A special column highlighting young scientists at Institute of Chemistry, Chinese Academy of Sciences (ICCAS)

Just seeing off the BOth anniversary of the Institute of Chemistry, Chinese Academy of Sciences （ICCAS）, we are here with pleasure to conduct A Special Column for Young Scientists at ICCAS published in Chinese Chemistry Letters （CCL） endeavoring to disseminate positive energy of several enthusiastic chemists and spread their recent research to the global scientific community.

Synthesis and Modulation of Low-Dimensional Transition Metal Chalcogenide Materials via Atomic Substitution

In recent years,low-dimensional transition metal chalcogenide(TMC)materials have garnered growing research attention due to their superior electronic,optical,and catalytic properties compared to their bulk counterparts.The controllable synthesis and manipulation of these materials are crucial for tailoring their properties and unlocking their full potential in various applications.In this context,the atomic substitution method has emerged as a favorable approach.It involves the replacement of specific atoms within TMC structures with other elements and possesses the capability to regulate the compositions finely,crystal structures,and inherent properties of the resulting materials.In this review,we present a comprehensive overview on various strategies of atomic substitution employed in the synthesis of zero-dimensional,one-dimensional and two-dimensional TMC materials.The effects of substituting elements,substitution ratios,and substitution positions on the structures and morphologies of resulting material are discussed.The enhanced electrocatalytic performance and photovoltaic properties of the obtained materials are also provided,emphasizing the role of atomic substitution in achieving these advancements.Finally,challenges and future prospects in the field of atomic substitution for fabricating low-dimensional TMC materials are summarized.

Room Temperature Synthesis of Vertically Aligned Amorphous Ultrathin NiCo-LDH Nanosheets Bifunctional Flexible Supercapacitor Electrodes

Developing a simple scalable method to fabricate electrodes with high capacity and wide voltage range is desired for the real use of electrochemical supercapacitors.Herein,we synthesized amorphous NiCo-LDH nanosheets vertically aligned on activated carbon cloth substrate,which was in situ transformed from Co-metal-organic framework materials nano-columns by a simple ion exchange process at room temperature.Due to the amorphous and vertically aligned ultrathin structure of NiCo-LDH,the NiCo-LDH/activated carbon cloth composites present high areal capacities of 3770 and 1480 mF cm^(-2)as cathode and anode at 2 mA cm^(-2),and 79.5%and 80%capacity have been preserved at 50 mA cm^(-2).In the meantime,they all showed excellent cycling performance with negligible change after>10000 cycles.By fabricating them into an asymmetric supercapacitor,the device achieves high energy densities(5.61 mWh cm^(-2)and 0.352 mW cm^(-3)).This work provides an innovative strategy for simplifying the design of supercapacitors as well as providing a new understanding of improving the rate capabilities/cycling stability of NiCo-LDH materials.

Carboxylates as green corrosion inhibitors of magnesium alloy for biomedical application

The efficiency of the green inhibitors(sodium salts of fumarate,glycolate and gluconate)in suppressing corrosion of the structural MA8 magnesium alloy(Mg–Mn–Ce)and the biomedical Mg–0.8Ca alloy was studied using the hydrogen evolution measurements,mass loss test,EIS,PDP,SVET/SIET.The analysis of the morphology,chemical composition,and growth kinetic of corrosion films formed in 0.9 wt%NaCl solution with and without corrosion inhibitors was carried out.The most compact surface film with the smallest thickness was formed in a saline solution with sodium fumarate.The Mg alloy samples exhibited the highest polarization resistance,the lowest localized electrochemical activity,and the lowest corrosion rate in saline with the addition of sodium fumarate and sodium glycolate.The efficiency of the applied inhibitors was up to 81%.The model of the corrosion mechanism based on the sorption of molecules of organic inhibitors is proposed.The results show the high compatibility of the used inhibitors with the calcium-phosphate PEO-matrix,indicating the possibility of forming a self-healing coating by means of these active substances.

Effect of Ta_(2)O_(5)nanoparticles on bioactivity,composition,structure,in vitro and in vivo behavior of PEO coatings on Mg-alloy

The present study investigates the physical and chemical characteristics,behavior in vitro and in vivo,and biocompatibility of coatings containing Ta_(2)O_(5),which are obtained by plasma electrolytic oxidation(PEO)on MA8 magnesium alloy.The obtained coatings demonstrate in vivo biocompatibility and in vitro bioactivity.Compared to the base PEO coating,the layers containing Ta_(2)O_(5)facilitate the development of apatite in simulated body fluid,suggesting that the inclusion of nanoparticles improves bioactivity of the coatings.It was found that incorporation of Ta_(2)O_(5)nanoparticles increases roughness and porosity of the formed layers by increasing particle concentration in electrolytes for the PEO process contributing to sufficient soft tissue ingrowth in vivo.Based on in vivo studies,these coatings also provide favorable tissue response and minimal inflammatory reaction in comparison with the bare magnesium alloy due to protection of living tissues from deleterious corrosion events of magnesium implant such as local alkalization and intense hydrogen evolution.The results obtained in the present study concluded biocompatibility,tissue integration of the PEO coatings containing Ta_(2)O_(5)nanoparticles making them a promising protective layer for biodegradable magnesium implants.

Effect of Low pH on Forming Process of Desulfurization Gypsum Composite Boards Strengthened by Melamine-formaldehyde Resin

Through exploring the effects of low pH on the composite system of desulfurization gypsum(DG)enhanced by melamine-formaldehyde resin(MF),it is found that the inducing of sulfate-ion,in contrast to chloride and oxalate ions,favors the longitudinal growth of the crystalline form of the hydration product,which was relatively simple and had the highest length to width(L/D)ratio.At the same time,MF can also improve L/D ratio of gypsum hydration products,which favors the formation of hydrated whiskers.Finally,in a composite system composed of hemihydrate gypsum,MF,and glass fibers,when dilute sulfuric acid was used to regulate pH=3-4,the tight binding formed among the components of the composite system compared to pH=5-6.The hydration product of gypsum adheres tightly to glass fiber surface and produces a good cross-linking and binding effect with MF.The flexural strength,compressive strength,elastic modulus,and water absorption of the desulphurized gypsum composite board is 22.7 MPa,39.8 MPa,5608 MPa,and 1.8%,respectively.

Effect of the anionic composition of sulfolane based electrolytes on the performances of lithium-sulfur batteries

In lithium-sulfur batteries,cell design,specifically electrolyte design,has a key impact on the battery performance.The effect of lithium salt anion donor number(DN)(DN[PF_(6)]^(-)=2.5,DN[N(SO_(2)CF_(3))_(2)]^(-)=5.4,DN[ClO_(4)]^(-)=8.4,DN[SO_(3)CF_(3)]^(-)=16.9,and DN[NO_(3)]^(-)=21.1)on the patterns of lithium-sulfur batteries and lithium metal electrode performances with sulfola ne-based electrolytes is investigated.An increase in DN of lithium salt anions leads to an increase in the depth and rate of electrochemical reduction of sulfur and long-chain lithium polysulfides and to a decrease in those for medium-and short-chain lithium polysulfides.DN of lithium salt anions has weak effect on the discharge capacity of lithium-sulfur batteries and the Coulomb efficiency during cycling,with the exception of LiSO_(3)CF_(3)and LiNO_(3).An increase in DN of lithium salt anions leads to an increase in the cycling duration of lithium metal anodes and to a decrease in the presence of lithium polysulfides.In sulfolane solutions of LiNO_(3)and LiSO_(3)CF_(3),lithium polysulfides do not affect the cycling duration of lithium metal anodes.

Approaches to Improving Selectivity During Photoelectrochemical Transformation of Small Molecules

Photoelectrochemical (PEC) small-molecule oxidation can selectively transform substrates into high-value-added fine chemicals and increase the rate of cathode hydrogen evolution. Nevertheless, achieving high-selectivity PEC oxidation of small molecules to produce specific products is a very challenging task. In general, selectivity can be improved by changing the surface catalyticsites of the photoanode and modulating the interfacial environments of the reactions. Herein, recent advances in approaches to improving selective PEC oxidation of small molecules are introduced. We first briefly discuss the basic concept and fundamentals of small-molecule PEC oxidation. The reported approaches to improving the performance of selective PEC oxidation of small molecules are highlighted from two aspects: (1) changing the surface properties of photoanodes by selecting suitable materials or modifying the photoanodes and (2) mediating the oxidation reactions using redox mediators. The PEC oxidation mechanism of these studies is emphasized. We also discuss the challenges in this research direction and offer a perspective on the further development of selective PEC-based small-molecule transformation.

Alleviating the sluggish kinetics of all-solid-state batteries via cathode single-crystallization and multi-functional interface modification

The application of Li-rich Mn-based cathodes, the most promising candidates for high-energy-density Liion batteries, in all-solid-state batteries can further enhance the safety and stability of battery systems.However, the utilization of high-capacity Li-rich cathodes has been limited by sluggish kinetics and severe interfacial issues in all-solid-state batteries. Here, a multi-functional interface modification strategy involving dispersed submicron single-crystal structure and multi-functional surface modification layer obtained through in-situ interfacial chemical reactions was designed to improve the electrochemical performance of Li-rich Mn-based cathodes in all-solid-state batteries. The design of submicron single-crystal structure promotes the interface contact between the cathode particles and the solid-state electrolyte,and thus constructs a more complete ion and electron conductive network in the composite cathode.Furthermore, the Li-gradient layer and the lithium molybdate coating layer constructed on the surface of single-crystal Li-rich particles accelerate the transport of Li ions at the interface, suppress the side reactions between cathodes and electrolyte, and inhibit the oxygen release on the cathode surface. The optimized Li-rich cathode materials exhibit excellent electrochemical performance in halide all-solid-state batteries. This study emphasizes the vital importance of reaction kinetics and interfacial stability of Lirich cathodes in all-solid-state batteries and provides a facile modification strategy to enhance the electrochemical performance of all-solid-state batteries based on Li-rich cathodes.

Introducing hydroxyl groups to tailor the d-band center of Ir atom through side anchoring for boosted ORR and HER

Tuning the coordination atoms of central metal is an effective means to improve the electrocatalytic activity of atomic catalysts.Herein,iridium(Ir) is proposed to be asymmetrically anchored by sp-N and pyridinic N of hydrogen-substituted graphdiyne(HsGDY),and coordinated with OH as an Ir atomic catalyst(Ir_(1)-N-HsGDY).The electron structures,especially the d-band center of Ir atom,are optimized by these specific coordination atoms.Thus,the as-synthesized Ir_(1)-N-HsGDY exhibits excellent electrocatalytic performances for oxygen reduction and hydrogen evolution reactions in both acidic and alkaline media.Benefiting from the unique structure of HsGDY,IrN_(2)(OH)_(3) has been developed and demonstrated to act as the active site in these electrochemical reactions.All those indicate the fresh role of the sp-N in graphdiyne in producing a new anchor way and contributing to promote the electrocatalytic activity,showing a new strategy to design novel electrochemical catalysts.

Probing the Nucleation and Growth Kinetics of Bismuth Nanoparticles via In-situ Transmission Electron Microscopy

The nucleation and growth mechanism of nanoparticles is an important theory,which can guide the preparation of nanomaterials.However,it is still lacking in direct observation on the details of the evolution of intermediate state structure during nucleation and growth.In this work,the evolution process of bismuth nanoparticles induced by electron beam was revealed by in-situ transmission electron microscopy(TEM)at atomic scale.The experimental results demonstrate that the size,stable surface and crystallographic defect have important influences on the growth of Bi nanoparticles.Two non-classical growth paths including single crystal growth and polycrystalline combined growth,as well as,corresponding layer-by-layer growth mechanism along{012}stable crystal plane of Bi nanoparticles with dodecahedron structure were revealed by in-situ TEM directly.These results provide important guidance and a new approach for in-depth understanding of the nucleation and growth kinetics of nanoparticles.

Alkyl chain modulation of asymmetric hexacyclic fused acceptor synergistically with wide bandgap third component for high efficiency ternary organic solar cells

Herein,two asymmetric hexacyclic fused small molecule acceptors(SMAs),namely BP4F-HU and BP4F-UU,were synthesized.The elongated outside chains in the BP4F-UU molecule played a crucial role in optimizing the morphology of blend film,thereby improving charge mobility and reducing energy loss within the corresponding film.Notably,the PM6:BP4F-UU device exhibited a higher open-circuit voltage(V_(oc))of 0.878 V compared to the PM6:BP4F-HU device with a V_(oc)of 0.863 V.Further,a new wide bandgap SMA named BTP-TA was designed and synthesized as the third component to the PM6:BP4F-UU host binary devices,which showed an ideal complementary absorption spectrum in PM6:BP4F-UU system.In addition,BTP-TA can achieve efficient intermolecular energy transfer to BP4F-UU by fluorescence resonance energy transfer(FRET)pathway,due to the good overlap between the photoluminescence(PL)spectrum of BTP-TA and the absorption region of BP4F-UU.Consequently,ternary devices with 15wt%BTP-TA exhibits broader photon utilization,optimal blend morphology,and reduced charge recombination compared to the corresponding binary devices.Consequently,PM6:BP4F-UU:BTP-TA ternary device achieved an optimal power conversion efficiency(PCE)of 17.83%with simultaneously increased V_(oc)of 0.905 V,short-circuit current density(J_(sc))of 26.14 mA/cm^(2),and fill factor(FF)of 75.38%.

Electro‑copolymerized film of ruthenium catalyst and redox mediator for electrocatalytic water oxidation

Electro-copolymerized film containing ruthenium complexes as electron-transfer(or redox)mediators and water-oxidation catalysts by an oxidative copolymerization method is presented.The addition of the redox mediator significantly improved the electrocatalytic water-oxidation activity and reduced the overpotential to 220 mV.The prepared electrode showed a water-oxidation catalytic rate constant kobs of 31.7 s^(-1)and an initial turnover frequency of 1.01 s^(-1)in 1000 s by potential electrolysis at 1.7 V applied bias vs NHE(normal hydrogen electrode).The kinetic isotope effect study suggests that the catalytic water oxidation reaction on the electrode surface occurs via a bimolecular coupling mechanism.

Assessing the dynamics of O_(2) desorption from cobalt phthalocyanine by in situ electrochemical scanning tunneling microscopy

We report here the in situ electrochemical scanning tunneling microscopy(ECSTM) study of cobalt phthalocyanine(CoPc)-catalyzed O_(2) evolution reaction(OER) and the dynamics of CoPc-O_(2) dissociation.The self-assembled CoPc monolayer is fabricated on Au(111) substrate and resolved by ECSTM in 0.1 M KOH electrolyte.The OH^(-)adsorption on CoPc prior to OER is observed in ECSTM images.During OER,the generated O_(2) adsorbed on Co Pc is observed in the CoPc monolayer.Potential step experiment is employed to monitor the desorption of OER-generated O_(2) from CoPc,which results in the decreasing surface coverage of CoPc-O_(2) with time.The rate constant of O_(2) desorption is evaluated through data fitting.The insights into the dynamics of Co-O_(2) dissociation at the molecular level via in situ imaging help understand the role of Co-O_(2) in oxygen reduction reaction(ORR) and OER.

Comparative Analysis of the Essential Oil of the Underground Organs of Valeriana spp. from Different Countries

Valeriana officinalis L.is a plant from the Caprifoliaceae family,which is widely distributed in various parts of the world,especially in Europe and Asia.All species of Valeriana are distinguished by their ability to synthesize essen-tial oil,which has a powerful effect on the physiological and mental aspects of the human body.The aim was to study the qualitative and quantitative composition of essential oil from valerian roots,collected in different coun-tries,using the gas chromatography method,and to establish marker compounds for valerian species.13 samples of commercial roots with rhizomes of V.officinalis from nine countries of the world and a sample of Valeriana pratensis and Valeriana stolonifera growing in Ukraine were selected for the study.The essential oil was obtained from dried valerian roots by the distillation method described in the European Pharmacopoeia.To determine the component composition of the essential oils of the selected samples,the methods of gas chromatography with a mass spectrometric detector and capillary gas chromatography were used.The commercial samples of V.offici-nalis from different countries yielded 0.21%–1.03%of essential oil.Only six of 13 samples contained essential oil in an amount that satisfies the requirement of the European Pharmacopoeia standard(not less than 4 mL/kg).150 compounds were identified in the essential oils of 13 samples of V.officinalis essential oils.The range and average content and coefficients of variation of the identified compounds were determined.The principal com-pounds of V.officinalis essential oils were bornyl acetate(1.6%–27.1%),valeranone(0.5%–17.9%),valerenal(0%–14.7%),camphene(0%–14.6%),α-fenchene(0%–10.6%),and valerenic acid(0%–8.5%).The samples of V.pratensis and V.stolonifera yielded rather high levels of essential oil(1.18%and 0.93%,respectively).Three chemotypes of V.officinalis samples were determined-bornyl acetate/valerenal,valeranone,and isovaleric acid.The composition of the three essential oils compared was rather similar.Based on the study results,we propose the following marker compounds for V.officinalis consistently present in all 16 examined samples:bornyl acetate(1.6%–27.1%),limonene(0.2–2.3),and valeranone(0.5%–17.9%).The study of samples from Ukraine indicates the prospects of using these species of the genus Valeriana with the aim of expanding the raw material base and creating potential herbal preparations with a sedative effect,which are extremely necessary for the population of the country in the war and post-war periods.

A review:Health benefits and physicochemical characteristics of blended vegetable oils

Oil blending is the method of choice used worldwide to improve oxidative stability and nutritional value.There is no such edible oil/fat that meets all the recommendations from the health point of view.The fatty acid composition of vegetable oils decides the fate of the oil.Pure single oil is unable to provide a balanced amount of fatty acids(FAs)required/recommended on a daily intake basis.Blending oils/fats is an appropriate procedure of physically mixing multiple oils in suitable proportions which may provide functional lipids with improved antioxidant potential and desirable physical and chemical properties.This review piled up the accessible data on the blending of diverse oils/fats in the combination of binary,ternary,quaternary,or other types of oils into a single blended oil.Blending can be found very convincing towards appropriate FA profile,enhancement in physicochemical characteristics,and augmented stability for the period of storage or when used as cooking/frying processes which could ultimately serve as an effectual dietary intervention towards the health protectiveness.

Highly efficient three-dimensional solar evaporator for zero liquid discharge desalination of high-salinity brine

Solar-driven interfacial evaporation is a promising technology for freshwater production from seawater,but salt accumulation on the evaporator surface hinders its performance and sustainability.In this study,we report a simple and green strategy to fabricate a three-dimensional porous graphene spiral roll(3GSR)that enables highly efficient solar evaporation,salt collection,and water production from near-saturated brine with zero liquid discharge(ZLD).The 3GSR design facilitates energy recovery,radial brine transport,and directional salt crystallization,thereby resulting in an ultrahigh evaporation rate of 9.05 kg m^(-2) h^(-1)6 in 25 wt%brine under 1-sun illumina-tion for 48 h continuously.Remarkably,the directional salt crystallization on its outer surface not only enlarges the evaporation area but also achieves an ultrahigh salt collection rate of 2.92 kg m^(-2) h^(-1),thus enabling ZLD desalination.Additionally,3GSR exhibits a record-high water production rate of 3.14 kg m^(-2) h^(-1) in an outdoor test.This innovative solution offers a highly efficient and continuous solar desalination method for water production and ZLD brine treatment,which has great implications for addressing global water scarcity and environmental issues arising from brine disposal.

Polymer Fiber Rigid Network with High Glass Transition Temperature Reinforces Stability of Organic Photovoltaics

Organic photovoltaics(OPVs)need to overcome limitations such as insufficient thermal stability to be commercialized.The reported approaches to improve stability either rely on the development of new materials or on tailoring the donor/acceptor morphology,however,exhibiting limited applicability.Therefore,it is timely to develop an easy method to enhance thermal stability without having to develop new donor/acceptor materials or donor–acceptor compatibilizers,or by introducing another third component.Herein,a unique approach is presented,based on constructing a polymer fiber rigid network with a high glass transition temperature(T_(g))to impede the movement of acceptor and donor molecules,to immobilize the active layer morphology,and thereby to improve thermal stability.A high-T_(g) one-dimensional aramid nanofiber(ANF)is utilized for network construction.Inverted OPVs with ANF network yield superior thermal stability compared to the ANF-free counterpart.The ANF network-incorporated active layer demonstrates significantly more stable morphology than the ANF-free counterpart,thereby leaving fundamental processes such as charge separation,transport,and collection,determining the device efficiency,largely unaltered.This strategy is also successfully applied to other photovoltaic systems.The strategy of incorporating a polymer fiber rigid network with high T_(g) offers a distinct perspective addressing the challenge of thermal instability with simplicity and universality.

Feasibility of compacted attapulgite/diatomite amended clayey soils as gas barrier materials

Compacted clay liners are extensively used as barriers to control the upward diffusion of vapors of volatile or semi-volatile organic contaminants released from unsaturated contaminated soils at industrycontaminated sites.This study aimed to investigate the gas diffusion barrier performance of compacted clayey soils amended with three agents including attapulgite and diatomite individually,and attapulgite/diatomite mixture.The properties including water retention,volumetric shrinkage,gas diffusion,and unconfined compressive strength were evaluated through a series of laboratory tests of amended compacted clayey soils.The results demonstrate that the decrease in volume proportions of interaggregate pores leads to an increase in unconfined compressive strength(qu).Both hydrophilic groups and microstructures of attapulgite and diatomite result in an increase in water retention percent(Wt)of compacted clayey soil specimens after amendment regardless of the type of agent or initial water content(w0).Furthermore,the ratio of the gas diffusion coefficient(De)to the gas diffusion coefficient in the air(Da)was significantly reduced owing to a decrease in volume proportions of inter-aggregate pores,hydrophilic group,and microstructures of attapulgite and diatomite.Scanning electron microscope analyses revealed that rod-shaped attapulgite filled the inter-aggregate pores formed by clay particles,whereas the disc-shaped diatomite particles,characterized by micropores,failed to obstruct the interaggregate pores due to their larger particle size.Mercury intrusion porosimetry(MIP)analyses showed a reduction in pore volume in the inter-aggregate pores,leading to a reduction in the total pore volume for both the attapulgite and attapulgite/diatomite mixture amended clays,which is in accordance with the scanning electron microscope(SEM)results.The findings are pertinent to the practical application of compacted clay liners as gas barriers against the upward migration of volatile or semi-volatile organic contaminants at contaminated sites.