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Structural and mechanistic understanding of an active and durable graphene carbocatalyst for reduction of 4-nitrophenol at room temperature

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Nano Research 2015年第12期8卷 3992-4006页

作者： huawen hu John H. Xin Hong hu Xiaowen Wang Nanotechnology Centre Institute of Textiles and Clothing The Hong Kong Polytechnic University Hong Kong SAR 999077 China

The development of an active, durable, and metal-free carbocatalyst that is able to replace metal-based catalysts is of increasing scientific and technological importance. The use of such a catalyst would avoid problems caused by metal- containing catalysts, for example, environmental pollution by heavy metals and depletion of rare metal resources. Herein, an active and durable graphene carbocatalyst is presented for the carbocatalytic conversion of 4-nitrophenol to 4-aminophenol at ambient temperature. The carbocatalyst was prepared via a mild, water-based reaction between L-ascorbic acid （AA） and graphene oxide （GO） and did not involve any other reactants. During the structure and catalytic property optimization, a series of carbocatalysts were fabricated at various reaction temperatures and AA/GO ratios. Using several characterization techniques, detailed structural features of these carbocatalysts were identified. Possible active species and sites on the carbocatalysts were also identified such as certain oxygen-containing groups, the ~x-conjugated system, and graphene sheet edges. In addition, the synergistic effect between these active species and sites on the resulting catalytic activity is highlighted. Furthermore, we clarified the origin of the high stability and durability of the optimized carbocatalyst. The work presented here aids the design of high-performance carbocatalysts for hydrogenation reactions, and increases understanding of the structural and mechanistic aspects at the molecular level that lead to high catalyst activity and durability.

关键词： metal-free graphene carbocatalyst activity and durability L-ascorbic acid active sites and domains synergistic effect carbocatalytic conversion of 4-nitrophenol (4NP) to 4-aminophenol (4AP)

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Highly dispersed CeO_(2-x)nanoparticles with rich oxygen vacancies enhance photocatalytic performance of g-C_(3)N_(4)toward methyl orange degradation under visible light irradiation

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Journal of Rare Earths 2022年第8期40卷 1255-1263页

作者： Xuejun Xu Tianhua huang Yisheng Xu huawen hu Shuang Liao Xiaohong hu Dongchu Chen Min Zhang School of Materials Science and Hydrogen Energy Foshan UniversityFoshan 528000China Guangdong Key Laboratory for Hydrogen Energy Technologies Foshan 528000China

CeO_(2)/g-C_(3)N_(4)photocatalysts have attracted tremendous attention in the photocatalytic degradation of organic *** design and construction of highly active CeO_(2)/g-C_(3)N_(4)photocatalysts without harsh conditions are still ***,highly dispersed CeO_(2-x)nanoparticles with rich oxygen vacancies were successfully precipitated on the surface of g-C_(3)N_(4)under mild *** fabricated CeO_(2-x)/g-C_(3)N_(4)exhibits remarkable activity and stability for photocatalytic degradation of MO *** optimal rate constant of MO degradation over CeO_(2-x)/g-C_(3)N_(4)is about 0.031 min^(-1),which is three times higher than that of g-C_(3)N_(4).A negligible activity decrease is observed after three cycling *** enhanced catalytic performance can be ascribed to the excellent dispersion of CeO_(2-x)with rich oxygen vacancies that benefit O_(2)adsorption and visible light *** addition,the proper band alignment between CeO_(2-x)and gC_(3)N_(4)is conducive to the highly efficient separation of photogenerated electron-hole pairs.

关键词： CeO_(2-x) G-C_(3)N_(4) Heterojunctions Oxygen vacancies Rare earths

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Multifunctional organically modified graphene with super-hydrophobicity

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Nano Research 2014年第3期7卷 418-433页

作者： huawen hu Chan C. K. Allan Jianhua Li Yeeyee Kong Xiaowen Wang John H. Xin Hong hu Institute of Textiles and Clothing The Hong Kong Polytechnic University Hong Kong Special Administrative Region (SAR) 999077 China

In order to bring graphene materials much closer to real world applications, it is imperative to have simple, efficient and eco-friendly ways to produce processable graphene derivatives. In this study, a hydrophilic low-temperature thermally functionalized graphene and its super-hydrophobic organically modified graphene derivative were fabricated. A unique structural topology was found and some of the oxygen functionalities were retained on the thermally functionalized graphene surfaces, which facilitated the subsequent highly effective organic modification reaction and led to the super-hydrophobic organically modified graphene with multi functional applications in liquid marbles and polymer nanocomposites. The organic modification reaction also restored the graphenic conjugated structure of the thermally functionalized graphene, particularly for organic modifiers having longer alkyl chains, as confirmed by various characteri- zation techniques such as electrical conductivity measurements, ultraviolet/visible spectroscopy and selected area electron diffraction. The free-standing soft liquid marble was fabricated by wrapping a water droplet with the super-hydrophobic organically modified graphene, and showed potential for use as a microreactor. As for the polymer nanocomposites, a strong interfacial adhesion is believed to exist between an organic polymer matrix and the modified graphene because of the organophilic coating formed on the graphene base, which resulted in large improvements in the thermal and mechanical properties of the polymer nanocomposites with the modified graphene, even at very low loading levels. A new avenue has therefore been opened up for large-scale production of processable graphene derivatives with various practicable applications.

关键词： low-temperature thermallyfunctionalized graphene organic modification organically modifiedgraphene liquid marbles polymer nanocomposites

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Continental hydrothermal sedimentary siliceous rock andgenesis of superlarge germanium(Ge)deposit hosted incoal:A study from the Lincang Ge deposit,Yunnan,China

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Science China Earth Sciences 2004年第11期47卷 973-984页

作者： QI huawen1,2,hu Ruizhong1,SU Wenchao1,QI Liang1 & FENG Jiayi1 1.Key Laboratory of Ore Deposit Geochemistry,Chinese Academy of Sciences,Guiyang 550002,China 2.Department of Earth Sciences,Nanjing University,Nanjing 210093,China Correspondence should be addressed to Qi huawen(email: qihuawen@***) Key Laboratory of Ore Deposit Geochemistry Chinese Academy of Sciences Guiyang China Department of Earth Sciences Nanjing University Nanjing China

There are abundant hydrothermal sedimentary structures and plant fragment fossils in the siliceous rocks from the Lincang Ge deposit. The major element compositions of these siliceous rocks are characterized by high content SiO2, low TiO2 and Al2O3concentrations, and low Al/(Al+Fe+Mn) ratios (0.010 on average). The siliceous rocks are distinctly enriched in Ge, Sb, As, W, and secondly enriched in Cs, U, Mo and Tl. Their total REE content are generally less than 1μg/g, LREE relatively concentrated, and the values of Eu anomaly and Ce anomaly vary from 0.452 to 5.141 and 0.997 to 1.174, respectively. Their NAS-normalized REE patterns are plain or left-inclined. The Oxygen isotope compositions of these siliceous rocks are similar to those of the hydrothermal siliceous sinter. The above characteristics, as well as the geological setting of the deposit, indicate these siliceous rocks formed in continental hydrothermal envi- ronment. As the interlayer or cliff of the Ge-rich coal seams, siliceous rocks tightly contacted with ore-body, and the contents of Ge in siliceous rocks vary from 5.6 to 360 μg/g (78 μg/g on aver- age). The Ge content increased in coal which close to the siliceous rocks. With the increase of Ge content, the typical trace element ratios (i.e., Ge/Ga, Nb/Ta and U/Th) and REE patterns of Ge-rich coal are more close to those of the siliceous rocks. The Ge concentrated in coal seams of the Lincang Ge deposit might be transported by the hydrothermal water, which demonstrated by the siliceous rocks, during the coal-forming processes.

关键词： siliceous rock, continental hydrothermal sedimentation, superlarge Ge deposit, Lincang.

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Distributed Heading Synchronization of Multi-Vehicle Systems via Pulse-Based Communication

Distributed Heading Synchronization of Multi-Vehicle Systems...

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第43届中国控制会议

作者： Yujie Wang huan Gao Jianhao Xu Yongfeng Zhi Shu Zhang huawen hu School of Automation Northwestern Polytechnical University School of Computer Science Northwestern Polytechnical University

Distributed collective motion coordination has found a variety of applications in both military operations and civilian *** a critical component of collective motion coordination,distributed heading synchronization of multi-vehicle systems has received increasing *** existing approaches usually employ continuous control design followed by discretization based *** two-stage strategy,however,cannot guarantee the original designed control performance in final implementation since discretization will harm or even destabilize the controller designed in the continuous-time *** this paper,motivated by the synchronization of pulse-coupled oscillators,we propose an integrated control and communication approach for distributed heading synchronization of multi-vehicle *** leveraging the pulse-based communication,our approach does not need discretization in final implementation,making it feasible to guarantee the original design performance and meanwhile obeying the discrete nature of ***,benefiting from pulse signals containing no information,our proposed approach brings higher degrees of reliability and lower complexity of *** simulations and experiments are provided to verify the effectiveness of our approach.

关键词： Distributed Heading Synchronization Multi-Vehicle Systems Pulse-Based Communication

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Experimental study on the interaction between peat,lignite and germanium-bearing solution at low temperature

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Science China Earth Sciences 2005年第9期48卷 1411-1417页

作者： QI huawen1,2, hu Ruizhong1 & QI Liang1 1. Key Laboratory of Ore Deposit Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China 2. Department of Earth Science, Nanjing University, Nanjing 210093, China Key Laboratory of Ore Deposit Geochemistry Chinese Academy of Sciences Guiyang China Department of Earth Science Nanjing University Nanjing Chin

The interaction between peat, lignite and germanium(Ge)-bearing solution with an initial Ge concentration of 5 mg/L was studied at 25―100℃ and at pH 2.96―12.08. The results show that the apparent transfer ratios of peat and lignite for Ge in the solution were positively correlated with temperature in acid environment (initial pH=2.96), and the ratios (up to 86.5%) of lignite were obviously higher than those (up to 58.5%) of peat, but the organic transfer ratios of lignite were lower than those of peat. The activation energy values for interaction between peat, lignite and Ge-bearing solution are 30.96 and 15.67 kJmol?1, respectively. The strong acid (initial pH=2.96) and the strong alkaline (initial pH=12.08) environment contribute to the transfer of Ge in the solution. At 4

关键词： low temperature, peat, lignite, Ge4+, complexation.

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Novel Stabilization Design for the Inertia Wheel Pendulum

Novel Stabilization Design for the Inertia Wheel Pendulum

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第二十七届中国控制会议

作者： Ye huawen,hu Yang,huang Shuqing,Gui Weihua School of Information Science and Engineering,Central South University,Changsha 410083,P.R.China

In this paper,a novel stabilization design is presented for the inertia wheel pendulum by using backstepping technique and a twice differentiable saturation *** global asymptotic stability is proven by showing that the closed-loop system has no finite escape time and eventually reduces to an asymptotically stable *** show that the proposed design is effective.

关键词： Stabilization Saturated control Inertia wheel pendulum Backstepping

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基于天然贻贝仿生制备聚多巴胺改性石墨烯基功能材料及其水体环境修复应用研究进展

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材料导报 2020年第11期34卷 11009-11021页

作者：朱武青全海燕彭叔森张敏陈东初户华文南昌航空大学材料科学与工程学院佛山科学技术学院材料科学与能源工程学院中国科学院广州能源所广东省新能源和可再生能源研究开发与应用重点实验室广东省石油与精细化工研究院广东省工业表面活性剂重点实验室

全球水污染问题日益严峻,而石墨烯具有大比表面积且除污性能优异,可作为水体环境修复的优良材料,但它的表面能高,极易发生团聚,这将会大大降低其比表面积和其他优异的物理化学性质。为此,受天然贻贝及其分泌的粘性蛋白结构所启发,将仿... 详细信息

全球水污染问题日益严峻,而石墨烯具有大比表面积且除污性能优异,可作为水体环境修复的优良材料,但它的表面能高,极易发生团聚,这将会大大降低其比表面积和其他优异的物理化学性质。为此,受天然贻贝及其分泌的粘性蛋白结构所启发,将仿生聚多巴胺(Pdop)用于改性石墨烯可有效解决石墨烯聚集的问题,并能赋予石墨烯新的表面性质和功能,如从疏水表面变成亲水表面、增加活性位点密度以及丰富其可设计性,这也使得Pdop改性石墨烯(Pdop-G)成为当前的一大研究热点,尤其在环境修复领域。本文回顾了近三年Pdop-G及其相关材料的多种设计、制备方法,并重点关注了Pdop-G在环境修复应用方面的研究进展,包括三种核心环境修复处理手段(即吸附、膜截留和光催化)。通过总结相关文献可知,Pdop-G及其相关材料在处理各类水体环境污染物方面具有良好的应用潜力,但是要达到商业应用的要求,还有待进一步改善制备工艺,完善后处理等问题。本文充分评述和分析了基于石墨烯化学和贻贝仿生学的各种环境修复材料和技术的优缺点,并提出了未来可尝试的研究方向,以明晰这些材料在环境修复中的应用范围和技术发展路线。本文有望给广大学者在Pdop-G及其相关材料研究方面提供指引,并为新型高性能石墨烯基环境修复材料的设计带来新思路和方向。

关键词：仿生聚多巴胺石墨烯吸附膜截留光催化环境修复

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校企合作平台建设研究与实践

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科教文汇 2014年第7期 161-161,165页

作者：胡华文徐国洪仙桃职业学院湖北仙桃433000

本文以仙桃职业学院机电专业群校企合作工作为背景,分析了校企合作平台构建的主要内容和运行机制,总结归纳了进一步推动校企合作的思路、措施和建议。

关键词：校企合作服务人才培养

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超声波熔体处理对铝合金组织和性能的影响

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特种铸造及有色合金 2004年第4期24卷 11-13页

作者：胡化文陈康华黄兰萍刘红卫郑强中南大学

通过在 70 5 5铝合金熔体浇注前作超声处理 ,超声波在熔体中产生空化作用 ,活化了熔体中微小的杂质粒子 (主要是Al2 O3 ) ,使其成为结晶核心 ,从而促进了形核 ,因此能细化晶粒 ,并得到较高抗拉强度和塑性的铸锭。研究超声作用对其显微... 详细信息

通过在 70 5 5铝合金熔体浇注前作超声处理 ,超声波在熔体中产生空化作用 ,活化了熔体中微小的杂质粒子 (主要是Al2 O3 ) ,使其成为结晶核心 ,从而促进了形核 ,因此能细化晶粒 ,并得到较高抗拉强度和塑性的铸锭。研究超声作用对其显微组织和力学性能的影响。结果表明 :对 70 5 5铝合金熔体作用超声能细化晶粒和均匀化组织 ,提高其抗拉强度。

关键词：超声熔体处理 7055铝合金超声振动声空化

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