Oxygen-contained amorphous MoS_(x) cocatalyst by one-step photodeposition to enhance H-adsorption affinity for efficient photocatalytic H_(2)generation

Traditional bulk MoS_(2) as an effective H_(2)-evolution cocatalyst is mainly subjected to the weak hydrogen-adsorption ability of highporpotion saturated S,resulting in a slow interfacial H_(2)-evolution reaction.In this paper,an efficient strategy for enhancing hydrogen adsorption of saturated S by manipulating electron density through O atoms is proposed to boost photocatalytic performance of CdS.Simultaneously,amorphization of MoS_(2) can further increase the unsaturated active S sites.Herein,oxygencontained amorphous MoS_(x)(a-MoOS_(x))nanoparticles(10-30 nm)were tightly loaded on the CdS surface through a mild photoinduced deposition method by using(NH_(4))_(2)[MoO(S_(4))_(2)]solution as the precursor at room temperature.The photocatalytic H_(2)-evolution result showed that the a-MoOS_(x)/CdS performed the superior H_(2)-production activity(382μmol·h^(-1),apparent quantum efficiencies(AQE)=11.83%)with a lot of visual H_(2)bubbles,which was 54.6,2.5,and 5.1 times as high as that of CdS,MoS_(x)/CdS,and annealed a-MoOS_(x)/CdS,respectively.Characterizations and density functional theory(DFT)calculations revealed the mechanism of improved H_(2)-evolution activity is that the O heteroatom in amorphous MoOS_(x) can enhance the atomic H-adsorption ability by manipulating the electron density to form electron-deficient S^((2-δ)-)sites.This study provides a new idea to improve the efficiency and number of H_(2)-evolution active sites for developing efficient cocatalysts in the field of photocatalytic hydrogen evolution.

Production of aryl oxygen-containing compounds from catalytic pyrolysis of bagasse lignin over LaTixFe1xO3

A new approach,named production of aryl oxygen-containing compounds from the catalytic pyrolysis of bagasse lignin(BL) over perovskite oxide,was proposed,A series of LaTixFe1-xO3(LTF-x) samples were prepared by the solid state reaction method.The crystal phase and morphology of LTF-x were characterized by XRD and SEM respectively.Catalytic pyrolysis performance of LTF-x was performed by TG-DTG and the distribution patterns of gaseous,liquid and solid products from BL was investigated using a fixed-bed micro-reactor.The optimal reaction conditions were determined:the pyrolysis temperature was 600℃,the mass ratio of mBL:mLTF-0.2 was 3:1,the veloeity of earrier gas was 100 ml·min-1.The gaseous produets were mainly eomposed of CO2,CO,CH4 and CnHm(n=2-4,m=2 n+2 or m=2 n),The main aryl oxygen-containing compounds in liquid products were phenolics,guaiacols,syringols and phenylates,the rest were benzenes,furans,esters and carboxylic acid.The total contents of aryl oxygencontaining compounds were from 62% up to more than 72% under the action of the perovskite.Moreover,the LTF-0.2 sample had nice regenerability.

Adsorption of cadmium ions from aqueous solutions by activated carbon with oxygen-containing functional groups

The adsorption of aqueous cadmium ions(Cd(Ⅱ)) have been investigated for modified activated carbon(AC-T)with oxygen-containing functional groups.The oxygen-containing groups of AC-T play an important role in Cd(Ⅱ) ion adsorption onto AC-T.The modified activated carbon is characterized by scanning electron microscopy,Fourier transform infrared spectroscopy(FT-IR) and X-ray photoelectron spectroscopy(XPS).The results of batch experiments indicate that the maximal adsorption could be achieved over the broad pH range of 4.5 to 6.5.Adsorption isotherms and kinetic study suggest that the sorption of Cd(Ⅱ) onto AC-T produces monolayer coverage and that adsorption is controlled by chemical adsorption.And the adsorbent has a good reusability.According to the FT-IR and XPS analyses,electrostatic attraction and cation exchange between Cd(Ⅱ) and oxygen-containing functional groups on AC-T are dominant mechanisms for Cd(Ⅱ) adsorption.

Structural Characterization and Octanol/water Partition Coefficients(LogP) Prediction for Oxygen-containing Organic Compounds

New descriptors were constructed and structures of some oxygen-containing organic compounds were parameterized. The multiple linear regression（MLR） and partial least squares regression（PLS） methods were employed to build two relationship models between the structures and octanol/water partition coefficients（LogP） of the compounds. The modeling correlation coefficients（R） were 0.976 and 0.922, and the ＂leave one out＂ cross validation correlation coefficients（R（CV）） were 0.973 and 0.909, respectively. The results showed that the structural descriptors could well characterize the molecular structures of the compounds; the stability and predictive power of the models were good.

Predominating stable adsorption and direct electrochemistry of glucose oxidase on carbon nanotubes by oxygen-containing groups

Stable adsorption and direct electrochemistry of glucose oxidase （COx） occurred on nitric acid （HNO3）-treated multi-walled carbon nanotubcs （MWNTs） instead of as-received MWNTs, demonstrating the critical roles of oxygen-containing groups in stable adsorption and direct electrochemistry of GOx on carbon nanotubcs （CNTs）.

Modeling Gas Chromatographic Retention Indices of Oxygen-containing Compounds by Novel Atom-type Topological Indices

Quantitative structure-retention relationship （QSRR） model for the estimation of retention indices （RIs） of 39 oxygen-containing compounds containing ketones and esters was established by our newly introduced distance-based atom-type indices DAI. The useful application of the novel DAI indices has been demonstrated by developing accurate predictive equations for gas chromatographic retention indices. The statistical results of the multiple linear regression for the final model are τ=0.9973 and s=8.23. Furthermore, an external test set of 10 oxo-containing compounds can be accurately predicted with the final equation giving the following statistical results： τpred：0.9966 and spred=8.56.

Oxygen-Containing Functional Groups Regulating the Carbon/Electrolyte Interfacial Properties Toward Enhanced K^(+)Storage

Oxygen-containing functional groups were found to e ectively boost the K^(+)storage performance of carbonaceous materials,however,the mechanism behind the performance enhancement remains unclear.Herein,we report higher rate capability and better long-term cycle performance employing oxygen-doped graphite oxide(GO)as the anode material for potassium ion batteries(PIBs),compared to the raw graphite.The in situ Raman spectroscopy elucidates the adsorption-intercalation hybrid K^(+)storage mechanism,assigning the capacity enhancement to be mainly correlated with reversible K^(+)adsorption/desorption at the newly introduced oxygen sites.It is unraveled that the C=O and COOH rather than C-O-C and OH groups contribute to the capacity enhancement.Based on in situ Fourier transform infrared(FT-IR)spectra and in situ electrochemical impedance spectroscopy(EIS),it is found that the oxygen-containing functional groups regulate the components of solid electrolyte interphase(SEI),leading to the formation of highly conductive,intact and robust SEI.Through the systematic investigations,we hereby uncover the K^(+)storage mechanism of GO-based PIB,and establish a clear relationship between the types/contents of oxygen functional groups and the regulated composition of SEI.

A REVIEW OF OXYGEN-CONTAINING SURFACE GROUPS AND SURFACE MODIFICATION OF ACTIVATED CARBON

This review focused on the recent reports related to the function, characterization and modification of oxygen-containing surface groups of activated carbon (AC). The Oxygen-containing surface groups were briefly described, and the most frequently used techniques for characterization of the oxygen-containing surface groups on ACs were also briefly stated. A detailed discussion of the effects of the oxygen-containing surface groups on the adsorptive capacity of AC was given. The recent progresses in modification of the oxygen-containing surface groups of AC were also reviewed.

Study on the Formation Mechanism of Oxygen-containing Groups on the Surfaces of Hypercrosslinked Polystyrenes

The synthetic parameters were changed to explore the formation mechanism of the oxygen-containing groups on the surfaces of the hypercrosslinked polymers. The FT-IR spectra and the Boehm titration were used to characterize the surface chemistry of the synthesized polymers. The GC-MS was applied to analyze nitrobenzene which was the solvent in the reaction. The functionalities such as carbonyls and phenols were formed through the oxidation of residual chloromethyl groups by nitrobenzene and the carboxylic groups were formed through further oxidation by oxygen. The nitrobenzene was deoxidized to nitrosobenzene and further to aniline.

Catalytic aquathermolysis of Shengli heavy crude oil with an amphiphilic cobalt catalyst

An interfacially active cobalt complex,cobalt dodecylbenzenesulfonate,was synthesized.Elemental analysis,atomic absorption spectroscopy,Fourier transform infrared spectroscopy（FT-IR）,thermogravimetric analysis,and surface/interfacial tension determination were performed to investigate the properties of the catalyst.Results showed that the synthesized catalyst showed active interfacial behavior,decreasing the surface tension and interfacial tension between heavy oil and liquid phase to below 30 and 1.5 mN/m,respectively.The catalyst was not thermally degraded at a temperature of 400 ℃,indicating its high thermal stability.Catalytic performance of the catalyst was evaluated by carrying out aquathermolysis.The viscosity determination showed that the viscosity of the heavy oil decreased by 38%.The average molecular weight,group compositions,and average molecular structure of various samples were analyzed using elemental analysis,FT-IR,electrospray ionization Fourier transform ion cyclotron resonance（ESI FT-ICR MS）,and ～1H nuclear magnetic resonance.Results indicated that the catalyst could attack the sulfur- and O_2-type heteroatomic compounds in asphaltene and resin,especially the compounds with aromatic structure,leading to a decrease in the molecular weight and then the reduction in the viscosity of heavy oil.Therefore,the synthesized catalyst might find an application in catalytic aquathermolysis of heavy oil,especially for the high-aromaticity heavy oil with high oxygen content.

Electrochemically reduced graphene oxide with enhanced electrocatalytic activity toward tetracycline detection

An electrochemically reduced graphene oxide sample, ERGO_0.8v, was prepared by electrochemical reduction of graphene oxide （GO） at -0.8 V, which shows unique electrocatalytic activity toward tetracycline （TTC） detection compared to the ERGO-12v （GO applied to a negative potential of-1.2 V）, GO, chemically reduced GO （CRGO）-modified glassy carbon electrode （GC） and bare GC electrodes. The redox peaks of TTC on an ERGO-0.8v-modifled glass carbon electrode （GC/ERGO-0.8v） were within 0-0.5 V in a pH 3.0 buffer solution with the oxidation peak current correlating well with TTC concentration over a wide range from 0.1 to 160 mg/L Physical characterizations with Fourier transform infrared （FT-IR）, Raman, and X-ray photoelectron spectroscopies （XPS） demonstrated that the oxygen-containing functional groups on GO diminished after the electrochemical reduction at -0.8 V, yet still existed in large amounts, and the defect density changed as new sp2 domains were formed. These changes demonstrated that this adjustment in the number of oxygen-containing groups might be the main factor affecting the electrocatalytic behavior of ERGO. Additionally, the defect density and sp2 domains also exert a profound influence on this behavior. A possible mechanism for the TTC redox reaction at the GC/ERGO-0.8v electrode is also presented. This work suggests that the electrochemical reduction is an effective method to establish new catalytic activities of GO by setting appropriate parameters.

Purified oxygenand nitrogen-modified multi-walled carbon nanotubes as metal-free catalysts for selective olefin hydrogenation

Oxygen and nitrogen-functionalized carbon nanotubes （OCNTs and NCNTs） were applied as metal-free catalysts in selective olefin hydro- genation. A series of NCNTs was synthesized by NH3 post-treatment of OCNTs. Temperature-programmed desorption, N2 physisorption, Raman spectroscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were employed to characterize the surface properties of OCNTs and NCNTs, aiming at a detailed analysis of the type and amount of oxygen- and nitrogen-containing groups as well as surface defects. The gas-phase treatments applied for oxygen and nitrogen functionalization at elevated temperatures up to 600 ℃ led to the increase of surface defects, but did not cause structural damages in the bulk. NCNTs showed a clearly higher activity than the pristine CNTs and OCNTs in the hydrogenation of 1,5-cyclooctadiene, and also the selectivity to cyclooctene was higher. The favorable catalytic properties are ascribed to the nitrogen-containing surface functional groups as well as surface defects related to nitrogen species. In contrast, oxygen-containing surface groups and the surface defects caused by oxygen species did not show clear contribution to the hydrogenation catalysis.

Preparation of Solid Waste-Based Activated Carbon and Its Adsorption Mechanism for Toluene

Regenerated activated carbon(RAC)samples were prepared by carbon activation using waste activated carbon from solid waste resources as the carbon source precursor coupled with adding alkaline additives,and then were further modified by potassium ferrate to finally prepare high-performance carbon for VOCs adsorption.At the same time,the samples before and after modification were systematically studied through characterization techniques such as SEM,Raman spectrometry,FT-IR,XPS,and dynamic/static adsorption.The results showed that the specific surface area and pore volume of the RAC after modification by the strong oxidant potassium ferrate increased by 1.4 times;the degree of defects was enhanced and the content of oxygen-containing functional groups on the surface increased significantly.Among them,the sample modified with potassium ferrate for 24 h had the best dynamic toluene adsorption performance(375.5 mg/g),and the dynamic adsorption capacity was twice that of the original sample(192.8 mg/g).The static adsorption test found that the maximum adsorption capacity of RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h was 796 mg/g,which indicated that the potassium ferrate modification treatment could significantly increase the VOCs adsorption performance of RAC.In addition,through consecutive toluene adsorption-desorption cycle tests,it was found that the RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h sample still retained 91%of adsorption activity after the fifth regeneration cycle.This indicates that RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h has good cycle stability and great application value for the efficient purification of industrial waste VOCs gas.

Mechanism of dibenzofuran hydrodeoxygenation on the Ni(1 1 1)surface

The low-temperature coal tar contains a considerable number of oxygen-containing compounds,which results in poor quality.The catalytic hydrodeoxygenation of oxygen-containing compound to an added-value chemical compound is one of the most efficient methods to upgrade coal tar.In this study,density functional theory calculations are employed to assess and analyze in detail the hydrodeoxygenation of dibenzofuran,as a model compound of coal tar,on the Ni(111)surface.The obtained results indicate that dibenzofuran can be firstly hydrogenated to tetra hy d rod i be nzofura n and hexahydfodibenzofufan.The five-membered-ring opening reaction of tetrahydrodibenzofuran is more straightforward than that of hexahydrodibenzofuran(Ea=0.71 eV vs.1.66 eV).Then,both pathways generate an intermediate 2-cyclohexylphenoxy compound.One part of 2-cyclohexylphenoxy is hydrogenated to 2-cyclohexylphenol and consecutively hydrogenated to cyclohexylcyclohexanol,and another part is directly hydrogenated to cyclohexylcyclohexanone.The hydrogenated intermediates of2-cyclohexylphenol have higher deoxygenation barriers than 2-cyclohexylphenol and cyclohexylcy clohexanol.During the hydrogenation process of cyclohexylcyclohexanone to cyclohexylcyclohexanol,the intermediate 26,formed by adding H to O atom of cyclohexylcyclohexanone,exhibits the lowest deoxygenation barrier of 1.08 eV.High hydrogen coverage may promote the hydrogenation of tetrahydrodibenzofuran,hexahydrodibenzofuran,and intermediate 26 to generate dodecahydrodibenzofuran and cyclohexylcyclohexanol.This dibenzofuran hydrodeoxygenation reaction mechanism corroborates well with previous experimental results and provides a theoretical basis for further optimization of the design of nickel-based catalysts.

Distribution of nitrogen and oxygen compounds in shale oil distillates and their catalytic cracking performance

The positive-and negative-ion electrospray ionization(ESI)coupled with Fourier transform-ion cyclotron resonance mass spectrometry(FT-ICR MS)was employed to identify the chemical composition of heteroatomic compounds in four distillates of Fushun shale oil,and their catalytic cracking performance was investigated.There are nine classes of basic nitrogen compounds(BNCs)and eleven classes of non-basic heteroatomic compounds(NBHCs)in the different distillates.The dominant BNCs are mainly basic N1 class species.The dominant NBHCs are mainly acidic O2 and O1 class species in the300-350℃,350-400℃,and 400-450℃distillates,while the neutral N1,N1 O1 and N2 compounds become relatively abundant in the>450℃fraction.The basic N1 compounds and acidic O1 and O2 compounds are separated into different distillates by the degree of alkylation(different carbon number)but not by aromaticity(different double-bond equivalent values).The basic N1 O1 and N2 class species and neutral N1 and N2 class species are separated into different distillates by the degrees of both alkylation and aromaticity.After the catalytic cracking of Fushun shale oil,the classes of BNCs in the liquid products remain unchanged,while the classes and relative abundances of NBHCs vary significantly.

QSPR Study on the Boiling Points of Some Oxygenand Sulfur-containing Organic Compounds

Structural and thermodynamic parameters of 56 oxygen-containing and 56 sulfur- containing organic compounds were computed at the B3LPY/6-311G＊＊ level using density functional theory （DFT） method. Furthermore,the dependent equations between the experimental data of boiling points （Tb） and theoretical parameters were proposed with SPSS12.0 for windows software,whose correlation coefficients R2 are 0.933 and 0.945. These dependent equations were validated by cross-validation method （q2 are 0.923 and 0.929,respectively）. VIF （variance inflation factors） and t-value methods were also used to verify the significance and self-correlationship of each variable. Results indicate that our dependent equation exhibits good prediction ability,and molecular polarizability （α） is the main factor affecting the Tb of oxygen- and sulfur-containing organic compounds. To our interest,obvious dependence could also be found among the oxygen- and sulfur-containing organic compounds＇ experimental data of boiling points （Tb） with R^2 of 0.857.

Preparation and H_2O_2oxidation of extract

Tongting coal(TTC) was exhaustively extracted with carbon disulfide and N-melthy-2-pyrolidinone(CS 2 /NMP) mixed solvents to afford brown particles of extract,which was characterized with proximate analyzer,transmission electron microscope(TEM) and Fourier transform infrared(FTIR) spectrometer.The results show that the nanometer particles of extract,which were free of ash,are superfine and superclean with tract content of 0.02% A d and particles size of about 100-150 nm.TTC and extract were then subject to oxidation with H 2 O 2 and oxidation products were subsequently analyzed with FTIR and gas chromatography/mass spectrometer(GC/MS).The results show that extract is more reactive with H 2 O 2 in comparison to TTC and richer in oxygen-containing species including phenols,alcohols,ethers,esters,carboxylic acids and anhydrides.

Origin and effect of surface oxygen-containing species on electrochemical CO or CO_(2) reduction reactions

Renewable-energy-powered electrochemical CO or CO_(2)reduction reactions(CO_(2)RR)provide one of the most promising strategies to upgrade CO_(2)to valuable products.In the past decade,the existence and the mechanistic role of oxygen-containing species,such as(sub)surface oxide,hydroxide and oxyhydroxide species,at the electrode–electrolyte interface under reductive conditions have emerged as a topic of acute discussion within the CO_(2)RR field.Oxide-derived Cu attracted the most attention,while other surfaces,including Au,Ag and Sn,were also widely investigated.This review identifies likely causes for contrasting results and views in the literature,summarizes possible oxygen sources for the interfacial oxygen-containing species at the CO_(2)RR conditions,and discusses potential roles these species could play in affecting the rate and product distribution.Finally,perspectives on future efforts to reveal the identity and role of oxygen-containing species in the CO_(2)RR are presented.

STUDY ON SIDE REACTION IN THE SYNTHESIS OF HYPERCROSSLINKED POLYMERS

The systematical study about side reactions have revealed the formation mechanism of oxygen-containing groups of hypercrosslinked polymers. Surface chemistry and functionality of the polymers are characterized by Fourier-transform infrared spectroscopy (FT-IR), solid state nuclear magnetic resonance (NMR) and contact angle. The results showed that the ether groups were from chloromethylated reaction, and the alcohol groups arose from partial hydrolysis of chloromethyl groups during the post-crosslinking reaction, and the carbonyl functionality was formed by further oxidation of the alcohol groups. Catalyst and solvent used in the postcrosslinking reaction would greatly influence the surface chemistry of the polymer.

表面含氧物种对电催化CO_(2)还原的内在促进机制

Oxygen-containing species have been demonstrated to play a key role in facilitating electrocatalytic CO_(2) reduction(CO_(2)RR),particularly in enhancing the selectivity towards multi-carbon(C2+)products.However,the underlying promotion mechanism is still under debate,which greatly limits the rational optimization of the catalytic performance of CO_(2)RR.Herein,taking CO_(2) and O_(2) co-electrolysis over Cu as the prototype,we successfully clarified how O_(2) boosts CO_(2)RR from a new perspective by employing comprehensive theoretical simulations.Our results demonstrated that O_(2) in feed gas can be rapidly reduced into^(*)OH,leading to the partial oxidation of Cu surface under reduction conditions.Surface^(*)OH accelerates the formation of quasi-specifically adsorbed K^(+)due to the electrostatic interaction between^(*)OH and K^(+)ions,which significantly increases the concentration of K^(+)near the Cu surface.These quasi-specifically adsorbed K+ions can not only lower the C-C coupling barriers but also promote the hydrogenation of CO_(2) to improve the CO yield rate,which are responsible for the remarkably enhanced efficiency of C^(2+)products.During the whole process,O_(2) co-electrolysis plays an indispensable role in stabilizing surface^(*)OH.This mechanism can be also adopted to understand the effect of high pH of electrolyte and residual O in oxide-derived Cu(OD-Cu)on the catalytic efficiency towards C^(2+)products.Therefore,our work provides new insights into strategies for improving C^(2+)products on the Cu-based catalysts,i.e.,maintaining partial oxidation of surface under reduction conditions.