Polymer‐stabilized Au nano clusters （NCs） with mean diameters of 2–10 nm exhibit unique catalytic properties. Several studies have shown that the key factors affecting the catalytic activity of poly‐mer‐stabiliz...Polymer‐stabilized Au nano clusters （NCs） with mean diameters of 2–10 nm exhibit unique catalytic properties. Several studies have shown that the key factors affecting the catalytic activity of poly‐mer‐stabilized Au NCs are control of the Au NC size, appropriate selection of polymers and optimi‐zation of the reaction conditions. This is because polymer‐stabilized Au NCs exhibit a clear size effect in several catalytic reactions, and the catalytic activity differs with the type of polymer used and the reaction conditions. In order to elucidate the reason underlying the catalytic activity of the polymer‐stabilized Au NCs, much attention is being devoted to the interplay of theoretical calcula‐tions and experiments in catalysis by polymer stabilized Au NCs. The present article mainly summa‐rizes our progress in understanding this interplay in polymer‐stabilized Au NC catalysis.展开更多
It is crucial to understand the mechanism of low temperature CO oxidation reaction catalyzed by gold nanoparticles so as to find out the origin of the high catalytic reactivity and extend the indus‐trialization appli...It is crucial to understand the mechanism of low temperature CO oxidation reaction catalyzed by gold nanoparticles so as to find out the origin of the high catalytic reactivity and extend the indus‐trialization applications of nano gold catalysts. In this work, some theoretical works on CO adsorp‐tion, O2 adsorption, atomic oxygen adsorption, formation of surface gold oxide films, reaction mechanisms of CO oxidation involving O2 reaction with CO and O2 dissociation before reacting with CO on gold surfaces and Au/metal oxide were summarized, and the influences of coordination number, charge transfer and relativity of gold on CO oxidation reaction were briefly reviewed. It was found that CO reaction mechanism depended on the systems with or without oxide and the strong relativistic effects might play an important role in CO oxidation reaction on gold catalysts. In particular, the relativistic effects are related to the unique behaviors of CO adsorption, O adsorption, O2 activation on gold surfaces, effects of coordination number and the wide gap between the chem‐ical inertness of bulk gold and high catalytic activity of nano gold. The present work helps us to understand the CO oxidation reaction mechanism on gold catalysts and the influence of relativistic effects on gold catalysis.展开更多
The deep understanding of 4f-correlated electron motion behavior is experimentally limited due to similar physicochemical properties of rare earth elements(REEs).While the solvent extraction behavior originating from ...The deep understanding of 4f-correlated electron motion behavior is experimentally limited due to similar physicochemical properties of rare earth elements(REEs).While the solvent extraction behavior originating from the continuous occupation of 4f electrons along the lanthanide family provides a particular platform to probe the 4f electrons motion behavior and its correlations to their versatile functions.Herein,the complexation between REEs and the prototypical extractant of diethyl phosphoric acid(DEP)was substantially studied based on quantum mechanical calculation.The results firstly show that the average bond lengths between Ln and six coordinated oxygen atoms are consistent with lanthanide contraction phenomenon,and gadolinium break effect is also obviously observed.Secondly,the"tetrad effect"is figured out based on the subtle discrepancy of 4f electrons occupation,namely La-Nd,Sm-Eu,Gd-Dy and Ho-Lu.Specifically,the main composition is 4f5d6p for La-Nd,while the discrepancy is due to the increasing electrons in the 5d shell,while it is 4f5d for Pm-Eu.For Gd-Dy,their 4f orbitals accept little electrons and the donating electrons flow into 6s5d subshells due to the half-filled stability and the enhancement of shielding effect.The electrons donate into 5d6p subshells due to multiply electrons occupation of 4f orbitals for Ho-Lu.These detailed analyses obviously clarify the"tetrad effect"along the lanthanide family due to the different variation of 4f orbital occupation.It is expected that these microscopic understandings provide important guidance for the separation of REEs and the design of new extractants.展开更多
The theoretical calculation of the charge mobility of 2,5-bis(trialkylsilylethynyl)-1,1,3,4-tetraphenylsiloles is presented.B3LYP/6-31* calculations demonstrated that these silole molecules possessed large coupling ma...The theoretical calculation of the charge mobility of 2,5-bis(trialkylsilylethynyl)-1,1,3,4-tetraphenylsiloles is presented.B3LYP/6-31* calculations demonstrated that these silole molecules possessed large coupling matrix elements and reorganization energies for electron and hole transfers and high electron mobilities.The bulkiness of the trialkyl substituents influenced the charge mobility of the silole molecules,with the smaller trimethyl group imparting higher charge mobility than triethyl and triisopropyl substituents.展开更多
High-mobility and strong luminescent materials are essential as an important component of organic photodiodes,having received extensive attention in the field of organic optoelectronics.Beyond the conventional chemica...High-mobility and strong luminescent materials are essential as an important component of organic photodiodes,having received extensive attention in the field of organic optoelectronics.Beyond the conventional chemical synthesis of new molecules,pressure technology,as a flexible and efficient method,can tune the electronic and optical properties reversibly.However,the mechanism in organic materials has not been systematically revealed.Here,we theoretically predicted the pressure-depended luminescence and charge transport properties of high-performance organic optoelectronic semiconductors,2,6-diphenylanthracene(DPA),by first-principle and multi-scale theoretical calculation methods.The dispersion-corrected density functional theory(DFT-D)and hybrid quantum mechanics/molecular mechanics(QM/MM)method were used to get the electronic structures and vibration properties under pressure.Furthermore,the charge transport and luminescence properties were calculated with the quantum tunneling method and thermal vibration correlation function.We found that the pressure could significantly improve the charge transport performance of the DPA single crystal.When the applied pressure increased to 1.86 GPa,the hole mobility could be doubled.At the same time,due to the weak exciton coupling effect and the rigid flat structure,there is neither fluorescence quenching nor obvious emission enhancement phenomenon.The DPA single crystal possesses a slightly higher fluorescence quantum yield~0.47 under pressure.Our work systematically explored the pressure-dependence photoelectric properties and explained the inside mechanism.Also,we proposed that the exte rnal pressure would be an effective way to improve the photoelectric perfo rmance of organic semiconductors.展开更多
By using OCMOSiH\-3(M=Ru, Rh, Pd) as models to imitate the chemisorption of CO on the silica\|supported catalysts, the geometries and frequencies have been performed for the complexes by Gaussian programs, at the B3LY...By using OCMOSiH\-3(M=Ru, Rh, Pd) as models to imitate the chemisorption of CO on the silica\|supported catalysts, the geometries and frequencies have been performed for the complexes by Gaussian programs, at the B3LYP/LANL1DZ level. An influence of the C\_O bond has been studied and the support effects of silica are obtained. The support effects of silica make the CO frequency an upward shift, which means that the weakened degree of C\_O decreases and the bond strength of C\_O increases naturally compared to those of the non\|silica\|supported catalysts. So the products on the silica\|supported catalysts shift to the oxygenates.展开更多
基金supported by Japan Science and Technology Agency (JST)Advanced Low Carbon Technology Research and Development Program (ALCA)Core Research for Evolutional Science and Technology (CREST)
文摘Polymer‐stabilized Au nano clusters （NCs） with mean diameters of 2–10 nm exhibit unique catalytic properties. Several studies have shown that the key factors affecting the catalytic activity of poly‐mer‐stabilized Au NCs are control of the Au NC size, appropriate selection of polymers and optimi‐zation of the reaction conditions. This is because polymer‐stabilized Au NCs exhibit a clear size effect in several catalytic reactions, and the catalytic activity differs with the type of polymer used and the reaction conditions. In order to elucidate the reason underlying the catalytic activity of the polymer‐stabilized Au NCs, much attention is being devoted to the interplay of theoretical calcula‐tions and experiments in catalysis by polymer stabilized Au NCs. The present article mainly summa‐rizes our progress in understanding this interplay in polymer‐stabilized Au NC catalysis.
基金supported by the National Natural Science Foundation of China (21103165)
文摘It is crucial to understand the mechanism of low temperature CO oxidation reaction catalyzed by gold nanoparticles so as to find out the origin of the high catalytic reactivity and extend the indus‐trialization applications of nano gold catalysts. In this work, some theoretical works on CO adsorp‐tion, O2 adsorption, atomic oxygen adsorption, formation of surface gold oxide films, reaction mechanisms of CO oxidation involving O2 reaction with CO and O2 dissociation before reacting with CO on gold surfaces and Au/metal oxide were summarized, and the influences of coordination number, charge transfer and relativity of gold on CO oxidation reaction were briefly reviewed. It was found that CO reaction mechanism depended on the systems with or without oxide and the strong relativistic effects might play an important role in CO oxidation reaction on gold catalysts. In particular, the relativistic effects are related to the unique behaviors of CO adsorption, O adsorption, O2 activation on gold surfaces, effects of coordination number and the wide gap between the chem‐ical inertness of bulk gold and high catalytic activity of nano gold. The present work helps us to understand the CO oxidation reaction mechanism on gold catalysts and the influence of relativistic effects on gold catalysis.
基金Project supported by the National Key Research and Development Project of China(2019YFC0605003)the StrategicPriority Research Program of Chinese Academy of Sciences(XDA02030100)。
文摘The deep understanding of 4f-correlated electron motion behavior is experimentally limited due to similar physicochemical properties of rare earth elements(REEs).While the solvent extraction behavior originating from the continuous occupation of 4f electrons along the lanthanide family provides a particular platform to probe the 4f electrons motion behavior and its correlations to their versatile functions.Herein,the complexation between REEs and the prototypical extractant of diethyl phosphoric acid(DEP)was substantially studied based on quantum mechanical calculation.The results firstly show that the average bond lengths between Ln and six coordinated oxygen atoms are consistent with lanthanide contraction phenomenon,and gadolinium break effect is also obviously observed.Secondly,the"tetrad effect"is figured out based on the subtle discrepancy of 4f electrons occupation,namely La-Nd,Sm-Eu,Gd-Dy and Ho-Lu.Specifically,the main composition is 4f5d6p for La-Nd,while the discrepancy is due to the increasing electrons in the 5d shell,while it is 4f5d for Pm-Eu.For Gd-Dy,their 4f orbitals accept little electrons and the donating electrons flow into 6s5d subshells due to the half-filled stability and the enhancement of shielding effect.The electrons donate into 5d6p subshells due to multiply electrons occupation of 4f orbitals for Ho-Lu.These detailed analyses obviously clarify the"tetrad effect"along the lanthanide family due to the different variation of 4f orbital occupation.It is expected that these microscopic understandings provide important guidance for the separation of REEs and the design of new extractants.
基金supported by the Research Grants Council of Hong Kong (602707,601608,ITP/008/09NP and 603505)the National Natural Science Foundation of China (20634020)+1 种基金the Ministry of Science and Technology of China (2002CD613401)support from the CAO GuangBiao Foundation of Zhejiang University
文摘The theoretical calculation of the charge mobility of 2,5-bis(trialkylsilylethynyl)-1,1,3,4-tetraphenylsiloles is presented.B3LYP/6-31* calculations demonstrated that these silole molecules possessed large coupling matrix elements and reorganization energies for electron and hole transfers and high electron mobilities.The bulkiness of the trialkyl substituents influenced the charge mobility of the silole molecules,with the smaller trimethyl group imparting higher charge mobility than triethyl and triisopropyl substituents.
基金supported by National Key R&D Program(No.2016YFB0401100)the National Natural Science Foundation of China(Nos.91833306,51633006)。
文摘High-mobility and strong luminescent materials are essential as an important component of organic photodiodes,having received extensive attention in the field of organic optoelectronics.Beyond the conventional chemical synthesis of new molecules,pressure technology,as a flexible and efficient method,can tune the electronic and optical properties reversibly.However,the mechanism in organic materials has not been systematically revealed.Here,we theoretically predicted the pressure-depended luminescence and charge transport properties of high-performance organic optoelectronic semiconductors,2,6-diphenylanthracene(DPA),by first-principle and multi-scale theoretical calculation methods.The dispersion-corrected density functional theory(DFT-D)and hybrid quantum mechanics/molecular mechanics(QM/MM)method were used to get the electronic structures and vibration properties under pressure.Furthermore,the charge transport and luminescence properties were calculated with the quantum tunneling method and thermal vibration correlation function.We found that the pressure could significantly improve the charge transport performance of the DPA single crystal.When the applied pressure increased to 1.86 GPa,the hole mobility could be doubled.At the same time,due to the weak exciton coupling effect and the rigid flat structure,there is neither fluorescence quenching nor obvious emission enhancement phenomenon.The DPA single crystal possesses a slightly higher fluorescence quantum yield~0.47 under pressure.Our work systematically explored the pressure-dependence photoelectric properties and explained the inside mechanism.Also,we proposed that the exte rnal pressure would be an effective way to improve the photoelectric perfo rmance of organic semiconductors.
文摘By using OCMOSiH\-3(M=Ru, Rh, Pd) as models to imitate the chemisorption of CO on the silica\|supported catalysts, the geometries and frequencies have been performed for the complexes by Gaussian programs, at the B3LYP/LANL1DZ level. An influence of the C\_O bond has been studied and the support effects of silica are obtained. The support effects of silica make the CO frequency an upward shift, which means that the weakened degree of C\_O decreases and the bond strength of C\_O increases naturally compared to those of the non\|silica\|supported catalysts. So the products on the silica\|supported catalysts shift to the oxygenates.
