We have examined the theoretical implications of combining two main and three auxiliary ligands to form several Ir(Ⅲ)complexes featuring a transition metal as their core atom to identify some appropriate organic ligh...We have examined the theoretical implications of combining two main and three auxiliary ligands to form several Ir(Ⅲ)complexes featuring a transition metal as their core atom to identify some appropriate organic lightemitting diode(OLED)materials.By utilizing electronic structure,frontier molecular orbitals,minimum single-line absorption,triplet excited states,and emission spectral data derived from the density functional theory,the usefulness of these Ir(Ⅲ)complexes,including(piq)_(2)Ir(acac),(piq)_(2)Ir(tmd),(piq)_(2)Ir(tpip),(fpiq)_(2)Ir(acac),(fpiq)_(2)Ir(tmd),and(fpiq)_(2)Ir(tpip),in OLEDs was examined,where piq=1-phenylisoquinoline,fpiq=1-(4-fluorophenyl)isoquinoline,acac=(3Z)-4-hydroxypent-3-en-2-one,tmd=(4Z)-5-hydroxy-2,2,6,6-tetramethylhept-4-en-3-one,and tpip=tetraphenylimido-diphosphonate.These complexes all have low-efficiency roll-off properties,especially(fpiq)_(2)Ir(tpip).Some researchers have successfully synthesized complexes extremely similar to(piq)_(2)Ir(acac)through the Suzuki-Miyaura coupling reaction.展开更多
By adopting stochastic density functional theory(SDFT)and mixed stochastic-deterministic density functional theory(MDFT)methods,we perform first-principles calculations to predict the shock Hugoniot curves of boron(pr...By adopting stochastic density functional theory(SDFT)and mixed stochastic-deterministic density functional theory(MDFT)methods,we perform first-principles calculations to predict the shock Hugoniot curves of boron(pressure P=7.9×10^(3)-1.6×10^(6) GPa and temperature T=25-2800 eV),silicon(P=2.6×10^(3)-7.9×10^(5) GPa and T=21.5-1393 eV),and aluminum(P=5.2×10^(3)-9.0×10^(5) GPa and T=25-1393 eV)over wide ranges of pressure and temperature.In particular,we systematically investigate the impact of different cutoff radii in norm-conserving pseudopotentials on the calculated properties at elevated temperatures,such as pressure,ionization energy,and equation of state.By comparing the SDFT and MDFT results with those of other first-principles methods,such as extended first-principles molecular dynamics and path integral Monte Carlo methods,we find that the SDFT and MDFT methods show satisfactory precision,which advances our understanding of first-principles methods when applied to studies of matter at extremely high pressures and temperatures.展开更多
Ab initio modeling of dynamic structure factors(DSF)and related density response properties in the warm dense matter(WDM)regime is a challenging computational task.The DSF,convolved with a probing X-ray beam and instr...Ab initio modeling of dynamic structure factors(DSF)and related density response properties in the warm dense matter(WDM)regime is a challenging computational task.The DSF,convolved with a probing X-ray beam and instrument function,is measured in X-ray Thom-son scattering(XRTS)experiments,which allow the study of electronic structure properties at the microscopic level.Among the various ab initio methods,linear-response time-dependent density-functional theory(LR-TDDFT)is a key framework for simulating the DSF.The standard approach in LR-TDDFT for computing the DSF relies on the orbital representation.A significant drawback of this method is the unfavorable scaling of the number of required empty bands as the wavenumber increases,making LR-TDDFT impractical for modeling XRTS measurements over large energy scales,such as in backward scattering geometry.In this work,we consider and test an alternative approach to LR-TDDFT that employs the Liouville–Lanczos(LL)method for simulating the DSF of WDM.This approach does not require empty states and allows the DSF at large momentum transfer values and over a broad frequency range to be accessed.We compare the results obtained from the LL method with those from the solution of Dyson’s equation using the standard LR-TDDFT within the projector augmented-wave formalism for isochorically heated aluminum and warm dense hydrogen.Additionally,we utilize exact path integral Monte Carlo results for the imaginary-time density-density correlation function(ITCF)of warm dense hydrogen to rigorously benchmark the LL approach.We discuss the application of the LL method for calculating DSFs and ITCFs at different wavenumbers,the effects of pseudopotentials,and the role of Lorentzian smearing.The successful validation of the LL method under WDM conditions makes it a valuable addition to the ab initio simulation landscape,supporting experimental efforts and advancing WDM theory.展开更多
A sparsely introduced basal intrinsic 2-type stacking fault(I_(2)-SF)with a dense segregation of clusters(cluster-arranged layer;CAL)inα-Mg exerts a sufficient strengthening effect with a reduced content of additive ...A sparsely introduced basal intrinsic 2-type stacking fault(I_(2)-SF)with a dense segregation of clusters(cluster-arranged layer;CAL)inα-Mg exerts a sufficient strengthening effect with a reduced content of additive elements.Moreover,the dynamic nucleation and growth of CALs during deformation largely improves the creep resistance.This paper analyzes the cosegregation behaviors of yttrium(Y)and zinc(Zn)atoms at an I_(2)-SF in bulk and at basal edge dislocations using density functional theory calculations.We also study the modification of the generalized stacking-fault energy(GSFE)curves associated with the cosegregation.The segregation energies of Y and Zn atoms in the I_(2)-SF are relatively small during the initial segregation of a cluster,but increases stepwise as the cluster grows.After introducing Y and Zn atoms in the I_(2)-SF in an energetically stable order,we obtain an L1_(2)-type cluster resembling that reported in the literature.Small structural changes driven by vacancy diffusion produce an exact L1_(2)-type cluster.Meanwhile,the core of the Shockley partial dislocation generates sufficient segregation energy for cluster nucleation.Migration of the Shockley partial dislocation and expansion of the I_(2)-SF part are observed at a specific cluster size.The migration is triggered by a large modification of the GSFE curve and destabilization of the hexagonal close-packed stacking(hcp)by the segregated atoms.At this point,the cluster has reached sufficient size and continues to follow the growth in the I_(2)-SF part.According to our findings,the CAL at elevated temperature is formed through repeated synchronized behavior of cluster nucleation at the Shockley partial dislocation,dislocation migration triggered by the destabilized hcp stacking,and following of cluster growth in the I_(2)-SF part of the dislocation.展开更多
Metal-organic framework(MOF) has been widely applied in photocatalysis, which is significant for addressing energy crises and environmental issues. Based on density functional theory calculations,the performances of C...Metal-organic framework(MOF) has been widely applied in photocatalysis, which is significant for addressing energy crises and environmental issues. Based on density functional theory calculations,the performances of Cu-BTC, a copper-based MOF, and its derivatives Cu TM-BTC via the substitution of transition metal(TM) elements at the Cu site for photocatalytic overall water splitting(POWS) have been studied. POWS of Cu-BTC suffers from the sluggish hydrogen evolution reaction due to the large overpotential of 2.02 V and limited solar utilization due to a wide HOMO-LUMO gap of 4.11 e V. Via TM substitution, the HOMO-LUMO gap narrows but still satisfies the redox potentials when taken 3d-TM of Cr, Fe, Co or Ni, 4d-TM of Rh or Pd, or 5d-TM of Re or Pt into consideration, benefiting for the light absorption. Furthermore, Cr and Re could serve as active sites for hydrogen evolution with remarkably lowered overpotentials of 0.79 V and 0.28 V, respectively;similarly, oxygen evolution activities could be enhanced by Fe, Co and Rh because of their reduced overpotentials which are less than 0.5 V. Therefore,our findings pave guidance for designing Cu-BTC derivatives in overall water splitting.展开更多
Localized corrosion of 304 stainless steel being the significant parts of Starship rocket seriously threatens the long-term service of such aerospace equipment.Scanning electron microscopy,in situ instruments combinin...Localized corrosion of 304 stainless steel being the significant parts of Starship rocket seriously threatens the long-term service of such aerospace equipment.Scanning electron microscopy,in situ instruments combining electrochemical workstation and Raman spectroscopy,and Density Dunctional Theory(DFT)calculations were employed.The surface morphologies,alloying elements,molecular fingerprint Raman evidence and theoretical mechanism for the localized corrosion of 304 stainless steel during the electrochemical polarization in the mixture solutions containing 0.5 mol/L H_(2)SO_(4) and 2,2'-bipyridine(bipy)with concentrations of 0.001,0.010,0.100 mol/L were discussed.In comparison,the presence of bipy up to 0.100 mol/L in such mixture solutions displayed the neglectable effect on the Fe(Ⅱ)/Fe(Ⅲ)reaction in the polarization process.Raman vibrational frequency around 1492 cm^(-1)was the evidence of pink color appearance due to the formation of[Fe^(Ⅱ)(bipy)_(3)]^(2+).Raman and DFT indicated the yellow color emergence due to the presence ofμ-O-[Fe^(Ⅲ)(bipy)_(2)(H_(2)O)]_(2)^(4+)due to the oxidation reaction of[Fe^(Ⅱ)(bipy)_(3)]^(2+)with H_(2)O_(2) oxidant,and the dimerization of[Fe^(Ⅲ)(bipy)_(3)]^(3+),Furthermore,a quantitative model between[Fe^(Ⅱ)(bipy)_(3)]^(2+)concentration and Raman intensity at 1492 cm^(-1) has been built up.Two linear functions were revealed when[Fe^(Ⅱ)(bipy)_(3)]^(2+)concentrations were at 0-0.002 mol/L and 0.002-0.004 mol/L and a concentration error of less than 5%was evidenced in comparison with that investigated by the inductively coupled plasma.The proposed passivation mechanism and quantitative concentration model of 304 stainless steel have certain significance for its corrosion protection andcorrosionevaluation.展开更多
The Dynamical Density Functional Theory(DDFT)algorithm,derived by associating classical Density Functional Theory(DFT)with the fundamental Smoluchowski dynamical equation,describes the evolution of inhomo-geneous flui...The Dynamical Density Functional Theory(DDFT)algorithm,derived by associating classical Density Functional Theory(DFT)with the fundamental Smoluchowski dynamical equation,describes the evolution of inhomo-geneous fluid density distributions over time.It plays a significant role in studying the evolution of density distributions over time in inhomogeneous systems.The Sunway Bluelight II supercomputer,as a new generation of China’s developed supercomputer,possesses powerful computational capabilities.Porting and optimizing industrial software on this platform holds significant importance.For the optimization of the DDFT algorithm,based on the Sunway Bluelight II supercomputer and the unique hardware architecture of the SW39000 processor,this work proposes three acceleration strategies to enhance computational efficiency and performance,including direct parallel optimization,local-memory constrained optimization for CPEs,and multi-core groups collaboration and communication optimization.This method combines the characteristics of the program’s algorithm with the unique hardware architecture of the Sunway Bluelight II supercomputer,optimizing the storage and transmission structures to achieve a closer integration of software and hardware.For the first time,this paper presents Sunway-Dynamical Density Functional Theory(SW-DDFT).Experimental results show that SW-DDFT achieves a speedup of 6.67 times within a single-core group compared to the original DDFT implementation,with six core groups(a total of 384 CPEs),the maximum speedup can reach 28.64 times,and parallel efficiency can reach 71%,demonstrating excellent acceleration performance.展开更多
This study explores the molecular design of sulfur-containing polymers with high refractive indices(RI)and optimized Abbe numbers for advanced optical applications.The high molar refraction and low dispersion of sulfu...This study explores the molecular design of sulfur-containing polymers with high refractive indices(RI)and optimized Abbe numbers for advanced optical applications.The high molar refraction and low dispersion of sulfur make it an ideal component for enhancing the optical properties of polymers.Density functional theory(DFT)calculations were employed to predict the RI and Abbe numbers for a range of sulfurbased polymers.To improve the accuracy of the theoretical predictions,a correction function was developed by comparing the calculated values with experimental data.The key polymer families investigated included sulfur-containing polycarbonates,heterocyclic optical resins,and cycloolefins,all modified to balance RI enhancement with dispersion control.The results demonstrate that increasing the sulfur content and introducing specific heterocycles and bridged rings can effectively increase the RI while maintaining desirable Abbe numbers.Polymers incorporating 1,4-dithiane and sulfur-bridged rings exhibit excellent optical clarity and minimal visible light absorption,making them suitable for lens and coating applications.The study also calculated the UV-visible spectra for the most promising polymers,confirming their high transparency.This work establishes a predictive framework for developing high-performance optical polymers and offers a systematic approach for balancing the refractive index and dispersion,thereby providing valuable insights for the design of next-generation optical materials.展开更多
In this study,a framework for predicting the gas-sensitive properties of gas-sensitive materials by combining machine learning and density functional theory(DFT)has been proposed.The framework rapidly predicts the gas...In this study,a framework for predicting the gas-sensitive properties of gas-sensitive materials by combining machine learning and density functional theory(DFT)has been proposed.The framework rapidly predicts the gas response of materials by establishing relationships between multisource physical parameters and gas-sensitive properties.In order to prove its effectiveness,the perovskite Cs_(3)Cu_(2)I_(5) has been selected as the representative material.The physical parameters before and after the adsorption of various gases have been calculated using DFT,and then a machine learning model has been trained based on these parameters.Previous studies have shown that a single physical parameter alone is not enough to accurately predict the gas sensitivity of materials.Therefore,a variety of physical parameters have been selected for machine learning,and the final machine learning model achieved 92%accuracy in predicting gas sensitivity.It is important to note that although there have been no previous reports on the response of Cs_(3)Cu_(2)I_(5) to hydrogen sulfide,the resulting model predicts the gas response of H2S;it is subsequently confirmed experimentally.This method not only enhances the understanding of the gas sensing mechanism,but also has a universal nature,making it suitable for the development of various new gas-sensitive materials.展开更多
Using the Skyrme density functional theory,potential energy surfaces of^(240)Pu with constraints on the axial quadrupole and octupole deformations(q_(20)and q_(30))were calculated.The volume-like and surface-like pair...Using the Skyrme density functional theory,potential energy surfaces of^(240)Pu with constraints on the axial quadrupole and octupole deformations(q_(20)and q_(30))were calculated.The volume-like and surface-like pairing forces,as well as a combination of these two forces,were used for the Hartree–Fock–Bogoliubov approximation.Variations in the least-energy fission path,fission barrier,pairing energy,total kinetic energy,scission line,and mass distribution of the fission fragments based on the different forms of the pairing forces were analyzed and discussed.The fission dynamics were studied based on the timedependent generator coordinate method plus the Gaussian overlap approximation.The results demonstrated a sensitivity of the mass and charge distributions of the fission fragments on the form of the pairing force.Based on the investigation of the neutron-induced fission of^(239)Pu,among the volume,mixed,and surface pairing forces,the mixed pairing force presented a good reproduction of the experimental data.展开更多
Atrazine causes concern due to its resistant to biodegradation and could be accumulated in aquatic organisms,causing pollution in lakes.This study measured the concentration of atrazine in ice and the water under ice ...Atrazine causes concern due to its resistant to biodegradation and could be accumulated in aquatic organisms,causing pollution in lakes.This study measured the concentration of atrazine in ice and the water under ice through a simulated icing experiment and calculated the distribution coefficient K to characterize its migration ability in the freezing process.Furthermore,density functional theory(DFT)calculations were employed to expatiate the migration law of atrazine during icing process.According to the results,it could release more energy into the environment when atrazine staying in water phase(-15.077 kcal/mol)than staying in ice phase(-14.388 kcal/mol),therefore it was beneficial for the migration of atrazine from ice to water.This explains that during the freezing process,the concentration of atrazine in the ice was lower than that in the water.Thermodynamic calculations indicated thatwhen the temperature decreases from268 to 248 K,the internal energy contribution of the compound of atrazine and ice molecule(water cluster)decreases at the same vibrational frequency,resulting in an increase in the free energy difference of the compound from-167.946 to-165.390 kcal/mol.This demonstrated the diminished migratory capacity of atrazine.This study revealed the environmental behavior of atrazine during lake freezing,which was beneficial for the management of atrazine and other pollutants during freezing and environmental protection.展开更多
In traditional finite-temperature Kohn–Sham density functional theory(KSDFT),the partial occupation of a large number of high-energy KS eigenstates restricts the use of first-principles molecular dynamics methods at ...In traditional finite-temperature Kohn–Sham density functional theory(KSDFT),the partial occupation of a large number of high-energy KS eigenstates restricts the use of first-principles molecular dynamics methods at extremely high temperatures.However,stochastic density functional theory(SDFT)can overcome this limitation.Recently,SDFT and the related mixed stochastic–deterministic density functional theory,based on a plane-wave basis set,have been implemented in the first-principles electronic structure software ABACUS[Q.Liu and M.Chen,Phys.Rev.B 106,125132(2022)].In this study,we combine SDFT with the Born–Oppenheimer molecular dynamics method to investigate systems with temperatures ranging from a few tens of eV to 1000 eV.Importantly,we train machine-learning-based interatomic models using the SDFT data and employ these deep potential models to simulate large-scale systems with long trajectories.Subsequently,we compute and analyze the structural properties,dynamic properties,and transport coefficients of warm dense matter.展开更多
Machine learning(ML)has demon-strated significant potential in en-hancing the predictive capabilities of density functional theory methods.In this study,we develop an ML model for correcting B3LYP-D,a density function...Machine learning(ML)has demon-strated significant potential in en-hancing the predictive capabilities of density functional theory methods.In this study,we develop an ML model for correcting B3LYP-D,a density functional approximation that incorporates dispersion correc-tions for non-covalent interactions.This model utilizes semilocal elec-tron density descriptors,and is trained with accurate reference data for both relative and ab-solute energies.Extensive benchmark tests reveal that the ML correction substantially en-hances the generalization ability of the B3LYP-D functional,improving the predictions of at-omization and dissociation energies for complex molecular systems.It retains the accuracy of B3LYP-D in predicting reaction barrier heights and non-covalent interactions while enabling efficient,fully self-consistent field calculations.This work signifies a promising advancement in the development of ML-corrected functionals that surpass the performance of traditional B3LYP-D.展开更多
As primary degradation products of phthalate esters,phthalate monoesters(MPEs)have been widely detected in various aquatic environments and drawn growing toxicological concerns.Hydrolysis kinetics that is of importanc...As primary degradation products of phthalate esters,phthalate monoesters(MPEs)have been widely detected in various aquatic environments and drawn growing toxicological concerns.Hydrolysis kinetics that is of importance for assessing environmental persistence of chemicals remain elusive for MPEs.Herein,kinetics of base-catalyzed and neutral hydrolysis for 18 MPEs with different leaving groups was investigated by density functional theory calculation.Results indicate that MPEs with leaving groups having p Kaof<10 prefer dissociative transition states.MPEs are more persistent than their parents,and their hydrolysis half-lives were calculated to vary from 3.4 min to 79.2 years(p H=7–9).A quantitative structure-activity relationship model was developed for predicting the hydrolysis kinetics parameters.It was found that p Kaof the leaving groups and electronegativity of the MPEs are key factors determining the hydrolysis kinetics.This work may lay a theoretical foundation for better understanding the chemical process that governs MPE persistence in aquatic environments.展开更多
Understanding the adsorption interactions between carbon materials and sulfur compounds has far-reaching impacts,in addition to their well-known important role in energy storage and conversion,such as lithium-ion batt...Understanding the adsorption interactions between carbon materials and sulfur compounds has far-reaching impacts,in addition to their well-known important role in energy storage and conversion,such as lithium-ion batteries.In this paper,properties of intrinsic B or Si single-atom doped,and B-Si codoped graphene(GR)and graphdiyne(GDY)were investigated by using density functional theory-based calculations,in which the optimal doping configurations were explored for potential applications in adsorbing sulfur compounds.Results showed that both B or Si single-atom doping and B-Si codoping could substantially enhance the electron transport properties of GR and GDY,improving their surface activity.Notably,B and Si atoms displayed synergistic effects for the codoped configurations,where B-Si codoped GR/GDY exhibited much better performance in the adsorption of sulfurcontaining chemicals than single-atom doped systems.In addition,results demonstrated that,after B-Si codoping,the adsorption energy and charge transfer amounts of GDY with sulfur compounds were much larger than those of GR,indicating that B-Si codoped GDY might be a favorable material for more effectively interacting with sulfur reagents.展开更多
Calix[n]arenes was utilized to detect PABA,the primary sunscreen component.This study investigates the interaction of calix[4]arene(C4),calix[6]arene(C6),and PABA using the Langmuir method and first-principle density ...Calix[n]arenes was utilized to detect PABA,the primary sunscreen component.This study investigates the interaction of calix[4]arene(C4),calix[6]arene(C6),and PABA using the Langmuir method and first-principle density functional theory(DFT).Using the Langmuir-Schaefer(LS)technique,an ultrathin film composed of calix[n]arenes and their complexes with PABA was deposited on various substrates.Based on the Langmuir study,the PABA molecule was bonded to the lower rims of both C4 and C6 with the host-vip ratio of 1:1.All of the LS films formed were then characterized by ultravioletvisible spectroscopy(UV-Vis),Fourier-transform infrared spectroscopy(FTIR)and carbon,hydrogen,nitrogen,sulfur elemental analyzer(CHNS).The band gap reduction obtained in the DFT study denotes the charge transfer interaction with promising reactivity between the calix[n]arenes and PABA.The sensing of PABA by C4 and C6 is successful based on the formation of bonding between them due to the hosts’effective trapping capacity.The outcomes of this study could be applied to drug delivery systems for future pharmaceutical and medical applications.展开更多
To improve the adsorption and catalytic performance of heterogeneous Fenton-like catalysts for oil wastes,amino acids were used to modify nanoscale zero-valent iron(AA@Fe^(0)),which were applied in the Fenton-like deg...To improve the adsorption and catalytic performance of heterogeneous Fenton-like catalysts for oil wastes,amino acids were used to modify nanoscale zero-valent iron(AA@Fe^(0)),which were applied in the Fenton-like degradation of organic solvents(tributyl phosphate and n-dodecane,named TBP and DD).Twelve amino acids,i.e.,glycine(Gly),alanine(Ala),leucine(Leu),proline(Pro),phenylalanine(Phe),methionine(Met),cysteine(Cys),asparagine(Asn),serine(Ser),glutamic acid(Glu),lysine(Lys)and arginine(Arg),were selected and calculated by density functional theory(DFT).The optimized structure,charge distribution,the highest occupied molecular orbital(HOMO),the lowest unoccupied molecular orbital(LUMO),interaction region indicator(IRI)isosurface map and adsorption energy of AA@Fe^(0),AA@Fe^(0)-TBP and AA@Fe^(0)-DD were studied,which indicated that Fe is more likely to approach and charge transfer with-COO and-NH_(3) on theα-carbon of amino acids.There is strong attraction between Fe and–COO,and Van der Waals force between Fe and-NH_(3),respectively.In the interaction of AA@Fe^(0)with TBP and DD,Van der Waal force plays an important role.AA@Fe^(0)was synthesized in laboratory and characterized to investigate physicochemical properties.In Fenton-like degradation of organic solvents,the change of COD in water phase during the degradation process as well as the volume of the organic phase after the reaction were investigated.The results of calculations combined with experiments showed that Ser-modified Fe^(0)performed the best in these amino acids,with 98%removal of organic solvents.A possible catalytic mechanism was proposed in which amino acids acted a linking role between Fe and organic solvents,activating H_(2)O_(2)to generate hydroxyl radicals for the degradation of organic solvents.展开更多
Recently,the preparation of ultra-high temperature HfC ceramic coating has gained significant attention,particularly through the application of the HfCl_(4)-CH_(4)-H_(2)-Ar system via Chemical Vapor Deposition(CVD),wh...Recently,the preparation of ultra-high temperature HfC ceramic coating has gained significant attention,particularly through the application of the HfCl_(4)-CH_(4)-H_(2)-Ar system via Chemical Vapor Deposition(CVD),which has been found widely applied to C/C composites.Herein,an analysis of the reactions that occur in the initial stage of the CVD-HfC coating process is presented using Density Functional Theory(DFT)and Transition State Theory(TST)at the B3LYP/Lanl2DZ level.The results reveal that HfCl4 can only cleave to produce hypochlorite,which will further react with methyl to synthesize intermediates to form HfC.According to the analysis of the energy barrier and reaction constant,HfCl preferentially reacts with methyl groups to form complex adsorptive intermediates at 1573 K.With a C—Hf bond production energy of 212.8 kcal/mol(1 kcal=4.18 kJ),the reaction rate constant of HfCl+CH is calculated to be 2.15×10^(-18) cm^(3)/s at 1573 K.Additionally,both the simulation and experimental results exhibit that the upward trend of reaction rate constants with temperature is also consistent with the deposition rate,indicating that the growth curve of the reaction rate constants tends to flatten out.The proposed reaction model of the precursor’s decomposition and reconstruction during deposition process has significant implication for the process guidance.展开更多
The conversion of solar energy to chemical energies by virtue of semiconductor photocatalysis has shown great significance in sustaining future energy demands,and have a deep understanding of the relationship between ...The conversion of solar energy to chemical energies by virtue of semiconductor photocatalysis has shown great significance in sustaining future energy demands,and have a deep understanding of the relationship between photocatalyst and photocatalytic activity is essential.Density functional theory(DFT)calculations are becoming increasingly important for revealing the intrinsic electronic structure properties of materials and energy properties of reactions,which has been greatly developed with the development of computational methods.In this review,the applications of DFT calculations in photocatalysis are summarized and exemplified by various representative investigations in the up-to-date reports.To specify,we show how to collect,analyse and utilize the informations on photocatalysts and photocatalytic reactions with the help of the DFT calculations,such as electronic structures,surface catalytic sites,catalytic activities,possible reaction mechanisms,etc.Our discussion is intended to provide an overview on applications of the current theoretical calculations in the field of photocatalysis for a better understanding of the composition-structure-function relationships,and also to guide future experiments and computations toward the understanding and development of novel solar-energy-conversion catalysts.展开更多
Polarons are widely considered to play a crucial role in the charge transport and photocatalytic performance of materials,but the mechanisms of their formation and the underlying driving factors remain a matter of con...Polarons are widely considered to play a crucial role in the charge transport and photocatalytic performance of materials,but the mechanisms of their formation and the underlying driving factors remain a matter of controversy.This study delves into the formation of polarons in different crystalline forms of TiO_(2) and their connection with the materials'structure.By employing density functional theory calculations with on-site Coulomb interaction correction(DFT+U),we provide a detailed analysis of the electronic polarization behavior in the anatase and rutile forms of TiO_(2).We focus on the polarization properties of defect-induced and photoexcited excess electrons on various TiO_(2) surfaces.The results reveal that the defect electrons can form small polarons on the anatase TiO_(2)(101)surface,while on the rutile TiO_(2)(110)surface,both small and large polarons(hybrid-state polarons)are formed.Photoexcited electrons are capable of forming both small and large polarons on the surfaces of both crystal types.The analysis indicates that the differences in polaron distribution are primarily determined by the intrinsic properties of the crystals;the structural and symmetry differences between anatase and rutile TiO_(2) lead to the distinct polaron behaviors.Further investigation suggests that the polarization behavior of defect electrons is also related to the arrangement of electron orbitals around the Ti atoms,while the polarization of photoexcited electrons is mainly facilitated by the lattice distortions.These findings elucidate the formation mechanisms of different types of polarons and may contribute to understanding the performance of TiO_(2)in different fields.展开更多
文摘We have examined the theoretical implications of combining two main and three auxiliary ligands to form several Ir(Ⅲ)complexes featuring a transition metal as their core atom to identify some appropriate organic lightemitting diode(OLED)materials.By utilizing electronic structure,frontier molecular orbitals,minimum single-line absorption,triplet excited states,and emission spectral data derived from the density functional theory,the usefulness of these Ir(Ⅲ)complexes,including(piq)_(2)Ir(acac),(piq)_(2)Ir(tmd),(piq)_(2)Ir(tpip),(fpiq)_(2)Ir(acac),(fpiq)_(2)Ir(tmd),and(fpiq)_(2)Ir(tpip),in OLEDs was examined,where piq=1-phenylisoquinoline,fpiq=1-(4-fluorophenyl)isoquinoline,acac=(3Z)-4-hydroxypent-3-en-2-one,tmd=(4Z)-5-hydroxy-2,2,6,6-tetramethylhept-4-en-3-one,and tpip=tetraphenylimido-diphosphonate.These complexes all have low-efficiency roll-off properties,especially(fpiq)_(2)Ir(tpip).Some researchers have successfully synthesized complexes extremely similar to(piq)_(2)Ir(acac)through the Suzuki-Miyaura coupling reaction.
基金supported by the National Key R&D Program of China under Grant No.2025YFB3003603the National Natural Science Foundation of China under Grant Nos.12135002 and 12105209.
文摘By adopting stochastic density functional theory(SDFT)and mixed stochastic-deterministic density functional theory(MDFT)methods,we perform first-principles calculations to predict the shock Hugoniot curves of boron(pressure P=7.9×10^(3)-1.6×10^(6) GPa and temperature T=25-2800 eV),silicon(P=2.6×10^(3)-7.9×10^(5) GPa and T=21.5-1393 eV),and aluminum(P=5.2×10^(3)-9.0×10^(5) GPa and T=25-1393 eV)over wide ranges of pressure and temperature.In particular,we systematically investigate the impact of different cutoff radii in norm-conserving pseudopotentials on the calculated properties at elevated temperatures,such as pressure,ionization energy,and equation of state.By comparing the SDFT and MDFT results with those of other first-principles methods,such as extended first-principles molecular dynamics and path integral Monte Carlo methods,we find that the SDFT and MDFT methods show satisfactory precision,which advances our understanding of first-principles methods when applied to studies of matter at extremely high pressures and temperatures.
基金supported by the Center for Advanced Systems Understanding(CASUS),financed by Germany’s Federal Ministry of Education and Research(BMBF)and the Saxon State Government out of the State Budget approved by the Saxon State Parliamentfunding from the European Research Council(ERC)under the European Union’s Horizon 2022 research and innovation programme(Grant Agreement No.101076233,“PREXTREME”)funding from the European Union’s Just Transition Fund(JTF)within the project Röntgenlaser-Optimierung der Laserfusion(ROLF),Contract No.5086999001,co-financed by the Saxon State Government out of the State Budget approved by the Saxon State Parliament.
文摘Ab initio modeling of dynamic structure factors(DSF)and related density response properties in the warm dense matter(WDM)regime is a challenging computational task.The DSF,convolved with a probing X-ray beam and instrument function,is measured in X-ray Thom-son scattering(XRTS)experiments,which allow the study of electronic structure properties at the microscopic level.Among the various ab initio methods,linear-response time-dependent density-functional theory(LR-TDDFT)is a key framework for simulating the DSF.The standard approach in LR-TDDFT for computing the DSF relies on the orbital representation.A significant drawback of this method is the unfavorable scaling of the number of required empty bands as the wavenumber increases,making LR-TDDFT impractical for modeling XRTS measurements over large energy scales,such as in backward scattering geometry.In this work,we consider and test an alternative approach to LR-TDDFT that employs the Liouville–Lanczos(LL)method for simulating the DSF of WDM.This approach does not require empty states and allows the DSF at large momentum transfer values and over a broad frequency range to be accessed.We compare the results obtained from the LL method with those from the solution of Dyson’s equation using the standard LR-TDDFT within the projector augmented-wave formalism for isochorically heated aluminum and warm dense hydrogen.Additionally,we utilize exact path integral Monte Carlo results for the imaginary-time density-density correlation function(ITCF)of warm dense hydrogen to rigorously benchmark the LL approach.We discuss the application of the LL method for calculating DSFs and ITCFs at different wavenumbers,the effects of pseudopotentials,and the role of Lorentzian smearing.The successful validation of the LL method under WDM conditions makes it a valuable addition to the ab initio simulation landscape,supporting experimental efforts and advancing WDM theory.
基金supported by the Japan Science and Technology Agency(JST),CREST(grant number JapanJPR2094)。
文摘A sparsely introduced basal intrinsic 2-type stacking fault(I_(2)-SF)with a dense segregation of clusters(cluster-arranged layer;CAL)inα-Mg exerts a sufficient strengthening effect with a reduced content of additive elements.Moreover,the dynamic nucleation and growth of CALs during deformation largely improves the creep resistance.This paper analyzes the cosegregation behaviors of yttrium(Y)and zinc(Zn)atoms at an I_(2)-SF in bulk and at basal edge dislocations using density functional theory calculations.We also study the modification of the generalized stacking-fault energy(GSFE)curves associated with the cosegregation.The segregation energies of Y and Zn atoms in the I_(2)-SF are relatively small during the initial segregation of a cluster,but increases stepwise as the cluster grows.After introducing Y and Zn atoms in the I_(2)-SF in an energetically stable order,we obtain an L1_(2)-type cluster resembling that reported in the literature.Small structural changes driven by vacancy diffusion produce an exact L1_(2)-type cluster.Meanwhile,the core of the Shockley partial dislocation generates sufficient segregation energy for cluster nucleation.Migration of the Shockley partial dislocation and expansion of the I_(2)-SF part are observed at a specific cluster size.The migration is triggered by a large modification of the GSFE curve and destabilization of the hexagonal close-packed stacking(hcp)by the segregated atoms.At this point,the cluster has reached sufficient size and continues to follow the growth in the I_(2)-SF part.According to our findings,the CAL at elevated temperature is formed through repeated synchronized behavior of cluster nucleation at the Shockley partial dislocation,dislocation migration triggered by the destabilized hcp stacking,and following of cluster growth in the I_(2)-SF part of the dislocation.
基金the financial support from National Natural Science Foundation of China (No. 21503097)Postgraduate Research & Practice Innovation Program of Jiangsu Province (No. KYCX23_3905)。
文摘Metal-organic framework(MOF) has been widely applied in photocatalysis, which is significant for addressing energy crises and environmental issues. Based on density functional theory calculations,the performances of Cu-BTC, a copper-based MOF, and its derivatives Cu TM-BTC via the substitution of transition metal(TM) elements at the Cu site for photocatalytic overall water splitting(POWS) have been studied. POWS of Cu-BTC suffers from the sluggish hydrogen evolution reaction due to the large overpotential of 2.02 V and limited solar utilization due to a wide HOMO-LUMO gap of 4.11 e V. Via TM substitution, the HOMO-LUMO gap narrows but still satisfies the redox potentials when taken 3d-TM of Cr, Fe, Co or Ni, 4d-TM of Rh or Pd, or 5d-TM of Re or Pt into consideration, benefiting for the light absorption. Furthermore, Cr and Re could serve as active sites for hydrogen evolution with remarkably lowered overpotentials of 0.79 V and 0.28 V, respectively;similarly, oxygen evolution activities could be enhanced by Fe, Co and Rh because of their reduced overpotentials which are less than 0.5 V. Therefore,our findings pave guidance for designing Cu-BTC derivatives in overall water splitting.
基金supported by the National Natural Science Foundation of China(No.51701239)the University-Industry Collaborative Education Program of MOEinChina(No.BINTECH-KJZX-20220831-35)the Basic-Scientific-Research-Business-Fee Supporting Project of Henan Province,China(Nos.2023KY35,2023KY40).
文摘Localized corrosion of 304 stainless steel being the significant parts of Starship rocket seriously threatens the long-term service of such aerospace equipment.Scanning electron microscopy,in situ instruments combining electrochemical workstation and Raman spectroscopy,and Density Dunctional Theory(DFT)calculations were employed.The surface morphologies,alloying elements,molecular fingerprint Raman evidence and theoretical mechanism for the localized corrosion of 304 stainless steel during the electrochemical polarization in the mixture solutions containing 0.5 mol/L H_(2)SO_(4) and 2,2'-bipyridine(bipy)with concentrations of 0.001,0.010,0.100 mol/L were discussed.In comparison,the presence of bipy up to 0.100 mol/L in such mixture solutions displayed the neglectable effect on the Fe(Ⅱ)/Fe(Ⅲ)reaction in the polarization process.Raman vibrational frequency around 1492 cm^(-1)was the evidence of pink color appearance due to the formation of[Fe^(Ⅱ)(bipy)_(3)]^(2+).Raman and DFT indicated the yellow color emergence due to the presence ofμ-O-[Fe^(Ⅲ)(bipy)_(2)(H_(2)O)]_(2)^(4+)due to the oxidation reaction of[Fe^(Ⅱ)(bipy)_(3)]^(2+)with H_(2)O_(2) oxidant,and the dimerization of[Fe^(Ⅲ)(bipy)_(3)]^(3+),Furthermore,a quantitative model between[Fe^(Ⅱ)(bipy)_(3)]^(2+)concentration and Raman intensity at 1492 cm^(-1) has been built up.Two linear functions were revealed when[Fe^(Ⅱ)(bipy)_(3)]^(2+)concentrations were at 0-0.002 mol/L and 0.002-0.004 mol/L and a concentration error of less than 5%was evidenced in comparison with that investigated by the inductively coupled plasma.The proposed passivation mechanism and quantitative concentration model of 304 stainless steel have certain significance for its corrosion protection andcorrosionevaluation.
基金supported by National Key Research and Development Program of China under Grant 2024YFE0210800National Natural Science Foundation of China under Grant 62495062Beijing Natural Science Foundation under Grant L242017.
文摘The Dynamical Density Functional Theory(DDFT)algorithm,derived by associating classical Density Functional Theory(DFT)with the fundamental Smoluchowski dynamical equation,describes the evolution of inhomo-geneous fluid density distributions over time.It plays a significant role in studying the evolution of density distributions over time in inhomogeneous systems.The Sunway Bluelight II supercomputer,as a new generation of China’s developed supercomputer,possesses powerful computational capabilities.Porting and optimizing industrial software on this platform holds significant importance.For the optimization of the DDFT algorithm,based on the Sunway Bluelight II supercomputer and the unique hardware architecture of the SW39000 processor,this work proposes three acceleration strategies to enhance computational efficiency and performance,including direct parallel optimization,local-memory constrained optimization for CPEs,and multi-core groups collaboration and communication optimization.This method combines the characteristics of the program’s algorithm with the unique hardware architecture of the Sunway Bluelight II supercomputer,optimizing the storage and transmission structures to achieve a closer integration of software and hardware.For the first time,this paper presents Sunway-Dynamical Density Functional Theory(SW-DDFT).Experimental results show that SW-DDFT achieves a speedup of 6.67 times within a single-core group compared to the original DDFT implementation,with six core groups(a total of 384 CPEs),the maximum speedup can reach 28.64 times,and parallel efficiency can reach 71%,demonstrating excellent acceleration performance.
基金supported by the Project of Shenzhen Science and Technology(Nos.JCYJ20210324095210028 and JSGGZD20220822095201003)the Shenzhen University 2035Program for Excellent Research(No.000003011002)the National Natural Science Foundation of China(No.U21A2087)。
文摘This study explores the molecular design of sulfur-containing polymers with high refractive indices(RI)and optimized Abbe numbers for advanced optical applications.The high molar refraction and low dispersion of sulfur make it an ideal component for enhancing the optical properties of polymers.Density functional theory(DFT)calculations were employed to predict the RI and Abbe numbers for a range of sulfurbased polymers.To improve the accuracy of the theoretical predictions,a correction function was developed by comparing the calculated values with experimental data.The key polymer families investigated included sulfur-containing polycarbonates,heterocyclic optical resins,and cycloolefins,all modified to balance RI enhancement with dispersion control.The results demonstrate that increasing the sulfur content and introducing specific heterocycles and bridged rings can effectively increase the RI while maintaining desirable Abbe numbers.Polymers incorporating 1,4-dithiane and sulfur-bridged rings exhibit excellent optical clarity and minimal visible light absorption,making them suitable for lens and coating applications.The study also calculated the UV-visible spectra for the most promising polymers,confirming their high transparency.This work establishes a predictive framework for developing high-performance optical polymers and offers a systematic approach for balancing the refractive index and dispersion,thereby providing valuable insights for the design of next-generation optical materials.
基金supported by Natural Science Foundation of Jiangsu Province(No.BK20210494)National Natural Science Foundation of China(No.52303356).
文摘In this study,a framework for predicting the gas-sensitive properties of gas-sensitive materials by combining machine learning and density functional theory(DFT)has been proposed.The framework rapidly predicts the gas response of materials by establishing relationships between multisource physical parameters and gas-sensitive properties.In order to prove its effectiveness,the perovskite Cs_(3)Cu_(2)I_(5) has been selected as the representative material.The physical parameters before and after the adsorption of various gases have been calculated using DFT,and then a machine learning model has been trained based on these parameters.Previous studies have shown that a single physical parameter alone is not enough to accurately predict the gas sensitivity of materials.Therefore,a variety of physical parameters have been selected for machine learning,and the final machine learning model achieved 92%accuracy in predicting gas sensitivity.It is important to note that although there have been no previous reports on the response of Cs_(3)Cu_(2)I_(5) to hydrogen sulfide,the resulting model predicts the gas response of H2S;it is subsequently confirmed experimentally.This method not only enhances the understanding of the gas sensing mechanism,but also has a universal nature,making it suitable for the development of various new gas-sensitive materials.
基金supported by the National Key R&D Program of China(No.2022YFA1602000)National Natural Science Foundation of China(Nos.12275081,U2067205,11790325,and U1732138)the Continuous-support Basic Scientific Research Project。
文摘Using the Skyrme density functional theory,potential energy surfaces of^(240)Pu with constraints on the axial quadrupole and octupole deformations(q_(20)and q_(30))were calculated.The volume-like and surface-like pairing forces,as well as a combination of these two forces,were used for the Hartree–Fock–Bogoliubov approximation.Variations in the least-energy fission path,fission barrier,pairing energy,total kinetic energy,scission line,and mass distribution of the fission fragments based on the different forms of the pairing forces were analyzed and discussed.The fission dynamics were studied based on the timedependent generator coordinate method plus the Gaussian overlap approximation.The results demonstrated a sensitivity of the mass and charge distributions of the fission fragments on the form of the pairing force.Based on the investigation of the neutron-induced fission of^(239)Pu,among the volume,mixed,and surface pairing forces,the mixed pairing force presented a good reproduction of the experimental data.
基金This work was supported by the Key Research and Development Program of Shandong Province(No.2019GHY112033)the National Natural Science Foundation of China(No.51609207).
文摘Atrazine causes concern due to its resistant to biodegradation and could be accumulated in aquatic organisms,causing pollution in lakes.This study measured the concentration of atrazine in ice and the water under ice through a simulated icing experiment and calculated the distribution coefficient K to characterize its migration ability in the freezing process.Furthermore,density functional theory(DFT)calculations were employed to expatiate the migration law of atrazine during icing process.According to the results,it could release more energy into the environment when atrazine staying in water phase(-15.077 kcal/mol)than staying in ice phase(-14.388 kcal/mol),therefore it was beneficial for the migration of atrazine from ice to water.This explains that during the freezing process,the concentration of atrazine in the ice was lower than that in the water.Thermodynamic calculations indicated thatwhen the temperature decreases from268 to 248 K,the internal energy contribution of the compound of atrazine and ice molecule(water cluster)decreases at the same vibrational frequency,resulting in an increase in the free energy difference of the compound from-167.946 to-165.390 kcal/mol.This demonstrated the diminished migratory capacity of atrazine.This study revealed the environmental behavior of atrazine during lake freezing,which was beneficial for the management of atrazine and other pollutants during freezing and environmental protection.
基金supported by the National Natural Science Foundation of China under Grant Nos.12122401 and 12074007.
文摘In traditional finite-temperature Kohn–Sham density functional theory(KSDFT),the partial occupation of a large number of high-energy KS eigenstates restricts the use of first-principles molecular dynamics methods at extremely high temperatures.However,stochastic density functional theory(SDFT)can overcome this limitation.Recently,SDFT and the related mixed stochastic–deterministic density functional theory,based on a plane-wave basis set,have been implemented in the first-principles electronic structure software ABACUS[Q.Liu and M.Chen,Phys.Rev.B 106,125132(2022)].In this study,we combine SDFT with the Born–Oppenheimer molecular dynamics method to investigate systems with temperatures ranging from a few tens of eV to 1000 eV.Importantly,we train machine-learning-based interatomic models using the SDFT data and employ these deep potential models to simulate large-scale systems with long trajectories.Subsequently,we compute and analyze the structural properties,dynamic properties,and transport coefficients of warm dense matter.
基金supported by the National Natural Science Foundation of China(Nos.22393912,22425301,22373091,22173088)the AI for Science Foundation of Fudan University(No.Fudan X24AI023)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0450101).
文摘Machine learning(ML)has demon-strated significant potential in en-hancing the predictive capabilities of density functional theory methods.In this study,we develop an ML model for correcting B3LYP-D,a density functional approximation that incorporates dispersion correc-tions for non-covalent interactions.This model utilizes semilocal elec-tron density descriptors,and is trained with accurate reference data for both relative and ab-solute energies.Extensive benchmark tests reveal that the ML correction substantially en-hances the generalization ability of the B3LYP-D functional,improving the predictions of at-omization and dissociation energies for complex molecular systems.It retains the accuracy of B3LYP-D in predicting reaction barrier heights and non-covalent interactions while enabling efficient,fully self-consistent field calculations.This work signifies a promising advancement in the development of ML-corrected functionals that surpass the performance of traditional B3LYP-D.
基金supported by the National Natural Science Foundation of China (No.22136001)the National Key R&D Program of China (No.2022YFC3902100)+2 种基金the Key R&D Program of Hebei Province (No.21374001D)the Supercomputing Center of Dalian University of Technologythe National Supercomputer Center in Tianjin。
文摘As primary degradation products of phthalate esters,phthalate monoesters(MPEs)have been widely detected in various aquatic environments and drawn growing toxicological concerns.Hydrolysis kinetics that is of importance for assessing environmental persistence of chemicals remain elusive for MPEs.Herein,kinetics of base-catalyzed and neutral hydrolysis for 18 MPEs with different leaving groups was investigated by density functional theory calculation.Results indicate that MPEs with leaving groups having p Kaof<10 prefer dissociative transition states.MPEs are more persistent than their parents,and their hydrolysis half-lives were calculated to vary from 3.4 min to 79.2 years(p H=7–9).A quantitative structure-activity relationship model was developed for predicting the hydrolysis kinetics parameters.It was found that p Kaof the leaving groups and electronegativity of the MPEs are key factors determining the hydrolysis kinetics.This work may lay a theoretical foundation for better understanding the chemical process that governs MPE persistence in aquatic environments.
基金the support of the National Natural Science Foundation of China(Grant No.51472074).
文摘Understanding the adsorption interactions between carbon materials and sulfur compounds has far-reaching impacts,in addition to their well-known important role in energy storage and conversion,such as lithium-ion batteries.In this paper,properties of intrinsic B or Si single-atom doped,and B-Si codoped graphene(GR)and graphdiyne(GDY)were investigated by using density functional theory-based calculations,in which the optimal doping configurations were explored for potential applications in adsorbing sulfur compounds.Results showed that both B or Si single-atom doping and B-Si codoping could substantially enhance the electron transport properties of GR and GDY,improving their surface activity.Notably,B and Si atoms displayed synergistic effects for the codoped configurations,where B-Si codoped GR/GDY exhibited much better performance in the adsorption of sulfurcontaining chemicals than single-atom doped systems.In addition,results demonstrated that,after B-Si codoping,the adsorption energy and charge transfer amounts of GDY with sulfur compounds were much larger than those of GR,indicating that B-Si codoped GDY might be a favorable material for more effectively interacting with sulfur reagents.
基金Funded by the Sultan Idris Education University(UPSI)(No.2020-0256-103-02(FRGS/1/2020/STG07/UPSI/02/2))provided by the Ministry of Higher Education,Malaysia。
文摘Calix[n]arenes was utilized to detect PABA,the primary sunscreen component.This study investigates the interaction of calix[4]arene(C4),calix[6]arene(C6),and PABA using the Langmuir method and first-principle density functional theory(DFT).Using the Langmuir-Schaefer(LS)technique,an ultrathin film composed of calix[n]arenes and their complexes with PABA was deposited on various substrates.Based on the Langmuir study,the PABA molecule was bonded to the lower rims of both C4 and C6 with the host-vip ratio of 1:1.All of the LS films formed were then characterized by ultravioletvisible spectroscopy(UV-Vis),Fourier-transform infrared spectroscopy(FTIR)and carbon,hydrogen,nitrogen,sulfur elemental analyzer(CHNS).The band gap reduction obtained in the DFT study denotes the charge transfer interaction with promising reactivity between the calix[n]arenes and PABA.The sensing of PABA by C4 and C6 is successful based on the formation of bonding between them due to the hosts’effective trapping capacity.The outcomes of this study could be applied to drug delivery systems for future pharmaceutical and medical applications.
基金supported by the National Natural Science Foundation of China (No.22176067)。
文摘To improve the adsorption and catalytic performance of heterogeneous Fenton-like catalysts for oil wastes,amino acids were used to modify nanoscale zero-valent iron(AA@Fe^(0)),which were applied in the Fenton-like degradation of organic solvents(tributyl phosphate and n-dodecane,named TBP and DD).Twelve amino acids,i.e.,glycine(Gly),alanine(Ala),leucine(Leu),proline(Pro),phenylalanine(Phe),methionine(Met),cysteine(Cys),asparagine(Asn),serine(Ser),glutamic acid(Glu),lysine(Lys)and arginine(Arg),were selected and calculated by density functional theory(DFT).The optimized structure,charge distribution,the highest occupied molecular orbital(HOMO),the lowest unoccupied molecular orbital(LUMO),interaction region indicator(IRI)isosurface map and adsorption energy of AA@Fe^(0),AA@Fe^(0)-TBP and AA@Fe^(0)-DD were studied,which indicated that Fe is more likely to approach and charge transfer with-COO and-NH_(3) on theα-carbon of amino acids.There is strong attraction between Fe and–COO,and Van der Waals force between Fe and-NH_(3),respectively.In the interaction of AA@Fe^(0)with TBP and DD,Van der Waal force plays an important role.AA@Fe^(0)was synthesized in laboratory and characterized to investigate physicochemical properties.In Fenton-like degradation of organic solvents,the change of COD in water phase during the degradation process as well as the volume of the organic phase after the reaction were investigated.The results of calculations combined with experiments showed that Ser-modified Fe^(0)performed the best in these amino acids,with 98%removal of organic solvents.A possible catalytic mechanism was proposed in which amino acids acted a linking role between Fe and organic solvents,activating H_(2)O_(2)to generate hydroxyl radicals for the degradation of organic solvents.
基金financially supported by the National Natural Science Foundation of China (Nos. 52293373 and 52130205)the National Key Research and Development Program of China (No. 2021YFA0715803)ND Basic Research Funds of Northwestern Polytechnical University, China (No. G2022WD)
文摘Recently,the preparation of ultra-high temperature HfC ceramic coating has gained significant attention,particularly through the application of the HfCl_(4)-CH_(4)-H_(2)-Ar system via Chemical Vapor Deposition(CVD),which has been found widely applied to C/C composites.Herein,an analysis of the reactions that occur in the initial stage of the CVD-HfC coating process is presented using Density Functional Theory(DFT)and Transition State Theory(TST)at the B3LYP/Lanl2DZ level.The results reveal that HfCl4 can only cleave to produce hypochlorite,which will further react with methyl to synthesize intermediates to form HfC.According to the analysis of the energy barrier and reaction constant,HfCl preferentially reacts with methyl groups to form complex adsorptive intermediates at 1573 K.With a C—Hf bond production energy of 212.8 kcal/mol(1 kcal=4.18 kJ),the reaction rate constant of HfCl+CH is calculated to be 2.15×10^(-18) cm^(3)/s at 1573 K.Additionally,both the simulation and experimental results exhibit that the upward trend of reaction rate constants with temperature is also consistent with the deposition rate,indicating that the growth curve of the reaction rate constants tends to flatten out.The proposed reaction model of the precursor’s decomposition and reconstruction during deposition process has significant implication for the process guidance.
文摘The conversion of solar energy to chemical energies by virtue of semiconductor photocatalysis has shown great significance in sustaining future energy demands,and have a deep understanding of the relationship between photocatalyst and photocatalytic activity is essential.Density functional theory(DFT)calculations are becoming increasingly important for revealing the intrinsic electronic structure properties of materials and energy properties of reactions,which has been greatly developed with the development of computational methods.In this review,the applications of DFT calculations in photocatalysis are summarized and exemplified by various representative investigations in the up-to-date reports.To specify,we show how to collect,analyse and utilize the informations on photocatalysts and photocatalytic reactions with the help of the DFT calculations,such as electronic structures,surface catalytic sites,catalytic activities,possible reaction mechanisms,etc.Our discussion is intended to provide an overview on applications of the current theoretical calculations in the field of photocatalysis for a better understanding of the composition-structure-function relationships,and also to guide future experiments and computations toward the understanding and development of novel solar-energy-conversion catalysts.
文摘Polarons are widely considered to play a crucial role in the charge transport and photocatalytic performance of materials,but the mechanisms of their formation and the underlying driving factors remain a matter of controversy.This study delves into the formation of polarons in different crystalline forms of TiO_(2) and their connection with the materials'structure.By employing density functional theory calculations with on-site Coulomb interaction correction(DFT+U),we provide a detailed analysis of the electronic polarization behavior in the anatase and rutile forms of TiO_(2).We focus on the polarization properties of defect-induced and photoexcited excess electrons on various TiO_(2) surfaces.The results reveal that the defect electrons can form small polarons on the anatase TiO_(2)(101)surface,while on the rutile TiO_(2)(110)surface,both small and large polarons(hybrid-state polarons)are formed.Photoexcited electrons are capable of forming both small and large polarons on the surfaces of both crystal types.The analysis indicates that the differences in polaron distribution are primarily determined by the intrinsic properties of the crystals;the structural and symmetry differences between anatase and rutile TiO_(2) lead to the distinct polaron behaviors.Further investigation suggests that the polarization behavior of defect electrons is also related to the arrangement of electron orbitals around the Ti atoms,while the polarization of photoexcited electrons is mainly facilitated by the lattice distortions.These findings elucidate the formation mechanisms of different types of polarons and may contribute to understanding the performance of TiO_(2)in different fields.
