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Planar polyphthalocyanine cobalt absorbed on carbon black as stable electrocatalysts for direct methanol fuel cell

JOURNAL OF POWER SOURCES 2010年第15期195卷 4731-4735页

作者： Xu, Guofeng Li, Zhongfang wang, suwen Yu, Xianjin Shandong Univ Technol Sch Chem Engn Zibo 255049 Shandong Peoples R China

In this work, a novel catalyst is prepared by dispersing planar polyphthalocyanine cobalt (PPcCo) synthesized by polymerizing cobalt (II)-4, 4',4",4''' phthalocyanine tetracarboxylic acid (TcPcCo) using a high surface area carbon powder (Vulcan XC 72), and then heat-treated in argon (Ar) atmosphere. The polymer and PPcCo/C catalysts are characterized systematically by a variety of methods, such as ultraviolet-visible (UV-vis) spectrophotometer, Fourier transform infrared spectrometer (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscope (TEM). Results show that the PPcCo obtained is stable below 600 degrees C. The active site of PPcCo/C is CoN4 in phthalocyanine ring, and the PPcCo is dispersed homogeneously on the surface of XC 72. Electrocatalytic properties and electrochemical stability of the catalysts in 0.5 mol L-1 H2SO4 are evaluated by RDE measurements. The initial potential for O-2 reduction in O-2-saturated H2SO4 is 0.81 V and it catalyzed O-2 reduction mainly through a four-electron process. Almost no performance degradation is observed over continuous cyclic voltammetry (CV) at 10,000 cycles (4 days). Polarization curves obtained by linear sweep voltammetry (LSV) at 200 cycles also show no change. PPcCo/C catalysts display significant electrocatalytic performance for O-2 reduction, tolerance towards methanol, and long-term stability. (C) 2010 Elsevier B.V. All rights reserved.

关键词： Direct methanol fuel cell Electrocatalyst Oxygen reduction reaction Polyphthalocyanine cobalt Stability

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Simple synthesis of iron^III sulfophenyl phosphate nanosheets as a high temperature inorganic-organic proton conductor

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IONICS 2014年第10期20卷 1399-1406页

作者： Liu, Guohong Li, Zhongfang Jin, Lei wang, suwen Shandong Univ Technol Sch Chem Engn Zibo 255049 Shandong Peoples R China

Iron(III) sulfophenyl phosphate (FeSPP) is successfully synthesized by an optimized process from the reaction of iron(III) chloride and m-sulfophenyl phosphonic acid (msPPA) by a simple and environmentally friendly method. Experimental results show FeSPP has a kind of layered structure, and multilayer sheet is about 2 nm thick. FeSPP exhibits good thermal stability and does not decompose under 200 A degrees C. Protons transfer through vehicle and Grotthuss mechanisms at different relative humidities (RH). The conductivity of FeSPP can reach to 0.115 S/cm at 180 A degrees C and RH = 100 %. Under this condition, vehicle mechanism plays the leading role, and the Grotthuss mechanism plays the minor role. At low RH, Grotthuss plays the leading role, and vehicle plays the minor role. In a drying oven at 180 A degrees C, the proton conductivity remains 2.15 x 10(-3) S/cm. Good conductivities at different RH and thermal stabilities clearly demonstrate that FeSPP is a highly effective conductor. It can be used as catalysts, chemical sensors, and in the preparation of composite membrane.

关键词： Proton conductor Iron(III)sulfophenyl phosphate Nanostructure powder Proton conductivity Relative humidity

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α-MnO2 nanorods supported on three dimensional graphene as high activity and durability cathode electrocatalysts for magnesium-air fuel cells

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CATALYSIS TODAY 2020年 355卷 304-310页

作者： Zhang, Tingwei Li, Zhongfang Sun, Peng wang, Likai Niu, Xueliang wang, suwen Shandong Univ Technol Sch Chem & Chem Engn Zibo 255049 Peoples R China Anshan Normal Univ Sch Chem & Life Sci Anshan 114007 Peoples R China

Magnesium-air fuel cells are considered as a potential energy conversion device owing to a high theoretical specific capability, economic viability and environmental friendliness. In this work, alpha-MnO2 nanorods are supported on three-dimensional graphene (3D-G) which is fabricated with coal tar pitch as the carbon precursor and MgO as the template via hydrothermal reaction. The synergistic interactions between alpha-MnO2 nanorods and 3D-G improve the activity and durability performance for oxygen reduction reaction in 0.1 mol L-1 KOH solution. alpha-MnO2/3D-G exhibits a high half-wave potential (0.81 V) and superior to alpha-MnO2/C (0.72 V) and alpha-MnO2/rGO (0.76 V), and close to 20 wt% PVC (0.83 V). alpha-MnO2/3D-G also possesses higher durability than commercial PVC. Furthermore, the magnesium-air fuel cells based on alpha-MnO2/3D-G, air-cathode display the peak power density (106.2 mW cm(-2)), and continuously durability (discharge for 16 h at 50 mA cm(-2) with the mere decay of cell voltage by 7.6%). These results prove that alpha-MnO2 /3D-G catalyst with high activity and durability can be a promising electrocatalyst in magnesium-air fuel cells.

关键词： Magnesium-air fuel cells Oxygen reduction reaction alpha-MnO2 nanorods Three-dimensional graphene Electrocatalyst

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Pico-Kelvin thermometry and temperature stabilization using a resonant optical cavity

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OPTICS EXPRESS 2017年第4期25卷 3578-3593页

作者： Tan, Si wang, suwen Saraf, Shailendhar Lipa, John A. Stanford Univ Dept Mech Engn 440 Escondido Mall Stanford CA 94305 USA Stanford Univ Hansen Expt Phys Lab 452 Lomita Mall Stanford CA 94305 USA Hainan Trop Ocean Univ Hainan 572022 Peoples R China SN&N Elect Inc Santa Clara 95050 CA USA Stanford Univ Dept Phys 382 Via Pueblo Mall Stanford CA 94305 USA

Ultra-high sensitivity temperature sensing and stable thermal control are crucial for many science experiments testing fundamental theories to high precision. Here we report the first pico-kevin scale thermometer operating at room temperature with an exceptionally low theoretical noise figure of similar to 70 pK/root Hz at 1 Hz and a high dynamic range of similar to 500 K. We have experimentally demonstrated a temperature sensitivity of < 3 : 8 nK /root Hz at 1 Hz near room temperature, which is an order of magnitude improvement over the state of the art. We have also demonstrated an ultra-high stability thermal control system using this thermometer, achieving 3 : 7 nK stability at 1 s and similar to 120 pK at 10(4) s, which is 10-100 times more stable than the state of the art. With some upgrades to this proof-of-principle device, we can expect it to be used for very high resolution tests of special relativity and in critical point phenomena.

关键词： Laser sources Phase modulation Power spectral density Reflection coefficient Temporal resolution Whispering gallery modes

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Two-dimensional closely packed amide polyphthalocyanine iron absorbed on Vulcan XC-72 as an efficient electrocatalyst for oxygen reduction reaction

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CATALYSIS TODAY 2020年 353卷 279-286页

作者： Sun, Chongyun Li, Zhongfang Yang, Jianwei wang, suwen Zhong, Xizhan wang, Likai Shandong Univ Technol Sch Chem & Chem Engn Zibo 255049 Peoples R China

It is crucial to design the inexpensive and highly efficient electrocatalysts for oxygen reduction reaction (ORR) for the future commercialization of fuel cell devices. Herein, a closely packed amide polyphthalocyanine iron (CPMPcFe) with two-dimensional planar structure supported by Vulcan XC-72 was firstly prepared, and then the precursor was sintered at 400 degrees C under an Ar flow to obtain the CPMPcFe/C (1:1) catalyst. The SEM and TEM images of the CPMPcFe/C catalysts confirmed that CPMPcFe was well distributed on the surface of Vulcan XC-72. X-ray photoelectron spectroscopy (XPS) further identified the active center of CPMPcFe/C (1:1, 400 degrees C) was FeN4 in the polyphthalocyanine ring. Electrochemically, CPMPcFe/C displays excellent oxygen reduction reaction electrocatalytical properties. Firstly, it showed a half-wave potential of 0.87 V, which was more positive than those of iron phthalocyanine/C (FePc/C, 0.71 V) and 6 wt% Pt/C (0.83 V). The oxygen reduction current loss of CPMPcFe/C after 5000-cycle cyclic voltammetry test was 0.05 mA cm(-2), while that of FePc/C was 0.35 mA cm(-2). Chronoamperometry tests showed that FePc/C exhibited a rapid decrease of the current density by about 28.2%, while there was only about 16.9% loss for the current density of CPMPcFe/C under the same operation.

关键词： Oxygen reduction reaction Electrocatalysts Polyphthalocyanine iron The durability

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Comment on "Mineralization age of the Xiangshan uranium ore field, South China redefined by hydrothermal apatite U-Pb geochronology" by wang et al., (Ore Geology Reviews, 2023, https://***/10.1016/j. oregeorev.2023.105586)

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ORE GEOLOGY REVIEWS 2025年 180卷

作者： Zhu, suwen Li, Guangrong wang, Yun Guo, Fusheng Qin, Ao East China Univ Technol Natl Key Lab Uranium Resources Explorat Min & Nucl Nanchang 330013 Peoples R China East China Univ Technol State Key Lab Nucl Resources & Environm Nanchang 330013 Peoples R China

Recently,wang et al., (2023) published their apatite U-Pb ages from Xiangshan uranium ore field, South China and concluded that uranium mineralization age is synchronously formed to the hosting rock. This conclusion presents a significant departure from traditional views and offers novel insights into the timing of uranium mineralization. This paper raises evidence based on our research results in Xiangshan area in the past decade. Firstly, field observations indicate that uraniferous veins cut the well crystallized volcanic complex, suggesting a later hydrothermal event. Additionally, the synchronicity of apatite formation with uranium enrichment is questioned, as type 2 apatite crystals show complex relationships with uranium minerals. Discrepancies in previous U-Pb dates on U-minerals and Ar-Ar dates are discussed as well, and the result suggests that the age of volcanic complex hosting uranium minerals is mainly concentrated between 130 and 145 Ma, and the time difference between mineralization and diagenesis varies greatly. The paper emphasizes the need to reconcile the differences between various dating methods to accurately determine the mineralization age.

关键词： Uranium mineralization Hydrothermal apatite Xiangshan uranium ore field Geochronology discrepancies

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Spinel MnCo₂O₄ Nanoparticles Supported on Three-Dimensional Graphene with Enhanced Mass Transfer as an Efficient Electrocatalyst for the Oxygen Reduction Reaction

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CHEMSUSCHEM 2018年第16期11卷 2730-2736页

作者： Zhang, Tingwei Li, Zhongfang wang, Likai Sun, Peng Zhang, Zhixu wang, suwen Shandong Univ Technol Sch Chem & Chem Engn 266 Xincun West Rd Zibo 255049 Shandong Peoples R China

The rational design of highly efficient and durable oxygen reduction reaction (ORR) catalysts is critical for the commercial application of fuel cells. Herein, three-dimensional graphene (3D-G) is synthesized by the template method, which used coal tar pitch as the carbon source and nano MgO as the template. Then, spinel MnCo2O4 is in situ supported on the 3D-G by a facile hydrothermal method, giving MnCo2O4/3D-G. The resultant MnCo2O4/3D-G retains the multilayered mesoporous graphene structure where MnCo2O4 nanoparticles are deposited on the inner walls of pores in the 3D-G. The catalyst MnCo2O4/3D-G shows high electrocatalytic activity with a half-wave potential of 0.81V versus reversible hydrogen electrode, which is clearly superior to those of MnCo2O4/reduced graphene oxide (0.78V), MnCo2O4/carbon nanotubes (0.74V), MnCo2O4/C (0.72V), and 20wt% Pt/C (0.80V). The electron transfer number of MnCo2O4/3D-G indicates a four-electron process of ORR. The durability test demonstrates that the MnCo2O4/3D-G catalyst has a much better durability than 20wt% Pt/C. Our work makes an inspiring strategy to prepare high-performance electrocatalysts for the development of fuel cells.

关键词： fuel cells hydrothermal method oxygen reduction reaction spinel MnCo2O4 three-dimensional graphene

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Construction of proton channels and reinforcement of physicochemical properties of oPBI/FeSPP/GF high temperature PEM via building hydrogen bonding network

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2017年第21期42卷 14572-14582页

作者： Sun, Peng Li, Zhongfang Jin, Lei wang, suwen Yin, Xiaoyan Shandong Univ Technol Sch Chem Engn Zibo 255049 Peoples R China

Composite high temperature proton exchange membranes (HT-PEMs) comprising poly[4,4'(diphenyl ether)-5,5'-bibenzimidazole] (oPBI), ferric sulfophenyl phosphate (FeSPP) and glass fiber (GF) were prepared by the hot-pressing method. Doping FeSPP as a novel insoluble proton conductor not only provided good proton conductivity at high temperature but also enhanced their methanol blocking property, dimensional stability and oxidative resistance. Good dispersion, construction of proton channels and reinforcement of the physicochemical properties were achieved by building hydrogen bonding network among oPBI, FeSPP and GF. After incorporation of 3wt% GF into the oPBI/FeSPP(30wt%) composite membrane, the tensile strength was enhanced by 370% while the swelling ratio reduced to around 55%. The oxidative stability and methanol resistance were also enhanced while the proton conductivity was slightly affected. The membranes were thermally stable in the working temperature range for HT-PEM fuel cells. The proton conductivity of oPBI/FeSPP(30wt%) and oPBI/FeSPP(30wt%)/GF(3wt%) membranes reached 0.089 and 0.074 S cm(-1) at 180 degrees C and 100% relative humidity, respectively. At 180 degrees C, the proton conductivity of oPBI/FeSPP(30wt%) and oPBI/FeSPP(30wt%)/GF(3wt%) was 0.052 and 0.042 S cm(-1) at 50% RH, respectively. oPBI/FeSPP(30wt%)/GF(3wt%) exhibited good selectivity of 3.84 x 10(5) S s cm(-3) indicating good potential for applications in direct methanol fuel cells. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

关键词： High temperature proton exchange membrane Poly[4,4 '-(diphenylether)-5,5 '-bibenzimidazole] Ferric sulfophenyl phosphate Glass fiber Hydrogen bond

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A novel cathode catalyst for aluminum-air fuel cells: Activity and durability of polytetraphenylporphyrin iron (II) absorbed on carbon black

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2014年第35期39卷 20171-20182页

作者： Xu, Shihua Li, Zhongfang Ji, Yanfeng wang, suwen Yin, Xiaoyan wang, Yuxin Shandong Univ Technol Sch Chem Engn Zibo 255049 Peoples R China Tianjin Univ Sch Chem Engn State Key Lab Chem Engn Tianjin 300072 Peoples R China

A polytetraphenylporphyrin iron (II) (PTPPFe) oxygen reduction reaction (ORR) catalyst for aluminum-air fuel cells (AAFCs) is prepared. Thermogravimetric analysis results show that PTPPFe is stable at temperatures below 600 degrees C. X-ray photoelectron spectroscopy reveals that the active site of PTPPFe/C is Fe-N-4 in the porphyrin ring. Rotating disk electrode measurements in 1 mol L-1 NaOH solution demonstrate that the initial potential for ORR is 0.142 V vs. Hg/HgO/OH- (1 mol L-1 KOH, 0.098 V vs. NHE) at 20 degrees C, and that ORR mainly occurs through a four-electron process. The half-wave potentials for PTPPFe/C and the Pt/C catalyst are 0.071 and 0.079 V, respectively. Almost no performance degradation is observed over continuous cyclic voltammetry at 10 000 cycles, linear sweep voltammetry at 200 cycles, and 60 h of chronoamperometry test. After durability tests, the ultraviolet visible spectrum of PTPPFe does not change from the initial characteristics. The discharge performance of AAFC has a power density of 47.5 mW cm(-2) at 20 degrees C in 6 mol L-1 NaOH electrolyte solution. During continuous discharge for 10 h, the potential of AAFC decreases by less than 0.01 V at 40 mA cm(-2). Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

关键词： Aluminum-air fuel cells Air electrode Polytetraphenylporphyrin iron Oxygen reduction reaction Durability

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Comprehensive performance enhancement of polybenzimidazole based high temperature proton exchange membranes by doping with a novel intercalated proton conductor

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2018年第21期43卷 9994-10003页

作者： wang, suwen Sun, Peng Li, Zhongfang Liu, Guohong Yin, Xiaoyan Shandong Univ Technol Sch Chem & Chem Engn Zibo 255049 Peoples R China

On the study of high temperature proton exchange membrane (HTPEM), the trade-off between proton conductivity and physico-chemical property (such as mechanical strength, dimensional stability and methanol resistance) remained a main obstacle for comprehensive performance enhancement. To address this issue, novel HTPEM was prepared by doping phosphotungstic acid intercalated ferric sulfophenyl phosphate (FeSPP-PWA) into polybenzimidazole (PBI) via hot pressed method. Intense hydrogen bonding network was built between PBI and FeSPP-PWA, rendering construction of proton channels and reinforcement of physico-chemical property. As a novel proton conductor, FeSPP-PWA facilitated formation of efficient proton transfer pathway. The layered morphology and inorganic intrinsity of FeSPP-PWA also improved the mechanical and dimensional stability while reducing the methanol permeability of the PBI/FeSPP-PWA membranes. The composite membrane exhibited good thermal stability up to 200 degrees C. The proton conductivity of PBI/FeSPP-PWA (30 wt%) reached 110 mS cm(-1) at 170 degrees C and 100% RH, and was 69.3 mS cm(-1) at 180 degrees C and 50% RH. The PBI/FeSPP-PWA also showed low methanol permeability and high membrane selectivity for application in direct methanol fuel cells. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

关键词： High temperature proton exchange membrane Polybenzimidazole Hydrogen bonding network Intercalated proton conductor Proton conductivity

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