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An asymmetric fiber-shaped supercapacitor (FSC) with roll-type configuration, displaying high power and energy density characteristics, has been fabricated for energy storage in wearable devices. The positive and negative electrodes of the asymmetric FSC consist of polyaniline (PANI) and MoO3, respectively, and are deposited on a carbon fiber (CF) substrate using a chemical bath deposition method. A polyvinyl alcohol/H2SO4 gel is used as electrolyte, which also maintains the CF electrodes in fiber form. The asymmetric PANI//MoO3 roll-type FSC exhibits a wider potential range than its symmetric PANI//PANI counterpart, resulting in higher energy and power densities. The asymmetric PANI//MoO3 roll-type FSC shows an energy density of 67.51 µWh/cm3 with a power density of 59.71 mW/cm3 at a current of 10 mA, which is more than twice the energy density of symmetric PANI//PANI roll-type FSC (30.42 µWh/cm3 and 25.12 mW/cm3). [ABSTRACT FROM AUTHOR]

Supercapacitors (SCs) have been considered as inspiring energy storage devices due to the long cycle lifetime and high power densities. However, their energy density is limited due to the low capacitance of cathode materials and inferior cycling stability at practically useable potential windows >1.2 V. In this paper, we demonstrate the synthesis of a novel ternary Fe 3 O 4 -rGO-MoO 3 nano-composite (FGM) with nanoparticles-like morphology (NPs) by utilizing the fast and facile microwave hydrothermal process. The optimized composition of FGM nanocomposite is characterized by the XPS, EDS, Raman, SEM, TEM and HRTEM techniques. The FGM-NPs supported on the carbon cloth (FGM@CC) electrode is used to investigate the electrochemical charge storage properties in basic potassium hydroxide (KOH) electrolyte. The charge-storage properties of the FGM@CC electrode were studied by the CV, GCD and EIS techniques. The obtained results of FGM@CC electrode in aqueous electrolyte showed excellent electrochemical performance as compared with single metal oxides: maximum specific capacitance of 1666.50 F g−1 (FGM@CC), 1075.26 F g−1 (Fe 3 O 4 NPs) and 952.38 F g−1 (MoO 3 NPs) at a current density of 2.5 A g−1. The capacitance retention was 95.01% (FGM@CC), 94.1% (Fe 3 O 4 NPs) and 92.5% (MoO 3 NPs) after 5000 cycles. Further, the charge storage mechanism is analyzed in the light of power's law and systematical investigated the capacitive and diffusion controlled based stored charge in FGM@CC electrode. Thus FGM nano-composite showed best performance as the cathode material for the next generation flexible supercapacitors. The FGM@CC electrode showed excellent electrochemical performance with as high as C sp of 1666.50 F g−1 at 2.5 A g−1. The FGM@CC electrode possesses 55% of stored energy from surface capacitive storage process and 45% from diffusion controlled process. Image 1 • A ternary Fe3O4-rGO-MoO3 nano-composite is synthesized through a facile microwave strategy. • FGM supported on carbon cloth electrode (FGM@CC) exhibits exceptional high charge storage performance. • FGM@CC electrode reached at high potential window of 1.2 V in aqueous electrolyte. • FGM@CC electrode shows excellent cycling stability >95%. [ABSTRACT FROM AUTHOR]

The effect of introducing MoO3 (Molybdenum oxide) nanoparticle in the epoxy coating was analyzed by EIS and SECM methods in natural seawater. The aminopropyl triethoxy silane (APTES) was treated with the nanoparticle for the proper dispersion and chemical interaction of nanoparticle with the epoxy resin. The introduction of MoO3 nanoparticle in the epoxy coating enhances the charge transfer resistance (Rct) as well as the film resistance (Rf). The observation of iron dissolution and oxygen consumption was carried out by applying the appropriate SECM tip potential in the MoO3 modified nanocomposite coated steel. The epoxy and epoxy-MoO3 nanocomposite-coated samples were used to study the mechanical, adhesion and anticorrosion properties. The analysis using SEM/EDX displayed that the enriched Mo was detected in the nanocomposite coated steel. The presence of the nano level corrosion product containing Mo was confirmed by FIB-TEM analysis. The high corrosion protection properties of the epoxy based nanocomposite coating was due to the complex nanoscale layer formed and chemical interactions of epoxy resin with surface-modified nanoparticle in nanocomposites. [ABSTRACT FROM AUTHOR]

• Synthesis and characterization of nanorods, nanowires, and nanoplates MoO 3 nanostructures. • Dissolution of MoO 3 nanostructures at different pHs. • Mo ion produces complexation and is also able to degrade methylene blue. • The photogenerated holes in the nanomaterials play an important role in photodegradation of MB. The role of shape, dissolution, and chemical properties of MoO 3 nanomaterials with visible light photocatalytic activity are still largely unknown. In the present study, we investigate the photodegradative properties and role of dissolution products under different pH values of three MoO 3 nanomaterials with different shapes and chemical properties (nanorods, nanowires, and nanoplates). We show that different morphologies of MoO 3 present different solubility behaviors with increasing pH (with the highest solubility occurring at pH 10), and this dissolution depends on the oxidative state and nature of the Mo O bonds, not just the size and morphology of the nanostructures. Nanoparticle dissolution seems to favorably affect the discoloration rate of methylene blue (MB) but not its photocatalytic degradation. It is important to differentiate MB discoloration as opposed to photocatalytic degradation since discoloration involves not only photocatalytic degradation but also adsorption and ion complexation processes. Our experiments for the removal of MB show that the nanorods present the best photocatalytic-based degradation activity, while the nanowires, which present the highest dissolution, decolorize MB the fastest. MoO 3 photocatalytic degradation mechanism was investigated via the quantification of nanoparticle-produced reactive oxygen species (ROS) and measurement of MB photocatalytic degradation inhibition due to the presence of ROS scavengers. According to the results, photogenerated holes in the nanomaterial govern the degradative process by allowing production of hydrogen peroxide. This study demonstrates that MoO 3 nanostructure chemical and physical properties, as well as nanostructure dissolution process, influence the photocatalytic properties of MoO 3 nanostructures. [ABSTRACT FROM AUTHOR]

In this paper, porous SiC-mullite ceramics (PSMCs) with high flexural strength and gas permeability were prepared with various mass fractions of MoO 3 and Al 2 O 3. Higher performance was achieved at low sintering temperatures and the problem of large amounts of cristobalite phase in the PSMCs was solved. The results show that 4 wt% MoO 3 is optimal for the growth of mullite rods at a sintering temperature of 850 °C. Porosity was effectively controlled by the formation of interlocking structure and mechanical strength was not obviously affected. Therefore, the optimal content of Al 2 O 3 was 25 wt% in samples prepared at 850–1200 °C, as the flexural strength was generally higher than that in samples with other Al 2 O 3 contents. The highest flexural strength of 66.02 MPa was achieved at an open porosity of 45.4%, gas permeability of 2.32 × 10−13 m2, and permeance of 4.62 × 10−5 mol m−2 s−1 Pa−1 in samples sintered at 1000 °C. This work is of significance for the industrial preparation of PSMCs from photovoltaic silicon waste. [ABSTRACT FROM AUTHOR]

The formation and qualification of redox sites in transition metal oxides are always the active fields related to electronics, catalysis, sensors, and energy-storage units. In the present study, the temperature dependence of thermal reduction of MoO3 was surveyed at the range of 350 °C to 750 °C. Upon reduction, the formed redox species characterized by EPR spectroscopy are the MoV ion and superoxide anion radical (O2−) when the reduction was induced at the optimal temperature of 300−350 °C. When heating-up from 350 °C, the EPR signals started to decline in amplitude. The signals in the range of 400−450 °C decreased to half of that at 350 °C, and then to zero at ∼600 °C. Further treatment at even higher temperature or prolonged heating time at 500 °C caused more reduction and more free electrons were released to the MoO3 bulk, which results in a delocalized means similar to the anti-ferromagnetic coupling. These data herein are helpful to prepare and study the metal-oxide catalysts. [ABSTRACT FROM AUTHOR]

To improve the hydrogen sorption kinetics of MgH 2 , the MoO 3 nanobelts were added into MgH 2 by mechanical milling, leading to fine distribution of MoO 3 in the MgH 2 matrix. Compared to uncatalyzed MgH 2 , the hydriding and dehydriding rates of MoO 3 -catalyzed MgH 2 were significantly improved. The MgH 2 doped with 2 mol% MoO 3 exhibited fast dehydrogenation without activation, and the initial dehydrogenation amount of 5 wt% could be reached within 900 s at 300 °C. The dehydrogenation apparent activation energy is decreased down to 114.7 kJ/mol. The excellent catalytic effect of MoO 3 originates from its specific role as fast hydrogen diffusion pathways. In the hydrogenation process, the MoO 3 transformed to MoO 2 , resulting in the fading of catalytic activity. • The MoO 3 nanobelts were finely dispersed in the MgH 2 by mechanical milling. • The MoO 3 has excellent catalytic effect on the dehydrogenation of MgH 2. • The excellent catalytic activity of MoO 3 is related to its multi-valence and its specific role as hydrogen diffusion pathway. [ABSTRACT FROM AUTHOR]

Highly crystalline molybdenum trioxide nanobelts (MoO 3 NBs) are synthesized via one-step hydrothermal method and the resulting NBs are incorporated with poly(ethylene oxide) (PEO)/carboxymethyl cellulose (CMC) blend matrix via a solution-casting method to be applicable in various nanoelectronics. The structural, optical, and dielectric characteristics of the polymer nanocomposite PEO/CMC-(x)MoO 3 (x = 2, 4, 6, and 8 %wt) films are comprehensively examined by different techniques, including X-ray diffraction (XRD), Fourier-transform infrared (FTIR), ultraviolet–visible (UV–Vis) spectroscopy, and broadband dielectric spectroscopy. XRD results confirm the presence of nanofiller in the (PEO/CMC) blend at a higher fraction (8 wt%). Furthermore, FTIR investigations show an electrostatic interaction between the PEO/CMC polymer composite and MoO 3 nanobelts, leading to the generation of metal oxides/polymer complexes. Optical properties of the synthesized PEO/CMC-(x) MoO 3 matrix, including direct and indirect bandgap energies are decreased by increasing the content of MoO 3 NBs in the PEO/CMC blend matrix, showing the promise of photocatalytic activity. The AC conductivity and dielectric parameters (ε ′ and ε ′′) are markedly increased at a higher fraction of MoO 3 (8 wt%). The optical and electrical conductivity properties of the synthesized PEO/CMC-(x) MoO 3 design confirms its ability to be used in optoelectronic devices. • MoO 3 nanobelts (NBs) are prepared via hydrothermal method in a highly acidic medium. • The optical and dielectric properties of (CMC/PEO) blend matrix filled with MoO 3 NBs are investigated. • MoO 3 NBs increased the amorphous content in the blend structure and improved the entire dielectric properties. [ABSTRACT FROM AUTHOR]

MoO 3 /N, P co-doped carbon sheets are fabricated, which exhibit the excellent water splitting reactivity. [Display omitted] • MoO 3 /N, P co-doped carbon sheets are fabricated. • MoO 3 is anchored on N, P co-doped carbon sheets. • It exhibits excellent water oxidation reactivity with 231 mV at 10 mA/cm2. • It drives alkaline water splitting with a low voltage of 1.59 V at 10 mA/cm2. Catalytic water splitting into H 2 is a prospective way to alleviate the fossil fuels crisis. To date, α-MoO 3 nanostructures show the low activity in water electrolysis reaction because of their poor conductive ability. The rational design of α-MoO 3 with tunable electron structure is greatly desired to promote electrocatalytic performance. Herein, we utilize a facile one-pot method to prepare MoO 3 /N, P co-doped carbon sheets (MoO 3 /NPC). Carbon sheets are regulated by N and P doping, which are generated by thermal pyrolysis of melamine phosphate. Accordingly, the partial reduction of MoO 3 nanosheets is elaborated by coordinative unsaturated Mo5+ sites. Experimental investigations show that MoO 3 nanosheets are anchored on N and P co-doped carbon sheets. The electrochemical studies indicate that MoO 3 /NPC presents excellent water oxidation reactivity with 231 mV@10 mA/cm2, which is superior to RuO 2 (283 mV). In comparison to α-MoO 3 nanosheets (204 mV), the enhanced water reduction reactivity is achieved on MoO 3 /NPC with 144 mV at 10 mA/cm2. Serving as the bi-functional catalysts to drive water splitting, MoO 3 /NPC exhibits a low voltage of 1.59 V at 10 mA/cm2. Our work highlights that heteroatom engineering could mediate the electron state of MoO 3 and thereby accelerate water splitting rate. [ABSTRACT FROM AUTHOR]

To improve the sensitivity of MoO 3 sensors for hydrogen sulfide (H 2 S), two-dimensional MoO 3 nanoflakes with enriched oxygen vacancies were synthesized by hydrothermal method. The relationship between the oxygen vacancies concentration, the hydrothermal method temperature, and the solution concentration (ethanol) was studied. The morphology, structure, and gas-sensing performance of MoO 3 were measured and compared. Through qualitative analysis of lattice movement characterized by XRD, as well as the Mo5+ and adsorbed oxygen content determined by XPS, it was found that the synthesized material MoO 3−x -13021 had the highest concentration of oxygen vacancies. The synthesized material coded as MoO 3−x -13021 with the highest oxygen vacancy concentration showed enhanced H 2 S-sensing properties compared to defect-free MoO 3 sensors. The response value reached 282.6 at 15 ppm. The optimum operating temperature was 140 ℃. Density Functional Theory (DFT) calculations were performed to establish the H 2 S sensitization mechanism model. Adsorption energies, bond lengths, charge transfer, and density of states (DOS) of H 2 S adsorbed on stoichiometric and reduced MoO 3 (010) surfaces were calculated and compared. The increase of oxygen vacancies on reduced MoO 3 leads to the movement of the conduction band, which reduces the band gap of MoO 3. This promotes the charge transfer between the gas molecules and MoO 3 , enhancing the response. [Display omitted] • 2D MoO 3 with enriched oxygen vacancies were synthesized. • The content of oxygen vacancies in MoO 3 was controlled by adjustment of experimental conditions. • The oxygen vacancies reduced the band gap of MoO 3 which was found by DFT calculation. [ABSTRACT FROM AUTHOR]

Thermal oxidation in air of molybdenum disulfide (MoS 2) into layer structured molybdenum trioxide (α-MoO 3) is investigated using a combination of thermal analysis, electron microscopy, Raman, X-ray diffraction and photoelectron spectroscopy. The phase evolutions occurred during the thermal process is characterized by the surface oxidation of MoS 2 , followed by the bulk oxidation to form α-MoO 3 and the formation of Mo 17 O 47 at higher temperatures. The single-phase MoO 3 formed at optimum temperature condition is found to possess crystalline defects and considerably greater values of Li-ion storage cycling and rate performances in comparison with samples prepared at alternative temperatures and also the initial MoS 2. This sample (P-MoO 3 -820) exhibits a charge capacity of 628 mA h g−1 after 250 cycles (100 mA g−1) with a Li+ diffusion coefficient of 2.3 × 10-13 cm2 s−1, substantially greater than that of initial MoS 2 (8.1 × 10−16 cm2 s−1). The electrochemical performance of P-MoO 3 -820 in full-cell configuration against a commercial LiFePO 4 cathode is evaluated and a specific capacity of 100 mAh g−1 after 500 cycles is recorded. This article, for the first time, discusses the thermal oxidation in air of MoS 2 as a simple and relatively clean approach to fabricate defective crystalline MoO 3 with enhanced Li-ion storage kinetics. • Thermal oxidation of molybdenum disulfide; thermochemistry and phase evolution. • Thermal conversion of MoS 2 into layer structured α-MoO 3 with crystalline defects. • Enhanced Li-ion storage performance and electrochemical kinetics. [ABSTRACT FROM AUTHOR]

In this article, serial MoO 3 - or WO 3 -modified CoO x adsorbents were synthesized using the sol-gel method. With the introduction of WO 3 , an enhanced Hg0 removal ability was achieved within the investigated temperature range; compared to the virgin CoO x , the theoretical Hg0 capture capacity of WO 3 -CoO x almost tripled, doubled, and even increased by sixteen times at 150, 200, and 250 °C, respectively. While adding MoO 3 resulted in a shift of the adsorbent's operation temperature window towards higher temperatures. Doping WO 3 or MoO 3 introduced extra acid sites onto the CoO x surface, which facilitated the adsorption of Hg0. The existing certain amount of active Co3+ could still efficiently oxidize the adsorbed Hg0, thus enabling W-Co with an improved Hg0 capture capacity. By contrast, the relatively low oxidative ability of Co3+ could not effectively oxidize the adsorbed Hg0, thus interfering with the Hg0 removal process over Mo-Co at lower temperatures. As the Hg0 capture process continued, the consumption of Co3+ and acid sites caused a gradual increment in the outlet Hg0 concentration. The modification of MoO 3 or WO 3 accelerated the re-oxidation of Co3+, which alleviated the aforementioned negative effects, thus aiding in retaining a relatively stable Hg0 removal performance during the continual Hg0 capture process. [Display omitted] • Adding MoO 3 interferes with the Hg0 capture process at lower temperatures. • Doping WO 3 enhances the Hg0 removal ability of CoO x between 150 and 250 °C. • A superior re-oxidative ability ensures the stable operation of the adsorbents. • Novel acid and redox features ensure the effective removal of Hg0 in the initial stage. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Ag/MoO 3 sensor possessed a rapid response and recovery time of 4 s and 14 s. • The Ag/MoO 3 microspheres shows an excellent response and ultrahigh selectivity to triethylamine. • Ag particles lead to noble metal catalytic spillover effect that enhanced sensing performance. In this work, Ag-decorated MoO 3 microspheres with regular morphology were prepared by a simple dipping method. The gas-sensing measurement results show that the optimum operating temperature of the Ag/MoO 3 sensor decreased 20 ℃ compared with the pure MoO 3 , and the response to 20 ppm triethylamine increased 10 times. Furthermore, the Ag/MoO 3 sensor manifests fast response/recovery times (4/14 s), good selectivity and reliable stability to triethylamine at 220 ℃. The improved triethylamine gas-sensing properties of Ag/MoO 3 sensor is mainly due to the spillover effect and high oxygen vacancy ratio brought about by the introduction of Ag nanoparticles, which greatly speeds up the carrier migration rate. The Ag-decorated MoO 3 microspheres provide a new pathway for the development and design of new triethylamine gas sensors. [ABSTRACT FROM AUTHOR]

Improvements in the charge storage properties of ⍺-MoO 3 used as an electrode with a 30 m ZnCl 2 water-in-salt electrolyte have been achieved by enhancements in electron and ion transport enabled by an inventive synthesis route. Electron transport was improved through the integration of MoO 3 with dopamine-derived carbon via a chemical preintercalation route, and enhanced ion transport was achieved by incorporating oxygen vacancies in MoO 3 structure through ethanol reduction under hydrothermal conditions. The presence of carbon was confirmed by corresponding D and G bands observed in Raman spectroscopy measurements. The presence of oxygen vacancies was proven through correlated XPS, TGA, Raman spectroscopy and XRD analyses, with the introduction of oxygen vacancies leading to an expanded interlayer region. Four-point probe measurements provided evidence of increased electronic conductivity due to the incorporation of carbon, and cyclic voltammetry-based charge storage mechanism analyses revealed increases in ion transport kinetics due to oxygen vacancy formation. Tuning the oxygen vacancy concentration is critical, as excessive concentrations of these point defects leads to structural instability and poor capacity retention. This work demonstrates the combined potential of carbon and oxygen vacancies in moderate concentrations to enhance the charge storage properties of transition metal oxides. The strategies developed in this study offer a path to the development of promising materials for high-rate, high-capacity, and long-duration electrochemical energy storage technologies. [Display omitted] • Adding dopamine and ethanol into synthesis of α-MoO 3 led to improved charge storage. • Dopamine served as a carbon precursor and a reducing agent to form oxygen vacancies. • Incorporation of ethanol allowed to increase concentration of oxygen vacancies. • Formed carbon and oxygen vacancies facilitated charge transport in MoO 3-x /C materials. • The best performance in aqueous Zn-ion cells with WISE was shown by ⍺-MoO 3-x /C-50μL. [ABSTRACT FROM AUTHOR]

• Interface investigation between high-work-function MoO 3 and Pt on 4H-SiC(0001). • Growth behaviors of Pt on MoO 3 /4H-SiC(0001) were in situ studied by NAP-XPS and UPS. • Surface evolution of Pt/MoO 3 /4H-SiC(0001) system via annealing in O 2 , H 2 ambient and under UHV condition was investigated via in situ NAP-XPS and UPS. • Pt showed its thermal stability while Mo underwent various chemical changes. • The surface work function decreased sharply after annealing in H 2 but increased after annealing in O 2 and under UHV condition. Achieving effective Ohmic contact between SiC and metal electrodes remains a challenge due to the high Schottky barrier resulting from the large mismatch between the deep-lying valence band of SiC and Fermi level of metals. One promising approach to address this issue is to introduce a high-work-function interfacial layer between the metal and semiconductor. However, the interaction mechanisms of the inserted high-work-function interfacial layer between metal electrodes and the SiC substrate have been rarely studied systematically. In this work, layers of high-work-function molybdenum trioxide (MoO 3) and platinum (Pt) were successively grown on the 4H-SiC(0001) surface via conventional physical vapour deposition (PVD). We investigated the chemical and electronic structure evolutions upon Pt deposition on MoO 3 /4H-SiC(0001) using in situ near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and ultraviolet photoelectron spectroscopy (UPS). Subsequently, the evolutions of Pt/MoO 3 /4H-SiC(0001) system during annealing under ultra-high vacuum (UHV) or various gas phase environments (H 2 and O 2) were studied via in situ NAP-XPS and UPS. Our results reveal that Pt showed its thermal stability during the annealing process, while Mo presented its versatile chemical characteristics. These results depict a detailed chemical feature of the Pt/MoO 3 /4H-SiC(0001) system and help gain a better understanding about the impact of different environments on Pt/MoO 3 interface. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • EMI shielding potential of metal nanoparticle hybridized molybdenum trioxide is studied. • PVA-based films incorporated with metal NPs and MoO 3 are studied as flexible materials for EMI shielding. • Energy-absorbing properties of MoO 3 /PVA films on hybridization with silver NPs is studied by UV–Vis spectroscopy. • The photocatalytic behavior of the nanocomposite film is evaluated for Methylene blue dye degradation. MoO 3 -PVA films hybridized with silver and copper nano-particles mediated by microwave heating were studied for energy applications. The composites films were characterized by Infra-red (FTIR), Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), UV–Visible spectroscopy and X-ray diffraction (XRD). The crystallite size from XRD peak width was estimated to be about 60–65 nm in the nanocomposite. The electromagnetic interference (EMI) shielding efficiency of so generated composites showed that metal containing composites have higher efficiency in X-band. The EMI study showed promising scope for application in low shielding requirement areas. The so-generated silver containing hybrid system resulted in visible light tunable band-gap (2.34–2.81 eV). Ag-MoO 3 -PVA (Sample PV-C) showed more than 90 % photocatalytic degradation of methylene blue dye. [ABSTRACT FROM AUTHOR]

Flexible MoO3/silver nanowire (AgNW)/MoO3/TiO2/Epoxy electrodes with comparable performance to ITO were fabricated by a scalable solution-processed method with lamination assistance for transparent and conductive applications. Silver nanoparticle-based electrodes were also prepared for comparison. Using a simple spin-coating and lamination-assisted planarization method, a full solution-based approach allows preparation of AgNW-based composite electrodes at temperatures as low as 140 °C. The resulting flexible AgNW-based electrodes exhibit higher transmittance of 82% at 550 nm and lower sheet resistance about 12–15 Ω sq−1, in comparison with the values of 68% and 22–25 Ω sq−1 separately for AgNP based electrodes. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) reveals that the multi-stacked metal-oxide layers embedded with the AgNWs possess lower surface roughness (

Abstract Exploration of high‐performance cathode materials for rechargeable aqueous Zn ion batteries (ZIBs) is highly desirable. The potential of molybdenum trioxide (MoO3) in other electrochemical energy storage devices has been revealed but held understudied in ZIBs. Herein, a demonstration of orthorhombic MoO3 as an ultrahigh‐capacity cathode material in ZIBs is presented. The energy storage mechanism of the MoO3 nanowires based on Zn2+ intercalation/deintercalation and its electrochemical instability mechanism are particularly investigated and elucidated. The severe capacity decay of the MoO3 nanowires during charging/discharging cycles arises from the dissolution and the structural collapse of MoO3 in aqueous electrolyte. To this end, an effective strategy to stabilize MoO3 nanowires by using a quasi‐solid‐state poly(vinyl alcohol)(PVA)/ZnCl2 gel electrolyte to replace the aqueous electrolyte is developed. The capacity retention of the assembled ZIBs after 400 charge/discharge cycles at 6.0 A g−1 is significantly boosted, from 27.1% (in aqueous electrolyte) to 70.4% (in gel electrolyte). More remarkably, the stabilized quasi‐solid‐state ZIBs achieve an attracting areal capacity of 2.65 mAh cm−2 and a gravimetric capacity of 241.3 mAh g−1 at 0.4 A g−1, outperforming most of recently reported ZIBs.

MoS 2 is a two-dimensional layered transition metal dichalcogenide with unique electronic and optical properties. The fabrication of ultrathin MoS 2 is vitally important, since interlayer interactions in its ultrathin varieties will become thickness-dependent, providing thickness-governed tunability and diverse applications of those properties. Unlike with a number of studies that have reported detailed information on direct bandgap emission from MoS 2 monolayers, reliable experimental evidence for thickness-induced evolution or transformation of the indirect bandgap remains scarce. Here, the sulfurization of MoO 3 thin films with nominal thicknesses of 30 nm, 5 nm and 3 nm was performed. All sulfurized samples were examined at room temperature with spectroscopic ellipsometry and photoluminescence spectroscopy to obtain information about their dielectric function and edge emission spectra. This investigation unveiled an indirect-to-indirect crossover between the transitions, associated with two different Λ and K valleys of the MoS 2 conduction band, by thinning its thickness down to a few layers.

The development of bifunctional catalysts that facilitate both the hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR) in alkaline environment is crucial for realizing unitized regenerative anion-exchange membrane fuel cells. In this study, a novel strategy to modulate the electron density of MoO 3 through Ni doping (sample named Ni x Mo 1- x O 3 ) is reported. Ni is incorporated to replace Mo atoms in MoO 3 . Specifically, Ni x Mo 1- x O 3 is combined with optimal adsorption energy, along with MoO 2 /Mo 2 N hybrid with high conductivity. The resulting Ni x Mo 1- x O 3 supported on MoO 2 /Mo 2 N hybrid (sample named as Ni x Mo 1- x O 3 -H) exhibits excellent alkaline HER activity, with an overpotential of only 16 mV at 10 mA cm -2 and a Tafel slope of 54 mV dec -1 . In addition, the Ni x Mo 1- x O 3 -H demonstrates an ultrahigh HOR performance with a high exchange current density (3.852 mA cm -2 ). The catalyst's breakdown potential of 0.23 V indicates its ability to withstand higher voltages without breaking down. As evidenced by the results, this characteristic leads to improved stability. These results are higher than those of the other catalysts reported, which indicates that the electron density of MoO 3 can be effectively modulated through Ni doping, leading to excellent HER and HOR performance., (© 2023 Wiley-VCH GmbH.)

Layered molybdenum trioxide (MoO 3 ) is being investigated as a cathode material with high theoretical capacity and holds promise for aqueous secondary batteries. Unfortunately, the severe structural degradation of MoO 3 and insufficient intrinsic properties hinder its practical application. Herein, a Na + preintercalation strategy is reported as an effective method to construct cathodes with high performance for aqueous zinc/sodium batteries (AZSBs). Compared with pristine MoO 3 , the Na + preintercalated Na 0.25 MoO 3 cathode delivers a reversible capacity of 251.1 mAh g -1 at 1 A g -1 , achieves a capacity retention of 79.2% after 500 cycles, and exhibits a high rate capability (121.5 mAh g -1 at 20 A g -1 ), which is superior to that in most of the previous reports. Through the experimental measurements and density functional theory (DFT) calculations, the preintercalation method could shorten the forbidden band gap and modulate the electronic structure and hence effectively inhibit the structural collapse of MoO 3 microrods, induce reversible Na + insertion, and enhance the discharge potential. This work is of significance for further research on molybdenum-based compounds as cathode materials for aqueous secondary batteries.

Rod shaped structures of molybdenum trioxide (MoO 3) were synthesized at low temperature using simple and low cost method. The synthesized materials were characterized by different characterization techniques. The effect of annealing temperature on crystal structure and optical properties of MoO 3 was investigated. The hexagonal phase (h-MoO 3) was observed up to 300 °C and beyond this temperature, the phase of the MoO 3 is changed to orthorhombic (α-MoO 3). The transition of crystal phase (h-MoO 3 to α-MoO 3) was investigated by analyzing the X-ray diffraction (XRD), Raman and DSC measurements. The shift in the wavenumber position of 971 cm−1 (Mo–O stretching) peak with temperature also substantiates the phase transition in MoO 3 structure. The shape of nanostructured MoO 3 was modified with annealing temperature. The change in crystal phases and shapes with temperature may result defects in the structure, which essentially modify the structural and optical properties of the material. The photocatalytic properties of the synthesized materials were studied on methylene blue (MB) dye under UV-irradiation. The sample annealed at 400 °C (M4) show excellent photodegradation compared to other samples. It could be due to the combined effects of shape (helical) and defects (oxygen vacancies) present in M4, as supported by the electron paramagnetic resonance (EPR) measurements. Among the various radicals, OH plays an important role in photodegardation of the MB dye. • Hexagonal and orthorhombic crystal phases of MoO 3 were synthesized. • Raman peak at ∼971 cm−1 is designated as a signature peak to characterize temperature induced phase transition in MoO 3. • The α-MoO 3 shows excellent photocatalytic activity compared to h-MoO 3. • The.•OH is the main reactive species involved in the photodegradation of MB dye. [ABSTRACT FROM AUTHOR]

• A flexible aqueous Al-ion battery was reported for the first time. • The flexible Al-ion battery exhibits exceptional flexibility and safety. • The Al-ion battery delivers excellent electrochemical cycling stability. • This work paves the way for Al-ion battery application in wearable electronics. With the fast development of flexible and wearable electronics, the design of secondary energy storage system based on aqueous metal ion battery with outstanding flexibility, safety and low cost is critical for their practical application. As low-cost alternatives to lithium ion battery, multivalent metal ion technologies including Mg2+, Zn2+, Ca2+, and Al3+ are investigated increasingly in the past few years. The investigation based on Al-ion chemistry is also underway considering the aluminum's advantages of natural abundance, small ion size together with three-electron-redox properties. Herein, a flexible aqueous Al-ion battery is successfully fabricated for the first time with copper hexacyanoferrate cathode and polypyrrole (PPy) coated MoO 3 anode sandwiched by gel electrolyte. The as-assembled Al-ion battery based on intercalation chemistry exhibits an excellent cycling stability of 83.2% capacity retention after 100 cycles and good rate capability benefiting from the conductive PPy coating layer on MoO 3 anode. Besides, the battery demonstrates impressive flexibility and safety to sustain various deformations and mechanical abuse including bending, squeezing, folding, twisting as well as arbitrary drilling and tailoring into any desired shapes. Obviously, the flexible aqueous Al-ion battery developed in this study paves the way of multivalent metal ion battery as energy storage device towards various wearable electronics. [ABSTRACT FROM AUTHOR]

• New series of MoO 3 catalysts supported on SiO 2 were synthesized. • The catalysts were tested in the hydrodeoxygenation (HDO) of palmitic acid. • Citric acid used for the preparation of MoO 3 catalysts results in superior catalytic materials. • XPS measurements showed that oxidation states of the Mo species play a crucial role in their catalytic performance. A series of MoO 3 catalysts supported on SiO 2 were prepared. The aim of this work is to understand the factors that determine their catalytic performance in hydrodeoxygenation (HDO) of fatty acids. The impregnation of Mo species was carried out by using citric acid (CA) or malonic acid (MA) in aqueous solutions. The use of organic acids resulted in changing the oxidation states of Mo in the materials. The performance of the catalyst prepared with CA was the best in this series. We found that oxidation states of Mo species play a major role in the HDO of palmitic acid. [ABSTRACT FROM AUTHOR]

In this study, a novel MoO 3 @MoS 2 /TiO 2 photocatalyst with higher photocatalytic hydrogen production efficiency was prepared via a hydrothermal followed by quenching method. The prepared composites were characterized by X-ray diffraction (XRD), Raman spectroscopy, UV–Vis Spectrophotometers, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). The photocatalytic performance for hydrogen evolution was also investigated. The results show that MoS 2 -340 °C/TiO 2 exhibits excellent photocatalytic hydrogen production efficiency (4669 μmol g−1 h−1), which is 5.8 times higher than that of unquenched MoS 2 /TiO 2 under the same conditions. MoO 3 on the surface and edges of large layered MoS 2 creates more traps adjacent to the joint. More photogenerated electrons can be enriched during the photocatalytic reaction, which achieve the purpose of exposing more active sites. • Surface partially oxidized MoS2 nanosheets are synthesized via a hydrothermal followed by quenching method. • The novel MoO3@MoS2/TiO2 photocatalyst with higher photocatalytic hydrogen production efficiency was prepared. • The hydrogen production efficiency of MoS2-340˚C/TiO2 is enhanced by 5.8 times compared to the unmodified MoS2/TiO2. • The existence of many active sites of surface partially oxidized MoS2 leads to higher efficiency hydrogen evolution. [ABSTRACT FROM AUTHOR]

In this study, a facile impregnation-calcination strategy was applied in order to synthesize Mo2C modified MoO3 (Mo2C/MoO3), which was then employed as catalyst for the photoreduction of Cr (VI) and photodegradation of methyl orange (MO) upon irradiation by visible light (λ > 400 nm). The apparent rate constant (k) of Mo2C/MoO3 for the MO photocatalyzed degradation reaction under visible-light irradiation was found to be 0.0171 min-1, which was 4.59 and 67.38 times higher than that of Pt/MoO3 and pristine MoO3, respectively. Study of the photocatalytic mechanism revealed that the •O2- species played a major role in MO degradation. Moreover, the addition of Mo2C enhanced the light response region of MoO3, and also promoted the photocatalytic activity of MoO3. This was due to the enhanced separation efficiency of photogenerated electron-hole pairs and broader photoresponse region. This work suggests a new use for the easily accessible Mo2C/MoO3 heterostructure and could facilitate the application of photocatalysts for wastewater treatment． [ABSTRACT FROM AUTHOR]

• MoO 2 spheres with a novel mesoporous structure is fabricated for supercapacitor. • The capacitive behavior of MoO 2 and MoO 3 are evaluated and compared. • The MoO 2 shows a specific capacitance of 381.0 F g−1, 7 times higher than MoO 3. MoO 2 and MoO 3 with specific morphologies are synthesized on flexible carbon cloth through a facile hydrothermal method as supercapacitor electrodes. The prepared prismatic MoO 3 shows a specific capacitance of 54.7 F g−1 in 1 M LiOH electrolyte. Moreover, the prepared MoO 2 presents a spherical profile with hierarchical porous structure. Each MoO 2 sphere is stacked with several layers of MoO 2 "spindle" which is further built by amounts of MoO 2 nanoparticles. A high specific capacitance of 381.0 F g−1 is achieved for the MoO 2 sphere electrode, 7 times higher than that of MoO 3. [ABSTRACT FROM AUTHOR]

MoO3/MoS2 microspheres were successfully synthesized via one-step solvothermal method. The crystal structure, morphology, and composition of MoO3/MoS2 microspheres were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). And MoO3/MoS2 microspheres exhibited excellent photocatalytic performance in the degradation of methyl orange under visible light irradiation. The photocatalytic degradation rate of MoO3/MoS2 microsphere is 18.5 and 2.5 times of pure MoO3 and MoS2, respectively. The enhanced photocatalytic activity of MoO3/MoS2 should be attributed to the formation of heterojunctions between MoO3 and MoS2 nanosheets, resulting in the effective separation and utilization of the photo-generated charge carries. [ABSTRACT FROM AUTHOR]

It has been demonstrated that high efficiency and brightness can be achieved in phosphorescent organic light-emitting diodes (PHOLEDs) by using molybdenum oxide (MoO3)/poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) as dual hole injection layers (HILs) on indium tin oxide (ITO) substrate. The dual HILs were simply fabricated by spin-coating PEDOT:PSS solution on a thin MoO3 layer deposited by vacuum thermal evaporation. This work reveals that PEDOT:PSS coating on MoO3 resulted in a smoother surface, simultaneously MoO3 lamella prevented acid corrosion of PEDOT:PSS on ITO. Meanwhile, with the insertion of PEDOT:PSS and MoO3 as HILs between anode and hole transporting layer (HTL), the energy barrier has been reduced and gave rise to effective hole injection. OLEDs with dual HILs resulted in the maximum current efficiency (CE) of 61.3 cd A − 1 and maximum luminance of 112200 cd cm − 2 , which showed a superior performance compared to those devices with single HIL of PEDOT:PSS or MoO3. Our results proved the composition of PEDOT:PSS and MoO3 as HILs were beneficial for high performance OLEDs. [ABSTRACT FROM AUTHOR]

In this research, thin film nanocomposite (TFN) membranes were developed using novel polyethersulfone– molybdenum oxide (PES–MoO3) nanocomposite substrate. The effects of MoO3 nanoparticles on the PES substrate morphologies, surface roughness, hydrophilicity, and water permeability were investigated by measuring the water contact angles, scanning electron microscope (SEM) imaging, FT‐IR spectroscopy, and atomic force microscope (AFM) analysis. The MoO3 nanoparticle modified membranes were used in the forward osmosis (FO) process with both PRO mode (the membrane active layer facing draw solution) and FO (the membrane active layer facing feed solution) mode. The results indicated enhanced water permeability of the modified membranes upon the MoO3 addition, leading to significant enhancement in the water flux and the desalination performance. [ABSTRACT FROM AUTHOR]

Beside the noble metal nanoparticles (NPs), plasmonic semiconductors are being developed nowadays for a variety of applications such as catalyst, phototherapy and sensing technologies. In the present study, colloidal plasmonic MoO 3 NPs with <20 nm mean size are prepared by flame synthesis as a rapid, cost effective, catalyst-free and atmospheric route. A Mo rod was converted to oxide nanopowder in an oxyhydrogen flame and collected on a water-cooled rotating substrate. Colloidal solutions of these particles were made by dispersing the MoO 3 NPs into DI water. As a palladium precursor, solutions of aqueous PdCl 2 were added to the colloidal NPs to make them sensitive to hydrogen. Formation of cubic Pd NPs in among the MoO 3 NPs were recognized in TEM images for hydrogen-exposed samples. Upon hydrogen injection, a localized surface plasmon resonance (LSPR) absorption band was appeared in the UV–Vis absorption spectra at 700–800 nm region, which began to decline by further exposure time. Within few seconds of gas exposure, samples turned blue and longer exposure made them brownish. The LSPR peaks exhibited a spectral blue shift with a more hydrogenation, in agreement with the existing plasmonic model. In addition, a correlation between optical band gap and LSPR intensity was found. The colloidal Pd-MoO 3 solutions then were employed for LSPR sensing of hydrogen at a concentration range of 0–5%. A pronounced LSPR linear sensitivity toward low concentration (<2.5%) of hydrogen was observed. • MoO 3 nanoparticles with dimensions under 20 nm were synthesized by the flame synthesis method. • A homemade oxyhydrogen generator was used to produce the flame. • PdCl 2 solution was added to produce palladium nanoparticles as a hydrogen catalyst. • The PdCl 2 -MoO 3 colloidal solution showed coloration and LSPR formation after hydrogen exposure. • The plasmonic PdCl 2 -MoO 3 colloidal solution was used to monitor different hydrogen concentration. [ABSTRACT FROM AUTHOR]

The influence of molybdenum on the selective catalytic reduction (SCR) performance and SO 2 durability of V/Mo-Ti catalysts was investigated. The characteristics of the catalysts were investigated by Brunauer-Emmett-Teller (BET) surface area analysis, field-emission transmission electron microscopy (FE-TEM), Raman spectroscopy, NH 3 -temperature programmed desorption (NH 3 -TPD), in-situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTs), SO 2 temperature-programmed desorption (SO 2 -TPD), and X-ray photoelectron spectroscopy (XPS). The V/Mo-Ti catalysts exhibited improved SCR performances and SO 2 resistances at 250 °C compared to those of V/W/Ti catalysts. The improved catalytic activity was shown to be imparted by amorphous MoOx. The formation of amorphous MoOx species with the addition of molybdenum to titanic acid was found to be more significant than that by the addition of molybdenum to crystalline TiO 2. The increased density of NH 3 -adsorption and Brønsted-acid sites by addition of molybdenum was found to have a positive effect on catalyst performance. Since the reaction between SO 2 and VOx was suppressed by the addition of molybdenum, the area of the SO 2 -TPD peak due to desorption of adsorbed SO 2 from the catalyst surface was reduced. This decrease in the amount of adsorbed SO 2 improved the SO 2 resistances of the catalysts. The V/Mo-Ti catalysts exhibited increasing activities and SO 2 resistances with increasing Mo6+ ratio (and Mo6+ atoms/cm3). Furthermore, they exhibited suppressed formation of ammonium sulfate salts due to decreased SO 2 adsorption, as the reaction of terminal V O groups and adsorbed SO 2 is inhibited by the addition of molybdenum. Thus, the V/Mo-Ti catalysts exhibited better catalytic activities and SO 2 durability than those of V/W/Ti catalysts. Unlabelled Image • The addition of Mo to V/Ti shows increased acid sites while reducing SO 2 adsorption. • The added molybdenum is more effective when present as amorphous MoOx. • Increasing the Mo6+ atoms/cm3 and Mo6+ ratio increases SO 2 resistance. [ABSTRACT FROM AUTHOR]

• Ex situ formation of supported Mo carbide species for CH 4 aromatization was explored. • Mo carbide species formed at lower temperature by slow reduction/carburization were more stable in reaction. • Heating Mo oxides in He before exposing to CH 4 caused a drop in surface area. • Mo carbide species formed by slow reduction/carburization we more dispersed. • This higher Mo dispersion was maintained even after reaction and Mo exposure remained high despite the formation of C deposits. The synthesis of zeolite-supported Mo carbide species was studied by testing different reduction/carburization conditions applied to a zeolite-supported Mo oxide catalyst, with the aim to find the optimized treatment conditions necessary to form stable supported Mo carbide catalysts ex situ for application in methane dehydroaromatization reaction. Four types of treatment were performed and studied using temperature-programmed reduction and carburization profiles: (1) heating the catalyst in a reducing gas, H 2 , up to reaction temperature and switching to CH 4 ; (2) heating the catalyst in a reducing gas, H 2 , mixed with dilute CH 4 ; (3) heating the catalyst in CH 4 up to reaction temperature; and (4) heating the catalyst in an inert gas (commonly He) up to reaction temperature and then switching to CH 4 or to H 2 followed by CH 4 or to H 2 /CH 4 mixture. Each of these processes were stopped at intermediate points to analyze the phases that were present in order to identify the structural evolution of the supported Mo carbides that originate from the supported Mo oxides. Once the supported carbides were formed, they were quenched under the same gas mixture, and then they were each tested in methane dehydroaromatization via previous heating to reaction temperature in He flow. Despite all of them showing only presence of Mo 2 C species on HZSM-5, the catalytic properties were dramatically different. Catalysts treated in H 2 or CH 4 /H 2 showed remarkably higher stability. These catalysts exhibited a higher Mo dispersion and thus exposure on the active surface. [ABSTRACT FROM AUTHOR]

The potentiometric CO2 gas sensors based on Li3PO4 thin film using different MoO3-doped Li2CO3 as sensing electrodes were investigated. The sensing electrode materials were prepared by screen printing while the Li3PO4 electrolyte thin film by thermal evaporation. The materials' phase composition and the microstructures were characterized by X-ray diffraction (XRD), energy-dispersive spectrum (EDS), and scanning electron microscopy (SEM). The sensors were tested at the temperature ranging from 350 °C to 500 °C with an interval of 25 °C. The results showed that all sensors have better sensing properties at higher working temperatures. Among them, the sensor attached with 10 wt% MoO3-doped Li2CO3 exhibit excellent sensing performance, and its sensitivity attains to 95.7 mV/decade and the response and recovery time are 16 s and 22 s respectively at 500 °C. Its output EMF is more stable than any other sensors annealed at 550 °C. The MoO3-doped Li2CO3 sensing electrodes can significantly improve the sensors' properties because of the porous microstructure and catalytic characteristics during the reaction period. [ABSTRACT FROM AUTHOR]

A rice krispies sphere constructed by hundreds of MoO3 nanoparticles of ∼100 nm with carbon dots of ∼5 nm (MoO3/CDs) is created via a one‐pot hydrothermal synthesis process using CDs as nucleation seeds. The MoO3/CDs shows a reversible capacity of 897.5 mAh g−1 after 100 cycles at a current density of 0.1 A g−1 as an anode material for lithium‐ion battery. Moreover, a discharge capacity of 507 mAh g−1 is achieved after 255 full cycles under a high current density of 0.5 A g−1. The electrochemical performance of the MoO3/CDs is promising due to the MoO3 nanoparticles connected by ultrafine CDs with excellent conductivity. The unique structure effectively alleviate the volume change during the charging/discharging process and improve the ionic and electronic mobility to enhancing the reversible reaction of MoO3. [ABSTRACT FROM AUTHOR]

• Properties of MoO 3 and V 2 O 5 ultra-thin films from first-principles calculations. • Tuning DFT + U to describestructure, band gap, dielectric constant and thermodynamics. • Study of the dependence of the properties on the number of layers. The structural and electronic properties of bulk and ultrathin films of V 2 O 5 and MoO 3 layered oxides have been studied with first-principles density functional theory calculations including Van der Waals dispersion corrections. The U parameter in the DFT + U approach has been determined in order to properly reproduce geometry, band-gap, macroscopic dielectric constant, and formation enthalpies of the two materials. The mono-, and multi-layers are cleaved along the 〈0 0 1〉 and 〈0 1 0〉 stable crystallographic orientations for V 2 O 5 and MoO 3 , respectively. Three layers are needed in order to recover bulk-like properties of V 2 O 5 and MoO 3. Spin-orbit effects have been incorporated in our simulations, and they result in marginal effects (∼20–30 meV) on the electronic band-gap of V 2 O 5 and a more pronounced (∼200 meV) effect on the band gap of bulk MoO 3. We also discuss the importance of including local field effects for the reproduction of the anisotropy of the dielectric constant, which reflects the crystal structure of these materials. [ABSTRACT FROM AUTHOR]

All-inorganic perovskite CsPbI 2 Br has received much attention recently due to its suitable bandgap and excellent thermal stability. Herein, we demonstrated a low temperature solution process to obtain high quality CsPbI 2 Br films and fabricate devices with a facile n-i-p structure (ITO/SnO 2 /CsPbI 2 Br/Spiro-OMeTAD/MoO 3 /Ag), in which MoO 3 was introduced as interfacial layer that led to high efficient charge extraction and suppressed carrier recombination. As a result, the champion cells exhibited a relatively high power conversion efficiency of 14.05% and superb fill factor of 81.5%. More importantly, unencapsulated PSCs with MoO 3 interfacial layers showed outstanding stabilities with retaining 80% of initial PCE with thermal treatment at 85 °C for 140 min in ambient air, 80% of initial PCE under continuous illumination for 120 min in ambient air, and 89% of initial PCE after being stored in N 2 glove-box over 60 days. Meantime, it should be mentioned that all interlayers and active layer were processed at temperature below 160 °C, and hence, this fabrication technique is promising for flexible energy devices and future commercialization. Low temperature processed high performance all-inorganic perovskite solar cells with MoO 3 as interfacial layer have been achieved with PCE exceeding 14% via sequential graded thermal annealing process. Moreover, the unencapsulated device exhibited enhanced operational stability under continuously simulated sunlight illumination, thermal stability and outstanding air stability after 60 days of storage under N 2 condition. Image 1 • High performance with PCE of 14 % and FF of 81.5 % are achieved by using low temperature solution processed CsPbI 2 Br. • The MoO 3 interfacial layer has been introduced to enhance charge extraction and suppressed carrier recombination. • The unencapsulated device exhibited enhanced operational stability and thermal stability. [ABSTRACT FROM AUTHOR]

Abstract We have studied the formation, polymorphism, and electrical conductivity of Bi 2 O 3 -based compounds with the general formula (Bi 2 O 3) x (Nd 2 O 3) y (MoO 3) z (x + y + z = 1) in the ternary system Bi 2 O 3 –Nd 2 O 3 –MoO 3. It has been shown that the system contains Bi 2 O 3 -based solid solutions with cubic, tetragonal, monoclinic, and rhombohedral structures, depending on composition. Bi 2 O 3 -based compounds with the cubic fluorite structure have been identified in two broad composition regions: 0.56 ≤ x ≤ 0.9, 0.03 ≤ y ≤ 0.22, 0.03 ≤ z ≤ 0.23 and 0.36 ≤ x ≤ 0.6, 0.25 ≤ y ≤ 0.47, 0 ≤ z ≤ 0.21. In addition, a large region of tetragonal compounds has been detected, with 0.37 ≤ x ≤ 0.56, 0.19 ≤ y ≤ 0.38, and 0.23 ≤ z ≤ 0.33. The conductivity of the samples studied increases with Bi 2 O 3 concentration: from 0.01 ((Bi 2 O 3) 0.36 (Nd 2 O 3) 0.45 (MoO 3) 0.19 sample) to 0.7 S/cm ((Bi 2 O 3) 0.9 (Nd 2 O 3) 0.07 (MoO 3) 0.03 sample) at 800 °C. The cubic and tetragonal symmetries of the samples persist after rapid heating and cooling, but prolonged annealing in a limited temperature range can lower the symmetry of some samples. Heating the samples to above their instability range restores their original structure and properties. In addition, we have identified (Bi 2 O 3) x (Nd 2 O 3) y (MoO 3) z compounds that remain stable, without symmetry changes, at any temperature, even at long annealing times. Graphical abstract Image 1 Highlights • Wide stability fields of Bi 2 O 3 -based phases exist in Bi 2 O 3 –Nd 2 O 3 –MoO 3 system. • Cubic, tetragonal, monoclinic, and rhombohedral compounds were found. • Some compounds may decrease their symmetry in a limited temperature range. • Some compounds remain stable at any temperatures and annealing time. • The conductivity rises with increase of Bi 2 O 3 concentration. [ABSTRACT FROM AUTHOR]