Strong electronic coupling of CoNi and N-doped-carbon for efficient urea-assisted H2 production at a large current density

Exploiting efficient urea oxidation reaction(UOR)and hydrogen evolution reaction(HER)catalysts are significant for energy-saving H2 production through urea-assisted water electrolysis,but it is still challenging.Herein,carbon-encapsulated CoNi coupled with CoNiMoO(CoNi@CN-CoNiMoO)is prepared by solvothermal method and calcination to enhance the activity/stability of urea-assisted water electrolysis at large current density.It exhibits good activity for UOR(E10/1,000=1.29/1.40 V)and HER(E-10/-1000=-45/-245 mV)in 1.0 M KOH+0.5 M urea solution.For the UOR||HER system,CoNi@CN-CoNiMoO only needs 1.58 V at 500 mA cm-2 and shows good stability.Density functional theory calculation suggests that the strong electronic interaction at the interface between NiCo alloy and N-doping-carbon layers can optimize the adsorption/desorption energy of UOR/HER intermediates and accelerate the water dissociation,which can expedite urea decomposition and Volmer step,thus increasing the UOR and HER activity,respectively.This work provides a new solution to design UOR/HER catalysts for H2 production through urea-assisted water electrolysis.

In situ characterizations of advanced electrode materials for sodium-ion batteries toward high electrochemical performances

Energy storage is an ever-growing global concern due to increased energy needs and resource exhaustion.Sodium-ion batteries(SIBs)have called increasing attention and achieved substantial progress in recent years owing to the abundance and even distribution of Na resources in the crust,and the predicted low cost of the technique.Nevertheless,SIBs still face challenges like lower energy density and inferior cycling stability compared to mature lithium-ion batteries(LIBs).Enhancing the electrochemical performance of SIBs requires an in-deep and comprehensive understanding of the improvement strategies and the underlying reaction mechanism elucidated by in situ techniques.In this review,commonly applied in situ techniques,for instance,transmission electron microscopy(TEM),Raman spectroscopy,X-ray diffraction(XRD),and X-ray absorption near-edge structure(XANES),and their applications on the representative cathode and anode materials with selected samples are summarized.We discuss the merits and demerits of each type of material,strategies to enhance their electrochemical performance,and the applications of in situ characterizations of them during the de/sodiation process to reveal the underlying reaction mechanism for performance improvement.We aim to elucidate the composition/structure-per formance relationship to provide guidelines for rational design and preparation of electrode materials toward high electrochemical performance.

Lignin-based materials for electrochemical energy storage devices

Lignin is the most abundant aromatic polymer in nature,which is rich in a large number of benzene ring structures and active functional groups.The molecular structure of lignin has unique designability and controllability,and is a class of functional materials with great application prospects in energy storage and conversion.Here,this review firstly focuses on the concept,classification,and physicochemical property of lignin.Then,the application research of lignin in the field of electrochemical storage materials and devices are summarized,such as lignin-carbon materials and lignin-carbon composites in supercapacitors and secondary batteries.Finally,this review points out the bottlenecks that need to be solved urgently and the prospects for future research priorities.

Heteroatom tuning in agarose derived carbon aerogel for enhanced potassium ion multiple energy storage

The incorporation of heteroatoms into carbon aerogels(CAs)can lead to structural distortions and changes in active sites due to their smaller size and electronegativity compared to pure carbon.However,the evolution of the electronic structure from single-atom doping to heteroatom codoping in CAs has not yet been thoroughly investigated,and the impact of codoping on potassium ion(K+)storage and diffusion pathways as electrode material remains unclear.In this study,experimental and theoretical simulations were conducted to demonstrate that heteroatom codoping,composed of multiple heteroatoms(O/N/B)with different properties,has the potential to improve the electrical properties and stability of CAs compared to single-atom doping.Electronic states near the Fermi level have revealed that doping with O/N/B generates a greater number of active centers on adjacent carbon atoms than doping with O and O/N atoms.As a result of synergy with enhanced wetting ability(contact angle of 9.26°)derived from amino groups and hierarchical porous structure,ON-CA has the most optimized adsorption capacity(−1.62 eV)and diffusion barrier(0.12 eV)of K^(+).The optimal pathway of K^(+)in ON-CA is along the carbon ring with N or O doping.As K^(+)storage material for supercapacitors and ion batteries,it shows an outstanding specific capacity and capacitance,electrochemical stability,and rate performance.Especially,the assembled symmetrical K^(+)supercapacitor demonstrates an energy density of 51.8 Wh kg^(−1),an ultrahigh power density of 443Wkg^(−1),and outstanding cycling stability(maintaining 83.3%after 10,000 cycles in 1M KPF6 organic electrolyte).This research provides valuable insights into the design of highperformance potassium ion storage materials.

Exploring the Cation Regulation Mechanism for Interfacial Water Involved in the Hydrogen Evolution Reaction by In Situ Raman Spectroscopy

Interfacial water molecules are the most important participants in the hydrogen evolution reaction(HER).Hence,understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism.Unfortunately,investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment.Here,the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry,in situ core-shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques.Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction.When comparing the different cation electrolyte systems at a given potential,the frequency of the interfacial water peak increases in the specified order:Li+<Na^(+)<K^(+)<Ca^(2+)<Sr^(2+).The structure of interfacial water was optimized by adjusting the radius,valence,and concentration of cation to form the two-H down structure.This unique interfacial water structure will improve the charge transfer efficiency between the water and electrode further enhancing the HER performance.Therefore,local cation tuning strategies can be used to improve the HER performance by optimizing the interfacial water structure.

Applications of metal–organic frameworks for green energy and environment: New advances in adsorptive gas separation, storage and removal

The separation of gas molecules with similar physicochemical properties is of high importance but practically entails a substantial energy penalty in chemical industry. Meanwhile, clean energy gases such as H_2 and CH_4 are considered as promising candidates for the replacement of traditional fossil fuels. However, the technologies for the storage of these gases are still immature. In addition, the release of anthropogenic toxic gases into the atmosphere is a worldwide threat of growing concern. Both in academia and industry, considerable research efforts have been devoted to developing advanced porous materials for the effective and energy-efficient separation, storage, or capture of the related gases. In contrast to conventional inorganic porous materials such as zeolites and activated carbons, metal–organic frameworks(MOFs) are considered as a type of promising materials for gas separation and storage. In this contribution, we review the recent research advance of MOFs in some relevant applications, including CO_2 capture, O_2 purification, separation of light hydrocarbons, separation of noble gases, storage of gases(CH_4,H_2, and C_2 H_2) for energy, and removal of some gaseous air pollutants(NH_3, NO_2, and SO_2). Finally, an outlook regarding the challenges of the future research of MOFs in these directions is given.

Surfactant-aided hydrothermal preparation of La(2-x)Sr_xCuO_4 single crystallites and their catalytic performance on methane combustion

Perovskite-like oxide La2-xSrxCuO4 （x = 0, 1） single crystallites with microrod-like morphologies and tetragonal crystal structures were prepared hydrothermally at 240 ℃ with poly（ethylene glycol） （PEG） or hexadecyltrimethyl ammonium bromide （CTAB） as a surfactant and after calcination at 850 ℃. The physicochemical properties of the materials were characterized by means of XRD, BET, SEM, TEM/SAED （selected-area electron diffraction）, XPS and H2-TPR techniques. It is found that doping Sr2＋ to La2CuO4 lattice enhanced the catalytic activity for methane combustion and the LaSrCuO4 catalyst derived from PEG is the best among the tested ones. It is concluded that factors, such as adsorbed oxygen species concentration, reducibility and surface area, determined the catalytic performance of such single-crystalline materials.

Amperometric Determination of lndole-3-acetic Acid Based on Platinum Nanowires and Carbon Nanotubes

Platinum nanowire （PtNW） can be grown by electrodeposition in polycarbonate membrane, with the average diameter of the nanowires about 250 nm. The PtNW and multiwalled carbon nanotubes （CNT） are then dispersed into chitosan （CHIT） solution. The resulting PtNW-CNT-CHIT material brings new capabilities for electrochemical devices by using the synergistic action of the electrocatalytic activity of PtNW and CNT. By dropping the PtNW-CNT-CHIT film onto the glassy carbon （GO） electrode surface, and after evaporation an amperometric sensor for the determination of indole-3-acetic acid （IAA） was developed. The oxidation current of IAA increased significantly at the PtNW-CNT-CHIT film coated GC electrode, in contrast to that at the CNT-CHIT modified GC. The linear response of the sensor is from 50 ng/ml to 50 μg/ml with a detection limit of 25 ng/mL.

Genesis of underground brine along south coast of Laizhou Bay:hydrochemical characteristics

Hydrochemistry of underground brines along south coast of Laizhou Bay, Shandong, China has been analyzed. Brine samples were collected from 43 wells in this area. It was considered that the brines were originated from seawater. However, whether they were formed by seawater evaporation or seawater freezing was not fully sure. We created a simple method by plotting Na/Cl vs. seawater concen-tration factor (SCF) and Ca/Mg vs. SCF to determine the brine formation geochemically. Comparison of our results to previous seawater freezing and evaporation experiments indicated that the brines were formed by seawater evaporation. The ratios of HCO3/Cl of some low salinity brines in the study area were relatively higher, indicating that the brines may have mixed with other waters after the generation. The Br/Cl ratios of the brines decreased annually in the past 20 to 30 years of exploitation, indicating down-ward permeation of the brine from which bromine was extracted.

Enhanced catalytic performance of Cu-and/or Mn-loaded Fe-Sep catalysts for the oxidation of CO and ethyl acetate

The Fe-modi fied sepiolite-supported Mn–Cu mixed oxide(Cux Mny/Fe-Sep) catalysts were prepared using the co-precipitation method.These materials were characterized by means of the XRD,N_2 adsorption–desorption,XPS,H_2-TPR,and O_2-TPD techniques,and their catalytic activities for CO and ethyl acetate oxidation were evaluated.The results show that catalytic activities of the Cux Mny/Fe-Sep samples were higher than those of the Cu1/Fe-Sep and Mn2/Fe-Sep samples,and the Mn/Cu molar ratio had a distinct in fluence on catalytic activity of the sample.Among the Cux Mny/Fe-Sep and Cu1Mn2/Sep samples,Cu1Mn2/Fe-Sep performed the best for CO and ethyl acetate oxidation,showing the highest reaction rate and the lowest T50 and T90 of 4.4×10^(-6) mmol·g-1·s-1,110,and 140 °C for CO oxidation,and 1.9×10^(-6) mmol·g-1·s-1,170,and210 °C for ethyl acetate oxidation,respectively.Moreover,the Cu1Mn2/Fe-Sep sample possessed the best lowtemperature reducibility and the lowest temperature of oxygen desorption as well as the highest surface Mn^(4+)/Mn^(3+) and Cu^(2+)/CuO atomic ratios.It is concluded that factors,such as the strong interaction between the Cu or Mn and the Fe-Sep support,good low-temperature reducibility,and good mobility of chemisorbed oxygen species,might account for the excellent catalytic activity of Cu1Mn2/Fe-Sep.

A comparative investigation of NdSrCu_(1-x) Co_x O_(4-δ) and Sm_(1.8) Ce_(0.2) Cu_(1-x) Co_x O_(4-δ) (x:0–0.4) for NO decomposition

A series of single-phase T-structured NdSrCu 1-x Co x O 4-δ with oxygen vacancies and T -structured Sm 1.8 Ce 0.2 Cu 1-x Co x O 4-δ （x： 0–0.4） with oxygen excess were prepared using ultrasound-assisted citric acid complexing method, and characterized by means of techniques such as thermogravimetric analysis and NO temperature-programmed desorption （NO-TPD）. The catalytic activities of these materials were evaluated for the decomposition of NO. It was found that the NdSrCu 1-x Co x O 4-δ catalysts were of oxygen vacancies whereas the Sm 1.8 Ce 0.2 Cu 1？x Co x O 4-δ ones possessed excessive oxygen （i.e., over-stoichiometric oxygen）; with a rise in Co doping level, the oxygen vacancy density of NdSrCu 1-x Co x O 4-δ decreased while the over-stoichiometric oxygen amount of Sm 1.8 Ce 0.2 Cu 1-x Co x O 4-δ increased. The NO-TPD results revealed that NO could be activated much easier over the oxygen-deficient perovskite-like oxides than over the oxygen-excessive perovskite-like oxides, with the NdSrCuO 3.702 catalyst showing the best efficiency in activating NO molecules. Under the conditions of 1.0% NO/helium, 2800 hr -1 , and 600–900°C, the catalytic activity of NO decomposition followed the order of NdSrCuO 3.702 〉 NdSrCu 0.8 Co 0.2 O 3.736 〉 NdSrCu 0.6 Co 0.4 O 3.789 〉 Sm 1.8 Ce 0.2 Cu 0.6 Co 0.4 O 4.187 〉 Sm 1.8 Ce 0.2 Cu 0.8 Co 0.2 O 4.104 〉 Sm 1.8 Ce 0.2 CuO 4.045 , in concord with the sequence of decreasing oxygen vacancy or oxygen excess density. Based on the results, we concluded that the higher oxygen vacancy density and the stronger Cu 3＋ /Cu 2＋ redox ability of NdSrCu 1-x Co x O 4-δ account for the easier activation of NO and consequently improve the catalytic activity of NO decomposition over the catalysts.

EFFECT OF ELECTROACUPUNCTURE AND CALCIUM-CHANNEL INHIBITORS ON CYTOPLASMIC FREE CALCIUM CONCENTRATION OF MOUSE BRAIN CELLS

Objective: To study the effect of electroacupuncture (EA) and Verapamil and Nifedipine (calcium channel inhibitors) on free calcium concentrations of cells and intrasynaptosomes in hypothalamus (HT), periaqueductual grey matter (PAG) and hippocampus (HIP) of mice. Methods: The female ICR mice were randomly divided into control, EA, CaCl2 and CaCl2+EA groups (n=8 in each group). Pain threshold was detected by using radiation-heat irradiation-induced tail flick method. EA (8 Hz, a suitable stimulating strength, dense-sparse waves and duration of 30 min) was applied to“Shuigou” (水沟 GV 26) and “Chengjiang” (承浆CV 24). CaCl2 (10 μL, 0.2 μmol/L) was injected into the lateral cerebral ventricle of mice after EA. The concentrations of cytosolic free calcium ([Ca 2+]i) in HIP, PAG, HT cell suspension specimen and hippocampal intrasynaptosome suspension of mice were determined by the fluorescent calcium indicator Fura-2-AM and a spectrofluorometer. Results: During EA analgesia, the intracellular free [Ca 2+]i in HT and PAG specimens and intrsynaptosomal [Ca 2+]i of the 3 cerebral regions decreased considerably (P<0.05～0.01), but that in hippocampal cell suspension increased significantly (P<0.01) in comparison with control group. The concentrations of hippocampal intrasynaptosomal free [Ca 2+]i decreased significantly after adding Verapamil and Nifedipine to the extracted hippocampal intrasynaptosomal specimen. Microinjection of CaCl2 into lateral ventricle had no apparent influence on degree of analgesia (DA)% and intracellular and intrasynapsotomal [Ca 2+]i, but significantly lower DA% and reduce changes of cytosolic and intrasynaptosomal [Ca 2+]i induced by EA stimulation. Conclusion: Calcium ion in the neurons and intrasynaptosome of HT, PAG and HIP is involved in electroacupuncture analgesia.

PREPARATION AND SURFACE PROPERTIES OF ACRYLIC COPOLYMERS CONTAINING FLUORINATED MONOMERS

A series of copolymers comprising butylmethacrylate, styrene, butylacrylate, hydroxypropyl acrylate and perfluoroalkyl methacrylate were synthesized by the free radical polymerization using BPO as an initiator. The surface property of the copolymer films was subsequently characterized. The contact angle measurements and energy dispersive analysis of X-ray （EDAX） show that the length and content of perfluoroalkyl side chains in the copolymers are crucial for the preparation of the film with low surface energy. At a given content of fluorinated monomers in the copolymers, the longer the perfluoroalkyl side chain, the larger the water contact angle of the copolymer films will be. On the other hand, the higher the content of fluorinated monomers, the lower the surface energy is. The water contact angle increases with the increase of the fluorinated monomer content and reaches a plateau at 3 wt% of fluorinated monomer content.

Preparation of Ultrafine Cobalt Powder by Chemical Reduction in Aqueous Solution

Nanocrystalline cobalt powders have been prepared from aqueous solution by reducing their corresponding metal salts under suitable conditions. The experimental conditions have been studied in detail. X-ray powder diffraction patterns show that the cobalt powder is hexagonal crystallite. The average particle size of the ultrafine cobalt powder is 55 nm.

Effects of Microwave Torrefaction with Mg（OH）2 on Characteristics of Bio-oil from Co-pyrolysis of Straw Stalk and Soapstock

This study investigated the effects of torrefaction with Mg(OH)2 on the properties of bio-oil formed from the microwave-assisted catalytic fast co-pyrolysis of straw stalk and soapstock.The effects of torrefaction temperature and residence time on the yield and composition of bio-oil were discussed.Results showed that the torrefaction temperature and residence time remarkably influenced the yield and composition of bio-oil.With the increase in temperature and time,the bio-oil yield and the proportion of oxygen-containing compounds decreased,while the proportion of aromatic compounds increased.When the feedstocks were subject to torrefaction reaction for 20 min at 260°C,the proportion of oxygen-containing compounds decreased from 29.89%to 16.49%.Meanwhile,Mg(OH)2 could render the deoxidization function of torrefaction process increasingly noticeable.The proportion of the oxygen-containing compounds reached a minimum(14.41%),when the biomass-to-Mg(OH)2 ratio was 1:1.

Syntheses and Structural Characterization of Multi-component Chalcogenide Compounds Based on Pyridine/1,2-Ethanedithiol Solvent

Reactions of Sn powder, cadmium iodide, rubidium carbonate, and sodium sulfide yielded two new compounds： three-dimensional chalcogenide Rb Na_3Cd_2Sn_2S_8（1） and layered ternary compound Na_2CdS_2（2）. 1 and 2 have been determined by single-crystal X-ray diffraction： 1 belongs to the orthorhombic space group Pca21, with a = 13.486（3）, b = 6.7310（14）, c = 18.401（4） ？ and Z = 4; 2 crystallizes in the R 3 m space group, with a = 3.718（3）, c = 26.170（4） ？ and Z = 3. Study of the yellow block shaped crystals of 1 reveals that the structure consists of tetrahedral CdS_4 and SnS_4. The {Cd_2Sn_2S_8} cluster shows a 12-numbered ring structure assembled by corner-sharing of alternating SnS_4 and CdS_4, and the rubidium and sodium ions act as void-filling and charge compensating cations. The dark orange hexagonal crystal of compound 2 consists of a unique 1$[CdS_2]^（2-） layer, which are separated by the Na＋. UV/Vis absorption spectrum exhibits the materials 1 and 2 have semiconductor properties.

Synthesis and Catalytic Properties of ZSM-5 Zeolite with Alkyl-polyamine Triethylene-tetramine as Directing Agent

With alkyl-polyamine triethylene-tetramine as the structure-directing agent, aluminosilicate zeolite ZSM-5（MFI） crystals were synthesized and characterized by XRD, SEM, FTIR, and TG-DTA. The results indicate that the organic amine has a certain influence on the crystal shape and size. The alkaline condition was in favor of the crystallization of ZSM-5 zeolite in the triethylene-tetramine system. The catalytic activity of as-synthesized crystals was examined for the aqueous hydroxylation of phenol with hydrogen peroxide. The phenol conversion was 13.6%, and the selectivities of the as-synthesized samples for catechol, hydroquinone, and benzoquinone were 66.0%, 23.6%, and 10.4%, respectively. The as-synthesized ZSM-5 sample shows a relatively high selectivity towards catechol and could be a promising catalyst.

Synthesis,Crystal Structure and Thermal Property of a 2D Brick Wall Framework Constructed from a New Mononuclear Complex

One new coordination polymer with the chemical formula [CoCu2L2·K2·1.5C2H5OH]n（H4L = 2-hydroxy-3-[（E）-（{3-[（2-hydroxybenzoyl）amino]propyl}imino）methyl] benzoic acid） has been synthesized based on the slow diffusion method,and characterized by IR spectroscopy,thermalgravimetric and X-ray diffraction analysis.It crystallizes in the monoclinic system,space group P21/n with a = 11.98860（10）,b = 24.4279（3）,c = 14.9008（2） ,β = 104.7490（10）°,V = 4220.01（8） 3,Z = 2,Mr = 1009.94,Dc = 1.590 g/cm3,F（000） = 2056,μ（MoKα） = 1.649 mm-1,the final R = 0.0411 and wR = 0.1178 for 5920 observed reflections with I 2σ（I）.The compound possesses a 2D brick wall structure constructed from trinuclear units.

Microsatellite alterations in phenotypically normal esophageal squamous epithelium and metaplasia-dysplasia-adenocarcinoma sequence

AIM: To investigate the microsatellite alterations in phenotypically normal esophageal squamous epithelium and metaplasia-dysplasia-adenocarcinoma sequence. METHODS: Forty-one specimens were obtained from esophageal cancer (EC) patients. Histopathological assessment identified 23 squamous cell carcinomas (SCC) and 18 adenocarcinomas (ADC), including only 8 ADC with Barrett esophageal columnar epithelium (metaplasia) and dysplasia adjacent to ADC. Paraffin-embedded normal squamous epithelium, Barrett esophageal columnar epithelium (metaplasia), dysplasia and esophageal tumor tissues were dissected from the surrounding tissues under microscopic guidance. DNA was extracted using proteinase K digestion buffer, and DNA was diluted at 1:100, 1:1000, 1:5000, 1:10 000 and 1:50 000, respectively. Seven microsatellite markers (D2S123, D3S1616, D3S1300, D5S346, D17S787, D18S58 and BATRII loci) were used in this study. Un-dilution and dilution polymerase chainreactions (PCR) were performed, and microsatellite analysis was carried out. RESULTS: No statistically significant difference was found in microsatellite instability (MSI) and loss of heterozygosity (LOH) of un-diluted DNA between SCC and ADC. The levels of MSI and LOH were high in the metaplasia-dysplasia-adenocarcinoma sequence of diluted DNA. The more the diluted DNA was, the higher the rates of MSI and LOH were at the above 7 loci, especially at D3S1616, D5S346, D2S123, D3S1300 and D18S58 loci. CONCLUSION: The sequence of metaplasia-dysplasia-adenocarcinoma is associated with microsatellite alterations, including MSI and LOH. The MSI and LOH may be the early genetic events during esophageal carcinogenesis, and genetic alterations at the D3S1616, D5S346 and D3S123 loci may play a role in the progress of microsatellite alterations.

Synthesis and Crystal Structure of a Heterometallic Chain Coordination Polymer:{[Ni_2Mn_2L_2(CH_3CH_2OH)(H_2O)]·CH_3OH·2H_2O}_n

A chain-like coordination polymer with the chemical formula of {[Ni2Mn2L2（CH3CH2OH）-（H2O）]·CH3OH·2H2O}n has been synthesized by the assembly reaction of K2NiL·H2O and Mn（OAC）2·4H2O with a 1：1 mole ratio in methanol,where OAC-=CH3COO-and H4L=2-hydroxy-3-[（E）-（{2-[（2-hydroxybenzoyl）imino]ethyl}imino）methyl]benzoic acid.The crystal structure was determined by single-crystal X-ray diffraction analysis.It belongs to the triclinic system,space group P1,with a=9.9464（8）,b=13.4718（11）,c=14.3877（12）,α=87.1930（10）,β=85.4280（10）, ）, =74.6470（10）°, V= 1852.4（3） A^3, Z = 2, Dc= 1.807 g/cm^3, Mr= 1008.03, 2（MoKa） = 0.71073 A, μ（MoKa） = 1.794 mm^-1, F（000） = 1032, R = 0.0527 and wR = 0.1284 （I 〉 2σ（I））. The compound exhibits a chain-like structure formed by dissymmetrical tetranuclear units.