Effect of Ni Loading on the Catalytic Properties of Molybdenum Oxides for the Isomerization of Heptane

The catalytic properties of MoOx and incorporation Ni onto the MoOx for the isomerization of heptane have been investigated under atmospheric pressure at different conditions such as different flow rate of H2, different reaction temperature etc.. Compared with MoOx, the Ni addition to the MoOx markedly improved the isomerization activity of heptane by improving the reducibility of MoO3 and activation of H2 in reaction.

Facile solution-processed molybdenum oxide as hole transporting material for efficient organic solar cell

The large energy barrier in hole extraction still remains a great challenge in developing hole transporting layer (HTL) materials for organic solar cells (OSCs).Thus,solution-processed HTL materials with excellent hole collection ability and good compatibility with large-area processing technique are strongly desired for OSCs.Herein,we developed a cost-effective and solution-processed MoO_(3)HTL for efficient OSCs.By adding a small amount of glucose as reducing reagent into the ammonium molybdate precursor solution,a deeply n-doped MoO_(3),namely G:Mo,was prepared through the sol–gel method.Compared to pristine MoO_(3),the conductivity of G:Mo was enhanced by two orders of magnitude,which greatly improved the hole collection ability of the HTL.OSCs with G:Mo can exhibit comparable PCE to the PEDOT:PSS device.Using PBDB-TF:BTP-eC9 as the active layer,a PCE of 17.1%is obtained for the device,which is the highest PCE value for OSC using a solution-processed MoO_(3)HTL.More importantly,G:Mo is well compatible with the blade-coating processing.The OSC using a blade-coated G:Mo showed almost no PCE loss as compared to the device with spin-coated G:Mo HTL.The results from this work indicate that G:Mo is a promising HTL material for the practical production of OSCs.

FORMATION OF MOLYBDENUM OXIDE NANOSTRUCTURES CONTROLLED BY POLY(ETHYLENE OXIDE)

Polymeric systems have played an important role as structure-directing agents and in the control of nucleation and growth of crystals.This article reviews the work of our research group in the field of the polymer-assisted crystallization of inorganic materials,mainly focused on the formation of highly ordered,porous molybdenum oxide nanostructures.Different experimental parameters including the influence of poly(ethylene oxide)-containing polymers on the morphology and structure of the products obtained fr...

PREPARATION OF ELECTRICAL CONDHCTIVE MOLYBDENUM OXIDE BY THERMAL DECOMPOSITION OE HYDRAZINE-CONTAINING MOLYBDENUM SALT

A new method of preparing electrical conductive molybdenum oxide by thermal decomposition from hydrazine-containing molybdenum salt was described.The process of the thermal decomposition of hydrazine- containing molybdemum salt was investigated by thermal analysis(TG and DTA) and the thermally decomposed product was studied by S.E.M.and chemical analysis.The result indicated that the molybdenum oxide obtained in this way was electrical conductive.

Synaptic Transistor Implemented Using Quasi-2D Molybdenum Oxide

Recent years has seen increasing interest in building artificial synaptic devices to emulate the computation performed by biological synapses.Biological synapses are functional links between neurons,through which information is transmitted in the neuron network.The information can be stored and processed simultaneously in the same synapse through tuning synaptic weight,which is defined as the strength of the correlation between

H_(2)O_(2) actuated molybdenum oxide nanodots:Multi-enzyme-like activities,leverage of Fenton reaction,and dual-mode sensitive detection of alendronate sodium

Unexpected benefits to the catalytic performance of materials often originate from the presence of surface defects.Here,novel Dpenicillamine modified molybdenum oxide nanodots,with abundant oxygen vacancy defects,were fabrication by a mild,simple,and cost-effective method.Ultraviolet–visible(UV–Vis)absorption spectra analysis showed that the nanodots had peroxidaselike and catalase-like activities.The reactive oxygen species were probed by electronic paramagnetic resonance technique and spectroscopic methods,demonstrating that the nanodots also had oxidase-like activity.Interestingly,the peroxidase-like activity of nanodots was synergistically enhanced in the presence of ferrous ions or ferric ions.Remarkably,less than nanomolar levels of ferrous ions were required to display this phenomenon,meaning Fenton reagent acted as leverage.Based on this,a sensitive colorimetric and fluorescent dual-mode sensor for alendronate sodium was developed.The linear ranges for colorimetric and fluorescence analysis were 0.2–2.5 and 0.2–2.0μM,with detection limits of 31.21 and 71.84 nM,correspondingly.The method has a simple large-scale material preparation process with higher sensitivity and shorter reaction time,which can inspire and enlighten the design of nanozyme sensors.

Covalency triggers high catalytic activity of amorphous molybdenum oxides for oxidative desulfurization

Oxidative desulfurization(ODS)is a promising technology to produce clean fuel with requiring superior catalysts to lower kinetic barriers.Although most ODS catalysts are based on crystalline transition-metal oxides(TMOs),extraordinary activity also can be achieved with amorphous TMOs.However,the origin of the remarkable catalytic activity of the amorphous TMOs remains greatly ambiguous.Here,we found the crucial role of Mo–O covalency in ruling the intrinsic catalytic activity of amorphous molybdenum oxides(MoO_(x)).Experimental and theoretical analysis indicated that the nonequivalent connectivity in the amorphous structure strongly enhanced Mo–O covalency,thereby increasing the content of electrophilic oxygen and nucleophilic molybdenum to favor the MoO_(x)–H_(2)O_(2) interaction.With the boosted Mo–O covalency to improve the flexibility of the charge state,the amorphous MoO_(x)-based composite catalyst(PE-MoO_(x)/S-0.05)exhibited outstanding catalytic activity for ODS of fuel oil.The turnover frequency(TOF)value of the catalyst(18.63 h^(-1))was almost an order of magnitude higher than that of most reported crystalline MoO_(x)/molecular sieve composite catalysts.The in-depth understanding of the origin of the amorphous TMOs activity for ODS provides a valuable reference for developing ODS catalysts.

Synergistic tribological effect between polyisobutylene succinimide-modified molybdenum oxide nanoparticle and zinc dialkyldithiophosphate for reducing friction and wear of diamond-like carbon coating under boundary lubrication

Organic molybdenum lubricant additive like molybdenum dialkyl dithiocarbamate(MoDTC)can cause wear acceleration of diamond-like carbon(DLC)coating coupled with steel under boundary lubrication,which hinders its industrial application.Therefore,polyisobutylene succinimide(PIBS),an organo molybdenum amide,was adopted to modify molybdenum oxide affording molybdenum polyisobutylene succinimidemolybdenum oxide nanoparticles(MPIBS-MONPs)with potential to prevent the wear acceleration of DLC coating.The thermal stability of MPIBS-MONPs was evaluated by thermogravimetric analysis.Their tribological properties as the additives in di-isooctyl sebacate(DIOS)were evaluated with MoDTC as a control;and their tribomechanism was investigated in relation to their tribochemical reactions and synergistic tribological effect with zinc dialkyldithiophosphate(ZDDP)as well as worn surface characterizations.Findings indicate that MPIBS-MONPs/ZDDP added in DIOS can significantly reduce the friction and wear of DLC coating,being much superior to MoDTC.This is because MPIBS-MONPs and ZDDP jointly take part in tribochemical reactions to form a composite tribofilm that can increase the wear resistance of DLC coating.Namely,the molybdenum amide on MPIBS-MONPs surface can react with ZDDP to form MoS2 film with excellent friction-reducing ability;and MPIBS-MONPs can release molybdenum oxide nanoparticle to form deposited lubrication layer on worn surfaces.The as-formed composite tribofilm consisting of molybdenum oxide nanocrystal,amorphous polyphosphate,and molybdenum disulfide as well as a small amount of Mo2C accounts for the increase in the wear resistance of DLC coating under boundary lubrication.

Solution-processed Molybdenum Oxide Hole Transport Layer Stabilizes Organic Solar Cells

The hole transport layer(HTL)affects the device performance and stability of organic solar cells.In this work,a stable molybdenum oxide(MoO_(x))hole transport layer with low cost was prepared by adjusting the state of the precursor solution with an alcoholic solution of molybdenum acetylacetonate through an oxidant.The MoO_(x) transport layer has good transmittance with a work function of 5.07 eV and higher surface energy.The PM6:Y6 devices using MoO_(x) HTL achieve a high efficiency of 16.8%.MoO_(x) HTL exhibits good applicability with excellent performance in both ternary and all-polymer systems.Air storage stability T80 of the all-polymer device using MoO_(x) HTL was over 600 h,much higher than 70 h of the PEDOT:PSS-based device,and its thermal stability at 85℃ and operational stability under light show better stability than that of the PEDOT:PSS hole transport layer.This work provides a facile and low-cost method to fabricate HTL for organic solar cells,which is beneficial to improve their efficiency and stability.

Sub-gap defect density characterization of molybdenum oxide: An annealing study for solar cell applications

The application of molybdenum oxide in the photovoltaic field is gaining traction as this material can be deployed in doping-free heterojunction solar cells in the role of hole selective contact.For modeling-based optimization of such contact,knowledge of the molybdenum oxide defect density of states(DOS)is crucial.In this paper,we report a method to extract the defect density through nondestructive optical measures,including the contribution given by small polaron optical transitions.The presence of defects related to oxygen-vacancy and of polaron is supported by the results of our opto-electrical characterizations along with the evaluation of previous observations.As part of the study,molybdenum oxide samples have been evaluated after post-deposition thermal treatments.Quantitative results are in agreement with the result of density functional theory showing the presence of a defect band fixed at 1.1 eV below the conduction band edge of the oxide.Moreover,the distribution of defects is affected by post-deposition treatment.

One-step synthesis of carbon-coated monocrystal molybdenum oxides nanocomposite as high-capacity anode materials for lithiumion batteries

Benefitting from higher specific capacities,acceptable cost,nontoxicity and unique crystal structures,the molybdenum oxides have been studied as the anode materials for lithium ion batteries(LIBs).Herein,a direct current(DC)arc-discharge plasma technique has been developed to in-situ synthesize carboncoated monocrystal molybdenum oxides((MoO3NRs/MoO2NPs)@C)nanocomposites,using coarse MoO_(3) bulk as the raw material and methane(CH4)gas as the carbon source.It is indicated that crystallographic traits of MoO_(3) and MoO2 nuclei give rise to an anisotropic growth of monocrystal MoO3 nanorods(NRs)along<100>direction and an isotropic growth of monocrystal MoO_(2) nanoparticles(NPs).The carbon shells on MoO3/MoO2 nanostructures are generated from the absorption of carbon atoms in surrounding atmosphere or the release of supersaturated carbon atoms in MoeOeC solid solution.Unique constitution and pseudo-capacitive behavior of(MoO3NRs/MoO2NPs)@C bring merits to excellent cycling performance and rate capability,i.e.a remarkable specific capacity of 840 mAh·g^(-1) after 100 cycles at a current density of 0.1 Ag^(-1) and a retained capacity of 210 mAh·g^(-1) at 6.4 A g^(-1).This work has offered a simple and efficient approach to fabricate the carbon-coated molybdenum oxides nanostructures for promising anode materials of LIBs。

Controllable synthesis and surface modification of molybdenum oxide nanowires: a short review

Transition metal oxides are found to have overwhelming applications in energy,electronics,catalytic,and bio-and micromechanical systems.A recent report emphasized the current advancements in molybdenum oxide(MoO_(x))nanowire synthesis and the corresponding surface-functionalized nanostructured materials based on our previously reported investigations.The preparation of the nanowires and their applications were systematically summarized.MoO_(x) nanowires combined with substrates exhibited remarkable performances for high energy storage and power densities with high stability.In addition,the review concluded the future advancements of MoO_(x) nanowires.

Millisecond-timescale electrodeposition of platinum atom-doped molybdenum oxide as an efficient electrocatalyst for hydrogen evolution reaction

We present a straightforward method for one-pot electrodeposition of platinum atoms-doped molybdenum oxide(Pt·MoO_(3-x))films and show their superior electrocatalytic activity in the hydrogen evolution reaction(HER).A~15-nm-thick Pt·MoO_(3-x) film was prepared by one-pot electrodeposition at-0.8 V for 1 ms.Due to considerably different solute concentrations,the content of Pt atoms in the electrode-posited composite electrocatalyst is low.No Pt crystals or islands were observed on the flat Pt-MoO_(3-x) films,indicating that Pt atoms were homogeneously dispersed within the MoO_(3-x) thin film.The catalytic performance and physicochemical features of Pt·MoO_(3-x) as a HER electrocatalyst were characterized.The results showed that our Pt·MoO_(3-x) film exhibits 23-and 11-times higher current density than Pt and MoO_(3-x) electrodeposited individually under the same conditions,respectively.It was found that the dramatic enhancement in the HER performance was principally due to the abundant oxygen defects.The use of the developed one-pot electrodeposition and doping method can potentially be extended to various catalytically active metal oxides or hydroxides for enhanced performance in various energy storage and conversion applications.

Near infrared molybdenum oxide quantum dots with high photoluminescence and photothermal performance

The synthesized near infrared molybdenum oxide quantum dots perform excellent red fluorescence imaging performance and photothermal performance,which have 600,650 and 700 nm three unique peaks excited at 540 nm,with a high quantum yield around 20%.Meanwhile,with 808 nm NIR laser excitation,10 mg/mL modified Molybdenum oxide quantum dots can increase temperature up to 72.2℃within 150 s and 77.7℃within 270 s,respectively.

Boosted Electrocatalytic Glucose Oxidation Reaction on Noble-Metal-Free MoO_(3)-Decorated Carbon Nanotubes

Electrocatalytic glucose oxidation reaction(GOR)has attracted much attention owing to its crucial role in biofuel cell fabrication.Herein,we load MoO_(3)nanoparticles on carbon nanotubes(CNTs)and use a discharge process to prepare a noblemetal-free MC-60 catalyst containing MoO_(3),Mo_(2)C,and a Mo_(2)C–MoO_(3)interface.In the GOR,MC-60 shows activity as high as 745μA/(mmol/L cm^(2)),considerably higher than those of the Pt/CNT(270μA/(mmol/L cm^(2)))and Au/CNT catalysts(110μA/(mmol/L cm^(2))).In the GOR,the response minimum on MC-60 is as low as 8μmol/L,with a steady-state response time of only 3 s.Moreover,MC-60 has superior stability and anti-interference ability to impurities in the GOR.The better performance of MC-60 in the GOR is attributed to the abundant Mo sites bonding to C and O atoms at the MoO_(3)–Mo_(2)C interface.These Mo sites create active sites for promoting glucose adsorption and oxidation,enhancing MC-60 performance in the GOR.Thus,these results help to fabricate more effi cient noble-metal-free catalysts for the fabrication of glucose-based biofuel cells.

The properties of transparent conducting molybdenum-doped ZnO films grown by radio frequency magnetron sputtering

Transparent conducting molybdenum-doped zinc oxide films are prepared by radio frequency（RF） magnetron sputtering at ambient temperature.The MoO3 content in the target varies from 0 to 5 wt%,and each film is polycrystalline with a hexagonal structure and a preferred orientation along the c axis.The resistivity first decreases and then increases with the increase in MoO3 content.The lowest resistivity achieved is 9.2 × 10^-4.cm,with a high Hall mobility of 30 cm^2.V-1.s-1 and a carrier concentration of 2.3×10^20 cm^-3 at an MoO3 content of 2 wt%.The average transmittance in the visible range is reduced from 91% to 80% with the increase in the MoO3 content in the target.

Investigation on the Performance of Supported Molybdenum Carbide for the Partial Oxidation of Methane

The performance of supported and unsupported molybdenum carbide for thepartial oxidation of methane (POM) to syngas was investigated. An evaluation of the catalystsindicates that bulk molybdenum carbide has a higher methane conversion during the initial stage buta lower selectivity to CO and H_2/CO ratio in the products. The rapid deactivation of the catalystis also a significant problem. However, the supported molybdenum carbide catalyst shows a muchhigher methane conversion, increased selectivity and significantly improved catalytic stability. Thecharacterization by XRD and BET specific area measurements depict an improved dispersion ofmolybdenum carbide when using alumina as a carrier. The bulk or the supported molybdenum carbideexists in the β-MO_2C phase, while it is transformed into molybdenum dioxide postcatalysis which isan important cause of molybdenum carbide deactivation.

Improving the electrochemical performance of α-MoO_(3) electrode using aluminium trifluoromethanesulfonate water-in-salt electrolyte

Orthorhombic molybdenum trioxide(α-MoO_(3)) electrode material experiences severe capacity fading and poor cycling stability in aqueous electrolytes.We investigated the charge-storage performance of α-MoO_(3) electrode in aluminium trifluoromethanesulfonate(Al(OTf)_(3))-based salt-in-water electrolyte(SiWE) and water-in-salt electrolyte(WiSE).It was found that α-MoO_(3) electrode exhibits significantly different cycling stabilities in both electrolytes with capacity retentions of 8% using the former and87% using the latter.This is because α-MoO_(3) electrode maintains its crystal structure upon cycling in WiSE,but experiences substantial structural collapses and partial dissolution upon cycling in SiWE.This behaviour was inferred from both operando electrogravimetry and ex situ analyses.Research results suggest that the predominant charge-storage mechanism in a-MoO_(3) electrode using WiSE is the intercalation of protons produced from electrolyte hydrolysis with some contribution from surface pseudocapacitance enabled by Al3+ions.A two-volt full cell fabricated from α-MoO_(3) electrode as anode and copper hexacyanoferrate(CuHCF) electrode as cathode using WiSE delivers volumetric and gravimetric energies of 10.4 Wh/L and 26.5 Wh/kg,respectively,with 78% capacity retention after 2500 cycles.This study provides an insightful understanding of the electrochemical performance of α-MoO_(3) electrode in Al(OTf)_(3)-based electrolytes.

Superior lithium storage performance in MoO_(3) by synergistic effects:Oxygen vacancies and nanostructures

Molybdenum trioxide(MoO_(3))has recently attracted wide attention as a typical conversion-type anode of Li-ion batteries(LIBs).Nevertheless,the inferior intrinsic conductivity and rapid capacity fading during charge/discharge process seriously limit large-scale commercial application of MoO_(3).Herein,the density function theory(DFT)calculations show that electron-proton co-doping preferentially bonds symmetric oxygen to form unstable HxMoO_(3).When the-OH-group in HxMoO_(3) is released into the solution in the form of H_(2)O,it is going to form MoO_(3-x)with lower binding energy.By the means of both electron-proton co-doping and high-energy nanosizing,oxygen vacancies and nanoflower structure are introduced into MoO_(3) to accelerate the ion and electronic diffusion/transport kinetics.Benefitting from the promotion of ion diffusion kinetics related to nanostructures,as well as both the augmentation of active sites and the improvement of electrical conductivity induced by oxygen vacancies,the MoO_(3-x)/nanoflower structures show excellent lithium-ion storage performance.The prepared specimen has a high lithium-ion storage capacity of 1261 mA h g^(-1)at 0.1 A g^(-1)and cyclic stability(450 cycle),remarkably higher than those of previously reported MoO_(3)-based anode materials.

MoO_3-TiO_2纳米晶体复合材料光降解糖蜜(英文)

A MoO3-TiO2 nanocrystalline composite material was prepared by a simple solgel method.The synthesized material was charac-terized by X-ray diffraction,scanning electron microscopy with an electron dispersion spectroscopy,transmission electron microscopy,and Fourier transform infrared spectroscopy.Melanoidin is a dark brown pigment found in wastewater from the sugar industry and it pollutes water.This polluted water is generally referred to as molasses and it undergoes fermentation and is solely responsible for water,soil,and air pollution.The synthesized catalytic material was found to be effective in degrading molasses under UV-visible radiation.Analysis of treated and untreated molasses was carried out by measuring its color,chemical oxygen demand,biological oxygen demand,pH,and total dissolved solid.Results from these analyses indicate the effective photodegradation of the molasses.This methodology has several advantages such as high photocatalytic activity,non-toxicity,cleanliness,and reusability of the catalytic material.