Progress on Transition Metal Ions Dissolution Suppression Strategies in Prussian Blue Analogs for Aqueous Sodium-/Potassium-Ion Batteries

Aqueous sodium-ion batteries(ASIBs)and aqueous potassium-ion batteries(APIBs)present significant potential for large-scale energy storage due to their cost-effectiveness,safety,and environmental compatibility.Nonetheless,the intricate energy storage mechanisms in aqueous electrolytes place stringent require-ments on the host materials.Prussian blue analogs(PBAs),with their open three-dimensional framework and facile synthesis,stand out as leading candidates for aqueous energy storage.However,PBAs possess a swift capacity fade and limited cycle longevity,for their structural integrity is compromised by the pronounced dis-solution of transition metal(TM)ions in the aqueous milieu.This manuscript provides an exhaustive review of the recent advancements concerning PBAs in ASIBs and APIBs.The dissolution mechanisms of TM ions in PBAs,informed by their structural attributes and redox processes,are thoroughly examined.Moreover,this study delves into innovative design tactics to alleviate the dissolution issue of TM ions.In conclusion,the paper consolidates various strategies for suppressing the dissolution of TM ions in PBAs and posits avenues for prospective exploration of high-safety aqueous sodium-/potassium-ion batteries.

Fluorescence Enhancement of Polyamine Derivatives of 1,8-Naphthalimide with Transition Metal Ions

A series of fluorescent chemosensors 1-3 were synthesized to detect transition metal ions. At the room temperature, fluorescence intensities of these chemosensors in acetonitrile without transition metal ions were found to be very weak, due to the process of the efficient intramolecular photoinduced electron transfer （PET）. However, after addition of the transition metal ions, the chemoscnsor 1-3 exhibits obvious fluorescence enhancement. Moreover, the intensity of the fluorescence emission of chemosensors increases significantly in the presence of Zn^2＋ and Cd^2＋. The fluorescent chemosensors with different polyamine as receptors show diverse affinity abilities to the transition metal ions and signal the receptor-metal ion interaction by the intensity change of fluorescence emission.

Selective preparation of light aromatic hydrocarbons from catalytic fast pyrolysis vapors of coal tar asphaltene over transition metal ion modified zeolites

The catalytic cracking of coal tar asphaltene(CTA)pyrolysis vapors was carried out over transition metalion modified zeolites to promote the generation of light aromatic hydrocarbons(L-ArHs)in a pyrolysisgas chromatography/mass spectrometry(Py-GC/MS)micro-reactor system.The effects of ultra stable Y(USY),Co/USY and Mo/USY on the selectivity and yield of L-ArHs products and the extent of deoxygenation(Edeoxygenation),lightweight(Elightweight)from CTA pyrolysis volatiles were investigated.Results showed that the yields of L-ArHs are mainly controlled by the acid sites and specific surface area of the catalysts,while the deoxygenation effect is determined by theirs pore size.The Eligltweight of CTA pyrolysis volatiles over USY is 9.65%,while the Edeoxygenation of CTA pyrolysis volatiles over Mo/USY reaches 20.85%.Additionally,the modified zeolites(Mo/USY and Co/USY)exhibit better performance than USY on L-ArHs production,owing to the synergistic effect of metal ions(Mo,Co)and acid sites of USY.Compared with the non-catalytic fast pyrolysis of CTA,the total yield of L-ArHs obtained over USY(4032 mg·kg^(-1)),Co/USY(4363 mg·kg^(-1))and Mo/USY(4953 mg·kg^(-1))were increased by 27.03%,38.19%and 54.78%,respectively.Furthermore,the possible catalytic conversion mechanism of transition metal ion(Co and Mo)modified zeolites was proposed based on the distribution of products and the characterizations of catalysts.

The effect of transition metal ions (M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)) on the chemical synthesis polyaniline as counter electrodes in dye-sensitized solar cells

The effect of transition metal ions(M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)) on the chemical synthesis of polyaniline(PANI) used as a platinum-free counter electrode(CE) in dye-sensitized solar cells(DSSCs) was investigated.PANI was synthesized by co-polymerization of aniline in the presence of different transition metal ions by using potassium dichromate in acidic medium. It was found that the ion doping of PANI showed a certain catalytic activity for the regeneration of traditional iodide/triiodide(I^-/I_3^-) redox couples. The power conversion efficiency(η) of PANI CEs doped with Mn^(2+),Ni^(2+),Co^(2+) (4.41%, 2.36% and 2.10%, respectively) were higher than 1.94%, the value measured for PANI CE without doping. Doping with Cu^(2+)decreased the power conversion efficiency of PANI CE(PANI-Cu^(2+) η = 1.41%). The electrical properties of the PANI, PANI-Ni^(2+), PANI-Co^(2+),PANI-Mn^(2+) and PANI-Cu^(2+) were studied by cyclic voltammetry(CV), impedance(EIS), and Tafel polarization curve. The experimental results confirmed that PANI was affected by the doping of different transition metal ions(M^(2+)=Mn^(2+),Ni^(2+),Co^(2+),Cu^(2+)). These results indicate a potential application of ion doped PANI as counter electrode in cost-effective DSSCs.

Transforming a Two-Dimensional Layered Insulator into a Semiconductor or a Highly Conductive Metal through Transition Metal Ion Intercalation

Atomically thin two-dimensional(2D) materials are the building bricks for next-generation electronics and optoelectronics, which demand plentiful functional properties in mechanics, transport, magnetism and photoresponse.For electronic devices, not only metals and high-performance semiconductors but also insulators and dielectric materials are highly desirable. Layered structures composed of 2D materials of different properties can be delicately designed as various useful heterojunction or homojunction devices, in which the designs on the same material(namely homojunction) are of special interest because preparation techniques can be greatly simplified and atomically seamless interfaces can be achieved. We demonstrate that the insulating pristine ZnPS_3, a ternary transition-metal phosphorus trichalcogenide, can be transformed into a highly conductive metal and an n-type semiconductor by intercalating Co and Cu atoms, respectively. The field-effect-transistor(FET) devices are prepared via an ultraviolet exposure lithography technique. The Co-ZnPS_3 device exhibits an electrical conductivity of 8 × 10^(4) S/m, which is comparable to the conductivity of graphene. The Cu-ZnPS_3 FET reveals a current ON/OFF ratio of 1-05 and a mobility of 3 × 10^(-2 )cm^(2)·V^(-1)·s^(-1). The realization of an insulator, a typical semiconductor and a metallic state in the same 2D material provides an opportunity to fabricate n-metal homojunctions and other in-plane electronic functional devices.

Solvation structure design for stabilizing MXene in transition metal ion solutions

Although MXene has attracted great interest in diverse fields,it is susceptible to oxidation in water(H_(2)O)with transition metal ions such as Co^(2+),Fe^(2+),and Cu^(2+),which is pronounced at high temperatures.This impedes the preparation of MXene-based composites and their functional applications.Here,this study revealed that Co^(2+)increases the maximum and average atomic charge of H in H_(2)O to improve the reactivity of H_(2)O,which leads to the fact that Co^(2+)catalyzes the oxidation of Ti_(3)C_(2)T_(x)MXene.Furthermore,the addition of N,Ndimethyl formamide(DMF)reduces theH_(2)Oactivity and improves the oxidation stability of Ti_(3)C_(2)T_(x)in the presence of Co^(2+)via preferentially forming coordination bonds with Co^(2+).This strategy is also effective in enhancing the oxidation tolerance of Ti_(3)C_(2)T_(x)to Fe^(2+)in H_(2)O.Moreover,it is feasible to enhance the oxidation stability of Ti2CTx MXene in H_(2)O with the existence of Co^(2+).By virtue of these,the CoO/Ti_(3)C_(2)T_(x)composite was successfully prepared without obvious Ti_(3)C_(2)T_(x)oxidation,which is desirable to harness the advantages of Ti_(3)C_(2)T_(x)as the complementary component for lithium-ion batteries.This work provides a straightforward paradigm to enhance the oxidation resistance of MXene in H_(2)O in the presence of transition metal ions and at high temperatures,which opens a new vista to use MXene for target applications.

Suppression of Co(Ⅱ)ion deposition and hazards:Regulation of SEI film composition and structure

Despite the presence of Li F components in the solid electrolyte interphase(SEI)formed on the graphite anode surface by conventional electrolyte,these Li F components primarily exist in an amorphous state,rendering them incapable of effectively inhibiting the exchange reaction between lithium ions and transition metal ions in the electrolyte.Consequently,nearly all lithium ions within the SEI film are replaced by transition metal ions,resulting in an increase in interphacial impedance and a decrease in stability.Herein,we demonstrate that the SEI film,constructed by fluoroethylene carbonate(FEC)additive rich in crystalline Li F,effectively inhibits the undesired Li^(+)/Co^(2+)ion exchange reaction,thereby suppressing the deposition of cobalt compounds and metallic cobalt.Furthermore,the deposited cobalt compounds exhibit enhanced structural stability and reduced catalytic activity with minimal impact on the interphacial stability of the graphite anode.Our findings reveal the crucial influence of SEI film composition and structure on the deposition and hazards associated with transition metal ions,providing valuable guidance for designing next-generation electrolytes.

Selective detection of phosphaphenanthrene-containing luminophors with aggregation-induced emission enhancement to transition metal ions

Transition metal ions(Pb^(2+),Zn^(2+),Cd^(2+),Co^(2+),Mn^(2+),Cu^(2+),Ni^(2+),Hg^(2+),Ag^(+),Fe^(3+))in water are used to quench emission of 2-(6-oxido-6H-dibenz<c,e><1,2>oxaphosphorin-6-yl)-1,4-phenylene-bis(p-pentyloxylbenzoate)s(MD5)with aggregation-induced emission enhancement(AIEE)in water-acetonitrile(AN)mixture(80:20 by volume).Among all metal ions,Fe^(3+)exhibits the highest quenching efficiency on AIEE of MD5 even when the concentration of Fe^(3+)is lower than 1×10^(-6) mol/L.The quenching efficiency of Hg^(2+)is lower than that of Fe^(3+)at the same concentration,though MD5 is used to detect Hg^(2+)efficiently,too.To other metal ions,low quenching efficiency has few relations with a wider concentration range.The UV absorbance spectra show only red shift of absorbance wavelength in the presence of Hg^(2+)and Fe^(3+),which indicates a salt-induced Jaggregation.SEM photos reveal larger aggregation and morphological change of nanoparticles of MD5 in water containing Hg^(2+)and Fe^(3+),which reduce the surface area of MD5 emission for further aggregation.The selective quenching effect of transition metal ions to emission of MD5 has a potential application in chemical sensors of some metal ions.

Enhanced Pervaporative Separation of Thiophene/n-Heptane Using Metal Loaded PEBAX/PAN Membranes

The mass transfer of thiophene through pervaporation（PV） membranes could be facilitated by certain transitional metal ions like Ag+, Mn2+, and Cr3+ thanks to their p complexation with thiophene. In this study, Ag+, Mn2+, and Cr3+ ions were loaded onto the polyether block amide（PEBAX）/PAN composite membranes and were tested on the performance for separation of thiophene/n-heptane mixture. Pervaporation test results showed that the pervaporative separation index increased significantly to 73.1%, 75.5%, and 97.2% at 30 oC for the Ag+-, Mn2+-, Cr3+-loaded PEBAX membranes, respectively,as compared to the pristine PEBAX/PAN composite membrane.

Facile construction of a multilayered interface for a durable lithium‐rich cathode

Layered lithium-rich manganese-based oxide(LRMO)has the limitation of inevitable evolution of lattice oxygen release and layered structure transformation.Herein,a multilayer reconstruction strategy is applied to LRMO via facile pyrolysis of potassium Prussian blue.The multilayer interface is visually observed using an atomic-resolution scanning transmission electron microscope and a high-resolution transmission electron microscope.Combined with the electrochemical characterization,the redox of lattice oxygen is suppressed during the initial charging.In situ X-ray diffraction and the high-resolution transmission electron microscope demonstrate that the suppressed evolution of lattice oxygen eliminates the variation in the unit cell parameters during initial(de)lithiation,which further prevents lattice distortion during long cycling.As a result,the initial Coulombic efficiency of the modified LRMO is up to 87.31%,and the rate capacity and long-term cycle stability also improved considerably.In this work,a facile surface reconstruction strategy is used to suppress vigorous anionic redox,which is expected to stimulate material design in high-performance lithium ion batteries.

Inhibiting Voltage Decay in Li-Rich Layered Oxide Cathode:From O3-Type to O2-Type Structural Design

Li-rich layered oxide(LRLO)cathodes have been regarded as promising candidates for next-generation Li-ion batteries due to their exceptionally high energy density,which combines cationic and anionic redox activities.However,continuous voltage decay during cycling remains the primary obstacle for practical applications,which has yet to be fundamentally addressed.It is widely acknowledged that voltage decay originates from the irreversible migration of transition metal ions,which usually further exacerbates structural evolution and aggravates the irreversible oxygen redox reactions.Recently,constructing O2-type structure has been considered one of the most promising approaches for inhibiting voltage decay.In this review,the relationship between voltage decay and structural evolution is systematically elucidated.Strategies to suppress voltage decay are systematically summarized.Additionally,the design of O2-type structure and the corresponding mechanism of suppressing voltage decay are comprehensively discussed.Unfortunately,the reported O2-type LRLO cathodes still exhibit partially disordered structure with extended cycles.Herein,the factors that may cause the irreversible transition metal migrations in O2-type LRLO materials are also explored,while the perspectives and challenges for designing high-performance O2-type LRLO cathodes without voltage decay are proposed.

C-S Activation of CS2 by Nb＋ in Gas Phase

The reaction of Nb＋ with CS2, producing cationic transition-metal sulfide and CS, was taken as a representative example to elucidate the overall mechanism of reactions of second- row early transition metal ions with CS2. The reactions in both triplet and quintet state were studied by using the UB3LYP density functional method with the Stuttgart pseudo potentials and corresponding basis sets for Nb＋ and the standard 6-311＋G（2d） basis sets for C and S. The geometries for reactants, the transition states, and the products were completely optimized. All the transition states were verified by vibrational analysis and intrinsic reaction coordinate calculations. The results show that the reaction mechanism between niobium ion and CS2 is an insertion-elimination mechanism. Intersystem crossing may occur in the reaction Nb＋ with CS2 and a minimum energy crossing point was found.

Revealing the critical effect of solid electrolyte interphase on the deposition and detriment of Co(Ⅱ) ions to graphite anode

"Dissolution,migration,and deposition"of transition metal ions (TMIs) result in capacity degradation of lithium-ion batteries (LIBs).Understanding such detrimental mechanism of TMIs is critical to the development of LIBs with long cycle life.In most previous works,TMIs were directly introduced into the electrolyte to investigate such a detrimental mechanism.In these cases,the TMIs are deposited directly on the fresh anode surface.However,in the practical battery system,the TMIs are deposited on the anode covered with solid electrolyte interphase (SEI) film.Whether the pre-presence of SEI film on anode surface influences the deposition and detriment of TMIs is unclear.In this work,the deposition of Co element on graphite anode with and without SEI film were systematically studied.The results clearly show that,in comparison with that of fresh graphite (SEI-free),the presence of SEI film aggravates the deposition of Co ions due to the Li^(+)–Co^(2+) ion exchange between the SEI and Co^(2+)-containing electrolyte without the driving of the electric field,leading to faster capacity fading of graphite anode.Therefore,how to regulate electrolytes and film-forming additives to design the components of SEI and prevent its exchange with TMIs,is a crucial way to inhibit the deposition and detriment of TMIs on graphite anode.

Impacting Factors of Elemental Mercury Re-emission across a Lab-scale Simulated Scrubber

Elemental mercury（Hg^0）re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber.Oxidized mercury（Hg^2 ＋）standard solution was injected into the simulated scrubber at a desired rate to simulate absorbing and dissolving of Hg^2 ＋in the flue gas across wet flue gas desulfurization（WFGD）systems. PS analytical mercury analyzer was used to continuously determine Hg0re-emission concentrations in the carrier gas from the scrubber.Sulfite ion in the slurry of CaSO3 was validated to reduce Hg ^2＋to Hg^ 0,while no Hg ^0 re-emission occurred from slurries of CaSO4 and CaO.Transitional metal ions with low chemical valence such as Fe^2 ＋,Pb ^2＋,Ni ^2＋, AsO2^-and Cu ^＋were used to prepare solutions with concentration levels of mmol·L^-1.Reduction reaction of Hg^2 ＋to Hg 0was observed from these solutions.Reduction capabilities for the different transitional metal ions in the solutions were：Pb^2 ＋〉Cu ^＋〉Fe^ 2＋〉 AsO2^-〉Ni ^2＋.

Applications of Transition Metals in Organic Synthesis and Polymerization

1 Results Classic oxidants require rigorous control of the experimental conditions added with the problem of lack of selectivity. Catalysis by transition metals with environmentally safe oxidants provides synthetic routes to minimize pollution by giving environmental benign by-products. Fe (Ⅵ) is a powerful and a selective oxidant with Fe(Ⅲ) as a by-product, while hydrogen peroxide is clean with water as the only by-product. Separation of sodium or potassium ferrates requires tedious processes. Associat...

Synthesis, Structure, and Properties of Two Supramolecular Compounds Based on Silicotungstic Acid and Transition Metal（ll） Coordinated Isonicotinic Acid

Two compounds, namely [Cd（HINA）2（μ2-H2O）（H2O）2]2[SiW1240].6H2O （1） and [Co（HINA）3（HzO）3]- [Co（HINA）2（H2O）4][SiW12O40]·2H2O （2）, have been synthesized from the aqueous mixture containing H4SiW12040, isonicotinic acid （HINA）, and M（CH3COO）2 （M=Cd and Co）. The compounds have been characterized by ele- mental analysis, IR spectroscopy, TG analysis, and single-crystal X-ray diffraction. The dinuclear coordinated cad- mium units in compound 1 are linked to form 2D layer parallel to ab plane through n-n interactions and hydrogen bonds. Compound 2 contains two different types of coordinated metal cations, [Co（HINA）3（HaO）3]2＋ and [Co（HINA）2（H2O）4]2＋, which construct 2D layer along be plane through π-π interactions and hydrogen bonds. In both compounds, the Keggin anions are located inside the channels and cavities formed from stack of the coordi- nated metal cations, which further achieve the 3D supramolecular structure through hydrogen bonds. The lumines- cent property of compounds 1 and 2 has been investigated.

A review of transition metal chalcogenide/graphene nanocomposites for energy storage and conversion

To meet the ever-increasing energy demands, advanced electrode materials are strongly requested for the exploration of advanced energy storage and conversion technologies, such as Li-ion batteries, Li-S batteries, Li-]Zn-air batteries, supercapacitors, dye-sensitized solar cells, and other electrocatalysis process （e.g., oxygen reductionlevolution reaction, hydrogen evolution reaction）. Transition metal chalcogenides （TMCs, Le., sulfides and selenides） are forcefully considered as an emerging candidate, owing to their unique physical and chemical properties. Moreover, the integration of TMCs with conductive graphene host has enabled the significant improvement of electrochemical performance of devices. In this review, the recent research progress on TMC]graphene composites for applications in energy storage and conversion devices is summarized. The preparation process of TMC]graphene nanocomposites is also included. In order to promote an in-depth understanding of performance improvement for TMC/graphene materials, the operating principle of various devices and technologies are briefly presented. Finally, the perspectives are given on the design and construction of advanced electrode materials.

A critical review of sulfate aerosol formation mechanisms during winter polluted periods

Sulfate aerosol contributes to particulate matter pollution and plays a key role in aerosol radiative forcing,impacting human health and climate change.Atmospheric models tend to substantially underestimate sulfate concentrations during haze episodes,indicating that there are still missing mechanisms not considered by the models.Despite recent good progress in understanding the missing sulfate sources,knowledge on different sulfate formation pathways during polluted periods still involves large uncertainties and the dominant mechanism is under heated debate,calling for more field,laboratory,and modeling work.Here,we review the traditional sulfate formation mechanisms in cloud water and also discuss the potential factors affecting multiphase S(Ⅳ)oxidation.Then recent progress in multiphase S(Ⅳ)oxidation mechanisms is summarized.Sulfate formation rates by different prevailing oxidation pathways under typical winter-haze conditions are also calculated and compared.Based on the literature reviewed,we put forward control of the atmospheric oxidation capacity as a means to abate sulfate aerosol pollution.Finally,we conclude with a concise set of research priorities for improving our understanding of sulfate formation mechanisms during polluted periods.

Multi-ion intercalated Ti_(3)C_(2)T_(x)MXene and the mutual modulation within interlayer

Intercalation of ions between the adjacent MXene layers can change the interlayer environment and influence the electrochemical ion storage capacity.In order to understand the effect of multi-ions confined by the MXene layers on the performance of electrochemical energy storage,Co^(2+),Mn^(2+)and Ni^(2+)intercalated into Ti_(3)C_(2)T_(x)MXene which already pre-intercalated Al3+are obtained by spontaneous static action.Based on the monitor of(002)crystal orientation,intercalated multi-ions can regulate and control the interlayer environment of MXenes via stress,which induces lattice shrinkage occurring in the c axis.Limited by ion storage mechanism-performance,the multi-ion occupies the interspace of MXene and affects the electrochemical performance.This work would offer guidance to understand the relationship among the multi-ion and MXene by two-dimensional(2D)layered materials.

Dielectric response of ANb_(2)O_(6)(A = Zn, Co, Mn, Ni) columbite niobates: From microwave to terahertz

In the upcoming 6-generation(6G)revolution,the achievement of low power consumption has become a key objective in research concerning terahertz devices.As an important component of passive devices,there are very few low-loss dielectric ceramics in the terahertz range.To elucidate the mechanism of loss and promote the application of microwave dielectric ceramics for future 6G technology(covering microwave and terahertz frequencies),the terahertz responses of ANb_(2)O_(6)(A=Zn,Co,Mn,and Ni)columbite niobates were studied.The influences of magnetic loss on the Qxf values in the microwave range with different transition metal ions in the A-site were reasonably analyzed.Moreover,due to the weakened magnetic relaxation properties in the terahertz range,the samples all exhibited low loss and approximate transparency,especially for MnNb_(2)O_(6) and NiNb_(2)O_(6)(tano<0.01 and absorption coefficient<10 cm^(-1) below 1.2 THz),which subverted the definition of traditional low-loss microwave dielectric ceramics.Ultimately,based on Mie theory,we designed a prototypical broadband metamaterial reflector to validate the applicability of the ANb_(2)O_(6) system in the terahertz band,which is highly important for the development of terahertz ceramic-based passive devices.