The hybridization between oxygen 2p and transition-metal 3d states largely determines the electronic structure near the Fermi level and related functionalities of transition-metal oxides(TMOs).Considerable efforts hav...The hybridization between oxygen 2p and transition-metal 3d states largely determines the electronic structure near the Fermi level and related functionalities of transition-metal oxides(TMOs).Considerable efforts have been made to manipulate the p-d hybridization in TMOs by tailoring the spatial orbital overlap via structural engineering.Here,we demonstrate enhanced p-d hybridization in Ba^(2+)-doped LaNiO_(3)epitaxial films by simultaneously modifying both the spatial and energetic overlaps between the O-2p and Ni-3d orbitals.Combining x-ray absorption spectroscopy and firstprinciples calculations,we reveal that the enhanced hybridization stems from the synergistic effects of a reduced chargetransfer energy due to hole injection and an increased spatial orbital overlap due to straightening of Ni-O-Ni bonds.We further show that the enhanced p-d hybridization can be utilized to promote the oxygen evolution activity of LaNiO_(3).This work sheds new insights into the fine-tuning of the electronic structures of TMOs for enhanced functionalities.展开更多
The rational design of metal single-atom catalysts(SACs)for electrochemical nitrogen reduction reaction(NRR)is challenging.Two-dimensional metal-organic frameworks(2DMOFs)is a unique class of promising SACs.Up to now,...The rational design of metal single-atom catalysts(SACs)for electrochemical nitrogen reduction reaction(NRR)is challenging.Two-dimensional metal-organic frameworks(2DMOFs)is a unique class of promising SACs.Up to now,the roles of individual metals,coordination atoms,and their synergy effect on the electroanalytic performance remain unclear.Therefore,in this work,a series of 2DMOFs with different metals and coordinating atoms are systematically investigated as electrocatalysts for ammonia synthesis using density functional theory calculations.For a specific metal,a proper metal-intermediate atoms p-d orbital hybridization interaction strength is found to be a key indicator for their NRR catalytic activities.The hybridization interaction strength can be quantitatively described with the p-/d-band center energy difference(Δd-p),which is found to be a sufficient descriptor for both the p-d hybridization strength and the NRR performance.The maximum free energy change(ΔG_(max))andΔd-p have a volcanic relationship with OsC_(4)(Se)_(4)located at the apex of the volcanic curve,showing the best NRR performance.The asymmetrical coordination environment could regulate the band structure subtly in terms of band overlap and positions.This work may shed new light on the application of orbital engineering in electrocatalytic NRR activity and especially promotes the rational design for SACs.展开更多
In the paper, density of states, band structure and electron density difference of Zn1-xCdxO are calculated by first principles, here x varies from 0 to 0.75 at intervals of 0.125, and the band gap obtained from band ...In the paper, density of states, band structure and electron density difference of Zn1-xCdxO are calculated by first principles, here x varies from 0 to 0.75 at intervals of 0.125, and the band gap obtained from band structure changes from 0.968 eV to 0.043 eV. The lattice strain and p-d repulsion theory are used to investigate variation of the band gap, the results obtained show that the variation is mainly due to the lattice tensile strain. The p-d repulsion in Zn1-xCdxO cannot be neglected. In addition, electron density difference can be used to verify the results.展开更多
Poly（d,l-lactide-co-p-dioxanone） （P（LA-co-PDO）） copolymers with different chain microstructures were synthesized by onestep or two-step bulk ring-opening polymerizations of d,l-lactide （LA） and p-dioxanone （...Poly（d,l-lactide-co-p-dioxanone） （P（LA-co-PDO）） copolymers with different chain microstructures were synthesized by onestep or two-step bulk ring-opening polymerizations of d,l-lactide （LA） and p-dioxanone （PDO） monomers using stannous octoate [Sn（Oct）2]/n-dodecanol as the initiating system. The average sequence lengths of the lactidyl （LLA） and dioxanyl （LpDo） units were calculated from the ^1H NMR spectra. It was found that both LLA and Lpoo values from the two-step syntheses were significantly longer than those from the corresponding one-step syntheses, indicating more blocky structure achieved for the twostep copolymers. Corresponding to this difference in microstructure, the two-step copolymers were semi-crystalline, while the one-step copolymers were completely amorphous. In conclusion, the crystallinity of P（LA-co-PDO） copolymers could be adjusted conveniently to meet specific applications by changing the microstructure of the copolymers via different polymerization routes.展开更多
In the quest to align with industrial benchmarks,a noteworthy gap remains in the field of electrochemical nitrogen fixation,particularly in achieving high Faradaic efficiency(FE)and yield.The electrocatalytic nitrogen...In the quest to align with industrial benchmarks,a noteworthy gap remains in the field of electrochemical nitrogen fixation,particularly in achieving high Faradaic efficiency(FE)and yield.The electrocatalytic nitrogen fixation process faces considerable hurdles due to the difficulty in cleaving the highly stable N=N triple bond.Additionally,the electrochemical pathway for nitrogen fixation is often compromised by the concurrent hydrogen evolution reaction(HER),which competes aggressively for electrons and active sites on the catalyst surface,thereby reducing the FE of nitrogen reduction reaction(NRR).To surmount these challenges,this study introduces an innovative bimetallic catalyst,CuGa_(2),synthesized through p-d orbital hybridization to selectively facilitate N2 electroreduction.This catalyst has demonstrated a remarkable NH_(3) yield of 9.82μg h^(-1) cm^(-2) and an associated FE of 38.25%.Our findings elucidate that the distinctive p-d hybridization interaction between Ga and Cu enhances NH3 selectivity by reducing the reaction energy barrier for hydrogenation and suppressing hydrogen evolution.This insight highlights the significance of p-d orbital hybridization in optimizing the electrocatalytic performance of CuGa_(2) for nitrogen fixation.展开更多
Orbital hybridization plays a crucial role in catalytic processes,yet elucidating its mechanism remains a significant challenge.Here,we have developed a strategy for the formation of Yb-C bond by unconventional p-d or...Orbital hybridization plays a crucial role in catalytic processes,yet elucidating its mechanism remains a significant challenge.Here,we have developed a strategy for the formation of Yb-C bond by unconventional p-d orbital hybridization,which induced carbon nitride modified by rare-earth metal element Yb.The optimal sample exhibits catalytic performance 11.2 times greater than that of g-C_(3)N_(4)with N vacancies(NvCN).Yb-C bond and N vacancies reduced the energy barrier and optimized the rate-determining step(*COO+*H→*CO+*OH).Additionally,the intense Yb-C interaction created a specific electrons bridge,which accelerated the transfer rate of electrons on the photocatalytic surface.Next,the CO_(2) conversion reaction mechanism was studied by in situ infrared spectroscopy and theoretical calculations,and the unconventional p-d orbital hybridization contributed to the generation of vital intermediate*CO.This study provides a theoretical basis for designing single-atom photocatalysts for the reduction of CO_(2).展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFA1402902)the National Natural Science Foundation of China(Grant Nos.12374179,12074119,12374145,051B22001,12104157,12134003,and 12304218)the Shanghai Pujiang Program(Grant No.23PJ1402200).
文摘The hybridization between oxygen 2p and transition-metal 3d states largely determines the electronic structure near the Fermi level and related functionalities of transition-metal oxides(TMOs).Considerable efforts have been made to manipulate the p-d hybridization in TMOs by tailoring the spatial orbital overlap via structural engineering.Here,we demonstrate enhanced p-d hybridization in Ba^(2+)-doped LaNiO_(3)epitaxial films by simultaneously modifying both the spatial and energetic overlaps between the O-2p and Ni-3d orbitals.Combining x-ray absorption spectroscopy and firstprinciples calculations,we reveal that the enhanced hybridization stems from the synergistic effects of a reduced chargetransfer energy due to hole injection and an increased spatial orbital overlap due to straightening of Ni-O-Ni bonds.We further show that the enhanced p-d hybridization can be utilized to promote the oxygen evolution activity of LaNiO_(3).This work sheds new insights into the fine-tuning of the electronic structures of TMOs for enhanced functionalities.
基金supported by the National Natural Science Foundation of China(21905253,51973200,and 52122308)the Natural Science Foundation of Henan(202300410372)the National Supercomputing Center in Zhengzhou
文摘The rational design of metal single-atom catalysts(SACs)for electrochemical nitrogen reduction reaction(NRR)is challenging.Two-dimensional metal-organic frameworks(2DMOFs)is a unique class of promising SACs.Up to now,the roles of individual metals,coordination atoms,and their synergy effect on the electroanalytic performance remain unclear.Therefore,in this work,a series of 2DMOFs with different metals and coordinating atoms are systematically investigated as electrocatalysts for ammonia synthesis using density functional theory calculations.For a specific metal,a proper metal-intermediate atoms p-d orbital hybridization interaction strength is found to be a key indicator for their NRR catalytic activities.The hybridization interaction strength can be quantitatively described with the p-/d-band center energy difference(Δd-p),which is found to be a sufficient descriptor for both the p-d hybridization strength and the NRR performance.The maximum free energy change(ΔG_(max))andΔd-p have a volcanic relationship with OsC_(4)(Se)_(4)located at the apex of the volcanic curve,showing the best NRR performance.The asymmetrical coordination environment could regulate the band structure subtly in terms of band overlap and positions.This work may shed new light on the application of orbital engineering in electrocatalytic NRR activity and especially promotes the rational design for SACs.
文摘In the paper, density of states, band structure and electron density difference of Zn1-xCdxO are calculated by first principles, here x varies from 0 to 0.75 at intervals of 0.125, and the band gap obtained from band structure changes from 0.968 eV to 0.043 eV. The lattice strain and p-d repulsion theory are used to investigate variation of the band gap, the results obtained show that the variation is mainly due to the lattice tensile strain. The p-d repulsion in Zn1-xCdxO cannot be neglected. In addition, electron density difference can be used to verify the results.
基金supported by the National Natural Sciences Fund of China(No.50603025)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University).
文摘Poly（d,l-lactide-co-p-dioxanone） （P（LA-co-PDO）） copolymers with different chain microstructures were synthesized by onestep or two-step bulk ring-opening polymerizations of d,l-lactide （LA） and p-dioxanone （PDO） monomers using stannous octoate [Sn（Oct）2]/n-dodecanol as the initiating system. The average sequence lengths of the lactidyl （LLA） and dioxanyl （LpDo） units were calculated from the ^1H NMR spectra. It was found that both LLA and Lpoo values from the two-step syntheses were significantly longer than those from the corresponding one-step syntheses, indicating more blocky structure achieved for the twostep copolymers. Corresponding to this difference in microstructure, the two-step copolymers were semi-crystalline, while the one-step copolymers were completely amorphous. In conclusion, the crystallinity of P（LA-co-PDO） copolymers could be adjusted conveniently to meet specific applications by changing the microstructure of the copolymers via different polymerization routes.
基金supported primarily by National Key Research and Development Program of China(2020YFA0710303)support from Natural Science Foundation of Fujian Province(2024J01258)Scientific Research Foundation of Fuzhou University(510936).
文摘In the quest to align with industrial benchmarks,a noteworthy gap remains in the field of electrochemical nitrogen fixation,particularly in achieving high Faradaic efficiency(FE)and yield.The electrocatalytic nitrogen fixation process faces considerable hurdles due to the difficulty in cleaving the highly stable N=N triple bond.Additionally,the electrochemical pathway for nitrogen fixation is often compromised by the concurrent hydrogen evolution reaction(HER),which competes aggressively for electrons and active sites on the catalyst surface,thereby reducing the FE of nitrogen reduction reaction(NRR).To surmount these challenges,this study introduces an innovative bimetallic catalyst,CuGa_(2),synthesized through p-d orbital hybridization to selectively facilitate N2 electroreduction.This catalyst has demonstrated a remarkable NH_(3) yield of 9.82μg h^(-1) cm^(-2) and an associated FE of 38.25%.Our findings elucidate that the distinctive p-d hybridization interaction between Ga and Cu enhances NH3 selectivity by reducing the reaction energy barrier for hydrogenation and suppressing hydrogen evolution.This insight highlights the significance of p-d orbital hybridization in optimizing the electrocatalytic performance of CuGa_(2) for nitrogen fixation.
基金financially supported by the National Natural Science Foundation of China(No.52370109)Guangdong Province Scientific Research Platform Project(Nos.2023ZDZX4052,2022ZDZX4046)+3 种基金Shaoguan Science and Technology Projects(No.230616088031998)High Level Talents Introduction Project of"Pearl River Talent Plan"in Guangdong Province(No.2019CX01L308)the Support Scheme of Guangzhou for Leading Talents in Innovation and Entrepreneurship Funding(No.2016015)the Science and Technology Research Program of Chongqing Municipal Education Commission of China(No.KJZDM202400802)
文摘Orbital hybridization plays a crucial role in catalytic processes,yet elucidating its mechanism remains a significant challenge.Here,we have developed a strategy for the formation of Yb-C bond by unconventional p-d orbital hybridization,which induced carbon nitride modified by rare-earth metal element Yb.The optimal sample exhibits catalytic performance 11.2 times greater than that of g-C_(3)N_(4)with N vacancies(NvCN).Yb-C bond and N vacancies reduced the energy barrier and optimized the rate-determining step(*COO+*H→*CO+*OH).Additionally,the intense Yb-C interaction created a specific electrons bridge,which accelerated the transfer rate of electrons on the photocatalytic surface.Next,the CO_(2) conversion reaction mechanism was studied by in situ infrared spectroscopy and theoretical calculations,and the unconventional p-d orbital hybridization contributed to the generation of vital intermediate*CO.This study provides a theoretical basis for designing single-atom photocatalysts for the reduction of CO_(2).
