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Enhancing the Electrochemical Activity of 2D Materials Edges through Oriented Electric Fields

ACS Nano 2024年第30期18卷 19828-19835页

作者： Wang, Hao Chen, Ding-Rui Lin, You-Chen Lin, Po-Han Chang, Jui-Teng Muthu, Jeyavelan Hofmann, Mario Hsieh, Ya-Ping Institute of Atomic and Molecular Sciences Academia Sinica Taipei10617 Taiwan Department of Physics National Taiwan University Taipei10617 Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Taipei10617 Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei10617 Taiwan Department of Low Dimensional Systems J. Heyrovský Institute of Physical Chemistry Prague18200 Czech Republic

The edges of 2D materials have emerged as promising electrochemical catalyst systems, yet their performance still lags behind that of noble metals. Here, we demonstrate the potential of oriented electric fields (OEFs) to enhance the electrochemical activity of 2D materials edges. By atomically engineering the edge of a fluorographene/graphene/MoS2 heterojunction nanoribbon, strong and localized OEFs were realized as confirmed by simulations and spatially resolved spectroscopy. The observed fringing OEF results in an enhancement of the heterogeneous charge transfer rate between the edge and the electrolyte by 2 orders of magnitude according to impedance spectroscopy. Ab initio calculations indicate a field-induced decrease in the reactant adsorption energy as the origin of this improvement. We apply the OEF-enhanced edge reactivity to hydrogen evolution reactions (HER) and observe a significantly enhanced electrochemical performance, as evidenced by a 30% decrease in Tafel slope and a 3-fold enhanced turnover frequency. Our findings demonstrate the potential of OEFs for tailoring the catalytic properties of 2D material edges toward future complex reactions. © 2024 The Authors. Published by American Chemical Society.

关键词： Electric fields

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Ultrahigh-quality graphene resonators by liquid-based strain-engineering

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Nanoscale Horizons 2023年第1期9卷 156-161页

作者： Chen, Ding-Rui Hu, I-Fan Chin, Hao-Ting Yao, Yu-Chi Raman, Radha Hofmann, Mario Liang, Chi-Te Hsieh, Ya-Ping Institute of Atomic and Molecular Sciences Academia Sinica Taipei10617 Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Taipei10617 Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei10617 Taiwan Department of Physics National Taiwan University Taipei10617 Taiwan Department of Physics National Central University Taoyuan320 Taiwan

Two-dimensional (2D) material-based nanoelectromechanical (NEM) resonators are expected to be enabling components in hybrid qubits that couple mechanical and electromagnetic degrees of freedom. However, challenges in their sensitivity and coherence time have to be overcome to realize such mechanohybrid quantum systems. We here demonstrate the potential of strain engineering to realize 2D material-based resonators with unprecedented performance. A liquid-based tension process was shown to enhance the resonance frequency and quality factor of graphene resonators six-fold. Spectroscopic and microscopic characterization reveals a surface-energy enhanced wall interaction as the origin of this effect. The response of our tensioned resonators is not limited by external loss factors and exhibits near-ideal internal losses, yielding superior resonance frequencies and quality factors to all previously reported 2D material devices. Our approach represents a powerful method of enhancing 2D NEM resonators for future quantum systems. © 2024 The Royal Society of Chemistry

关键词： Resonators

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Selective activation of MoS2 grain boundaries for enhanced electrochemical activity

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Nanoscale Horizons 2024年第6期9卷 946-955页

作者： Raman, Radha Muthu, Jeyavelan Yen, Zhi-Long Qorbani, Mohammad Chen, Yu-Xiang Chen, Ding-Rui Hofmann, Mario Hsieh, Ya-Ping Department of Physics National Central University Taoyuan32001 Taiwan Institute of Atomic and Molecular Sciences Academia Sinica Taipei10617 Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei10617 Taiwan Department of Physics National Taiwan University Taipei10617 Taiwan Nanoscience and Technology Program Taiwan International Graduate Program Academia Sinica Taipei115 Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Taipei10617 Taiwan Center for Condensed Matter Sciences National Taiwan University Taipei10617 Taiwan Center of Atomic Initiative for New Materials National Taiwan University Taipei10617 Taiwan

Molybdenum disulfide (MoS2) has emerged as a promising material for catalysis and sustainable energy conversion. However, the inertness of its basal plane to electrochemical reactions poses challenges to the utilization of wafer-scale MoS2 in electrocatalysis. To overcome this limitation, we present a technique that enhances the catalytic activity of continuous MoS2 by preferentially activating its buried grain boundaries (GBs). Through mild UV irradiation, a significant enhancement in GB activity was observed that approaches the values for MoS2 edges, as confirmed by a site-selective photo-deposition technique and micro-electrochemical hydrogen evolution reaction (HER) measurements. Combined spectroscopic characterization and ab-initio simulation demonstrates substitutional oxygen functionalization at the grain boundaries to be the origin of this selective catalytic enhancement by an order of magnitude. Our approach not only improves the density of active sites in MoS2 catalytic processes but yields a new photocatalytic conversion process. By exploiting the difference in electronic structure between activated GBs and the basal plane, homo-compositional junctions were realized that improve the photocatalytic synthesis of hydrogen by 47% and achieve performances beyond the capabilities of other catalytic sites. © 2024 The Royal Society of Chemistry

关键词： Electronic structure

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Accurate Kinetic Studies of OH + HO2 Radical-Radical Reaction through Direct Measurement of Precursor and Radical Concentrations with High-Resolution Time-Resolved Dual-Comb Spectroscopy

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Journal of Physical Chemistry Letters 2024年第14期15卷 3733-3739页

作者： Chen, I-Yun Chang, Che-Wei Fittschen, Christa Luo, Pei-Ling Institute of Atomic and Molecular Sciences Academia Sinica Taipei106319 Taiwan Department of Chemistry National Taiwan University Taipei10617 Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei11529 Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Taipei10617 Taiwan University Lille CNRS UMR 8522 PC2A−Physicochimie des Processus de Combustion et de l’Atmosphère LilleF-59000 France

The radical-radical reaction between OH and HO2 has been considered for a long time as an important reaction in tropospheric photochemistry and combustion chemistry. However, a significant discrepancy of an order of magnitude for rate coefficients of this reaction is found between two recent experiments. Herein, we investigate the reaction OH + HO2 via direct spectral quantification of both the precursor (H2O2) and free radicals (OH and HO2) upon the 248 nm photolysis of H2O2 using infrared two-color time-resolved dual-comb spectroscopy. With quantitative and kinetic analysis of concentration profiles of both OH and HO2 at varied conditions, the rate coefficient kOH+HO2 is determined to be (1.10 ± 0.12) × 10-10 cm3 molecule-1 s-1 at 296 K. Moreover, we explore the kinetics of this reaction under conditions in the presence of water, but no enhancement in the kOH+HO2 can be observed. This work as an independent experiment plays a crucial role in revisiting this prototypical radical-radical reaction. © 2024 The Authors. Published by American Chemical Society.

关键词： Kinetics

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Searching low-energy conformers of neutral and protonated di-, tri-, and tetra-glycine using first-principles accuracy assisted by the use of neural network potentials

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Physical Chemistry Chemical Physics 2024年第14期26卷 11126-11139页

作者： Dong, Hieu Cao Hsu, Po-Jen Kuo, Jer-Lai Institute of Atomic and Molecular Sciences Academia Sinica Taipei10617 Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei11529 Taiwan National Taiwan University Taipei10617 Taiwan Department of Chemistry National Tsing Hua University Hsinchu30013 Taiwan

In the last ten years, combinations of state-of-the-art gas-phase spectroscopies and quantum chemistry calculations have suggested several intuitive trends in the structure of small polypeptides that may not hold true. For example, the preference for the cis form of the peptide bond and multiple protonated sites was proposed by comparing experimental spectra with low-energy minima obtained from limited structural sampling using various density functional theory methods. For understanding the structures of polypeptides, extensive sampling of their configurational space with high-accuracy computational methods is required. In this work, we demonstrated the use of deep-learning neural network potential (DL-NNP) to assist in exploring the structure and energy landscape of di-, tri-, and tetra-glycine with the accuracy of high-level quantum chemistry methods, and low-energy conformers of small polypeptides can be efficiently located. We hope that the structures of these polypeptides we found and our preliminary analysis will stimulate further experimental investigations. © 2024 The Royal Society of Chemistry

关键词： Amino acids

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A first-principles exploration of the conformational space of sodiated di-saccharides assisted by semi-empirical methods and neural network potentials†

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Physical Chemistry Chemical Physics 2024年第12期26卷 9556-9567页

作者： Phan, Huu Trong Tsou, Pei-Kang Hsu, Po-Jen Kuo, Jer-Lai Institute of Atomic and Molecular Sciences Academia Sinica Taipei10617 Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei11529 Taiwan Department of Chemistry National Tsing Hua University Hsinchu30013 Taiwan National Taiwan University Taipei10617 Taiwan

Previous exploration of the conformational space of sodiated mono-saccharides using a random search algorithm leads to B103 structurally distinct conformers covering an energy range of B150 kJ mol-1. Thus, it is reasonable to expect that the number of distinct conformers for a given disaccharide would be on the order of 106. Efficient identification of distinct conformers at the first-principles level has been demonstrated with the assistance of neural network potential (NNP) with an accuracy of B1 kJ mol-1 compared to DFT. Leveraging a local minima database of neutral and sodiated glucose (Glc), we develop algorithms to systematically explore the conformation landscape of 19 Glc-based sodiated disaccharides. To accelerate the exploration, the NNP method is implemented. The NNP achieves an accuracy of B2.3 kJ mol-1 compared to DFT, offering a comparable quality to that of DFT. Through a multi-model approach integrating DFTB3, NNP and DFT, we can rapidly locate low-energy disaccharide conformers at the first-principles level. The methodology we show here can be used to efficiently explore the potential energy landscape of any di-saccharides when first-principles accuracy is required. © 2024 Royal Society of Chemistry. All rights reserved.

关键词： Potential energy

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Nitrogen Pretreatment of Growth Substrates for Vacancy-Saturated MoS2

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ACS Applied Materials and Interfaces 2023年第36期15卷 42746-42752页

作者： Yao, Yu-Chi Wu, Bo-Yi Chin, Hao-Ting Yen, Zhi-Long Ting, Chu-Chi Hofmann, Mario Hsieh, Ya-Ping Institute of Atomic and Molecular Sciences Academia Sinica Taipei10617 Taiwan Department of Physics National Taiwan University Taipei10617 Taiwan Graduate Institute of Opto-Mechatronics Department of Mechanical Engineering National Chung Cheng University Chia-Yi62102 Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Taipei10617 Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei10617 Taiwan

Two-dimensional transition-metal dichalcogenides (2D TMDCs) are considered promising materials for optoelectronics due to their unique optical and electric properties. However, their potential has been limited by the occurrence of atomic vacancies during synthesis. While post-treatment processes have demonstrated the passivation of such vacancies, they increase process complexity and affect the TMDC’s quality. We here introduce the concept of pretreatment as a facile and powerful route to solve the problem of vacancies in MoS2. Low-temperature nitridation of the sapphire substrate prior to growth provides a nondestructive method to MoS2 modification without introducing new processing steps or increasing the thermal budget. Spectroscopic characterization and atomic-resolution microscopy reveal the incorporation of nitrogen from the sapphire surface layer into chalcogen vacancies. The resulting MoS2 with nitrogen-saturated defects shows a decrease in midgap states and more intrinsic doping as confirmed by ab initio calculations and optoelectronic measurements. The demonstrated pretreatment method opens up new routes toward future, high-performance 2D electronics, as evidenced by a 3-fold reduction in contact resistance and a 10-fold improved performance of 2D photodetectors. © 2023 American Chemical Society

关键词： Molybdenum compounds

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Physicochemical properties of lard oil and rubber seed oil blends and their comprehensive characterization

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Chinese Journal of Chemical Engineering 2024年第11期75卷 1-13页

作者： Amonrat Thangthong Wuttichai Roschat Phongsakorn Pholsupho Aekkaphon Thammayod Sunti Phewphong Tappagorn Leelatam Preecha Moonsin Boonyawan Yoosuk Pathompong Janetaisong Vinich Promarak Program of Environment Science Faculty of Science and TechnologySakon Nakhon Rajabhat UniversityMueang DistrictSakon Nakhon 47000Thailand Biomass Energy Research Laboratory Center of Excellence on Alternative EnergyResearch and Development InstitutionSakon Nakhon Rajabhat UniversityMueang DistrictSakon Nakhon 47000Thailand Program of Chemistry Faculty of Science and TechnologySakon Nakhon Rajabhat UniversityMueang DistrictSakon Nakhon 47000Thailand Innovation in Chemistry for Community Research Unit Faculty of Science and TechnologySakon Nakhon Rajabhat UniversityMueang DistrictSakon Nakhon 47000Thailand Appropriated Technology Center Faculty of Science and TechnologySakon Nakhon Rajabhat UniversityMueang DistrictSakon Nakhon 47000Thailand Program of Chemistry Faculty of ScienceUbon Ratchathani Rajabhat UniversityMueang DistrictUbon Ratchathani 34000Thailand National Energy Technology Center(ENTEC) 114 Thailand Science ParkPhahonyothin RoadKlong LuangPathumthani 12120Thailand Department of Material Science and Engineering School of Molecular Science&EngineeringVidyasirimedhi Institute of Science and TechnologyWangchanRayong 21210Thailand

This research investigates the potential of blending complementary lard oil with rubber seed oil as feedstock for biodiesel *** seed oil,obtained through hexane extraction using the Soxhlet method,contains the major fatty acids of oleic acid(C_(18:1)),palmitic acid(C_(16:0)),linoleic acid(C_(18:2)),and stearic acid(C_(18:0)),while rubber seed oil primarily consists of linoleic acid(C_(18:2)),oleic acid(C_(18:1)),linolenic acid(C_(18:3)),palmitic acid(C_(16:0)),and stearic acid(C_(18:0)).The least acid value of lard oil(0.55 mg KOH/g)can benefit of reducing soap formation of rubber seed oil during transesterification process in biodiesel production due to its substantial-high acid value(16.28 mg KOH/g).Blending at ratios below 80:20 volume ratio produced biodiesel exceeding 85%,utilizing CaO as a *** oil demonstrated a higher reaction rate constant(11.88×10^(-3)min^(-1))than rubber seed oil(2.11×10^(-3)min^(-1)),indicating a significant difference in *** acid value and free fatty acids in rubber seed oil correlated with lower reaction *** a mixture ratio below 80:20 volume ratio optimized reaction rates during biodiesel *** obtained from blends below 80:20 volume ratio met ASTM D6751 and EN 14214 standards,demonstrating suitability for bio-auto *** drawbacks of using rubber seed oil as a raw material for biodiesel production are overcome by blending with lard oil,giving rise to expanding renewable energy options for rural communities,community enterprises,and large-scale biodiesel production.

关键词： Biodiesel oil Rubber seed oil Lard oil High free fatty acid Physicochemical properties Liquid biofuels

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Low-Temperature Methanolysis of Polycarbonate over Solid Base Sodium Aluminate

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Langmuir 2024年第10期40卷 5338-5347页

作者： Krisbiantoro, Philip Anggo Sato, Miyu Lin, Tzu-Ming Chang, Yu-Chia Peng, Tzu-Yun Wu, Yun-Chih Liao, Weisheng Kamiya, Yuichi Otomo, Ryoichi Wu, Kevin C.-W. Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei11529 Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Taipei10617 Taiwan Department of Chemical Engineering College of Engineering National Taiwan University Taipei10617 Taiwan Graduate School of Environmental Science Hokkaido University Nishi 5 Kita 10 Sapporo060-0810 Japan Faculty of Environmental Earth Science Hokkaido University Nishi 5 Kita 10 Sapporo060-0810 Japan Center of Atomic Initiative for New Materials National Taiwan University Taipei10617 Taiwan Department of Chemical Engineering and Materials Science Yuan Ze University Taoyuan320 Taiwan

Herein, a low-cost and readily available sodium aluminate (NaAlO2) was used as a solid base catalyst for the depolymerization of polycarbonate (PC) via methanolysis in the presence of tetrahydrofuran (THF) as a solvent. NaAlO2 was highly active for the reaction, and the performance was comparable to that of soluble strong base SrO and much higher than those of MgO and CaO. By the reaction over the catalyst, a highly pure and crystalline bisphenol A (BPA) was obtained. Among tested organic solvents, THF was the best in aiding PC methanolysis over NaAlO2 due to the polarity similar to PC according to Hansen solubility parameters (HSPs). At 60 °C, 98.1% PC conversion and 96.8% BPA yield were achieved within just 2 h. NaAlO2 was reusable without any severe catalyst deactivation in at least four runs. The mechanistic study revealed that the reaction proceeded via the methoxide pathway, with THF aiding the dissolution of PC. The reaction over NaAlO2 possessed a low apparent activation energy (Ea) of 75.1 kJ mol-1, which is the lowest ever reported so far for the reaction over solid catalysts. © 2024 The Authors. Published by American Chemical Society.

关键词： Sodium Aluminate

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Confined VLS Growth of Single-Layer 2D Tungsten Nitrides

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ACS Applied Materials and Interfaces 2024年第1期16卷 1705-1711页

作者： Chin, Hao-Ting Wang, Deng-Chi Wang, Hao Muthu, Jeyavelan Khurshid, Farheen Chen, Ding-Rui Hofmann, Mario Chuang, Feng-Chuan Hsieh, Ya-Ping Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei 106 Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Taipei 10617 Taiwan Institute of Atomic and Molecular Sciences Academia Sinica Taipei 106 Taiwan Department of Physics National Sun Yat-Sen University Kaohsiung 80424 Taiwan Department of Physics National Taiwan University Taipei 106 Taiwan Nano Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei 106 Taiwan Center for Theoretical and Computational Physics National Sun Yat-sen University Kaohsiung 80424 Taiwan Physics Division National Center for Theoretical Sciences Taipei 10617 Taiwan

Two-dimensional (2D) metal nitrides have garnered significant interest due to their potential applications in future electronics and quantum systems. However, the synthesis of such materials with sufficient uniformity and at relevant scales remains an unaddressed challenge. This study demonstrates the potential of confined growth to control and enhance the morphology of 2D metal nitrides. By restricting the reaction volume of vapor-liquid-solid reactions, an enhanced precursor concentration was achieved that reduces the nucleation density, resulting in larger grain sizes and suppression of multilayer growth. Detailed characterization reveals the importance of balancing the energetic and kinetic aspects of tungsten nitride formation toward this ability. The introduction of a promoter enabled the realization of large-scale, single-layer tungsten nitride with a uniform and high interfacial quality. Finally, our advance in morphology control was applied to the production of edge-enriched 2D tungsten nitrides with significantly enhanced hydrogen evolution ability, as indicated by an unprecedented Tafel slope of 55 mV/dec. © 2023 American Chemical Society.

关键词： 2D diode confinement growth HER promoter-assisted growth tungsten nitride VLS

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