查看更多>>摘要：Additive manufacturing features rapid production of complicated shapes and has been widely em-ployed in biomedical,aeronautical and aerospace applications.However,additive manufactured parts generally exhibit deteriorated fatigue resistance due to the presence of random defects and anisotropy,and the prediction of fatigue properties remains challenging.In this paper,recent advances in fatigue life prediction of additive manufactured metallic alloys via machine learning models are reviewed.Based on artificial neural network,support vector machine,random forest,etc.,a number of models on various systems were proposed to reveal the relationships between fatigue life/strength and de-fect/microstructure/parameters.Despite the success,the predictability of the models is limited by the amount and quality of data.Moreover,the supervision of physical models is pivotal,and machine learn-ing models can be well enhanced with appropriate physical knowledge.Lastly,future challenges and di-rections for the fatigue property prediction of additive manufactured parts are discussed.
查看更多>>摘要：Photo-rechargeable batteries can implement solar energy harvesting and storage simultaneously and have attracted strong interest from researchers.The development of photoactive electrodes is the key to pro-moting the development of high-performance photocells.Herein,a free-standing BiOI@MWCNTs film is developed as photoelectrode to achieve the effective separation of photogenerated electron-hole pairs for high-efficiency solar-electric-chemical energy conversion.Light can charge up photocells with a photo-conversion efficiency of～1.3％,as well as accelerate charge transfer without requiring any external bias voltage.Ex situ XRD and XPS tests prove that the enhanced electrochemical reaction kinetics can improve the chemical-electric energy conversion efficiency under illumination.The capacity of the proposed pho-tocell can be increased by 10.6％(from 195 mA h g-1 to 216 mA h g-1 at 0.2 A g-1)and 57.9％(from 76 mA h g-1 to 120 mA h g-1at 5.0 A g-1)in light condition,while exhibiting a cyclic life of up to 600 cycles.This work can help to deepen the understanding of photo-rechargeable batteries.
查看更多>>摘要：Hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)relying on high-performance and low-cost single-atom catalysts(SACs)driven by renewable energy sources offer a sus-tainable route to carbon-neutral chemicals and fuels.Herein,first-principles calculations were performed to investigate the catalytic HER/OER/ORR activity of a novel graphitic carbon nitride monolayer(g-C7N3)supported single transition metal(TM@g-C7N3).High stability as well as positively charged active site(TM-site)and desirable electrical conductivity lay the foundation for TM@g-C7N3 acting as efficient HER/OER/ORR electrocatalysts.We screened out the non-noble-metal Rh@g-C7N3 SAC exhibiting great po-tential as the trifunctional electrocatalysts for water splitting(ηHER=0.06 V and ηOER=0.46 V)and a metal-air battery(ηORR=0.28 V)on both kinetic and thermodynamic scales,whereas the Ni@g-C7N3 can be served as a bifunctional OER/ORR catalyst with a low overpotential of 0.33 V/0.31 V,for both of which the high thermodynamic stability and oxidation barrier guarantee their outstanding performances at ambient conditions.The mechanism analysis indicates the filling of d-orbital electrons of TM-atom can play an important role in determining the value of an energy descriptor(△GOH·),and the suitable△GOH.values make for the TM@g-C7N3 candidates to possess favorable OER/ORR overpotential.Particu-larly,the Rh-d orbital of Rh@g-C7N3 is evidently hybridized with the OH*-p orbital,resulting in the lone electrons initially distributed in the antibonding orbital pairing up and occupying the downward bonding orbital,ensuring OH*can be adsorbed on Rh@g-C7N3 appropriately.Moreover,multiple-level descriptors including d-band center,COHP,Nd,and φ are used to reveal the origin of the electrocatalytic activity.
查看更多>>摘要：Solar collector coatings can solve the current energy shortage and environmental pollution by converting clean solar energy into thermal energy.However,once the coating is adhered to a liquid,the performance of the solar thermal conversion will be seriously affected.Here,a cost-effective photothermal superhy-drophobic coating was designed by modulating the microstructure of a highly solar-absorbing material(MCN),followed by a simple spraying method combined with polyvinylidene fluoride resin(PVDF).The MCN in the coating provides excellent photothermal conversion performance,hence,the surface temper-ature of the coating can be rapidly increased to 97.5 ℃ at 1 kW/m2.In addition,the coating achieves a water contact angle(WCA)of 155.79° due to the combined micro-nano structure of MCN and PVDF cou-pled with the low surface energy of PVDF.More importantly,the coating possesses excellent mechanical properties and can be applied to different substrates.This cost-effective photothermal superhydropho-bic coating has promising applications in outdoor environments such as insulated tents and waterproof insulation packaging.
查看更多>>摘要：Recent advancements have shown the effectiveness of strengthening 316L with TiC particles addition through the laser powder bed fusion(LPBF)process.However,the question remains whether TiC under-goes decomposition into Ti and C atoms,primarily because of the challenges associated with measuring C at low concentrations.In this study,we employed atom probe tomography(APT)to provide evidence of decomposition by observing the presence of Ti and C atoms in the 316L matrix.The fast cooling rate of the LPBF process results in the supersaturation of Ti and C in the 316L matrix.Adding 3 wt％TiC particles increased the yield strength of LPBF-processed 316L from 599 MPa to 832 MPa.The subsequent annealing treatment resulted in the formation of more TiC nanoparticles as a result of precipitation from the super-saturated Ti and C in the 316L matrix.Consequently,the yield strength was further enhanced to 959 MPa after annealing at 700 ℃ for 1 h.This study marks the first direct demonstration of the decomposition of TiC in metal matrix composites.
查看更多>>摘要：Developing highly efficient S-scheme photocatalysts is a subject of immense interest for harnessing so-lar energy towards sustainable hydrogen production.Herein,a novel S-scheme heterojunction of oxygen vacancy-rich CoMoO4/CN(CMO/CN)photocatalyst was rationally constructed through loading CoMoO4 nanorods on carbon nitride(CN)nanosheets via a direct one-pot calcination method.The CMO/CN S-scheme heterojunction exhibited enhanced surface area,fine CN dispersion,rich oxygen vacancies,and accelerated charge separation/transfer efficiency,which were conducive to improving photocatalytic H2 evolution performance.Of note,the optimal 3％CMO/CN sample displayed the highest H2 production rate of 8.35 mmol g-1 h-1,which is 4.6 folds that of pristine CN.In situ irradiated X-ray photoelectron spectroscopy(XPS)and electron paramagnetic resonance(EPR)characterizations confirmed the S-scheme charge transfer path between CN and CMO,which greatly promoted spatial charge separation.Density functional theory(DFT)calculations together with contact angle tests revealed the reduced activation energies for H2O dissociation and enhanced hydrophilicity of the CMO/CN.The CMO/CN photocatalysts also presented high stability and fine reusability.This work may provide insights into the combination of defect engineering and heterojunction designing for high-efficiency solar-to-chemical energy conversion.
查看更多>>摘要：Developing innovative photocatalysts for the efficient degradation of pharmaceutical pollutants is crucial in environmental remediation.In this study,we investigate the synthesis of TiO2 nanosheets derived from MXene,specifically integrated onto highly conductive Ti3C2 MXene,and subsequently combined with zinc sulfide(ZnS)to form a heterojunction.This integration process is accomplished using a hydrothermal ap-proach followed by a self-assembly method.We aim to assess the effectiveness of this integrated sys-tem in enhancing the photocatalytic degradation of tetracycline(TC).TiO2/Ti3C2(TT)synthesized in situ exhibits high-energy lattice facets(001)of TiO2 nanosheets,thereby contributing to an exclusive hetero-junction within the TiO2/Ti3C2/ZnS(ZTT)heterostructure.The loading of ZnS nanoparticles significantly increases the surface area with a narrow band gap,enhancing the potential for light emission within the visible region.Consequently,ZnS synergistically affects the ZTTx(where x=wt％of ZnS on TT)het-erostructure matrix,notably promoting the separation and transfer abilities of the photogenerated carri-ers.The ZIT5 heterostructure exhibits remarkable adsorption and photoreduction efficiencies,achieving a 97.1％TC removal in 60 min under UV light.Moreover,under simulated solar light,the ZTT5 heterostruc-ture exhibits an impressive TC removal rate of～93.8％in 90 min.These results highlight the effective performance of the ZTT5 heterojunction catalyst in facilitating photogenerated charge carriers,leading to improved photocatalytic capabilities.Furthermore,the band structure and density of states ofTiO2(101),Ti3C2(002),and ZnS(111)were investigated using density functional theory.In addition,a photoreduc-tion mechanism was proposed for TC,involving the transfer of electrons from TiO2 to the MXene surface.After the transfer,the electrons react with O2 to generate·O2-,attributed to the high electron mobility of MXene.The results of this study emphasize the significant potential of the ZTT5 heterostructure for efficiently degrading pharmaceutical pollutants from wastewater.
Chenjie YaoWanqi RenTejas Dhanalaxmi RajuHo Jin Lee...
200-207页
查看更多>>摘要：In the pursuit to overcome the limitations posed by traditional hole injection layers(HILs),such as PE-DOT:PSS,researchers are focusing on innovative strategies to modify electrode/organic interfaces to facil-itate charge-carrier injection and reduce the turn-on voltage,particularly in the context of high-efficiency organic light-emitting diodes(OLEDs).Two-dimensional materials show great potential in addressing the energy barrier challenges at electrode/organic interfaces owing to their exceptional optoelectronic prop-erties and robust chemical stability.However,their implementation in OLEDs has been hindered by com-plex fabrication processes and work function(WF)mismatches.This study presents a novel approach by introducing a magnetron-sputtered MoTe2 as HIL via two-step O2 doping.This strategy enhances the crystallinity of MoTe2 at a relatively low annealing temperature(350 ℃),combined with a plasma-treated anode possessing high WF(approximately 5.05 eV),high transmittance(93％at 478 nm),and low sheet resistance(33 Ω/sq).Consequently,compared with the conventional blue thermally activated delayed-fluorescence OLED using MoO3 as a HIL,the external quantum efficiency of the manufactured device us-ing MoTe2 as a HIL was improved by 57％and turn-on voltage was reduced to 2.6 V.This study provides a new pathway for overcoming the limitations of conventional solution-based HILs and chemical vapor deposition techniques to industrialize the large-scale manufacturing and commercialization of OLEDs.
查看更多>>摘要：Thermoplastics flammability remains a considerable threat during fire incidents.Conventionally,halogen-free fire retardant(FR)additives are incorporated into thermoplastics to reduce fire hazards.However,the incorporation of FR additives compromises the mechanical properties(most notably,toughness)of thermoplastics,which has impeded the development of thermoplastic products that possess both high mechanical and fire retarding performances.This study reports an in situ nano-fibrillation strategy to fabricate thermoplastics that exhibit fire retarding properties and a combination of high stiffness and toughness.The proposed composites were composed of in situ thermoplastic polyester elastomer(SBC)nanofibers within a polystyrene(PS)matrix containing hexagonal boron nitride(hBN)as the FR addi-tive.The presence of elastomeric nanofibers successfully mitigated the losses in mechanical performances caused by the incorporation of 2 wt％hBN.Specifically,the inclusion of 15 wt％SBC nanofibers signifi-cantly enhanced the toughness of the PS-hBN composite by 350％with negligible effects on the stiffness as compared to neat PS.Furthermore,the presence of nanofibers resulted in synergies with hBN to fab-ricate composites with enhanced fire retarding performance since the total heat release(THR)of PS-hBN composite decreased from 212 to 189 MJ m-2 with 10 wt％nanofibers.Thus,nanofibers behave as a multifunctional component that compensated for the losses in mechanical performances caused by hBN incorporation,while enhancing the fire retarding performance.This strategy can be effectively imple-mented to fabricate the next generation of polymer composites with high fire retarding and mechanical properties for various applications including energy storage packs for batteries and electronics.
查看更多>>摘要：The dependencies of fluxes and forces were paid close attention to the phenomenological theory of On-sager.But in such a case,it seems that the Onsager's reciprocal relations are not necessarily fulfilled.In this work,the problem of thermo-diffusion was chosen as an example and a combination of the first and the second law of thermodynamics was adopted to describe the reversible and the irreversible process.Accordingly,the Gibbs-Duhem relation was found to be followed by not only the equilibrium but also the non-equilibrium thermodynamics,i.e.,the dependency of forces needs to be considered during the derivation of evolution equations.After that,a comparative study between the previous thermodynamic extremal principle(TEP)incorporating only the constraint from fluxes and the present TEP incorporating the constraints from both fluxes and forces was carried out.For the former,the well-known Dufour effect cannot be described,whereas,for the latter,both the well-known Soret effect and the Dufour effect can be predicted.Furthermore,the phenomenological equations were uniquely determined using the present TEP,and Onsager's reciprocal relations were found to be followed,thus solving the problem of the n-fold arbitrariness for the kinetic coefficients pointed out previously.The present work not only extends the TEP to non-isothermal thermodynamics but also might provide guidance for modeling dissipation systems with constraints from both fluxes and forces.
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