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In-situ observation of hydrogen nanobubbles formation on graphene surface by AFM-SECM

Electrochimica Acta 2024年 493卷

作者： Kholimatussadiah, Septia Hsu, Chia-Ling Ke, Shang-Wei Chou, Tsu-Chin Wu, Yung-Fu Yakimova, Rositsa Kumatani, Akichika Chen, Kuei-Hsien Chen, Li-Chyong Du, He-Yun Department of Physics National Taiwan University Taipei 10617 Taiwan Nano Science and Technology Taiwan International Graduate Program Academia Sinica Taipei 10617 Taiwan Center for Condensed Matter Sciences National Taiwan University Taipei 10617 Taiwan Center of Atomic Initiative for New Materials National Taiwan University Taipei 10617 Taiwan Department of Chemical Engineering Ming Chi University of Technology New Taipei City24301 Taiwan Institute of Atomic and Molecular Sciences Academia Sinica Taipei 10617 Taiwan Institute of Analytical and Environmental Sciences National Tsing Hua University Hsinchu 300044 Taiwan Department of Physics Chemistry and Biology Linköping University SE-581 83 Linköping Sweden Institute of Engineering Innovation School of Engineering The University of Tokyo Tokyo 113-8656 Japan Saitama 332-0012 Japan Tohoku University Sendai980-8577 Japan Battery Research Center of Green Energy Ming Chi University of Technology New Taipei City24301 Taiwan Biochemical Technology R&D Center Ming Chi University of Technology New Taipei City24301 Taiwan Center for Sustainability and Energy Technologies Chang Gung University Taoyuan City33302 Taiwan

Gas bubble evolution is an important phenomenon in many electrochemical processes and it is highly sensitive to the surface properties. Here we visualize the gas bubble dynamics on the surface of different graphene substrates during hydrogen evolution reaction (HER) using atomic force microscopy combined with scanning electrochemical microscopy. The low overpotential and low surface hydrophobicity of few-layer graphene formed on C-phase SiC causes the uniform distribution of hydrogen nanobubbles, which easily depart from the surface during the reaction. Conversely, the high overpotential and more hydrophobic surface of HOPG induces hydrogen bubbles to linger on the surface for an extended duration, leading to its accumulation and the subsequent formation of microbubbles. This in-situ nanoscale electrochemical mapping of hydrogen bubble dynamics provides new insight into electrocatalytic HER that occurs on non-metal electrodes. © 2024 Elsevier Ltd

关键词： Graphene

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Highly Dispersed ZnO Sites in a ZnO/ZrO2Catalyst Promote Carbon Dioxide-to-Methanol Conversion

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Angewandte Chemie 2024年第4期137卷

作者： Dr. Xibo Zhang Xiang Yu Dr. Rafael G. Mendes Dr. Peter Matvija Angela E. M. Melcherts Dr. Chunning Sun Dr. Xinwei Ye Prof. Bert M. Weckhuysen Dr. Matteo Monai Inorganic Chemistry and Catalysis Group Institute for Sustainable and Circular Chemistry Utrecht University Universiteitsweg 99 3584 CG Utrecht The Netherlands State Key Laboratory of Physical Chemistry of Solid Surfaces & Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 P. R. China Soft Condensed Matter Group Debye Institute for Nanomaterials Science Utrecht University Heidelberglaan 8 3584 CS Utrecht The Netherlands Charles University Faculty of Mathematics and Physics Department of Surface and Plasma Science V Holešovičkách 2 Prague 18000 Praha 8 Czech Republic

ZnO/ZrO 2 catalysts have shown better activity in the CO 2 hydrogenation to methanol compared with single component counterparts, but the interaction between ZnO and ZrO 2 is still poorly understood. In particular, the effect of the ZrO 2 support phase (tetragonal vs. monoclinic) was not systematically explored. Here, we have synthesized ZnO/ZrO 2 catalysts supported on tetragonal ZrO 2 (ZnO/ZrO 2 -t) and monoclinic ZrO 2 (ZnO/ZrO 2 -m), which resulted in the formation of different ZnO x species, consisting of sub-nanometer ZnO moieties and large-sized ZnO particles, respectively. ZnO/ZrO 2 -t exhibited a higher methanol selectivity (81 vs. 39 %) and methanol yield (1.25 vs. 0.67 mmol g −1 h −1 ) compared with ZnO/ZrO 2 -m. The difference in performance was attributed to the redox state and degree of dispersion of Zn, based on spectroscopy and microscopy results. ZnO/ZrO 2 -t had a high density of ZnO x -ZrO y sites, which favored the formation of active HCOO* species and enhanced the yield and selectivity of methanol along the formate pathway. Such ZnO clusters were further dispersed on ZrO 2 -t during catalysis, while larger ZnO particles on ZnO/ZrO 2 -m remained stable throughout the reaction. This study shows that the phase of ZrO 2 supports can be used to control the dispersion of ZnO and the catalyst surface chemistry, and lead to enhanced catalytic performance.

关键词： CO2 hydrogenation Methanol Zirconia Zinc oxide Support effects

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Mixed-linker strategy for suppressing structural flexibility of metal-organic framework membranes for gas separation

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Communications Chemistry 2023年第1期6卷 1-12页

作者： Chung-Kai Chang Yen-Chun Lin Yi-Pei Li Dun-Yen Kang Ting-Rong Ko Tsai-Yu Lin Heng-Liang Wu Hyun Jung Yu Jong Suk Lee Department of Chemical Engineering National Taiwan University No. 1 Sec. 4 Roosevelt Road Taipei 10617 Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University (NTU-MST) No. 1 Sec. 4 Roosevelt Road Taipei 10617 Taiwan Center of Atomic Initiative for New Materials National Taiwan University No. 1 Sec. 4 Roosevelt Road Taipei 10617 Taiwan Center for Condensed Matter Sciences National Taiwan University No. 1 Sec. 4 Roosevelt Road Taipei 10617 Taiwan Department of Chemical and Biomolecular Engineering Sogang University Baekbeom-ro 35 Mapo-gu Seoul 04107 Republic of Korea

Structural flexibility is a critical issue that limits the application of metal-organic framework (MOF) membranes for gas separation. Herein we propose a mixed-linker approach to suppress the structural flexibility of the CAU-10-based (CAU = Christian-Albrechts-University) membranes. Specifically, pure CAU-10-PDC membranes display high separation performance but at the same time are highly unstable for the separation of CO2/CH4. A partial substitution (30 mol.%) of the linker PDC with BDC significantly improves its stability. Such an approach also allows for decreasing the aperture size of MOFs. The optimized CAU-10-PDC-H (70/30) membrane possesses a high separation performance for CO2/CH4(separation factor of 74.2 and CO2permeability of 1,111.1 Barrer under 2 bar of feed pressure at 35°C). A combination of in situ characterization with X-ray diffraction (XRD) and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, as well as periodic density functional theory (DFT) calculations, unveils the origin of the mixed-linker approach to enhancing the structural stability of the mixed-linker CAU-10-based membranes during the gas permeation tests.

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Overcoming small-bandgap charge recombination in visible and NIR-light-driven hydrogen evolution by engineering the polymer photocatalyst structure

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Nature communications 2024年第1期15卷 707页

作者： Mohamed Hammad Elsayed Mohamed Abdellah Ahmed Zaki Alhakemy Islam M A Mekhemer Ahmed Esmail A Aboubakr Bo-Han Chen Amr Sabbah Kun-Han Lin Wen-Sheng Chiu Sheng-Jie Lin Che-Yi Chu Chih-Hsuan Lu Shang-Da Yang Mohamed Gamal Mohamed Shiao-Wei Kuo Chen-Hsiung Hung Li-Chyong Chen Kuei-Hsien Chen Ho-Hsiu Chou Department of Chemistry Faculty of Science Al-Azhar University Nasr City 11884 Cairo Egypt. Institute of Atomic and Molecular Sciences Academia Sinica Taipei 10617 Taiwan. Center for Condensed Matter Sciences National Taiwan University Taipei 10617 Taiwan. Department of Chemical Engineering National Tsing Hua University Hsinchu 300044 Taiwan. Department of Chemistry United Arab Emirates University Al Ain P.O. Box 15551 United Arab Emirates. Department of Chemistry Qena Faculty of Science South Valley University 83523 Qena Egypt. Chemical Physics and NanoLund Lund University 22100 Lund Sweden. Chemistry Department Faculty of Science Al-Azhar University Assiut 71542 Egypt. Sustainable Chemical Science and Technology Taiwan International Graduate Program Taipei Taiwan. Department of Applied Chemistry National Yang Ming Chiao Tung University Hsinchu 30010 Taiwan. Institute of Chemistry Academia Sinica 128 Sec 2 Academia Rd. Nankang Taipei 11529 Taiwan. Institute of Photonics Technologies National Tsing Hua University Hsinchu 300044 Taiwan. Center of Atomic Initiative for New Materials National Taiwan University Taipei 10617 Taiwan. Department of Chemical Engineering National Chung Hsing University Taichung 40227 Taiwan. Department of Materials and Optoelectronic Science Center for Functional Polymers and Supramolecular Materials National Sun Yat-Sen University Kaohsiung 804 Kaohsiung Taiwan. Department of Physics National Taiwan University Taipei 10617 Taiwan. Department of Chemical Engineering National Tsing Hua University Hsinchu 300044 Taiwan. hhchou@mx.nthu.edu.tw.

Designing an organic polymer photocatalyst for efficient hydrogen evolution with visible and near-infrared (NIR) light activity is still a major challenge. Unlike the common behavior of gradually increasing the charge recombination while shrinking the bandgap, we present here a series of polymer nanoparticles (Pdots) based on ITIC and BTIC units with different π-linkers between the acceptor-donor-acceptor (A-D-A) repeated moieties of the polymer. These polymers act as an efficient single polymer photocatalyst for H2 evolution under both visible and NIR light, without combining or hybridizing with other materials. Importantly, the difluorothiophene (ThF) π-linker facilitates the charge transfer between acceptors of different repeated moieties (A-D-A-(π-Linker)-A-D-A), leading to the enhancement of charge separation between D and A. As a result, the PITIC-ThF Pdots exhibit superior hydrogen evolution rates of 279 µmol/h and 20.5 µmol/h with visible (>420 nm) and NIR (>780 nm) light irradiation, respectively. Furthermore, PITIC-ThF Pdots exhibit a promising apparent quantum yield (AQY) at 700 nm (4.76%).

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CO2Hydrogenation over Copper/ZnO Single-Atom Catalysts: Water-Promoted Transient Synthesis of Methanol

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Angewandte Chemie 2022年第48期134卷

作者： Wenlong Wu Yanan Wang Lei Luo Menglin Wang Zhongling Li Yue Chen Zhiqi Wang Jingbo Chai Zeyan Cen Yongliang Shi Jin Zhao Jie Zeng Hongliang Li Hefei National Research Center for Physical Sciences at the Microscale CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes National Synchrotron Radiation Laboratory Department of Chemical Physics Department of Physics University of Science and Technology of China Hefei Anhui 230026 P. R. China Songshan Lake Materials Laboratory Dongguan Guangdong 523808 P. R. China Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China Center for Spintronics and Quantum Systems State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and Engineering Xi'an Jiaotong University Xi'an Shanxi 710049 P. R. China

The hydrogenation of CO 2 by renewable power-generated hydrogen offers a promising approach to a sustainable carbon cycle. However, the role of water during CO 2 hydrogenation is still under debate. Herein, we demonstrated that either too low or too high contents of water hampered the methanol synthesis over Cu/ZnO based catalysts. For Cu single atoms on ZnO supports, the optimal content of water was 0.11 vol. % under 30 bar (CO 2 : H 2 =1 : 3) at 170 °C. Upon the introduction of optimal-content water, the methanol selectivity immediately became 99.1 %, meanwhile the conversion of CO 2 underwent a volcano-type trend with the maximum of 4.9 %. According to mechanistic studies, water acted as a bridge between H atoms and CO 2 /intermediates, facilitating the transformation of COOH* and CH 2 O*. The enhanced activity induced the generation of more water to react with CO via water-gas shift reaction, resulting in the increase in methanol selectivity.

关键词： CO2 Cu/ZnO Methanol Single-Atom Catalysis Water

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Two-gap and three-gap superconductivity in AlB2-based films

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Physical Review B 2019年第9期100卷 094516-094516页

作者： Yinchang Zhao Chao Lian Shuming Zeng Zhenhong Dai Sheng Meng Jun Ni Department of Physics Yantai University Yantai 264005 People's Republic of China Materials Science and Engineering Program University of California-Riverside Riverside California 92521 USA Department of Chemical and Environmental Engineering University of California-Riverside Riverside California 92521 USA State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Tsinghua University Beijing 100084 People's Republic of China Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 Peoples Republic of China Collaborative Innovation Center of Quantum Matter Beijing 100084 People's Republic of China

In contrast to MgB2 superconducting at 39K, the isostructural AlB2 has no superconductivity due to the absence of metallization driven by the covalent state of boron in MgB2. In this paper, we investigate from first principles the superconducting behavior in ultrathin limit of AlB2, and reveal a two-gap superconducting nature with transition temperatures Tcs in the range of 17−26.5K. Our results indicate that the superconductivity in AlB2 films originates mainly from the surface-boron-plane-driven covalent state which crosses the Fermi level because of the quantum confinement. Therefore, the hyperstoichiometric AlB2+x films with the surface boron layer existing on each side of the systems also promise admirable superconductivity. In particular, a high Tc∼47K with an exciting three-gap nature is captured in the thinnest AlB2+x films that possess a stoichiometry of AlB4 and a sandwich configuration of B2−Al−B2. In addition, the effect of external strain on superconducting behavior in the thinnest AlB2 film and sandwich AlB4 film is also involved, which shows that a small compressive strain can further boost the Tcs in both films and a three-gap nature can be also observed in the thinnest AlB2 film under a biaxial tensile strain of 2.0%−2.5%. These findings pave the way not only for study of superconductivity in AlB2-based materials but also the search for multigap superconductors.

关键词： Multiband superconductivity Superconducting gap Superconductivity

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Moiré lattice-induced formation and tuning of hybrid dipolar excitons in twisted WS2/MoSe2 heterobilayers

arXiv

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arXiv 2019年

作者： Zhang, Long Zhang, Zhe Wu, Fengcheng Wang, Danqing Gogna, Rahul Hou, Shaocong Watanabe, Kenji Taniguchi, Takashi Kulkarni, Krishnamurthy Kuo, Thomas Forrest, Stephen R. Deng, Hui Physics Department University of Michigan 450 Church Street Ann ArborMI48109-2122 United States State Key Laboratory of Surface Physics Department of Physics Fudan University Shanghai200433 China Condensed Matter Theory Center Joint Quantum Institute Department of Physics University of Maryland College ParkMD20742 United States Applied Physics Program University of Michigan 450 Church Street Ann ArborMI48109-1040 United States Department of Electrical Engineering and Computer Science University of Michigan 450 Church Street Ann ArborMI48109-1040 United States National Institute for Materials Science Tsukuba Japan

Moiré superlattices formed in van der Waals bilayers have enabled the creation and manipulation of new quantum states, as is exemplified by the discovery of superconducting and correlated insulating states in twisted bilayer graphene near the magic angle. Twisted bilayer semiconductors may lead to tunable exciton lattices and topological states, yet signatures of moiré excitons have been reported only in closely angularly-aligned bilayers. Here we report tuning of moiré lattice in WS2 /MoSe2 bilayers over a wide range of twist angles, leading to the continuous tuning of moiré - lattice induced interlayer excitons and their hybridization with optically bright intralayer excitons. A pronounced revival of the hybrid excitons takes place near commensurate twist angles, 21.8◦ and 38.2◦, due to interlayer tunneling between states connected by a moiré reciprocal lattice vector. From the angle dependence, we obtain the effective mass of the interlayer excitons and the electron inter-layer tunneling strength. These findings pave the way for understanding and engineering rich moiré -lattice induced phenomena in angle-twisted semiconductor van dar Waals heterostructures. Copyright © 2019, The Authors. All rights reserved.

关键词： Excitons

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Lithium‐Ion Batteries: Cooling Induced surface Reconstruction during Synthesis of High‐Ni Layered Oxides (Adv. Energy Mater. 43/2019)

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Advanced Energy Materials 2019年第43期9卷

作者： Ming‐Jian Zhang Xiaobing Hu Maofan Li Yandong Duan Luyi Yang Chong Yin Mingyuan Ge Xianghui Xiao Wah‐Keat Lee Jun Young Peter Ko Khalil Amine Zonghai Chen Yimei Zhu Eric Dooryhee Jianming Bai Feng Pan Feng Wang School of Advanced Materials Peking University Shenzhen Graduate School Shenzhen 518055 P. R. China Sustainable Energy Technologies Department Brookhaven National Laboratory Upton NY 11973 USA Condensed Matter Physics and Materials Science Department Brookhaven National Laboratory Upton NY 11973 USA School of Science Hebei University of Science and Technology Shijiazhuang 050018 P. R. China Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo 315201 P. R. China National Synchrotron Light Source II Brookhaven National Laboratory Upton NY 11973 USA The Cornell High Energy Synchrotron Source Cornell University Ithaca NY 14853 USA Electrochemical Technology Program Chemical Sciences and Engineering Division Argonne National Laboratory 9700 South Cass Avenue Lemont IL 60439 USA Materials Science and Engineering Stanford University Stanford CA 94305 USA Institute for Research and Medical Consultations (IRMC) Imam Abdulrahman Bin Faisal University (IAU) Dammam 34212 Saudi Arabia

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Exploring Low Internal Reorganization Energies for Silicene Nanoclusters

arXiv

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arXiv 2017年

作者： Pablo-Pedro, Ricardo Lopez-Rios, Hector Mendoza-Cortes, Jose-L Kong, Jing Fomine, Serguei van Voorhis, Troy Dresselhaus, Mildred S. Department of Chemistry Massachusetts Institute of Technology 77 Massachusetts Avenue CambridgeMA02139 United States Instituto de Investigaciones en Materiales Universidad Nacional Autónoma de México Apartado Postal 70-360 CU Coyoacán Ciudad de México04510 Mexico Department of Chemical & Biomedical Engineering Florida A&M University Florida State University Joint College of Engineering Tallahassee FL32310 United States Scientific Computing Department Materials Science and Engineering Program High Performance Material Institute Condensed Matter Theory National High Magnetic Field Laboratory Florida State University TallahasseeFL32310 United States Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States Department of Physics Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States

High-performance materials rely on small reorganization energies to facilitate both charge separation and charge transport. Here, we performed DFT calculations to predict small reorganization energies of rectangular silicene nanoclusters with hydrogen-passivated edges denoted by H-SiNC. We observe that across all geometries, H-SiNCs feature large electron affinities and highly stabilized anionic states, indicating their potential as n-type materials. Our findings suggest that fine-tuning the size of H-SiNCs along the "zigzag" and "armchair" directions may permit the design of novel n-type electronic materials and spinctronics devices that incorporate both high electron affinities and very low internal reorganization energies. Copyright © 2017, The Authors. All rights reserved.

关键词： Silicene

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Exploring low internal reorganization energies for silicene nanoclusters

arXiv

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arXiv 2017年

关键词： Silicene

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