CO oxidative coupling to dimethyl oxalate(DMO) is the most crucial step in coal to ethylene glycol. Pdbased supported catalysts have been verified effective for generating DMO, but concomitant generation of dimethyl c...CO oxidative coupling to dimethyl oxalate(DMO) is the most crucial step in coal to ethylene glycol. Pdbased supported catalysts have been verified effective for generating DMO, but concomitant generation of dimethyl carbonate(DMC) is always unavoidable. It is generally accepted that Pd(0) is the active species for producing DMO, while Pd(II) for DMC. However, density functional theory calculations have proposed that the selectivity to DMO or DMC highly depends on the space state of Pd species rather than its oxidative state. It is thus urgently desired to develop high-efficient catalysts with well-defined structure,and further to elucidate the structure-performance relationship. In this work, HKUST-1 with unique structure of paired-Cu(Ⅱ) centers was chosen as ideal support to construct the catalysts with respective paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers via in situ Pd species doping. In despite of featuring Pdδ+(δ≈2) oxidation state, the synthesized paired-Pd(Ⅱ)/HKUST-1 catalyst still exhibited DMO as dominant product(90.8% of DMO selectivity). For isolated-Pd(Ⅱ)/HKUST-1 catalyst, however, the main product was DMC(84.8% of DMC selectivity). Based on catalyst characterizations, the structures of paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers were determined. DMO was generated from the coupling of adjacent *COOCH;intermediates adsorbed on paired-Pd(Ⅱ) centers, while DMC was produced from the reaction between methyl nitrite and the *COOCH;intermediates formed on isolated-Pd(Ⅱ) centers. Current work is the first MOFs-based catalyst with well-defined structure being applied in CO oxidative coupling reaction, which not only sheds light on the structure-performance relationship, but also inspires the potential of using MOFs as tunable platform to design high-efficient catalysts in heterogeneous catalysis.展开更多
Electrochemical conversion of carbon dioxide(CO_(2))to higher-value products provides a forward-looking way to solve the problems of environmental pollution and energy shortage.However,the low solubility of CO_(2)in a...Electrochemical conversion of carbon dioxide(CO_(2))to higher-value products provides a forward-looking way to solve the problems of environmental pollution and energy shortage.However,the low solubility of CO_(2)in aqueous electrolytes,sluggish kinetics,and low selectivity hamper the efficient conversion of CO_(2).Here,we report a Au-based hybrid nanomaterial by modifying Au nanoparticles(NPs)with the macrocyclic molecule cucurbit[6]uril(Au@CB[6]).Au@CB[6]displays the optimal selectivity of CO,with the highest CO Faraday efficiency(FECO)reaching 99.50%at−0.6 V vs.reversible hydrogen electrode(RHE).The partial current density of CO formed by Au@CB[6]increases dramatically,as 3.18 mA/cm2 at−0.6 V,which is more than ten times as that of oleylamine-coated Au NPs(Au@OAm,0.31 mA/cm2).Operando electrochemical measurement combined with density functional theory(DFT)calculations reveals that CB[6]can gather CO_(2)and lead the increased local CO_(2)concentration near metal interface,which realizes significantly enhanced electrochemical CO_(2)reduction reaction(CO_(2)RR)performance.展开更多
We review in this article our recent simulation works on modeling peptide T-jump and thermal unfolding Fourier transform infrared spectroscopy(FTIR) and two-dimensional infrared(2DIR) spectra. The theoretical and comp...We review in this article our recent simulation works on modeling peptide T-jump and thermal unfolding Fourier transform infrared spectroscopy(FTIR) and two-dimensional infrared(2DIR) spectra. The theoretical and computational techniques used,including Markov state model(MSM), integrated tempering sampling(ITS) and nonlinear exciton propagation(NEP), are first briefly introduced. The protocols for simulating the thermal unfolding as well as T-jump unfolding are then summarized in details. The simulated spectral features, such as the intensity and ellipticity, are demonstrated to agree well with the experimental observations.展开更多
Computational tools on top of first principle calculations have played an indispensable role in revealing the molecular details,thermodynamics,and kinetics in catalytic reactions.Here we proposed a highly efficient dy...Computational tools on top of first principle calculations have played an indispensable role in revealing the molecular details,thermodynamics,and kinetics in catalytic reactions.Here we proposed a highly efficient dynamic strategy for the calculation of thermodynamic and kinetic properties in heterogeneous catalysis on the basis of efficient potential energy surface(PES)and MD simulations.Taking CO adsorbate on Ru(0001)surface as the illustrative model system,we demonstrated the PES-based MD can efficiently generate reliable two-dimensional potential-of-mean-force(PMF)surfaces in a wide range of temperatures,and thus temperature-dependent thermodynamic properties can be obtained in a comprehensive investigation on the whole PMF surface.Moreover,MD offers an effective way to describe the surface kinetics such as adsorbate on-surface movement,which goes beyond the most popular static approach based on free energy barrier and transition state theory(TST).We further revealed that the dynamic strategy significantly improves the predictions of both thermodynamic and kinetic properties as compared to the popular ideal statistic mechanics approaches such as harmonic analysis and TST.It is expected that this accurate yet efficient dynamic strategy can be powerful in understanding mechanisms and reactivity of a catalytic surface system,and further guides the rational design of heterogeneous catalysts.展开更多
Tin oxides(SnO_(2))have been widely utilized in electronics,nanolithography,and catalysis.As the atomically precise models of SnO_(2),tin-oxo clusters(TOCs)not only provide opportunities for mechanism studies,but they...Tin oxides(SnO_(2))have been widely utilized in electronics,nanolithography,and catalysis.As the atomically precise models of SnO_(2),tin-oxo clusters(TOCs)not only provide opportunities for mechanism studies,but they also extend potential applications through structural modulation.However,to date,most of the reported TOCs belong to alkyl organotin complexes,which are usually toxic to the human body and the active sites are difficult to expose for catalysis.展开更多
An accurate description of catalytic selectivity poses an enormous challenge for theoretical simulations.Due to the absence of a well-defined benchmark set on the catalytic selectivity,the performance of even the wide...An accurate description of catalytic selectivity poses an enormous challenge for theoretical simulations.Due to the absence of a well-defined benchmark set on the catalytic selectivity,the performance of even the widely used density functional approximations(DFAs)is yet to be validated.This work reports a test set based on the selective hydrogenation ofα,β-unsaturated aldehydes catalyzed by ruthenium(Ru)hydride complexes.Special attention is paid to benchmark the regioselectivity of aldehydes to either unsaturated alcohols or saturated aldehydes.Accurate reference data were calculated by the massive parallel implementation of the coupled-cluster single,double,and perturbative triple excitations[CCSD(T)]approach,based completely on set limits.Furthermore,we performed the microkinetic simulation based on the CCSD(T)energy profiles,serving the most direct criteria for the performance of DFAs on catalytic selectivity of hydrogenation reactions.Using this test set,we uncovered the intrinsic difficulty of semilocal and hybrid functionals for such a purpose.In the context of the XYG3-type double hybrid(xDH)framework,we showed that this particular challenge could be addressed by the top rung functionals only when the many-body nondynamic correlation effect was accounted for adequately.A recently proposed xDH,namely scsRPA,showed unprecedented accuracy with only 5%error on average.The predicted kinetic selectivity by scsRPA is in close agreement with the reference value,revealing a unique versatility of the top rung DFAs for a reliable description of catalytic selectivity of hydrogenation reactions.展开更多
基金supported by the National Key Research and Development Program of China(2017YFA0206802,2017YFA0700103,2018YFA0704500)the Programs of the Chinese Academy of Sciences(QYZDJ-SSW-SLH028)the Natural Science Foundation of Shandong Province(ZR2020QB051)。
文摘CO oxidative coupling to dimethyl oxalate(DMO) is the most crucial step in coal to ethylene glycol. Pdbased supported catalysts have been verified effective for generating DMO, but concomitant generation of dimethyl carbonate(DMC) is always unavoidable. It is generally accepted that Pd(0) is the active species for producing DMO, while Pd(II) for DMC. However, density functional theory calculations have proposed that the selectivity to DMO or DMC highly depends on the space state of Pd species rather than its oxidative state. It is thus urgently desired to develop high-efficient catalysts with well-defined structure,and further to elucidate the structure-performance relationship. In this work, HKUST-1 with unique structure of paired-Cu(Ⅱ) centers was chosen as ideal support to construct the catalysts with respective paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers via in situ Pd species doping. In despite of featuring Pdδ+(δ≈2) oxidation state, the synthesized paired-Pd(Ⅱ)/HKUST-1 catalyst still exhibited DMO as dominant product(90.8% of DMO selectivity). For isolated-Pd(Ⅱ)/HKUST-1 catalyst, however, the main product was DMC(84.8% of DMC selectivity). Based on catalyst characterizations, the structures of paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers were determined. DMO was generated from the coupling of adjacent *COOCH;intermediates adsorbed on paired-Pd(Ⅱ) centers, while DMC was produced from the reaction between methyl nitrite and the *COOCH;intermediates formed on isolated-Pd(Ⅱ) centers. Current work is the first MOFs-based catalyst with well-defined structure being applied in CO oxidative coupling reaction, which not only sheds light on the structure-performance relationship, but also inspires the potential of using MOFs as tunable platform to design high-efficient catalysts in heterogeneous catalysis.
基金the financial support from the National Key R&D Program of China(Nos.2017YFA0700103 and 2018YFA0704502)the National Natural Science Foundation of China(No.22033008),and Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZZ103).
文摘Electrochemical conversion of carbon dioxide(CO_(2))to higher-value products provides a forward-looking way to solve the problems of environmental pollution and energy shortage.However,the low solubility of CO_(2)in aqueous electrolytes,sluggish kinetics,and low selectivity hamper the efficient conversion of CO_(2).Here,we report a Au-based hybrid nanomaterial by modifying Au nanoparticles(NPs)with the macrocyclic molecule cucurbit[6]uril(Au@CB[6]).Au@CB[6]displays the optimal selectivity of CO,with the highest CO Faraday efficiency(FECO)reaching 99.50%at−0.6 V vs.reversible hydrogen electrode(RHE).The partial current density of CO formed by Au@CB[6]increases dramatically,as 3.18 mA/cm2 at−0.6 V,which is more than ten times as that of oleylamine-coated Au NPs(Au@OAm,0.31 mA/cm2).Operando electrochemical measurement combined with density functional theory(DFT)calculations reveals that CB[6]can gather CO_(2)and lead the increased local CO_(2)concentration near metal interface,which realizes significantly enhanced electrochemical CO_(2)reduction reaction(CO_(2)RR)performance.
基金supported by the National Natural Science Foundation of China(21373201,21433014)the“Strategic Priority Research Program”of the Chinese Academy of Sciences(XDB10040304,XDB20010000)
文摘We review in this article our recent simulation works on modeling peptide T-jump and thermal unfolding Fourier transform infrared spectroscopy(FTIR) and two-dimensional infrared(2DIR) spectra. The theoretical and computational techniques used,including Markov state model(MSM), integrated tempering sampling(ITS) and nonlinear exciton propagation(NEP), are first briefly introduced. The protocols for simulating the thermal unfolding as well as T-jump unfolding are then summarized in details. The simulated spectral features, such as the intensity and ellipticity, are demonstrated to agree well with the experimental observations.
基金financially supported by Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZR109)the National Natural Science Foundation of China(Nos.21973094,22173104,22173105)the Opening Project of PCOSS of Xiamen University(No.201908)。
文摘Computational tools on top of first principle calculations have played an indispensable role in revealing the molecular details,thermodynamics,and kinetics in catalytic reactions.Here we proposed a highly efficient dynamic strategy for the calculation of thermodynamic and kinetic properties in heterogeneous catalysis on the basis of efficient potential energy surface(PES)and MD simulations.Taking CO adsorbate on Ru(0001)surface as the illustrative model system,we demonstrated the PES-based MD can efficiently generate reliable two-dimensional potential-of-mean-force(PMF)surfaces in a wide range of temperatures,and thus temperature-dependent thermodynamic properties can be obtained in a comprehensive investigation on the whole PMF surface.Moreover,MD offers an effective way to describe the surface kinetics such as adsorbate on-surface movement,which goes beyond the most popular static approach based on free energy barrier and transition state theory(TST).We further revealed that the dynamic strategy significantly improves the predictions of both thermodynamic and kinetic properties as compared to the popular ideal statistic mechanics approaches such as harmonic analysis and TST.It is expected that this accurate yet efficient dynamic strategy can be powerful in understanding mechanisms and reactivity of a catalytic surface system,and further guides the rational design of heterogeneous catalysts.
基金supported by the National Natural Science Foundation of China(nos.91961108,21922111,and 21973094)the National Key Research and Development Program of China(no.2017YFA0206801)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(no.XDB20000000)the Natural Science Foundation of Fujian Province(no.2019J01131).
文摘Tin oxides(SnO_(2))have been widely utilized in electronics,nanolithography,and catalysis.As the atomically precise models of SnO_(2),tin-oxo clusters(TOCs)not only provide opportunities for mechanism studies,but they also extend potential applications through structural modulation.However,to date,most of the reported TOCs belong to alkyl organotin complexes,which are usually toxic to the human body and the active sites are difficult to expose for catalysis.
基金supported by the National Natural Science Foundation of China(nos.21688102,21973015,21973094,and 91427301)the Science Challenge Project(no.TZ2018004)+1 种基金an innovative research team of high-level local universities in Shanghai,and a key laboratory program of the Education Commission of Shanghai Municipality(no.ZDSYS14005)the Natural Science Foundation of Fujian Province(no.2019J01131).
文摘An accurate description of catalytic selectivity poses an enormous challenge for theoretical simulations.Due to the absence of a well-defined benchmark set on the catalytic selectivity,the performance of even the widely used density functional approximations(DFAs)is yet to be validated.This work reports a test set based on the selective hydrogenation ofα,β-unsaturated aldehydes catalyzed by ruthenium(Ru)hydride complexes.Special attention is paid to benchmark the regioselectivity of aldehydes to either unsaturated alcohols or saturated aldehydes.Accurate reference data were calculated by the massive parallel implementation of the coupled-cluster single,double,and perturbative triple excitations[CCSD(T)]approach,based completely on set limits.Furthermore,we performed the microkinetic simulation based on the CCSD(T)energy profiles,serving the most direct criteria for the performance of DFAs on catalytic selectivity of hydrogenation reactions.Using this test set,we uncovered the intrinsic difficulty of semilocal and hybrid functionals for such a purpose.In the context of the XYG3-type double hybrid(xDH)framework,we showed that this particular challenge could be addressed by the top rung functionals only when the many-body nondynamic correlation effect was accounted for adequately.A recently proposed xDH,namely scsRPA,showed unprecedented accuracy with only 5%error on average.The predicted kinetic selectivity by scsRPA is in close agreement with the reference value,revealing a unique versatility of the top rung DFAs for a reliable description of catalytic selectivity of hydrogenation reactions.