqueous ammonium sulfite solution, the WP/CdS has shown high photocatalytic activity and stability in comparison with Pt and Pd noble metal cocatalysts. It is found that the 4.0 wt% WP loaded CdS photocatalyst can achieve as high as a 155.2 μmol h−1 hydrogen evolution rate, which is 11.67 times higher than that of the pure CdS photocatalyst and at about 1/3 of the hydrogen production rate (510.4 μmol h−1) of 0.5 wt% Pt loaded Pt/CdS. Electrochemical characterizations of the WP cocatalyst indicate that WP has high electrocatalytic activity and an efficient charge transfer rate between CdS and WP nanocrystals. These are the key factors responsible for the enhanced photocatalytic activity of the WP/CdS photocatalyst.
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RSC Advances
·
2015
·Vol. 5
·期 44
·35282-35290
·
IF 3.84
Si Chen,Guodong Tang,Bozhen Wu,Meng Ma,Xu Wang
The key effect of the self-assembly mechanism of dendritic gelators is researched by a comprehensive investigation of the gelation behavior of L-lysine dendritic gelators with different structures of three generations in 20 different solvents. The solvents investigation, 1H NMR, tube inversion method, DSC, rheology, FTIR and rheological measurements show that the reported dendritic gelators self-assemble through the main driving force of hydrogen bonds and the second driving force of π–π stackings. So the key effect of the self-assembling mechanism is that these factors can influence the driving force of the self-assembly process. This is the reason that L-lysine dendritic gelators tend to gelate in solvents with low α and β parameter values, which have less influence on the formation of hydrogen bonds between the gelators. Higher generations provide a much greater hydrogen bond density in the gelators, which makes them have a higher gelation ability. The benzyl terminal groups provide the second driving force of π–π stacking, making the Bzl-Gly-Lys gelators have much stronger gelation ability. This research reports a comprehensive insight into the precise ways in which the solubility parameters of the solvents, the gelator generation and the terminal group effects can influence the self-assembly and gelation of dendritic gelators. Gaining this type of fundamental understanding is essential if the key effect of this important class of self-assembling soft materials is to be truly understood.
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ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Chaozhong Guo,Rong Hu,Wenli Liao,Zhongbin Li,Lingtao Sun,Dongping Shi,Yanrong Li,Changguo Chen
Recycling and utilizing organic biowastes will effectively help to decrease the damage to the natural environment and synchronously facilitate the development of new carbon materials for energy applications. In this study, we directly convert protein-rich fish-scale biowaste to hierarchically porous three-dimentional (3D)-network nanocarbons via two-step pyrolysis process combined with ZnCl 2 activation and acidic-treatment. It is interestingly found that this material exhibits more excellent oxygen reduction electrocatalytic activity and stability compared to the commercial 20 wt% Pt/C catalyst in both alkaline and acidic solutions, which can be closely correlated to its chemical state of nitrogen atoms, BET surface area and inner porous structure. The addition of ZnCl 2 activator during pyrolysis process can help to produce the 3D network nanostructure and then to enhance the mesopore surface area, making for the improvement of oxygen reduction performance. More remarkably, the ORR onset potential on our material is about 60 mV higher than that on the Pt/C catalyst in alkaline electrolyte. In addition, we also propose that pyridinic- and graphitic-nitrogen species may be key factors to be responsible for the electrocatalytic activity. This study can encourage the exploration of high porosity nanocarbons from widely-existed biowastes, functioning as highly active and stable oxygen reduction electrocatalysts.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2017
·
IF 3.582
Cunbiao Song,Guitai Wu,Beilei Sun,Yao Xiong,Sheng Zhu,Yongming Hu,Haoshuang Gu,Yu Wang,Wanping Chen
Pt–WO 3 porous composite ceramics have been prepared from Pt and WO 3 nanoparticles through pressing and sintering. These ceramics exhibit extraordinary room-temperature sensing capabilities, including high sensitivities, fast response and recovery speeds, and good stability, for low concentrations of hydrogen (at and below 1000 ppm) in air; while for high concentrations of hydrogen (above 2000 ppm) in air, the recoveries in air are only partial in given amounts of time. We propose that for low concentrations of hydrogen, the response results from the reaction of hydrogen with chemisorbed oxygen on WO 3 ; while for high concentrations of hydrogen, hydrogen chemisorption on WO 3 will occur after all chemisorbed oxygen on WO 3 is reacted. The relatively high stability of chemisorbed hydrogen on WO 3 is responsible for the observed partial recoveries. Our results show that Pt–WO 3 composite ceramics are highly competitive for sensing low concentrations of hydrogen in air at room temperature among various metal oxide semiconductor bulk materials.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Jiajin Li,Minglei Lu,Yuxin Ge,Weiwei Lu,Zidi Liu,Hongde Xu,Yu Zhang,Zhihui Li,Zhuoyu Zheng,Pengxiang Gao,Qian Zhang,Tiejun Wang
Aqueous-phase reforming of methanol (APRM) is an important method for H 2 production, widely used in energy fields like polymer electrolyte membrane fuel cells (PEMFCs). However, traditional noble metal catalysts , being expensive and vulnerable to CO poisoning, restrict their practical application. Therefore, developing robust non-noble metal catalysts for efficient and sustainable H 2 production with low CO levels in APRM at low temperatures is highly significant. In this study, a novel approach was employed to synthesize carbon-encapsulated Cu catalyst via controlled pyrolysis , leading to Cu@CA-Val catalyst with excellent low-temperature catalytic activity. The optimal Cu@CA-Val-300 catalyst exhibited a high hydrogen production rate of 0.2–27.0 μmolH 2 /g cat /s over a wide temperature of 135–180 °C (base-free), surpassing the most Cu-based and Pt-based catalysts. The Cu@CA-Val-300 catalyst exhibited exceptional hydrothermal stability during continuous operation in a fixed reactor for 200 h. Efficient H 2 production was attributed to good wettability , enabling the diffusion of CH 3 OH and H 2 O molecules into Cu + /Cu 0 sites for activation, with CO being suppressed and transformed through the formate formation.
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