Ni3S2 has been emerging as one of the most promising hydrogen evolution reaction (HER) catalysts because of its moderate activity, exceptional electrical conductivity, as well as scalable methodologies, however, high energy barrier of H2O dissociation and weak desorption of H* intermediate severely hinder its HER kinetics. Here, a novel Cr-incorporated Ni3S2 is grown on Ni mesh substrate (denoted as Cr-Ni3S2/NM) by a one-step electrodeposition approach, which contributes large surface area with abundant Ni3S2/Cr2S3 heterojunctions. Consequently, it undergoes a surface reconstruction after in-situ activation (denoted as A-Cr-Ni3S2/NM), which not only enhances charge and mass transfer, but also alters the electronic structure by introducing more oxygen species on the catalyst surface and S vacancies. Using theoretical calculations, this in-situ activation is revealed not only to promote the charge transport but also boost the HER kinetics by strengthening OH* desorption for H2O dissociation and facilitating the desorption of H* intermediates. As a result, the fabricated A-Cr-Ni3S2/NM demonstrates exceptional HER performance with a small overpotential of 78 mV to deliver a current density of -10 mA/cm2 along with a stability of over 200 h, under 100 mA/cm2. Surface reconstruction has been intensively studied on the catalysts for oxygen-evolved reaction, while we illustrated that it also plays a great and positive role on Cr-Ni3S2 HER catalysts in this study, thus providing a pathway for achieving high-performance HER catalysts.
{"title":"In-situ activation induced surface reconstruction on Cr-incorporated Ni3S2 for enhanced alkaline hydrogen evolution reaction","authors":"Ruidi Li, Cong Chen, Junxia Shen, Zhihe Wei, Pierre-Yves Olu, Wen Dong, Yang Peng, Ronglei Fan, Mingrong Shen","doi":"10.1039/d5cp00813a","DOIUrl":"https://doi.org/10.1039/d5cp00813a","url":null,"abstract":"Ni3S2 has been emerging as one of the most promising hydrogen evolution reaction (HER) catalysts because of its moderate activity, exceptional electrical conductivity, as well as scalable methodologies, however, high energy barrier of H2O dissociation and weak desorption of H* intermediate severely hinder its HER kinetics. Here, a novel Cr-incorporated Ni3S2 is grown on Ni mesh substrate (denoted as Cr-Ni3S2/NM) by a one-step electrodeposition approach, which contributes large surface area with abundant Ni3S2/Cr2S3 heterojunctions. Consequently, it undergoes a surface reconstruction after in-situ activation (denoted as A-Cr-Ni3S2/NM), which not only enhances charge and mass transfer, but also alters the electronic structure by introducing more oxygen species on the catalyst surface and S vacancies. Using theoretical calculations, this in-situ activation is revealed not only to promote the charge transport but also boost the HER kinetics by strengthening OH* desorption for H2O dissociation and facilitating the desorption of H* intermediates. As a result, the fabricated A-Cr-Ni3S2/NM demonstrates exceptional HER performance with a small overpotential of 78 mV to deliver a current density of -10 mA/cm2 along with a stability of over 200 h, under 100 mA/cm2. Surface reconstruction has been intensively studied on the catalysts for oxygen-evolved reaction, while we illustrated that it also plays a great and positive role on Cr-Ni3S2 HER catalysts in this study, thus providing a pathway for achieving high-performance HER catalysts.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"63 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ana Parejo Vidal, Yuika Okura, Vijay Madhav Miriyala, Mattanjah S. de Vries, Keisuke Hirata, Pavel Hobza, Shun-ichi Ishiuchi, Masaaki Fujii
This study provides a comprehensive investigation of the structural and vibrational properties of protonated cytosine monomers and dimers. Experimental IRPD spectroscopy, combined with theoretical calculations, revealed distinct behaviors for monomers and dimers. We find that protonated cytosine monomers predominantly adopt the enol form in the gas phase, with a contribution from the keto form between 25% and 33%. For dimers, our computations predict a keto-enol configuration to be more stable than the keto-keto form by 1.5 kcal/mol. However, experimentally, the keto-keto form emerged as the dominant structure. The theoretically most stable keto-enol configuration undergoes a structural reorganization in MD simulations with explicit methanol, forming the dynamically unstable neutral-keto-protonated-keto complex. This reorganization highlights the role of environmental factors in modulating tautomer populations.
{"title":"i-Motif DNA in isolated Hemiprotonated Cytosine Dimers, Studied by IR Spectroscopy and Theoretical Calculations","authors":"Ana Parejo Vidal, Yuika Okura, Vijay Madhav Miriyala, Mattanjah S. de Vries, Keisuke Hirata, Pavel Hobza, Shun-ichi Ishiuchi, Masaaki Fujii","doi":"10.1039/d5cp00657k","DOIUrl":"https://doi.org/10.1039/d5cp00657k","url":null,"abstract":"This study provides a comprehensive investigation of the structural and vibrational properties of protonated cytosine monomers and dimers. Experimental IRPD spectroscopy, combined with theoretical calculations, revealed distinct behaviors for monomers and dimers. We find that protonated cytosine monomers predominantly adopt the enol form in the gas phase, with a contribution from the keto form between 25% and 33%. For dimers, our computations predict a keto-enol configuration to be more stable than the keto-keto form by 1.5 kcal/mol. However, experimentally, the keto-keto form emerged as the dominant structure. The theoretically most stable keto-enol configuration undergoes a structural reorganization in MD simulations with explicit methanol, forming the dynamically unstable neutral-keto-protonated-keto complex. This reorganization highlights the role of environmental factors in modulating tautomer populations.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"114 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marité Cardenás, Victoria Ariel Bjørnestad, Kari Kristine Almåsvold Borgos, Reidar Lund
Natural Occurring Deep Eutectic Solvents (NADES) are solvents made of metabolites occurring in living organisms, and are thought to play a special role in plants especially given that some of these metabolites exist in concentrations as high as 1 M. NADES have properties similar to ionic liquids, and have been shown to protect enzymes against loss of activity as well as proteins against thermal denaturation. Here, we explore the structure of lipid vesicles in NADES rich aqueous solutions and compare to concentrated saline aqueous solutions matching the various NADES osmolarity. The vesicle structure was analysed by Small Angle X-ray Scattering (SAXS) and dynamic light scattering (DLS). Two types of NADES were prepared using choline chloride and glucose or maleic acid at a molar ratio of 1:1 giving the solvents a neutral or an acidic nature, respectively. The stability of the vesicles in the various solvents was measured against time and temperature. The results of this work demonstrate that lipid bilayers retain their structure in NADES rich aqueous solutions as compared to pure water, in contrast to high saline aqueous solutions. Moreover, the vesicles are more stable against sedimentation and aggregation in NADES than in water.
{"title":"The Integrity of the Lipid Bilayer Structure is retained in Natural Occurring Deep Eutectic Solvent Water Mixtures – A Small Angle X-ray Scattering Study","authors":"Marité Cardenás, Victoria Ariel Bjørnestad, Kari Kristine Almåsvold Borgos, Reidar Lund","doi":"10.1039/d5cp00331h","DOIUrl":"https://doi.org/10.1039/d5cp00331h","url":null,"abstract":"Natural Occurring Deep Eutectic Solvents (NADES) are solvents made of metabolites occurring in living organisms, and are thought to play a special role in plants especially given that some of these metabolites exist in concentrations as high as 1 M. NADES have properties similar to ionic liquids, and have been shown to protect enzymes against loss of activity as well as proteins against thermal denaturation. Here, we explore the structure of lipid vesicles in NADES rich aqueous solutions and compare to concentrated saline aqueous solutions matching the various NADES osmolarity. The vesicle structure was analysed by Small Angle X-ray Scattering (SAXS) and dynamic light scattering (DLS). Two types of NADES were prepared using choline chloride and glucose or maleic acid at a molar ratio of 1:1 giving the solvents a neutral or an acidic nature, respectively. The stability of the vesicles in the various solvents was measured against time and temperature. The results of this work demonstrate that lipid bilayers retain their structure in NADES rich aqueous solutions as compared to pure water, in contrast to high saline aqueous solutions. Moreover, the vesicles are more stable against sedimentation and aggregation in NADES than in water.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"219 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Søren S. Sørensen, Daniel Boysen, Esben R. Lindbjerg, Helle N. Mortensen, Kaja T. Lippert, Sisse M. Diget, Zuzanna Konieczna, Matthieu Micolaut, Morten M Smedskjaer
The use of solid instead of liquid electrolytes can lead to increased battery capacity and safety. However, solid-state electrolytes feature a number of challenges, especially the lower ionic conductivity and the risk of material cracking, ultimately causing battery failure. This work addresses these challenges by probing the archetypical electrolyte family of lithium thiosilicate glasses (xLi2S-(100-x)SiS2) to study the influence of lithium sulfide content on the mechanical and ionic transport properties. Interestingly, we find a decreasing fracture toughness and increasing ionic conductivity with increasing Li2S content. We ascribe this to the depolymerization of the glassy network with increasing Li2S content and a decoupled activation mechanism of thermal diffusion and movement under mechanical strain. Ultimately, the investigated glasses offer insights into battery operation where the electrolyte is continuously cycled through high- and low-lithium content states. In turn, this highlights the need to consider the material properties across a wide range of compositions when engineering future solid-state electrolytes.
{"title":"Balancing fracture toughness and ionic conductivity in lithium thiosilicate glassy electrolytes","authors":"Søren S. Sørensen, Daniel Boysen, Esben R. Lindbjerg, Helle N. Mortensen, Kaja T. Lippert, Sisse M. Diget, Zuzanna Konieczna, Matthieu Micolaut, Morten M Smedskjaer","doi":"10.1039/d5cp00285k","DOIUrl":"https://doi.org/10.1039/d5cp00285k","url":null,"abstract":"The use of solid instead of liquid electrolytes can lead to increased battery capacity and safety. However, solid-state electrolytes feature a number of challenges, especially the lower ionic conductivity and the risk of material cracking, ultimately causing battery failure. This work addresses these challenges by probing the archetypical electrolyte family of lithium thiosilicate glasses (xLi2S-(100-x)SiS2) to study the influence of lithium sulfide content on the mechanical and ionic transport properties. Interestingly, we find a decreasing fracture toughness and increasing ionic conductivity with increasing Li2S content. We ascribe this to the depolymerization of the glassy network with increasing Li2S content and a decoupled activation mechanism of thermal diffusion and movement under mechanical strain. Ultimately, the investigated glasses offer insights into battery operation where the electrolyte is continuously cycled through high- and low-lithium content states. In turn, this highlights the need to consider the material properties across a wide range of compositions when engineering future solid-state electrolytes.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"9 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The van der Waals heterostructures are promising for electronic and optoelectronic devices. Here, we construct theoretically the blue phosphorene/SbN van der Waals heterostructures to investigate the band alignment, carrier mobility and optical properties, considering the influence of interlayer distance, biaxial strain and external electric field. The results show that the structure possess the characteristics of staggered type-II band alignment, which promotes electron and hole distribution inside different monolayers. Especially, the band alignment can be maintained under changes in interlayer distance, the application of biaxial strain, and the influence of electric fields. Relative to the effects of external electric fields and biaxial strain, the interlayer distance was found to have a more substantial influence on the electronic characteristics of the heterostructure, inducing a transition from conductor to semiconductor. Furthermore, compared to its individual components, the heterostructure demonstrates a significant enhancement in optical absorptivity across the infrared and visible regions. Our study further confirmed that tensile strain can cause the absorption spectrum to blueshift, which enhances ultraviolet absorption and broadens the optical absorption spectrum. These findings provide a significant guidance for the design and optimization of blue phosphorene-based van der Waals heterostructures for optoelectronic applications.
{"title":"Band alignment and optoelectronic characteristics of blue phosphorene/SbN van der Waals heterostructures heterostructures","authors":"Mengge Li, Yuhua Zhang, Yufei Wang, Weiguang Chen, Yanwei Luo, Liying Zhang","doi":"10.1039/d5cp01158b","DOIUrl":"https://doi.org/10.1039/d5cp01158b","url":null,"abstract":"The van der Waals heterostructures are promising for electronic and optoelectronic devices. Here, we construct theoretically the blue phosphorene/SbN van der Waals heterostructures to investigate the band alignment, carrier mobility and optical properties, considering the influence of interlayer distance, biaxial strain and external electric field. The results show that the structure possess the characteristics of staggered type-II band alignment, which promotes electron and hole distribution inside different monolayers. Especially, the band alignment can be maintained under changes in interlayer distance, the application of biaxial strain, and the influence of electric fields. Relative to the effects of external electric fields and biaxial strain, the interlayer distance was found to have a more substantial influence on the electronic characteristics of the heterostructure, inducing a transition from conductor to semiconductor. Furthermore, compared to its individual components, the heterostructure demonstrates a significant enhancement in optical absorptivity across the infrared and visible regions. Our study further confirmed that tensile strain can cause the absorption spectrum to blueshift, which enhances ultraviolet absorption and broadens the optical absorption spectrum. These findings provide a significant guidance for the design and optimization of blue phosphorene-based van der Waals heterostructures for optoelectronic applications.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"37 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guillaume Benas, Sofia De Sousa Coutinho, Brigitte Leridon, Fabio Finocchi
Despite the remarkable dielectric properties of Rb2Ti2O5 upon exposure to a humid atmosphere, its surfaces are still poorly known, to date. Here we study the atomic-scale structure of the clean (100), (010) and (001) surfaces, and the onset of water adsorption via density functional theory. Among them, the clean (001) surface has a very low surface energy, much smaller than most terminations of other perovskites or titania. Rb2Ti2O5 (001) is also very reactive towards water, which adsorbs as a molecule, forming regular water arrays on the surface. From the calculations, we conclude that Rb2Ti2O5 could very easily cleave under ambient conditions, forming (001) planes with ordered adsorbed water and almost null surface stress. Although Rb2Ti2O5 is a three-dimensional crystal, it behaves in this respect as a two-dimensional compound, such as graphite or layered perovskites.
{"title":"Clean and hydrated low-index Rb2Ti2O5 surfaces","authors":"Guillaume Benas, Sofia De Sousa Coutinho, Brigitte Leridon, Fabio Finocchi","doi":"10.1039/d4cp04441j","DOIUrl":"https://doi.org/10.1039/d4cp04441j","url":null,"abstract":"Despite the remarkable dielectric properties of Rb<small><sub>2</sub></small>Ti<small><sub>2</sub></small>O<small><sub>5</sub></small> upon exposure to a humid atmosphere, its surfaces are still poorly known, to date. Here we study the atomic-scale structure of the clean (100), (010) and (001) surfaces, and the onset of water adsorption <em>via</em> density functional theory. Among them, the clean (001) surface has a very low surface energy, much smaller than most terminations of other perovskites or titania. Rb<small><sub>2</sub></small>Ti<small><sub>2</sub></small>O<small><sub>5</sub></small> (001) is also very reactive towards water, which adsorbs as a molecule, forming regular water arrays on the surface. From the calculations, we conclude that Rb<small><sub>2</sub></small>Ti<small><sub>2</sub></small>O<small><sub>5</sub></small> could very easily cleave under ambient conditions, forming (001) planes with ordered adsorbed water and almost null surface stress. Although Rb<small><sub>2</sub></small>Ti<small><sub>2</sub></small>O<small><sub>5</sub></small> is a three-dimensional crystal, it behaves in this respect as a two-dimensional compound, such as graphite or layered perovskites.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"323 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study systematically investigates the effects of nitrogen doping, gold atom cluster loading, and their synergistic influence on the phonon dispersion relations and electronic structure of graphene, based on density-functional theory calculations. Gold atom loading induces significant changes in the low-frequency phonon modes of graphene, and affects the electronic density of states near the Fermi level, indicating strong interactions between gold d-orbitals and graphene’s π-orbitals. Nitrogen doping results in the complexity to the phonon spectrum by introducing high-frequency phonon modes and modifying the electronic structure. The synergistic effect of nitrogen doping and gold atom loading results in even more intricate modifications, characterized by the emergence of low-energy phonon modes, reflecting a profound impact on both the electronic and vibrational properties of graphene. Additionally, we compare the experimental electron energy loss spectroscopy of single Au atom loading on graphene with the simulated spectrum, revealing a good match between them. These findings provide a theoretical basis for designing graphene-based materials with tailored properties for applications in electronic devices and catalysis, suggesting that precise regulation of these properties can be achieved through controlled doping and metal atom loading.
{"title":"Theoretical Study on Synergistic Tuning of Graphene Phonons via Heteroatom Modifications","authors":"Shuang Li, Lifeng Zhang, Langli Luo, Xing Chen","doi":"10.1039/d5cp00791g","DOIUrl":"https://doi.org/10.1039/d5cp00791g","url":null,"abstract":"This study systematically investigates the effects of nitrogen doping, gold atom cluster loading, and their synergistic influence on the phonon dispersion relations and electronic structure of graphene, based on density-functional theory calculations. Gold atom loading induces significant changes in the low-frequency phonon modes of graphene, and affects the electronic density of states near the Fermi level, indicating strong interactions between gold d-orbitals and graphene’s π-orbitals. Nitrogen doping results in the complexity to the phonon spectrum by introducing high-frequency phonon modes and modifying the electronic structure. The synergistic effect of nitrogen doping and gold atom loading results in even more intricate modifications, characterized by the emergence of low-energy phonon modes, reflecting a profound impact on both the electronic and vibrational properties of graphene. Additionally, we compare the experimental electron energy loss spectroscopy of single Au atom loading on graphene with the simulated spectrum, revealing a good match between them. These findings provide a theoretical basis for designing graphene-based materials with tailored properties for applications in electronic devices and catalysis, suggesting that precise regulation of these properties can be achieved through controlled doping and metal atom loading.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"94 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Malek Ben Khalifa, Laurent Wiesenfeld, Jérôme Loreau
Observations of molecules with C3v symmetry, such as CH3CN, are particularly valuable in molecular clouds as the rotational transition selection rules of these molecules allow them to serve as gas thermometers. Interpreting their spectra in non-local thermodynamic equilibrium (non-LTE) conditions requires accurate collisional rate coefficients, especially for interactions with common interstellar species like H2. In this work, we present a five-dimensional potential energy surface for CH3CN in van der Waals interaction with H2 (1Σ+), computed using the CCSD(T)/F12 method and the aug-cc-pVTZ basis set. This potential energy surface is fitted with analytical functions suited for scattering calculations. Cross sections for rotational transitions in collisions between ortho-and para-CH3CN and para-H2 (j2 = 0) are computed using the close-coupling quantum scattering method, across energies from threshold up to 150 cm−1. These data are essential for interpreting interstellar CH3CN emission lines and advancing our understanding of diverse astronomical environments.
{"title":"Rotational (de-)excitation of CH3CN in collisions with H2 on an accurate potential energy surface","authors":"Malek Ben Khalifa, Laurent Wiesenfeld, Jérôme Loreau","doi":"10.1039/d4cp04479g","DOIUrl":"https://doi.org/10.1039/d4cp04479g","url":null,"abstract":"Observations of molecules with C3v symmetry, such as CH3CN, are particularly valuable in molecular clouds as the rotational transition selection rules of these molecules allow them to serve as gas thermometers. Interpreting their spectra in non-local thermodynamic equilibrium (non-LTE) conditions requires accurate collisional rate coefficients, especially for interactions with common interstellar species like H2. In this work, we present a five-dimensional potential energy surface for CH3CN in van der Waals interaction with H2 (1Σ+), computed using the CCSD(T)/F12 method and the aug-cc-pVTZ basis set. This potential energy surface is fitted with analytical functions suited for scattering calculations. Cross sections for rotational transitions in collisions between ortho-and para-CH3CN and para-H2 (j2 = 0) are computed using the close-coupling quantum scattering method, across energies from threshold up to 150 cm−1. These data are essential for interpreting interstellar CH3CN emission lines and advancing our understanding of diverse astronomical environments.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"16 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amanda R. Bubas, Amanda French, Kali Melby, Michael J. Rodriguez, Richard M Cox
The activation of C-H and C-C bonds by atomic metal cations remains a profitable area of research to utilize environmentally abundant methane to produce useful hydrocarbon fuel. Although methane activation by transition metal cations has been the focus of catalysis research for decades, less is known about the catalytic capabilities of lanthanide cations. Here we employ inductively coupled plasma tandem mass spectrometry to examine the kinetic energy dependences of the reactions of lanthanide cations Ce+, Pr+, Nd+, Sm+, and Eu+ with methane. The resulting energy-dependent reaction cross sections enable a measurement of the reaction thermochemistry and provide fundamental insight into the physical characteristics that enable Ln+ reactivity. We report values for the Ln+-D bond dissociation energies, D0(Ln+-D), and the first experimentally obtained values for D0(Ln+-CD3) and D0(Ln+-CD). We find that the observed reaction efficiencies correlate similarly with the promotion energies from the Ln+ ground state electronic configurations to the 5d2 or 5d6s electronic configuration indicating that the ability of Ln+ to effectively insert into C-H bonds requires an electron configuration with two unpaired valence electrons in non-f orbitals.
{"title":"An Inductively Coupled Plasma Tandem Mass Spectrometry Investigation of the Activation of Methane by Lanthanide Cations","authors":"Amanda R. Bubas, Amanda French, Kali Melby, Michael J. Rodriguez, Richard M Cox","doi":"10.1039/d5cp00343a","DOIUrl":"https://doi.org/10.1039/d5cp00343a","url":null,"abstract":"The activation of C-H and C-C bonds by atomic metal cations remains a profitable area of research to utilize environmentally abundant methane to produce useful hydrocarbon fuel. Although methane activation by transition metal cations has been the focus of catalysis research for decades, less is known about the catalytic capabilities of lanthanide cations. Here we employ inductively coupled plasma tandem mass spectrometry to examine the kinetic energy dependences of the reactions of lanthanide cations Ce+, Pr+, Nd+, Sm+, and Eu+ with methane. The resulting energy-dependent reaction cross sections enable a measurement of the reaction thermochemistry and provide fundamental insight into the physical characteristics that enable Ln+ reactivity. We report values for the Ln+-D bond dissociation energies, D0(Ln+-D), and the first experimentally obtained values for D0(Ln+-CD3) and D0(Ln+-CD). We find that the observed reaction efficiencies correlate similarly with the promotion energies from the Ln+ ground state electronic configurations to the 5d2 or 5d6s electronic configuration indicating that the ability of Ln+ to effectively insert into C-H bonds requires an electron configuration with two unpaired valence electrons in non-f orbitals.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"11 11 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Understanding the dissociation pattern of saccharides is key to establishing mass spectrometry-based methods as routine methods for identifying oligosaccharides. This work uses energetics at MP2/6-311+G(d,p) level of theory to set up a micro-kinetic model that aims at simulating the collision-induced dissociation mass spectrometry of Na+-tagged glucose, mannose, and galactose. The product concentrations obtained from the simulation can then be converted to mass spectra signals, which allow a direct comparison with the experiment. One crucial aspect of this work is the treatment of the system's temperature. In the experiment, the energy for overcoming the barriers of the dissociation processes comes from the activation process, in which the parent ion is brought to collision with neutral gas atoms/molecules. To match this situation, we have assumed that the system's temperature increases linearly and considered different temperature gradients. It could be shown that the temperature gradient only has a negligible impact on the final product distribution and relative signal intensities. All dissociation processes of the considered monosaccharides are finished when the system reaches a temperature between 600 K and 700 K. Because dehydration processes are favored by entropy at high temperatures > 1000 K, the intensities of the dehydration signals seem to be generally underestimated by our calculations. Nevertheless, our model predicts most trends in the signal intensities to be qualitatively correct, including the signal intensity ratio between the dehydration and the so-called cross-ring dissociation channels.
{"title":"Collision-Induced Dissociation Mass Spectra of Na+-Tagged Aldohexoses Simulated from First-Principles Calculations","authors":"Hai Thi Huynh, Jer-Lai Kuo, Cheng-chau Chiu","doi":"10.1039/d5cp00579e","DOIUrl":"https://doi.org/10.1039/d5cp00579e","url":null,"abstract":"Understanding the dissociation pattern of saccharides is key to establishing mass spectrometry-based methods as routine methods for identifying oligosaccharides. This work uses energetics at MP2/6-311+G(d,p) level of theory to set up a micro-kinetic model that aims at simulating the collision-induced dissociation mass spectrometry of Na<small><sup>+</sup></small>-tagged glucose, mannose, and galactose. The product concentrations obtained from the simulation can then be converted to mass spectra signals, which allow a direct comparison with the experiment. One crucial aspect of this work is the treatment of the system's temperature. In the experiment, the energy for overcoming the barriers of the dissociation processes comes from the activation process, in which the parent ion is brought to collision with neutral gas atoms/molecules. To match this situation, we have assumed that the system's temperature increases linearly and considered different temperature gradients. It could be shown that the temperature gradient only has a negligible impact on the final product distribution and relative signal intensities. All dissociation processes of the considered monosaccharides are finished when the system reaches a temperature between 600 K and 700 K. Because dehydration processes are favored by entropy at high temperatures > 1000 K, the intensities of the dehydration signals seem to be generally underestimated by our calculations. Nevertheless, our model predicts most trends in the signal intensities to be qualitatively correct, including the signal intensity ratio between the dehydration and the so-called cross-ring dissociation channels.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"2 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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