Pub Date : 2024-10-09DOI: 10.1021/acs.jpclett.4c0261910.1021/acs.jpclett.4c02619
Shixun Hu*, Wenjia Zhang, Chi Yao, Shangshi Huang, Zhen Luo, Xiyu Zhang, Xinhua Dong, Xin Yu, Jun Hu, Qi Li*, Xiangyang Peng and Jinliang He*,
How to fundamentally suppress charge transport is one of the essential issues in polymer dielectrics. This work reports significant charge transport suppression by glycidyl methacrylate (GMA) side group modification on polypropylene (PP). Experimental and computational investigations discover for the first time a quasi-hydrogen bond effect generated by carbonyl and epoxide of GMA in PP inter/intramolecular structure, while introducing trap energy levels within the HOMO–LUMO gap. These energy levels suppress the leakage current of GMA-modified PP thanks to the charge-trapping effect. The quasi-hydrogen bond originating from the interaction between the high-polar GMA group and flexible PP chain raises the thermostability while averaging the electron distribution between hydrogen and acceptor oxygen, which is conducive to lessening electric weak points, suppressing charge transport, and finally enhancing the electrical breakdown strength. This work provides new thinking on polymer dielectric design and charge transport regulation utilizing electron structure and weak interaction at the molecular scale.
{"title":"Quasi-Hydrogen Bond and Charge-Trapping Effect Originating from Polar Side Group Lead to Significantly Suppressed Charge Transport in Polypropylene","authors":"Shixun Hu*, Wenjia Zhang, Chi Yao, Shangshi Huang, Zhen Luo, Xiyu Zhang, Xinhua Dong, Xin Yu, Jun Hu, Qi Li*, Xiangyang Peng and Jinliang He*, ","doi":"10.1021/acs.jpclett.4c0261910.1021/acs.jpclett.4c02619","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02619https://doi.org/10.1021/acs.jpclett.4c02619","url":null,"abstract":"<p >How to fundamentally suppress charge transport is one of the essential issues in polymer dielectrics. This work reports significant charge transport suppression by glycidyl methacrylate (GMA) side group modification on polypropylene (PP). Experimental and computational investigations discover for the first time a quasi-hydrogen bond effect generated by carbonyl and epoxide of GMA in PP inter/intramolecular structure, while introducing trap energy levels within the HOMO–LUMO gap. These energy levels suppress the leakage current of GMA-modified PP thanks to the charge-trapping effect. The quasi-hydrogen bond originating from the interaction between the high-polar GMA group and flexible PP chain raises the thermostability while averaging the electron distribution between hydrogen and acceptor oxygen, which is conducive to lessening electric weak points, suppressing charge transport, and finally enhancing the electrical breakdown strength. This work provides new thinking on polymer dielectric design and charge transport regulation utilizing electron structure and weak interaction at the molecular scale.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1021/acs.jpclett.4c0233510.1021/acs.jpclett.4c02335
Surender Kumar, Torben Steenbock and Gabriel Bester*,
The origin of the high-frequency shoulder (HFS) observed above the longitudinal optical (LO) peak around 230 cm–1 in the Raman spectra of CdSe quantum dots (QDs) has been the subject of intense debate. We use state-of-the-art ab initio density functional theory applied to small CdSe QDs with various realistic surface passivations and find an intense Raman signal around 230 cm–1, which corresponds to a stretching vibration of a defective 2-fold coordinated Se atom. We interpret this signal as being the origin of the HFS. Since the signal disappears in fully passivated and defect-free (magic size cluster) structures, it can be used as a fingerprint to distinguish defective from nondefective structures.
在硒化镉量子点(CdSe quantum dots,QDs)的拉曼光谱中,在纵向光学峰(LO)上方约 230 cm-1 处观察到的高频肩(HFS)的起源一直是激烈争论的主题。我们将最先进的 ab initio 密度泛函理论应用于具有各种现实表面钝化的小型硒化镉量子点,发现 230 cm-1 附近有一个强烈的拉曼信号,它对应于一个有缺陷的 2 倍配位硒原子的伸缩振动。我们将这一信号解释为 HFS 的起源。由于该信号在完全钝化和无缺陷(神奇尺寸簇)结构中消失,因此可将其用作区分缺陷和非缺陷结构的指纹。
{"title":"Origin of the High-Frequency Shoulder in the Raman Spectra of CdSe Quantum Dots","authors":"Surender Kumar, Torben Steenbock and Gabriel Bester*, ","doi":"10.1021/acs.jpclett.4c0233510.1021/acs.jpclett.4c02335","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02335https://doi.org/10.1021/acs.jpclett.4c02335","url":null,"abstract":"<p >The origin of the high-frequency shoulder (HFS) observed above the longitudinal optical (LO) peak around 230 cm<sup>–1</sup> in the Raman spectra of CdSe quantum dots (QDs) has been the subject of intense debate. We use state-of-the-art <i>ab initio</i> density functional theory applied to small CdSe QDs with various realistic surface passivations and find an intense Raman signal around 230 cm<sup>–1</sup>, which corresponds to a stretching vibration of a defective 2-fold coordinated Se atom. We interpret this signal as being the origin of the HFS. Since the signal disappears in fully passivated and defect-free (magic size cluster) structures, it can be used as a fingerprint to distinguish defective from nondefective structures.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.jpclett.4c02335","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1021/acs.jpclett.4c0247610.1021/acs.jpclett.4c02476
Piotr Łaski, Lerato Bosman, Jakub Drapała, Radosław Kamiński, Dariusz Szarejko, Patryk Borowski, Andreas Roodt, Robert Henning, Alice Brink* and Katarzyna N. Jarzembska*,
The rare observation of transient Rh···Rh excimer formation in a single crystal is reported. The estimated excited-state lifetime at 100 K is 2 ns, which makes it the shortest-lived small-molecule species caught experimentally using the laser-pump/X-ray-probe time-resolved Laue method. Upon excitation with 390 nm laser light, the intermolecular Rh···Rh distance decreases from 3.379(4) to 3.19(1) Å, and the metal–metal contact gains more bonding character. On the basis of the experimental results and theoretical modeling, the structural changes determined with 100 ps time resolution reflect principally the S0 → S1 electronic transition.
{"title":"Nanosecond-Lived Excimer Observation in a Crystal of a Rhodium(I) Complex via Time-Resolved X-ray Laue Diffraction","authors":"Piotr Łaski, Lerato Bosman, Jakub Drapała, Radosław Kamiński, Dariusz Szarejko, Patryk Borowski, Andreas Roodt, Robert Henning, Alice Brink* and Katarzyna N. Jarzembska*, ","doi":"10.1021/acs.jpclett.4c0247610.1021/acs.jpclett.4c02476","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02476https://doi.org/10.1021/acs.jpclett.4c02476","url":null,"abstract":"<p >The rare observation of transient Rh···Rh excimer formation in a single crystal is reported. The estimated excited-state lifetime at 100 K is 2 ns, which makes it the shortest-lived small-molecule species caught experimentally using the laser-pump/X-ray-probe time-resolved Laue method. Upon excitation with 390 nm laser light, the intermolecular Rh···Rh distance decreases from 3.379(4) to 3.19(1) Å, and the metal–metal contact gains more bonding character. On the basis of the experimental results and theoretical modeling, the structural changes determined with 100 ps time resolution reflect principally the S<sub>0</sub> → S<sub>1</sub> electronic transition.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.jpclett.4c02476","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1021/acs.jpclett.4c0244610.1021/acs.jpclett.4c02446
Menglin Li, Jia Peng, Yuyu Jing, Yiran Yan, Cheng Wang, Wenjun Hou, Weiran Cao, Shuangpeng Wang and Haizheng Zhong*,
Brain-inspired electronics with synaptic functions hold significant promise for advancing artificial intelligent applications. In this study, we demonstrate the synaptic feature of quantum-dot light-emitting diodes (QLEDs), which can convert electrical pulses into synapse-like light signals (the brightness gradually increases as the electrical pulses are prolonged). These features are analogous to learning and forgetting in biological synapses. The enhancement of brightness can be attributed to the reduction of charge transfer from the quantum dots to ZnO electron transport layer and resistive switching effect. With an integrated complementary metal-oxide-semiconductor (CMOS) drive, arrayed synaptic QLEDs can simulate the visualization of brain-like learning processes, which can reduce the noise toward high image recognition rate (>95.0%) by deep neural networks. Our findings introduce a novel brain-inspired optoelectronic approach with potential applications in optical neuromorphic systems.
{"title":"Synaptic Feature of Quantum Dot Light-Emitting Diodes for Visualization of Learning Process","authors":"Menglin Li, Jia Peng, Yuyu Jing, Yiran Yan, Cheng Wang, Wenjun Hou, Weiran Cao, Shuangpeng Wang and Haizheng Zhong*, ","doi":"10.1021/acs.jpclett.4c0244610.1021/acs.jpclett.4c02446","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02446https://doi.org/10.1021/acs.jpclett.4c02446","url":null,"abstract":"<p >Brain-inspired electronics with synaptic functions hold significant promise for advancing artificial intelligent applications. In this study, we demonstrate the synaptic feature of quantum-dot light-emitting diodes (QLEDs), which can convert electrical pulses into synapse-like light signals (the brightness gradually increases as the electrical pulses are prolonged). These features are analogous to learning and forgetting in biological synapses. The enhancement of brightness can be attributed to the reduction of charge transfer from the quantum dots to ZnO electron transport layer and resistive switching effect. With an integrated complementary metal-oxide-semiconductor (CMOS) drive, arrayed synaptic QLEDs can simulate the visualization of brain-like learning processes, which can reduce the noise toward high image recognition rate (>95.0%) by deep neural networks. Our findings introduce a novel brain-inspired optoelectronic approach with potential applications in optical neuromorphic systems.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1021/acs.jpclett.4c02274
Lun Yao, Hai-Zhen Yu, Zhen Xie, Sai Duan
The measurement of thermodynamic properties for nanosystems is essential to comprehend the inherent characteristics of nanomaterials. Traditional spectroscopy measurements, such as Raman or ultraviolet–visible spectroscopies, are limited to offering insights near the Γ point in the Brillouin zone and thus cannot precisely determine the system’s thermodynamic properties, for example, heat capacity. Utilizing the intrinsic broad momentum distribution in highly confined plasmonic fields, here we take sp-hybridized carbyne as a proof-of-the-principle example to show that ultrahigh-resolution tip-enhanced Raman scattering (TERS) images have the ability to access all k-points in the phonon Brillouin zone of one-dimensional nanosystems, allowing the comprehensive determination of vibrational features and heat capacity for finite carbon chains. Comparing phonon dispersion spectra and heat capacities under different boundary conditions, i.e., linear carbon chains and cyclic carbon molecules, we find that the heat capacities of linear structures converge more rapidly than the counterparts of cyclic structures to the benchmark of ideal carbyne. We also study the effects of different terminal groups in linear structures as well as the aromaticity in cyclic structures on heat capacity. This study provides a practical method for characterizing the thermodynamic properties of nanosystems, demonstrating the potential applications of TERS imaging in nanomaterial science.
测量纳米系统的热力学性质对于了解纳米材料的固有特性至关重要。传统的光谱测量方法,如拉曼光谱或紫外-可见光谱,只能深入了解布里渊区Γ点附近的情况,因此无法精确测定系统的热力学性质,如热容量。利用高约束质子场中固有的宽动量分布,我们在此以sp-杂化氘代碳为例,证明超高分辨率的尖端增强拉曼散射(TERS)图像能够进入一维纳米系统声子布里渊区的所有k点,从而全面测定有限碳链的振动特征和热容量。通过比较不同边界条件(即线性碳链和环状碳分子)下的声子色散谱和热容量,我们发现线性结构的热容量比环状结构的热容量更快地趋近于理想碳链的基准。我们还研究了线性结构中不同末端基团以及环状结构中芳香性对热容量的影响。这项研究为表征纳米系统的热力学性质提供了一种实用方法,展示了 TERS 成像在纳米材料科学中的潜在应用。
{"title":"Extracting Thermodynamic Properties of Carbyne from Tip-Enhanced Raman Scattering Images","authors":"Lun Yao, Hai-Zhen Yu, Zhen Xie, Sai Duan","doi":"10.1021/acs.jpclett.4c02274","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02274","url":null,"abstract":"The measurement of thermodynamic properties for nanosystems is essential to comprehend the inherent characteristics of nanomaterials. Traditional spectroscopy measurements, such as Raman or ultraviolet–visible spectroscopies, are limited to offering insights near the Γ point in the Brillouin zone and thus cannot precisely determine the system’s thermodynamic properties, for example, heat capacity. Utilizing the intrinsic broad momentum distribution in highly confined plasmonic fields, here we take <i>sp</i>-hybridized carbyne as a proof-of-the-principle example to show that ultrahigh-resolution tip-enhanced Raman scattering (TERS) images have the ability to access all <i>k</i>-points in the phonon Brillouin zone of one-dimensional nanosystems, allowing the comprehensive determination of vibrational features and heat capacity for finite carbon chains. Comparing phonon dispersion spectra and heat capacities under different boundary conditions, i.e., linear carbon chains and cyclic carbon molecules, we find that the heat capacities of linear structures converge more rapidly than the counterparts of cyclic structures to the benchmark of ideal carbyne. We also study the effects of different terminal groups in linear structures as well as the aromaticity in cyclic structures on heat capacity. This study provides a practical method for characterizing the thermodynamic properties of nanosystems, demonstrating the potential applications of TERS imaging in nanomaterial science.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":6.475,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142383761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1021/acs.jpclett.4c0227410.1021/acs.jpclett.4c02274
Lun Yao, Hai-Zhen Yu, Zhen Xie* and Sai Duan*,
The measurement of thermodynamic properties for nanosystems is essential to comprehend the inherent characteristics of nanomaterials. Traditional spectroscopy measurements, such as Raman or ultraviolet–visible spectroscopies, are limited to offering insights near the Γ point in the Brillouin zone and thus cannot precisely determine the system’s thermodynamic properties, for example, heat capacity. Utilizing the intrinsic broad momentum distribution in highly confined plasmonic fields, here we take sp-hybridized carbyne as a proof-of-the-principle example to show that ultrahigh-resolution tip-enhanced Raman scattering (TERS) images have the ability to access all k-points in the phonon Brillouin zone of one-dimensional nanosystems, allowing the comprehensive determination of vibrational features and heat capacity for finite carbon chains. Comparing phonon dispersion spectra and heat capacities under different boundary conditions, i.e., linear carbon chains and cyclic carbon molecules, we find that the heat capacities of linear structures converge more rapidly than the counterparts of cyclic structures to the benchmark of ideal carbyne. We also study the effects of different terminal groups in linear structures as well as the aromaticity in cyclic structures on heat capacity. This study provides a practical method for characterizing the thermodynamic properties of nanosystems, demonstrating the potential applications of TERS imaging in nanomaterial science.
测量纳米系统的热力学性质对于了解纳米材料的固有特性至关重要。传统的光谱测量方法,如拉曼光谱或紫外-可见光谱,只能深入了解布里渊区Γ点附近的情况,因此无法精确测定系统的热力学性质,如热容量。利用高约束质子场中固有的宽动量分布,我们在此以sp-杂化氘代碳为例,证明超高分辨率的尖端增强拉曼散射(TERS)图像能够进入一维纳米系统声子布里渊区的所有k点,从而全面测定有限碳链的振动特征和热容量。通过比较不同边界条件(即线性碳链和环状碳分子)下的声子色散谱和热容量,我们发现线性结构的热容量比环状结构的热容量更快地趋近于理想碳链的基准。我们还研究了线性结构中不同末端基团以及环状结构中芳香性对热容量的影响。这项研究为表征纳米系统的热力学性质提供了一种实用方法,展示了 TERS 成像在纳米材料科学中的潜在应用。
{"title":"Extracting Thermodynamic Properties of Carbyne from Tip-Enhanced Raman Scattering Images","authors":"Lun Yao, Hai-Zhen Yu, Zhen Xie* and Sai Duan*, ","doi":"10.1021/acs.jpclett.4c0227410.1021/acs.jpclett.4c02274","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02274https://doi.org/10.1021/acs.jpclett.4c02274","url":null,"abstract":"<p >The measurement of thermodynamic properties for nanosystems is essential to comprehend the inherent characteristics of nanomaterials. Traditional spectroscopy measurements, such as Raman or ultraviolet–visible spectroscopies, are limited to offering insights near the Γ point in the Brillouin zone and thus cannot precisely determine the system’s thermodynamic properties, for example, heat capacity. Utilizing the intrinsic broad momentum distribution in highly confined plasmonic fields, here we take <i>sp</i>-hybridized carbyne as a proof-of-the-principle example to show that ultrahigh-resolution tip-enhanced Raman scattering (TERS) images have the ability to access all <i>k</i>-points in the phonon Brillouin zone of one-dimensional nanosystems, allowing the comprehensive determination of vibrational features and heat capacity for finite carbon chains. Comparing phonon dispersion spectra and heat capacities under different boundary conditions, i.e., linear carbon chains and cyclic carbon molecules, we find that the heat capacities of linear structures converge more rapidly than the counterparts of cyclic structures to the benchmark of ideal carbyne. We also study the effects of different terminal groups in linear structures as well as the aromaticity in cyclic structures on heat capacity. This study provides a practical method for characterizing the thermodynamic properties of nanosystems, demonstrating the potential applications of TERS imaging in nanomaterial science.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1021/acs.jpclett.4c0188910.1021/acs.jpclett.4c01889
Krishna Kant Singh, Deepak Kumar, Ajitesh Singh and Debabrata Goswami*,
Optical tweezers use strongly focused light for trapping, characterizing, and manipulating objects in the microscopic and nanoscopic regimes. However, fully understanding optical trapping at the nanoscale remains a significant challenge. This holds importance because the nanoscale is the frontier for numerous promising advancements, ranging from enhancing single-molecule investigations in biology to developing hybrid devices for nanoelectronics and photonics and exploring fundamental quantum phenomena in opto-mechanics. We report an experimental and theoretical study of nanoparticles of various sizes, showing the advantages of the immense peak power of ultrashort laser pulses over conventional optical tweezers. We also demonstrate highly stable trapping of nanoparticles for extended durations at low average laser power using femtosecond lasers.
{"title":"Precise Nanoparticle Manipulation Using Femtosecond Laser Trapping","authors":"Krishna Kant Singh, Deepak Kumar, Ajitesh Singh and Debabrata Goswami*, ","doi":"10.1021/acs.jpclett.4c0188910.1021/acs.jpclett.4c01889","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c01889https://doi.org/10.1021/acs.jpclett.4c01889","url":null,"abstract":"<p >Optical tweezers use strongly focused light for trapping, characterizing, and manipulating objects in the microscopic and nanoscopic regimes. However, fully understanding optical trapping at the nanoscale remains a significant challenge. This holds importance because the nanoscale is the frontier for numerous promising advancements, ranging from enhancing single-molecule investigations in biology to developing hybrid devices for nanoelectronics and photonics and exploring fundamental quantum phenomena in opto-mechanics. We report an experimental and theoretical study of nanoparticles of various sizes, showing the advantages of the immense peak power of ultrashort laser pulses over conventional optical tweezers. We also demonstrate highly stable trapping of nanoparticles for extended durations at low average laser power using femtosecond lasers.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1021/acs.jpclett.4c0221810.1021/acs.jpclett.4c02218
Jianyu Wang, Shyam Patel, Jorge Anibal Boscoboinik, Adrian Hunt, Iradwikanari Waluyo and Guangwen Zhou*,
This study investigates the oxidation behavior of Cu3Pt(100) in CO2 using a combination of ambient-pressure X-ray photoelectron spectroscopy, mass spectroscopy, and density functional theory modeling. Our in situ measurements reveal the simultaneous oxidation and reduction of Cu2O due to the opposing effects of atomic oxygen and CO generated from dissociative CO2 adsorption, leading to a dynamic equilibrium state of simultaneously occurring redox reactions. Complementary atomistic calculations elucidate the inhibitory effects of subsurface Pt enrichment and the counteracting roles of CO2 and CO in surface oxidation and reduction. These results provide mechanistic insights into the dissociative pathway of CO2 molecules and dynamic evolution of surface composition and reactivity of Cu-based alloy catalysts in CO2-rich environments, with broader implications for tuning gas–surface reactions by manipulating gas reactants or solid surface composition.
本研究采用常压 X 射线光电子能谱、质谱和密度泛函理论建模相结合的方法,研究了 Cu3Pt(100) 在 CO2 中的氧化行为。我们的现场测量结果表明,由于原子氧和二氧化碳离解吸附产生的一氧化碳的对立作用,Cu2O 同时发生氧化和还原反应,导致同时发生氧化还原反应的动态平衡状态。补充性原子论计算阐明了表面下铂富集的抑制作用以及二氧化碳和一氧化碳在表面氧化和还原中的抵消作用。这些结果从机理上揭示了富二氧化碳环境中二氧化碳分子的离解途径以及铜基合金催化剂表面成分和反应活性的动态演化,对通过操纵气体反应物或固体表面成分来调整气体-表面反应具有更广泛的意义。
{"title":"Self-Inhibition Phenomena in Cu3Pt Oxidation by CO2","authors":"Jianyu Wang, Shyam Patel, Jorge Anibal Boscoboinik, Adrian Hunt, Iradwikanari Waluyo and Guangwen Zhou*, ","doi":"10.1021/acs.jpclett.4c0221810.1021/acs.jpclett.4c02218","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02218https://doi.org/10.1021/acs.jpclett.4c02218","url":null,"abstract":"<p >This study investigates the oxidation behavior of Cu<sub>3</sub>Pt(100) in CO<sub>2</sub> using a combination of ambient-pressure X-ray photoelectron spectroscopy, mass spectroscopy, and density functional theory modeling. Our in situ measurements reveal the simultaneous oxidation and reduction of Cu<sub>2</sub>O due to the opposing effects of atomic oxygen and CO generated from dissociative CO<sub>2</sub> adsorption, leading to a dynamic equilibrium state of simultaneously occurring redox reactions. Complementary atomistic calculations elucidate the inhibitory effects of subsurface Pt enrichment and the counteracting roles of CO<sub>2</sub> and CO in surface oxidation and reduction. These results provide mechanistic insights into the dissociative pathway of CO<sub>2</sub> molecules and dynamic evolution of surface composition and reactivity of Cu-based alloy catalysts in CO<sub>2</sub>-rich environments, with broader implications for tuning gas–surface reactions by manipulating gas reactants or solid surface composition.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Since the proposition of the Hofmeister series, guanidinium (Gdm) salts hold a special mention in protein science owing to their contrasting effect on protein(s) depending on the counteranion(s). For example, while GdmCl is known to act as a potential protein denaturant, Gdm2SO4 offers minimal effect on protein structure. Despite the fact that theoretical studies reckon the formation of ion-pairing to be responsible for such behavior, experimental validation of this hypothesis is still in sparse. In this study, we combine electrochemical impedance spectroscopy (EIS) and THz spectroscopy to underline the effect of GdmCl and Gdm2SO4 on a model amide molecule N-methylacetamide (NMA). Molecular dynamics (MD) simulation studies predict that Gdm2SO4 forms heteroion pairing in water, which inhibits Gdm+ ions to approach NMA molecules, while in case of GdmCl, Gdm+ ions directly interact with NMA. The experimental findings on ion hydration, specifically the detailed analysis of the ion–water rattling mode, which appears in the THz frequency domain, unambiguously endorse this hypothesis. Our study establishes the fact that the propensity of ion-pairing in Gdm salts dictates their (de)stabilization effect on proteins.
{"title":"Ion-Pairing Propensity in Guanidinium Salts Dictates Their Protein (De)stabilization Behavior","authors":"Ria Saha, Subhadip Chakraborty, Krishnendu Sinha, Partha Pyne, Sreya Pal, Anjan Barman, Suman Chakrabarty and Rajib Kumar Mitra*, ","doi":"10.1021/acs.jpclett.4c0164610.1021/acs.jpclett.4c01646","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c01646https://doi.org/10.1021/acs.jpclett.4c01646","url":null,"abstract":"<p >Since the proposition of the Hofmeister series, guanidinium (Gdm) salts hold a special mention in protein science owing to their contrasting effect on protein(s) depending on the counteranion(s). For example, while GdmCl is known to act as a potential protein denaturant, Gdm<sub>2</sub>SO<sub>4</sub> offers minimal effect on protein structure. Despite the fact that theoretical studies reckon the formation of ion-pairing to be responsible for such behavior, experimental validation of this hypothesis is still in sparse. In this study, we combine electrochemical impedance spectroscopy (EIS) and THz spectroscopy to underline the effect of GdmCl and Gdm<sub>2</sub>SO<sub>4</sub> on a model amide molecule <i>N</i>-methylacetamide (NMA). Molecular dynamics (MD) simulation studies predict that Gdm<sub>2</sub>SO<sub>4</sub> forms heteroion pairing in water, which inhibits Gdm<sup>+</sup> ions to approach NMA molecules, while in case of GdmCl, Gdm<sup>+</sup> ions directly interact with NMA. The experimental findings on ion hydration, specifically the detailed analysis of the ion–water rattling mode, which appears in the THz frequency domain, unambiguously endorse this hypothesis. Our study establishes the fact that the propensity of ion-pairing in Gdm salts dictates their (de)stabilization effect on proteins.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1021/acs.jpclett.4c0260210.1021/acs.jpclett.4c02602
Hassan Abdoul-Carime*, Guillaume Thiam and Franck Rabilloud,
Reaction induced by slow electrons is implicated in a large field of research and applications. Below 3-4 eV, dissociative electron attachment efficiently fragments molecules via (1) shape resonance or (2) mediated by the formation of a dipole bound anion. While the temperature dependence of process 1 is well-known, that of 2 is not clearly established. Nitromethane is the prototypical molecule for which the electron attachment leads to the formation of both a dipole bound and a covalent anion. We provide here a comprehensive study of the fragmentation of nitromethane by <1 eV electron and the unusual temperature effects attributed principally to process 2.
慢速电子引起的反应涉及众多研究和应用领域。在 3-4 eV 以下,解离电子附着可通过(1)形状共振或(2)形成偶极结合阴离子而有效地分裂分子。虽然过程 1 与温度的关系众所周知,但过程 2 与温度的关系尚不明确。硝基甲烷是电子附着导致形成偶极结合阴离子和共价阴离子的典型分子。我们在此全面研究了硝基甲烷在 1 eV 电子作用下的碎裂过程,以及主要归因于过程 2 的不寻常温度效应。
{"title":"Production of Nitrogen Dioxide, NO2–, Anion from Dissociative Electron Attachment to Nitromethane below 1 eV and Its Temperature Dependence: Direct vs Dipole Bound Mediated Processes","authors":"Hassan Abdoul-Carime*, Guillaume Thiam and Franck Rabilloud, ","doi":"10.1021/acs.jpclett.4c0260210.1021/acs.jpclett.4c02602","DOIUrl":"https://doi.org/10.1021/acs.jpclett.4c02602https://doi.org/10.1021/acs.jpclett.4c02602","url":null,"abstract":"<p >Reaction induced by slow electrons is implicated in a large field of research and applications. Below 3-4 eV, dissociative electron attachment efficiently fragments molecules via (1) shape resonance or (2) mediated by the formation of a dipole bound anion. While the temperature dependence of process 1 is well-known, that of 2 is not clearly established. Nitromethane is the prototypical molecule for which the electron attachment leads to the formation of both a dipole bound and a covalent anion. We provide here a comprehensive study of the fragmentation of nitromethane by <1 eV electron and the unusual temperature effects attributed principally to process 2.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}