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Nano Research 2016年第7期9卷 2026-2033页

作者： Zhuo Wang Wei Jia Menglei Jiang Chen Chen Yadong Li Department of Chemistry & Collaborative Innovation Center for Nanomaterial Science and Engineering Tsinghua University Beijing 100084 China Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100190 China

Multi-shelled CoFe2O4 hollow microspheres with a tunable number of layers （1-4） were successfully synthesized via a facile one-step method using cyclodextrin as a template, followed by calcination. The structural features, including the shell number and shell porosity, were controlled by adjusting the synthesis parameters to produce hollow spheres with excellent capacity and durability. This is a straightforward and general strategy for fabricating metal oxide or bimetallic metal oxide hollow microspheres with a tunable number of shells.

关键词： hollow spheres multi-shelled CoFe2O4 supercapacitor

Au/CuSiO3 nanotubes: High-performance robust catalysts for selective oxidation of ethanol to acetaldehyde

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Nano Research 2016年第9期9卷 2681-2686页

作者： Xianjun Du Ninghua Fu Shaolong Zhang Chen Chen Dingsheng Wang Yadong Li Department of Chemistry & Collaborative Innovation Center for Nanomaterial Science and Engineering Tsinghua UniversityBeijing 100084China

Novel gold-supporting silicate nanotubes are synthesized via a hydrothermal method followed by colloid deposition. Their catalytic performance for the selective oxidation of ethanol to acetaldehyde is assessed. The results show that Au/CuSiO3nanotubes exhibit both high activity and selectivity at high gas hourly space velocity (GHSV). Ethanol conversion can reach up to ~98%, and the selectivity for acetaldehyde is ~93% at 250 °C and ~100,000 mL·gcat–1·h–1. In comparison, the catalytic activity of Au/MgSiO3nanotubes is relatively low, and ethanol conversion reaches only ~25% at 250 °C. However, when Cu species are added to Au/MgSiO3, the catalytic activity improves significantly, indicating that the interactions between Au nanoparticles and Cu species are responsible for the high performance for selective oxidation of ethanol to acetaldehyde. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

关键词： ultrathin nanowires AuPd alloy catalysts

Free-standing palladium-nickel alloy wavy nanosheets

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Nano Research 2016年第8期9卷 2244-2250页

作者： Weng-Chon Cheong Chuhao Liu Menglei Jiang Haohong Duan Dingsheng Wang Chen Chen Yadong Li Department of Chemistry and Collaborative Innovation Center for Nanomaterials Science and Engineering Tsinghua UniversityBeijing 100084 China

Two-dimensional nanomaterials （2DNMs） have attracted increasing attention due to their unique properties and promising applications. Unlike 2DNMs with lamellar structures, metal ultrathin 2DNMs are difficult to synthesize and stabilize because they tend to form close-packed crystal structures. Most reported cases consist of monometallic and heterogeneous nanostructures. The synthesis of metal alloy 2DNMs has been rarely reported. Here, we report the synthesis of PdNi alloy wavy nanosheets （WNSs） using an enhanced CO-confinement strategy. This strategy is also suitable to the synthesis of other Pd-based alloy WNSs such as PdCu, PdFe, and even a trimetallic PdFeNi.

关键词： Pd Ni alloy nanosheets carbon monoxide

Recent advances in the precise control of isolated single-site catalysts by chemical methods

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National Science Review 2018年第5期5卷 673-689页

作者： Zhijun Li Dehua Wang Yuen Wu Yadong Li Department of Chemistry iChEM Collaborative Innovation Center of Chemistry for Energy MaterialsUniversity of Science and Technology of China Department of Chemistry Tsinghua University School of Pharmaceutical and Chemical Engineering Taizhou University

The search for constructing high-performance catalysts is an unfailing topic in chemical fields. Recently, we have witnessed many breakthroughs in the synthesis of single-atom catalysts(SACs) and their applications in catalytic systems. They have shown excellent activity, selectivity, stability, efficient atom utilization and can serve as an efficient bridge between homogeneous and heterogenous catalysis. Currently, most SACs are synthesized via a bottom-up strategy; however, drawbacks such as the difficulty in accessing high mass activity and controlling homogeneous coordination environments are inevitably encountered, restricting their potential use in the industrial area. In this regard, a novel top-down strategy has been recently developed to fabricate SACs to address these practical issues. The metal loading can be increased to 5% and the coordination environments can also be precisely controlled. This review highlights approaches to the chemical synthesis of SACs towards diverse chemical reactions, especially the recent advances in improving the mass activity and well-defined local structures of SACs. Also, challenges and opportunities for the SACs will be discussed in the later part.

关键词： single-atom catalysts bottom-up top-down catalytic performance

Atomically dispersed Au_1 catalyst towards efficient electrochemical synthesis of ammonia

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Science Bulletin 2018年第19期63卷 1246-1253页

作者： Xiaoqian Wang Wenyu Wang Man Qiao Geng Wu Wenxing Chen Tongwei Yuan Qian Xu Min Chen Yan Zhang Xin Wang Jing Wang Jingjie Ge Xun Hong Yafei Li Yuen Wu Yadong Li Department of Chemistry iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) University of Science and Technology of China Hefei 230026 China Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials School of Chemistry and Materials Science. Nanjing Normal University Nanjing 210023 China Department of Chemistry and Collaborative Innovation Center for Nanomaterial Science and Engineering. Tsinghua University. Beijing 100084 China NEST Laboratory Department of Chemistry. College of Science Shanghai University Shanghai 200444 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230029 China

Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber-Bosch process which accounts for 1.4% of the annual energy consumption. In this study, atomically dispersed Au_1 catalyst is synthesized and applied in electrochemical synthesis of ammonia under ambient conditions. A high NH＋4 Faradaic efficiency of 11.1 % achieved by our Au_1 catalyst surpasses most of reported catalysts under comparable conditions. Benefiting from efficient atom utilization, an NH＋4 yield rate of 1,305 μg h-1 mg-1Au has been reached, which is roughly 22.5 times as high as that by sup- ported Au nanoparticles. We also demonstrate that by employing our Au_1 catalyst, NH＋4 can be electro- chemically produced directly from N_2 and H_2 with an energy utilization rate of 4.02 mmol kJ-1. Our study provides a possibility of replacing the Haber-Bosch process with environmentally benign and energy-efficient electrochemical strategies.

关键词： NH_3 synthesis Metal single sites Electrocatalysis Haber-Bosch process Nitrogen reduction

Porphyrin-like Fe-N4 sites with sulfur adjustment on hierarchical porous carbon for different rate-determining steps in oxygen reduction reaction

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Nano Research 2018年第12期11卷 6260-6269页

作者： Konglin Wu Xin Chen Shoujie Liu Yuan Pan Weng-Chon Cheong Wei Zhu Xing Cao Rongan Shen Wenxing Chen Jun LUO Wensheng Yan Lirong Zheng Zheng Chen Dingsheng Wang Qing Peng Chen Chen Yadong Li Department ofChemistry Tsinghua UniversityBeijing 100084China Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials Department of ChemistryUniversity of Science and Technology BeijingBeijing 100083China College of Chemistry and Materials Science Key Laboratory of Functional Molecular Solidsthe Ministry of EducationAnhui Normal UniversityWuhu 241002China Center for Electron Microscopy Tianjin University of TechnologyTianjin 300384China NationaISynchrotron Radiation Laboratory (NSRL) University of Science and Technology of ChinaHefei 230029China Beijing Synchrotron Radiation Facility (NSRF) Institute of High Energy PhysicsChinese Academy of ScienceBeijing 100049China

We developed a strategy based on coordination polymer to synthesize singleatom site Fe/N and S-codoped hierarchical porous carbon (Fe1/N,S-PC). The as-obtained Fe1/N,S-PC exhibited superior oxygen reduction reaction (ORR) performance with a half-wave potential (E1/2, 0.904 V vs. RHE) that was better than that of commercial Pt/C (E1/2, 0.86 V vs. RHE), single-atom site Fe/N-doped hierarchical porous carbon (Fe1/N-PC) without S-doped (E1/2, 0.85 V vs. RHE), and many other nonprecious metal catalysts in alkaline medium. Moreover, the Fe1/N,S-PC revealed high methanol tolerance and firm stability. The excellent electrocatalytic activity of Fe1/N,S-PC is attributed to the synergistic effects from the atomically dispersed porphyrin-like Fe-N4 active sites, the heteroatom codoping (N and S), and the hierarchical porous structure in the carbon materials. The calculation based on density functional theory further indicates that the catalytic performance of Fe1/N,S-PC is better than that of Fe1/N-PC owing to the sulfur doping that yielded different rate-determining steps.

关键词： single-atom catalyst heteroatom codoping porous materials oxygen reduction electrocatalysis

Heterogeneous catalysis for green chemistry based on nanocrystals

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National Science Review 2015年第2期2卷 150-166页

作者： Yuxi Liu Guofeng Zhao Dingsheng Wang Yadong Li Department of Chemistry Tsinghua University

Modern society has an ever-increasing demand for environmentally friendly catalytic processes. Catalysis research is working towards a solution through the development of efective heterogeneous catalysts for environment-related applications. Nanotechnologies have provided efective strategies for the preparation of nanocrystals(NCs) with well-deined sizes, shapes and compositions. Precise control of these NCs provides an important foundation for the studies of structure-performance relationships in catalysis, which is critical to the design of NCs with optimized catalytic performances for practical applications. We focus on recent advances in the development of botom-up strategies to control NCs structures for some key catalytic applications, including CO oxidation, selective oxidation of alcohols, semihydrogenation of alkynes, and selective hydrogenation of unsaturated aldehydes and nitrobenzene. hese key applications have been a popular research focus because of their signiicance in green chemistry. Herein we also discuss the scientiic understandings of the active species and active structures of these systems to gain an insight for rational design of eicient catalytic systems for these catalytic reactions.

关键词： nanocrystals heterogeneous catalysis green chemistry CO oxidation alcohol oxidation selective hydrogenation

An efficientfficient, controllable and facile two-step synthesis strategy： Fe3O4@RGO composites with various Fe3O4 nanoparticles and their supercapacitance properties

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Nano Research 2017年第10期10卷 3303-3313页

作者： Chao Lian Zhuo Wang Rui Lin Dingsheng Wang Chen Chen Yadong Li Department of Chemistry School of Science Beijing Jiaotong University Beijing 100044 China Department of Chemistry Tsinghua University Beijing 100084 China Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100190 China

An efficient, controllable, and facile two-step synthetic strategy to prepare graphene-based nanocomposites is proposed. A series of Fe3O4-decorated reduced graphene oxide （Fe3O4@RGO） nanocomposites incorporating Fe3O4 nanocrystals of various sizes were prepared by an ethanothermal method using graphene oxide （GO） and monodisperse Fe3O4 nanocrystals with diameters ranging from 4 to 10 nm. The morphologies and microstructures of the as-prepared composites were characterized by X-ray diffraction, Raman spectroscopy, nitrogen adsorption measurements, and transmission electron microscopy. The results show that GO can be reduced to graphene during the ethanothermal process, and that the Fe3O4 nanocrystals are well dispersed on the graphene sheets generated in the process. The analysis of the electrochemical properties of the Fe3O4@RGO materials shows that nanocomposites prepared with Fe3O4 nanocrystals of different sizes exhibit different electrochemical performances. Among all samples, FegO4@RGO prepared with Fe3O4 nanocrystals of 6 nm diameter possessed the highest specific capacitance of 481 F/g at 1 A/g, highlighting the excellent capability of this material. This work illustrates a promising route to develop graphene-based nanocomposite materials with a wide range of potential applications.

关键词： graphene Fe3O4 nanocomposite supercapacitor electrochemical capacitance

Preparation of hexagonal ultrathin WO3 nano-ribbons and their electrochemical performance as an anode material in lithium ion batteries

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Nano Research 2016年第2期9卷 435-441页

作者： Chao Lian Xiaoling Xiao Zheng Chen Yuxi Liu Enyue Zhao Dingsheng Wang Chen Chen Yadong Li Department of Chemistry & Collaborative Innovation Center for Nanomaterial Science and Engineering Tsinghua University Beijing 100084 China College of Materials Science and Opto-electronic Technology University of Chinese Academy of Sciences Beijing 100049 China

Hexagonal ultrathin WO3 nano-ribbons （HUWNRs） of subnanometer thicknesses, 2-5 nm widths, and lengths of up to several micrometers were prepared by a solvothermal method. The as-prepared HUWNRs grow along the [001] direction, and the main exposed facet is the （720） crystal plane. The HUWNRs exhibit good electrochemical performance as an anode material in lithium ion batteries because of their unique structure. It is believed that these unique materials may be applied in many fields.

关键词： hexagonal tungsten oxide ultrathin nano-ribbons low-dimensional structure anode materiallithium ion battery

Interface-induced formation of onion-like alloy nanocrystals by defects engineering

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Nano Research 2016年第2期9卷 584-592页

作者： Wei Jia Yuen Wu Yifeng Chen Dongsheng He Jinpeng Li Yu Wang Zhuo Wang Wei Zhu Chen Chen Qing Peng Dingsheng Wang Yadong Li Department of Chemistry and Collaborative Innovation Center for Nanomaterial Science and Engineering Tsinghua UniversityBeijing 100084 China Center of Advanced Nanocatalysis University of Science and Technology of China (CAN-USTC) Hefei 230026 China

The ability to controlled introduction of defects, particularly twin defects in Pt-based nanocrystals （NCs） provides a possibility to regulate the performance of Pt-based nanocatalyst. However, because of the high internal strain energy existed in twinned structures, the fabrication of defects in Pt-based NCs is sufficiently challenging. Here we demonstrate a ＂low-temperature interface-induced assembly＂ approach that provides precise control over Pt-Cu nanoparticles assembled at the hexadecylamine/water interface, yielding onion-like Pt-Cu NCs exposed a high density of twin defects. Moreover, a bending mechanism is proposed to elucidate the appearance of twin defects and lattice expanding （contraction） based on aberration corrected scanning transmission electron microscopy analysis. This work opens new routes to engineer defects in metal- based alloy NCs, enabling more opportunities in catalysis.

关键词： alloy nanocrystals assembly electroxidation twin defects interface