High responsivity photodetectors based on graphene/WSe_(2) heterostructure by photogating effect

Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency and rapid recombination of photoexcited carriers, leading to poor photodetection performance. Here, inspired by the photogating effect, we demonstrated a highly sensitive photodetector based on graphene/WSe_(2) vertical heterostructure where the WSe_(2) layer acts as both the light absorption layer and the localized grating layer. The graphene conductive channel is induced to produce more carriers by capacitive coupling. Due to the strong light absorption and high external quantum efficiency of multilayer WSe_(2), as well as the high carrier mobility of graphene, a high photocurrent is generated in the vertical heterostructure. As a result, the photodetector exhibits ultra-high responsivity of 3.85×10~4A/W and external quantum efficiency of 1.3 × 10~7%.This finding demonstrates that photogating structures can effectively enhance the sensitivity of graphene-based photodetectors and may have great potential applications in future optoelectronic devices.

Reinforced Lewis covalent bond by twinborn nitride heterostructure for lithium-sulfur batteries

The practical application of lithium-sulfur(Li-S)batteries,as promising next-generation batteries,is hindered by their shuttle effect and the slow redox kinetics.Herein,a tungsten and molybdenum nitride heterostructure functionalized with hollow metal-organic framework-derived carbon(W_(2)N/Mo_(2)N)was proposed as the sulfur host.The hollow spherical structure provides storage space for sulfur,enhances electrical conductivity,and inhibits volume expansion.The metal atoms in the nitrides bonded with lithium polysulfides(Li PSs)through Lewis covalent bonds,enhancing the high catalytic activity of the nitrides and effectively reducing the energy barrier of Li PSs redox conversion.Moreover,the high intrinsic conductivity of nitrides and the ability of the heterostructure interface to accelerate electron/ion transport improved the Li+transmission.By leveraging the combined properties of strong adsorption and high catalytic activity,the sulfur host effectively inhibited the shuttle effect and accelerated the redox kinetics of Li PSs.High-efficiency Li+transmission,strong adsorption,and the efficient catalytic conversion activities of Li PSs in the heterostructure were experimentally and theoretically verified.The results indicate that the W_(2)N/Mo_(2)N cathode provides stable,and long-term cycling(over 2000 cycles)at 3 C with a low attenuation rate of 0.0196%per cycle.The design strategy of a twinborn nitride heterostructure thus provides a functionalized solution for advanced Li-S batteries.

Visible-to-near-infrared photodetectors based on SnS/SnSe_(2)and SnSe/SnSe_(2)p−n heterostructures with a fast response speed and high normalized detectivity

The emergent two-dimensional(2D)material,tin diselenide(SnSe_(2)),has garnered significant consideration for its potential in image capturing systems,optical communication,and optoelectronic memory.Nevertheless,SnSe_(2)-based photodetection faces obstacles,including slow response speed and low normalized detectivity.In this work,photodetectors based on SnS/SnSe_(2)and SnSe/SnSe_(2)p−n heterostructures have been implemented through a polydimethylsiloxane(PDMS)−assisted transfer method.These photodetectors demonstrate broad-spectrum photoresponse within the 405 to 850 nm wavelength range.The photodetector based on the SnS/SnSe_(2)heterostructure exhibits a significant responsivity of 4.99×10^(3)A∙W^(−1),normalized detectivity of 5.80×10^(12)cm∙Hz^(1/2)∙W^(−1),and fast response time of 3.13 ms,respectively,owing to the built-in electric field.Meanwhile,the highest values of responsivity,normalized detectivity,and response time for the photodetector based on the SnSe/SnSe_(2)heterostructure are 5.91×10^(3)A∙W^(−1),7.03×10^(12)cm∙Hz^(1/2)∙W−1,and 4.74 ms,respectively.And their photodetection performances transcend those of photodetectors based on individual SnSe_(2),SnS,SnSe,and other commonly used 2D materials.Our work has demonstrated an effective strategy to improve the performance of SnSe_(2)-based photodetectors and paves the way for their future commercialization.

From charge storage mechanism to performance:A strategy toward boosted lithium/sodium storage through heterostructure optimization

Solving the problems of low electrical conductivity and poor cycling durability in transition metal oxidesbased anode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has already turned into an urgent requirement.In this paper,we successfully synthesized Co_(2)VO_(4)/Co compounds with Co-VMOF(metal-organic framework)as a sacrificial template and investigated their electrochemical mechanism in order to improve the electrochemical properties of LIBs and SIBs.The optimized heaping configuration and the existence of metallic Co catalyzed the formation of radical ions,thereby facilitating higher conductivity,shortening Li+and Na+transport paths,and providing more active sites.Co_(2)VO_(4)/Co constructed with 2-methylimidazole as a ligand showed a discharge capacity of 1605.1 mA h g^(-1)after 300 cycles at 0.1 A g^(-1)in LIB and 677.2 mA h g^(-1)in SIB.Density functional theory(DFT)calculation emphasizes the crucial role of Co_(2)VO_(4)/Co in enhancing electrode conductivity,decreasing the migratory energy barrier,and thereby strengthening electrochemical properties.This heterostructure building technique may pave the way for the development of high-performance LIBs and SIBs.Furthermore,the problem of the low first-loop coulombic efficiency faced by transition metal oxides is improved.

Atomic-level coupled RuO_(2)/BaRuO_(3) heterostructure for efficient alkaline hydrogen evolution reaction

The slow water dissociation is the rate-determining step that slows down the reaction rate in alkaline hydrogen evolution reaction(HER).Optimizing the surface electronic structure of the catalyst to lower the energy barrier of water dissociation and regulating the binding strength of adsorption intermediates are crucial strategy for boosting the catalytic performance of HER.In this study,RuO_(2)/BaRuO_(3)(RBRO)heterostructures with abundant oxygen vacancies and lattice distortion were in-situ constructed under a low temperature via the thermal decomposition of gel-precursor.The RBRO heterostructures obtained at 550℃ exhibited the highest HER activity in 1 M KOH,showing an ultra-low overpotential of 16 mV at 10 mA cm^(-2)and a Tafel slope of 33.37 m V dec^(-1).Additionally,the material demonstrated remarkable durability,with only 25 mV of degradation in overpotential after 200 h of stability testing at 10 mA cm^(-2).Density functional theory calculations revealed that the redistribution of charges at the heterojunction interface can optimize the binding energies of H*and OH*and effectively lower the energy barrier of water dissociation.This research offers novel perspectives on surpassing the water dissociation threshold of alkaline HER catalysts by means of a systematic design of heterogeneous interfaces.

Twisted Integration of Complex Oxide Magnetoelectric Heterostructures via Water‑Etching and Transfer Process

Manipulating strain mode and degree that can be applied to epitaxial complex oxide thin films have been a cornerstone of strain engineering.In recent years,lift-off and transfer technology of the epitaxial oxide thin films have been developed that enabled the integration of heterostructures without the limitation of material types and crystal orientations.Moreover,twisted integration would provide a more interesting strategy in artificial magnetoelectric heterostructures.A specific twist angle between the ferroelectric and ferromagnetic oxide layers corresponds to the distinct strain regulation modes in the magnetoelectric coupling process,which could provide some insight in to the physical phenomena.In this work,the La_(0.67)Sr_(0.33)MnO_(3)(001)/0.7Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.3PbTiO_(3)(011)(LSMO/PMN-PT)heterostructures with 45.and 0.twist angles were assembled via water-etching and transfer process.The transferred LSMO films exhibit a fourfold magnetic anisotropy with easy axis along LSMO<110>.A coexistence of uniaxial and fourfold magnetic anisotropy with LSMO[110]easy axis is observed for the 45°Sample by applying a 7.2 kV cm^(−1)electrical field,significantly different from a uniaxial anisotropy with LSMO[100]easy axis for the 0°Sample.The fitting of the ferromagnetic resonance field reveals that the strain coupling generated by the 45°twist angle causes different lattice distortion of LSMO,thereby enhancing both the fourfold and uniaxial anisotropy.This work confirms the twisting degrees of freedom for magnetoelectric coupling and opens opportunities for fabricating artificial magnetoelectric heterostructures.

Heterostructured Pt-Ni_(3)Mo_(3)N formed via ammonia-containing polyoxometalates for highly efficient electrocatalytic hydrogen evolution in acid medium

Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4)]·5H_(2)O polyoxometalates(NiMo_(6))are adopted as the cluster precursors for simple fabrication of heterostructured Pt-Ni_(3)Mo_(3)N nanohybrids supported by carbon black(Pt-Ni_(3)Mo_(3)N/C)without using additional N sources.The improved porosity and enhanced electronic interaction of Pt-Ni_(3)Mo_(3)N/C should be attributed to the integration of Pt with NiMo_(6),which favors the mass transport,promotes the formation of exposed catalytic sites,and benefits the regulation of intrinsic activity.Thus,the as-obtained Pt-Ni_(3)Mo_(3)N/C exhibits impressive and durable HER performance as indicated by the low overpotential of 13.7 mV at the current density of 10 mA cm^(-2) and the stable overpotential during continuous working at 100 mA cm^(-2) for 100 h.This work provides significant insights for the synthesis of new highly active heterostructured electrocatalysts for renewable energy devices.

Revealing interfacial charge redistribution of homologous Ru-RuS_(2) heterostructure toward robust hydrogen oxidation reaction

Precisely tailoring the surface electronic structures of electrocatalysts for optimal hydrogen binding energy and hydroxide binding energy is vital to improve the sluggish kinetics of hydrogen oxidation reac-tion(HOR).Herein,we employ a partial desulfurization strategy to construct a homologous Ru-RuS_(2) heterostructure anchored on hollow mesoporous carbon nanospheres(Ru-RuS_(2)@C).The disparate work functions of the heterostructure contribute to the spontaneous formation of a unique built-in electric field,accelerating charge transfer and boosting conductivity of electrocatalyst.Consequently,Ru-RuS_(2)@C exhibits robust HOR electrocatalytic activity,achieving an exchange current density and mass activity as high as 3.56 mA cm^(-2) and 2.13 mAμg_(Ru)^(-1),respectively.exceeding those of state-of-the-art Pt/C and most contemporary Ru-based HOR electrocatalysts.Surprisingly,Ru-RuS_(2)@C can tolerate 1000 ppm of cO that lacks in Pt/C.Comprehensive analysis reveals that the directional electron transfer across Ru-RuS_(2) heterointerface induces local charge redistribution in interfacial region,which optimizes and balances the adsorption energies of H and OH species,as well as lowers the energy barrier for water formation,thereby promoting theHoR performance.

Phonon resonance modulation in weak van der Waals heterostructures:Controlling thermal transport in graphene-silicon nanoparticle systems

The drive for efficient thermal management has intensified with the miniaturization of electronic devices.This study explores the modulation of phonon transport within graphene by introducing silicon nanoparticles influenced by van der Waals forces.Our approach involves the application of non-equilibrium molecular dynamics to assess thermal conductivity while varying the interaction strength,leading to a noteworthy reduction in thermal conductivity.Furthermore,we observe a distinct attenuation in length-dependent behavior within the graphene-nanoparticles system.Our exploration combines wave packet simulations with phonon transmission calculations,aligning with a comprehensive analysis of the phonon transport regime to unveil the underlying physical mechanisms at play.Lastly,we conduct transient molecular dynamics simulations to investigate interfacial thermal conductance between the nanoparticles and the graphene,revealing an enhanced thermal boundary conductance.This research not only contributes to our understanding of phonon transport but also opens a new degree of freedom for utilizing van der Waals nanoparticle-induced resonance,offering promising avenues for the modulation of thermal properties in advanced materials and enhancing their performance in various technological applications.

Rational design of vitamin C/defective carbon van der Waals heterostructure for enhanced activity,durability and storage stability toward oxygen reduction reaction

Metal-free defective carbon materials with abundant active sites have been widely studied as low-cost and efficient oxygen reduction reaction(ORR)electrocatalysts in metal-air batteries.However,the active sites in defective carbon are easily subjected to serious oxidation or hydroxylation during ORR or storage,leading to rapid degradation of activity.Herein,we design a van der Waals heterostructure comprised of vitamin C(VC)and defective carbon(DC)to not only boost the activity but also enhance the durability and storage stability of the DC-VC electrocatalyst.The formation of VC van der Waals between DC and VC is demonstrated to be an effective strategy to protect the defect active sites from oxidation and hydroxylation degradation,thus significantly enhancing the electrochemical durability and storage anti-aging performance.Moreover,the DC-VC van der Waals can reduce the reaction energy barrier to facilitate the ORR.These findings are also confirmed by operando Fourier transform infrared spectroscopy and density functional theory calculations.It is necessary to mention that the preparation of this DC-VC electrocatalyst can be scaled up,and the ORR performance of the largely produced electrocatalyst is demonstrated to be very consistent.Furthermore,the DC-VC-based aluminum-air batteries display very competitive power density with good performance maintenance.

Electrically-driven ultrafast out-of-equilibrium light emission from hot electrons in suspended graphene/hBN heterostructures

Nanoscale light sources with high speed of electrical modulation and low energy consumption are key components for nanophotonics and optoelectronics.The record-high carrier mobility and ultrafast carrier dynamics of graphene make it promising as an atomically thin light emitter which can be further integrated into arbitrary platforms by van der Waals forces.However,due to the zero bandgap,graphene is difficult to emit light through the interband recombination of carriers like conventional semiconductors.Here,we demonstrate ultrafast thermal light emitters based on suspended graphene/hexagonal boron nitride(Gr/hBN)heterostructures.Electrons in biased graphene are significantly heated up to 2800 K at modest electric fields,emitting bright photons from the near-infrared to the visible spectral range.By eliminating the heat dissipation channel of the substrate,the radiation efficiency of the suspended Gr/hBN device is about two orders of magnitude greater than that of graphene devices supported on SiO2or hBN.Wefurther demonstrate that hot electrons and low-energy acoustic phonons in graphene are weakly coupled to each other and are not in full thermal equilibrium.Direct cooling ofhigh-temperature hot electrons to low-temperature acoustic phonons is enabled by the significant near-field heat transfer at the highly localized Gr/hBN interface,resulting in ultrafast thermal emission with up to 1 GHz bandwidth under electrical excitation.It is found thatsuspending the Gr/hBN heterostructures on the SiO2trenches significantly modifies the light emission due to the formation of the optical cavity and showed a~440%enhancement inintensity at the peak wavelength of 940 nm compared to the black-body thermal radiation.The demonstration of electrically driven ultrafast light emission from suspended Gr/hBNheterostructures sheds the light on applications of graphene heterostructures in photonicintegrated circuits,such as broadband light sources and ultrafast thermo-optic phase modulators.

Electronic property and topological phase transition in a graphene/CoBr_(2) heterostructure

Recently,significant experimental advancements in achieving topological phases have been reported in van der Waals(vdW)heterostructures involving graphene.Here,using first-principles calculations,we investigate graphene/CoBr_(2)(Gr/CoBr_(2))heterostructures and find that an enhancement of in-plane magnetic anisotropy(IMA)energy in monolayer CoBr_(2) can be accomplished by reducing the interlayer distance of the vdW heterostructures.In addition,we clarify that the enhancement of IMA energy primarily results from two factors:one is the weakness of the Co-d_(xy) and Co-d_(x^(2)-y^(2)) orbital hybridization and the other is the augmentation of the Co-d_(yz) and Co-d_(z)2 orbital hybridization.Meanwhile,calculation results suggest that the Kosterlitz–Thouless phase transition temperature(TKT)of a 2D XY magnet Gr/CoBr_(2)(23.8 K)is higher than that of a 2D XY monolayer CoBr_(2)(1.35 K).By decreasing the interlayer distances,the proximity effect is more pronounced and band splitting appears.Moreover,by taking into account spin–orbit coupling,a band gap of approximately 14.3 meV and the quantum anomalous Hall effect(QAHE)are attained by decreasing the interlayer distance by 1.0 A.Inspired by the above conclusions,we design a topological field transistor device model.Our results support that the vdW interlayer distance can be used to modulate the IMA energy and QAHE of materials,providing a pathway for the development of new low-power spintronic devices.

Construction of MnS/MoS_(2) heterostructure on two-dimensional MoS_(2) surface to regulate the reaction pathways for high-performance Li-O_(2) batteries

The inherent catalytic anisotropy of two-dimensional(2D) materials has limited the enhancement of LiO_(2) batteries(LOBs) performance due to the significantly different adsorption energies on 2D and edge surfaces.Tuning the adsorption strength in 2D materials to the reaction intermediates is essential for achieving high-performance LOBs.Herein,a MnS/MoS_(2) heterostructure is designed as a cathode catalyst by adjusting the adsorption behavior at the surface.Different from the toroidal-like discharge products on the MoS_(2) cathode,the MnS/MoS_(2) surface displays an improved adsorption energy to reaction species,thereby promoting the growth of the film-like discharge products.MnS can disturb the layer growth of MoS_(2),in which the stack edge plane features a strong interaction with the intermediates and limits the growth of the discharge products.Experimental and theoretical results confirm that the MnS/MoS_(2) heterostructure possesses improved electron transfer kinetics at the interface and plays an important role in the adsorption process for reaction species,which finally affects the morphology of Li_2O_(2),In consequence,the MnS/MoS_(2) heterostructure exhibits a high specific capacity of 11696.0 mA h g^(-1) and good cycle stability over 1800 h with a fixed specific capacity of 600 mA h g^(-1) at current density of100 mA g^(-1) This work provides a novel interfacial engineering strategy to enhance the performance of LOBs by tuning the adsorption properties of 2D materials.

Bimetallic selenide heterostructure with directional built-in electricfield confined in N-doped carbon nanofibers for superior sodium storage with ultralong lifespan

Constructing heterostructure is considered as an effective strategy to address the sluggish electronic and ionic kinetics of anode materials for sodium ion batteries(SIBs).However,realizing the orientated growth and uniform distribution of the heterostructure is still a great challenge.Herein,the regulated novel CoSe_(2)/NiSe_(2)heterostructure confined in N-doped carbon nanofibers(CoSe_(2)/NiSe_(2)@N-C)are prepared by using Co/Ni-ZIF template,in which,the CoSe_(2)/NiSe_(2)heterostructures realize uniform distribution on a micro level.Benefiting from the unique heterostructure and N-doped carbon nanofibers,the CoSe_(2)/NiSe_(2)@N-C deliveries superior rate capability and durable cycle lifespan with a reversible capacity of 400.5 mA h g^(-1)after 5000 cycles at 2 A g^(-1).The Na-ion full battery with CoSe_(2)/NiSe_(2)@N-C anode and layered oxide cathode displays a remarkable energy density of 563 W h kg^(-1)with 241.1 W kg^(-1)at 0.1 A g^(-1).The theoretical calculations disclose that the periodic and directional built-in electric-field along with the heterointerfaces of CoSe_(2)/NiSe_(2)@N-C can accelerate electrochemical reaction kinetics.The in(ex)situ experimental measurements reveal the reversible conversion reaction and stable structure of CoSe_(2)/NiSe_(2)@N-C during Na+insertion/extraction.The study highlights the potential ability of precisely controlled heterostructure to stimulate the electrochemical performances of advanced anode for SIBs.

Spin transport characteristics modulated by the GeBi interlayer in Y_(3)Fe_(5)O_(12)/GeBi/Pt heterostructures

For the past few years,germanium-based semiconductor spintronics has attracted considerable interest due to its potential for integration into mainstream semiconductor technology.The main challenges in the development of modern semiconductor spintronics are the generation,detection,and manipulation of spin currents.Here,the transport characteristics of a spin current generated by spin pumping through a GeBi semiconductor barrier in Y_(3)Fe_(5)O_(12)/GeBi/Pt heterostructures were investigated systematically.The effective spin-mixing conductance and inverse spin Hall voltage to quantitatively describe the spin transport characteristics were extracted.The spin-injection efficiency in the Y_(3)Fe_(5)O_(12)/GeBi/Pt heterostructures is comparable to that of the Y_(3)Fe_(5)O_(12)/Pt bilayer,and the inverse spin Hall voltage exponential decays with the increase in the barrier thickness.Furthermore,the band gap of the GeBi layer was tuned by changing the Bi content.The spin-injection efficiency at the YIG/semiconductor interface and the spin transportation within the semiconductor barrier are related to the band gap of the GeBi layer.Our results may be used as guidelines for the fabrication of efficient spin transmission structures and may lead to further studies on the impacts of different kinds of barrier materials.

Duplex Interpenetrating-Phase FeNiZn and FeNi_(3)Heterostructure with Low-Gibbs Free Energy Interface Coupling for Highly Efficient Overall Water Splitting

The sluggish kinetics of both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)generate the large overpotential in water electrolysis and thus high-cost hydrogen production.Here,multidimensional nanoporous interpenetrating-phase FeNiZn alloy and FeNi_(3)intermetallic heterostructure is in situ constructed on NiFe foam(FeNiZn/FeNi_(3)@NiFe)by dealloying protocol.Coupling with the eminent synergism among specific constituents and the highly efficient mass transport from integrated porous backbone,FeNiZn/FeNi_(3)@NiFe depicts exceptional bifunctional activities for water splitting with extremely low overpotentials toward OER and HER(η_(1000)=367/245 mV)as well as the robust durability during the 400 h testing in alkaline solution.The as-built water electrolyzer with FeNiZn/FeNi_(3)@NiFe as both anode and cathode exhibits record-high performances for sustainable hydrogen output in terms of much lower cell voltage of 1.759 and 1.919 V to deliver the current density of 500 and 1000 mA cm^(-2)as well long working lives.Density functional theory calculations disclose that the interface interaction between FeNiZn alloy and FeNi_(3)intermetallic generates the modulated electron structure state and optimized intermediate chemisorption,thus diminishing the energy barriers for hydrogen production in water splitting.With the merits of fine performances,scalable fabrication,and low cost,FeNiZn/FeNi_(3)@NiFe holds prospective application potential as the bifunctional electrocatalyst for water splitting.

Pea-like MoS_(2)@NiS_(1.03)-carbon heterostructured hollow nanofibers for high-performance sodium storage

The rational synergy of chemical composition and spatial nanostructures of electrode materials play important roles in high-performance energy storage devices.Here,we designed pea-like MoS_(2)@NiS_(1.03)-carbon hollow nanofibers using a simple electrospinning and thermal treatment method.The hierarchical hollow nanofiber is composed of a nitrogen-doped carbon-coated NiS_(1.03) tube wall,in which pea-like uniformly discrete MoS_(2) nanoparticles are enclosed.As a sodium-ion battery electrode material,the MoS_(2)@NiS_(1.03)-carbon hollow nanofibers have abundant diphasic heterointerfaces,a conductive network,and appropriate volume variation-buffering spaces,which can facilitate ion diffusion kinetics,shorten the diffusion path of electrons/ion,and buffer volume expansion during Na^(+)insertion/extraction.It shows outstanding rate capacity and long-cycle performance in a sodium-ion battery.This heterogeneous hollow nanoarchitectures designing enlightens an efficacious strategy to boost the capacity and long-life stability of sodium storage performance of electrode materials.

Epitaxially Grown Ru Clusters-Nickel Nitride Heterostructure Advances Water Electrolysis Kinetics in Alkaline and Seawater Media

The epitaxial heterostructure can be rationally designed based on the in situ growth of two compatible phases with lattice similarity,in which the modulated electronic states and tuned adsorption behaviors are conducive to the enhancement of electrocatalytic activity.Herein,theoretical simulations first disclose the charge transfer trend and reinforced inherent electron conduction around the epitaxial heterointerface between Ru clusters and Ni_(3)N substrate(cRu-Ni_(3)N),thus leading to the optimized adsorption behaviors and reduced activation energy barriers.Subsequently,the defectrich nanosheets with the epitaxially grown cRu-Ni_(3)N heterointerface are successfully constructed.Impressively,by virtue of the superiority of intrinsic activity and reaction kinetics,such unique epitaxial heterostructure exhibits remarkable bifunctional catalytic activity toward electrocatalytic OER(226 mV@20 mA cm^(−2))and HER(32 mV@10 mA cm^(−2))in alkaline media.Furthermore,it also shows great application prospect in alkaline freshwater and seawater splitting,as well as solar-to-hydrogen integrated system.This work could provide beneficial enlightenment for the establishment of advanced electrocatalysts with epitaxial heterointerfaces.

Organic-Inorganic Interaction Recorded by Polycyclic Aromatic Steranes in Continental Epithermal Ore Deposits

Continental epithermal ore deposits are commonly associated with sedimentary organic matter,oils or solid bitumen.These organics embedded in mineral deposits can convey valuable information of the ore genesis.However,the extent to which the formation of ore minerals was recorded by organic compounds remains largely unknown,as also is how metal-rich ores interfere with the molecular proxies in the temperature regime envisaged for hydrothermal activity.The molecular compositional changes of various polycyclic aromatic steranes and polycyclic aromatic hydrocarbons and compounds derived from the Jinding Pb/Zn deposit,SW China provide new data.Aliphatic regular steranes are present as traces.The transformation from polycyclic aromatic steranes to unsubstituted polycyclic aromatic hydrocarbons is observed to show an increased trend with increasing hydrothermal alteration levels;this is consistent with the transformation from unsubstituted polycyclic aromatic hydrocarbons to heterocyclic compounds.Dehydrocyclization(aromatization)of polycyclic biological compounds and hydrodecyclization(dearomatization)of polycyclic aromatic compounds are two important reaction pathways in hydrothermal systems with moderate temperature.This detailed investigation of organicinorganic interactions of two groups of polycyclic compounds with metal-rich ores provides insights into the questions on how and to what extent the formation of Pb/Zn deposits can be recorded by organics.This work will improve our understanding of carbon reduction,oxidation or condensation in the deep Earth and the carbon exchange between the Earth's crust and mantle,and may shed light on the processes for ultra-deep hydrocarbon exploration.

Additive manufacturing of promising heterostructure for biomedical applications

As a new generation of materials/structures,heterostructure is characterized by heterogeneous zones with dramatically different mechanical,physical or chemical properties.This endows heterostructure with unique interfaces,robust architectures,and synergistic effects,making it a promising option as advanced biomaterials for the highly variable anatomy and complex functionalities of individual patients.However,the main challenges of developing heterostructure lie in the control of crystal/phase evolution and the distribution/fraction of components and structures.In recent years,additive manufacturing techniques have attracted increasing attention in developing heterostructure due to the unique flexibility in tailored structures and synthetic multimaterials.This review focuses on the additive manufacturing of heterostructure for biomedical applications.The structural features and functional mechanisms of heterostructure are summarized.The typical material systems of heterostructure,mainly including metals,polymers,ceramics,and their composites,are presented.And the resulting synergistic effects on multiple properties are also systematically discussed in terms of mechanical,biocompatible,biodegradable,antibacterial,biosensitive and magnetostrictive properties.Next,this work outlines the research progress of additive manufacturing employed in developing heterostructure from the aspects of advantages,processes,properties,and applications.This review also highlights the prospective utilization of heterostructure in biomedical fields,with particular attention to bioscaffolds,vasculatures,biosensors and biodetections.Finally,future research directions and breakthroughs of heterostructure are prospected with focus on their more prospective applications in infection prevention and drug delivery.