KAUST Catalysis Center (KCC)

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Now showing 1 - 5 of 3309
  • Article

    High Voltage Electrolyte Design Mediated by Advanced Solvation Chemistry Toward High Energy Density and Fast Charging Lithium-Ion Batteries

    (Wiley, 2024-02-25) Cheng, Haoran; Ma, Zheng; Kumar, Pushpendra; Liang, Honghong; Cao, Zhen; Xie, Hongliang; Cavallo, Luigi; Kim, Hun; Li, Qian; Sun, Yang-Kook; Ming, Jun; KAUST Catalysis Center King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia; KAUST Catalysis Center (KCC); Physical Science and Engineering (PSE) Division; Chemical Science Program; State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 P. R. China; School of Applied Chemistry and Engineering University of Science and Technology of China Hefei 230026 P. R. China; School of Physical Sciences Jawaharlal Nehru University New Delhi 110067 India; Department of Energy Engineering Hanyang University Seoul 133-791 Republic of Korea

    Electrolyte is critical for transporting lithium-ion (Li+) in lithium-ion batteries (LIBs). However, there is no universally applicable principle for designing an optimal electrolyte. In most cases, the design process relies on empirical experiences and is often treated as highly confidential proprietary information. Herein, a solvation structure-related model for the quantitative design of electrolytes is introduced, focusing on the principles of coordination chemistry. As a paradigmatic example, a high-voltage electrolyte (i.e., 4.5 V vs anode) aimed at achieving a high energy density and fast charging LIB, which is specifically composed of an emerging, well-constructed hybrid hard carbon-silicon/carbon-based anode, and lithium cobalt oxide cathode, is developed. Not only the functions of each electrolyte component at the molecular scale within the Li+ solvation structure are analyzed but also an interfacial model is introduced to elucidate their relationship with the battery performance. This study represents a pioneering effort in developing a methodology to guide electrolyte design, in which the mutual effects of the Li+ de-solvation process and solid electrolyte interface (SEI) on the electrode surface are explored concurrently to understand the root cause of superior performance. This innovative approach establishes a new paradigm in electrolyte design, providing valuable insights at the molecular level.

  • Article

    Synthesis of cyclohepta[b]indoles via gold mediated energy transfer photocatalysis

    (Royal Society of Chemistry (RSC), 2024) Zhao, Yuan; Voloshkin, Vladislav A.; Martynova, Ekaterina A.; Maity, Bholanath; Cavallo, Luigi; Nolan, Steven P.; KAUST Catalysis Center (KCC); Physical Science and Engineering (PSE) Division; Chemical Science Program; Department of Chemistry and Centre for Sustainable Chemistry Ghent University, Krijgslaan 281, S-3, 9000 Ghent, Belgium

    Photocatalysis involving energy transfer (EnT) has become a valuable technique for building intricate organic frameworks mostly through [2+2]-cycloaddition reactions. Herein, we report a synthetic method leading to functionalized cyclohepta[b]indoles, an important structural motif in natural products and pharmaceuticals, using gold-mediated energy transfer photocatalysis. The scope of this operationally simple and atom-economical strategy is presented. Density functional theory studies were employed in order to gain insights into the mechanism of formation of the cyclohepta[b]indole core.

  • Article

    Efficient and chemoselective imine synthesis catalyzed by a well-defined PN3-manganese(ii) pincer system

    (Royal Society of Chemistry (RSC), 2024) Gholap, Sandeep; Dakhil, Abdullah Al; Chakraborty, Priyanka; Dighe, Shashikant; Rahman, Mohammad Misbahur; Dutta, Indranil; Hengne, Amol; Huang, Kuo-Wei; KAUST Catalysis Center (KCC); Physical Science and Engineering (PSE) Division; Chemical Science Program; Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University, Riyadh 11432-5701 Saudi Arabia; Agency for Science, Technology and Research, Institute of Materials Research and Engineering and Institute of Sustainability for Chemicals, Energy and Environment, Singapore

    The highly efficient reductive amination of aldehydes with ammonia (NH3) and hydrogen (H2) to form secondary imines is described, as well as the dehydrogenative homocoupling of benzyl amines. Using an air-stable, well-defined PN3-manganese(ii) pincer complex as a catalyst precursor, various aldehydes are easily converted directly into secondary imines using NH3 as a nitrogen source under H2 in a one-pot reaction. Importantly, the same catalyst facilitates the dehydrogenative homocoupling of various benzylamines, exclusively forming imine products. These reactions are conducted under very mild conditions, without the addition of any additives, yielding excellent selectivities and high yields of secondary imines in a green manner by minimizing wastes.

  • Article

    Ballistic electrolyte ion transport with undisturbed pathways for ultrahigh-rate electrochemical energy storage devices

    (Royal Society of Chemistry (RSC), 2024) Cheng, Situo; Cao, Zhen; Liu, Yupeng; Zhang, Junli; Cavallo, Luigi; Xie, Erqing; Fu, Jiecai; KAUST Catalysis Center (KCC); Physical Science and Engineering (PSE) Division; Chemical Science Program; Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 P. R. China

    The efficient charge-discharge process in electrochemical energy storage devices is hinged on the sluggish kinetics of ion migration inside the layered/porous electrodes. Despite the progress achieved in nanostructure configuration and electronic properties engineering, the electrodes require a fluent pathway in the mesoscopic structure to avoid ion accumulation during the (de)intercalation processes. Herein, we carefully designed and validated a robust way of generating long regular channels in electrodes through experiments and density functional theory (DFT) calculations to enhance ion transport efficiency with the prototype of a two-dimensional conjugated metal-organic framework (2D c-MOF). The AA-stacking c-MOF electrode delivers a high areal capacitance (28.7 F cm−2 at 0.2 mV s−1) with a retained capacitance of 15.9 F cm−2 after the charge-discharge rate increases by 50 times, revealing the ultrafast ion kinetics, while the AB-stacking MOF electrode exhibits a capacitance retention of 17.5% (from 16 F cm−2 to 2.8 F cm−2).

  • Article

    Strategies to achieve effective nitrogen activation

    (Wiley, 2024-02-23) Chang, Bin; Zhang, Huabin; Sun, Shuhui; Zhang, Gaixia; KAUST Catalysis Center (KCC); Physical Science and Engineering (PSE) Division; Chemical Science Program; Institut National de la Recherche Scientifique (INRS) Centre Énergie Matériaux Télécommunications Varennes Québec Canada; Department of Electrical Engineering École de Technologie Supérieure (ÉTS) Montréal Québec Canada

    Ammonia serves as a crucial chemical raw material and hydrogen energy carrier. Aqueous electrocatalytic nitrogen reduction reaction (NRR), powered by renewable energy, has attracted tremendous interest during the past few years. Although some achievements have been revealed in aqueous NRR, significant challenges have also been identified. The activity and selectivity are fundamentally limited by nitrogen activation and competitive hydrogen evolution. This review focuses on the hurdles of nitrogen activation and delves into complementary strategies, including materials design and system optimization (reactor, electrolyte, and mediator). Then, it introduces advanced interdisciplinary technologies that have recently emerged for nitrogen activation using high-energy physics such as plasma and triboelectrification. With a better understanding of the corresponding reaction mechanisms in the coming years, these technologies have the potential to be extended in further applications. This review provides further insight into the reaction mechanisms of selectivity and stability of different reaction systems. We then recommend a rigorous and detailed protocol for investigating NRR performance and also highlight several potential research directions in this exciting field, coupling with advanced interdisciplinary applications, in situ/operando characterizations, and theoretical calculations.