MoO3 Nanorods Research Articles

Tailoring porous NiMoO4 nanotube via MoO3 nanorod precursor for environmental monitoring: Electrochemical detection of micro-sized polyvinylchloride

Globally, the hidden contaminants like microplastics (MPs) combined with other harmful substances have agglomerated in rivers and oceans that pose a threat to human health. Thus, evaluating the toxicity of MPs separately and in combination with other pollutants must be done quickly and precisely. This work reports the synthesis of porous NiMoO4 nanotubes (NTs) from the transformation of MoO3 nanorods (NRs) via two steps hydrothermal methods for the effective detection of polyvinyl chloride (PVC) MPs. Transformation of MoO3 NRs to porous NiMoO4 NTs was comprehensively deduced by evaluating the crystalline, structural, compositional and morphological properties. The hydrophobic nature of MoO3 NRs and porous NiMoO4 NTs was proven experimentally and also by DFT calculations. The electrochemical detection of PVC MPs by NiMoO4 NTs was investigated by the CV and EIS measurements. Porous NiMoO4 NTs based electrode expressed the good detection towards PVC MPs with a reasonable sensitivity of ∼1.43 × 10−4 μA/ppm.cm2, a low LOD of ∼18 ppm and R2 = ∼0.9781. EIS results revealed that porous NiMoO4 NTs electrode enabled to deliver sensing response at very low concentration of PVC MPs. Due to their easy interaction with hydrophobic PVC MPs, the hydrophobic NiMoO4 NTs controlled the sensing nature of the material and improved the electrochemical detection at the MP-NiMiO4 NTs interface.

High energy density supercapacitor based on Ag doped MoO3 nanorods on a flexible carbon cloth

In this study, the plain MoO3 and Ag-doped MoO3 nanorods are anchored on a flexible fibrous carbon cloth using a hydrothermal method, and their performances are thoroughly evaluated by fabricating the supercapacitors using both types of nanorods. The doped substrate shows drastic enhancement in specific capacitance which is nearly four times greater than undoped MoO3 nanorods at a current density of 0.5 mA/cm2. Additionally, the Ag doped MoO3 shows an excellent energy density of 43 µWh/cm2. The superior performance of the doped nanorods is attributed to its pseudocapacitive behaviour, higher conductivity, and improved charge kinetics at the electrode–electrolyte interface, enabling a more efficient and potential supercapacitor-based energy storage system to drive future low power flexible and wearable electronic devices.

Inhibiting irreversible Zn2+/H+ co-insertion chemistry in aqueous zinc-MoOx batteries for enhanced capacity stability

Rechargeable aqueous Zn-MoOx batteries are promising energy storage devices with high theoretical specific capacity and low cost. However, MoO3 cathodes suffer drastic capacity decay during the initial discharging/charging process in conventional electrolytes, resulting in a short cycle life and challenging the development of Zn-MoOx batteries. Here we comprehensively investigate the dissolution mechanism of MoO3 cathodes and innovatively introduce a polymer to inhibit the irreversible processes. Our findings reveal that this capacity decay originates from the irreversible Zn2+/H+ co-intercalation/extraction process in aqueous electrolytes. Even worse, during Zn2+ intercalation, the formed ZnxMoO3−x intermediate phase with lower valence states (Mo5+/Mo4+) experiences severe dissolution in aqueous environments. To address these challenges, we developed a first instance of coating a polyaniline (PANI) shell around the MoO3 nanorod effectively inhibiting these irreversible processes and protecting structural integrity during long-term cycling. Detailed structural analysis and theoretical calculations indicate that =N– groups in PANI@MoO3−x simultaneously weaken H+ adsorption and enhance Zn2+ adsorption, which endowed the PANI@MoO3−x cathode with reversible Zn2+/H+ intercalation/extraction. Consequently, the obtained PANI@MoO3−x cathode delivers an excellent discharge capacity of 316.86 mA h g−1 at 0.1 A g−1 and prolonged cycling stability of 75.49% capacity retention after 1000 cycles at 5 A g−1. This work addresses the critical issues associated with MoO3 cathodes and significantly advances the understanding of competitive multi-ion energy storage mechanisms in aqueous Zn-MoO3 batteries.

Synchronously Formed Hetero- and Hollow Core-Branch Nanostructure Toward Wideband Electromagnetic Wave Absorption.

The intrinsic limitation of low electrical conductivity of MoSe2 resulted in inferior dielectric properties, which restricts its electromagnetic wave absorption (EMWA) performances. Herein, a bimetallic selenide of MoSe2/CoSe2@N-doped carbon (NC) composites with hollow core-branch nanostructures are synthesized via the selenization treatment of MoO3 nanorods coated with ZIF-67. By adjusting the mass ratio of ZIF-67 to MoO3, the electromagnetic parameters and morphologies of composites are finely tuned, further ameliorating the impedance matching and EMWA performances. The involvement of NC improves the electronic conductivity of the composites. The synchronously formed heterostructure not only facilitates charge transfer but also leads to the accumulation and uneven distribution of charges, thus enhancing the conductive loss and polarization loss. The hollow core-branch nanostructure provides abundant conductive networks, heterointerfaces, and voids, significantly enhancing the EMWA property. Density functional theory implies that the heterostructures effectively boost charge transport and change charge distribution, which heightens the conductive loss and polarization loss. As a result, the composites demonstrate a minimum reflection loss value of -53.53 dB at 9.04 GHz, alongside a maximum effective absorption bandwidth of 6.32 GHz. This work offers invaluable insights into novel structural designs for future research and applications.

Hierarchical core-shell Ce-doped NiO@MoO2 architecture with Ni 3d-band center modulation for enhanced high-current-density oxygen evolution

Ce-doped NiO catalyst supported on MoO₂ nanorods (Ce-NiO@MoO₂) was constructed as a high-performance oxygen evolution reaction (OER) electrocatalyst. The introduction of Ce induced the formation of nanoflower-like NiO on the MoO₂ nanorod substrate. Ce doping not only created numerous unsaturated Ni coordination sites with higher oxidation states, serving as active sites, but also strengthened the adsorption of oxygen intermediates by upshifting the Ni 3d band center, thereby reducing the energy barrier of the rate-determining OH* → O* step. Consequently, the Ce-NiO@MoO₂ catalyst exhibited remarkable OER activity, with a low overpotential of 313 mV and outstanding 200-hour stability at 1000 mA cm⁻², which is attributed to unsaturated Ni active sites and promoted charge and mass transfer facilitated by the unique hierarchical structure. These findings highlight the crucial role of Ce doping in improving electrocatalytic performance and offer insights into developing efficient and cost-effective catalysts for large-scale hydrogen production via water electrolysis.

Boosting urea-assisted water splitting over P-MoO2@CoNiP through Mo leaching/reabsorption coupling CoNiP reconstruction

Combining the urea oxidation reaction (UOR) with the hydrogen evolution reaction (HER) is an effective technology for energy-saving hydrogen production. Herein, a bifunctional electrocatalyst with CoNiP nanosheet coating on P-doped MoO2 nanorods (P-MoO2@CoNiP) is obtained via a two-step hydrothermal followed a phosphorization process. The catalyst demonstrates exceptional alkaline HER performance due to the formation of MoO2 and the dissolution/absorption of Mo. Meanwhile, the inclusion of Co and P in the P-MoO2@CoNiP catalyst facilitated the formation of NiOOH, enhancing UOR performance. Density functional theory calculations reveal that the hydrogen adsorption Gibbs free energy (ΔGH*) of P-MoO2@CoNiP is closer to 0 eV than CoNiP, favoring the HER. The catalyst only needs −0.08 and 1.38 V to reach 100 mA cm−2 for catalyzing the HER and UOR, respectively. The full urea electrolysis system driven by P-MoO2@CoNiP requires 1.51 V to achieve 100 mA cm−2, 120 mV lower than the traditional water electrolysis.

Construct heterostructures of MoO3 nanorods modified with Fe2O3 rice grains to improve the performance of light-involved Li-O2 battery

Light-involved Li-O2 batteries have received widespread attention in recent years. However, slow reaction kinetics and high charge/discharge overpotentials at high current densities, as well as rapid recombination of photogenerated holes and electrons have hindered their further development. In this study, we propose a design strategy to grow Fe2O3 rice grains in situ on α-MoO3 nanorods to fabricate heterostructures for Li-O2 batteries at high current densities. The heterostructure α-MoO3@Fe2O3 serves as dual-function cathode catalysts for light-involved Li-O2 batteries by facilitating oxygen reduction/oxidation reactions and enhancing the separation of photogenerated charges, thereby effectively improving photoelectrocatalytic performance. Under light irradiation conditions, the heterostructure α-MoO3@Fe2O3 exhibits low charge/discharge overpotential (0.99 V) while demonstrating good cycling stability (stable cycling for 120 cycles at a high current density of 0.5 mA cm−2 with a fixed capacity of 0.5 mAh cm−2) and good rate performance, which significantly better than that was reported the currently popular light-involved Li-O2 batteries under a high current density.

Optimizing Mo2C-based catalytic system for efficient CO2 conversion and CO selectivity through carbon-nitrogen supporting and potassium promotion

Preparing highly active, stable, and selective catalysts for the reverse water gas shift (RWGS) reaction is challenging because of the aggregation of the active catalyst at high RWGS reaction temperatures and deactivation of the active sites. Herein, we present a comparative evaluation and optimization of a molybdenum carbide system using a carbon-nitrogen (CN) support and alkali promotion. Hydrothermally prepared MoO3 nanorods were carburized at 700 °C using H2:CO (4:1) to prepare unsupported Mo2C, while CN-supported Mo2C (Mo2C@CN) was prepared using Mo-based metal-organic framework (Mo-MOF) as a sacrificial template. The as-prepared Mo2C@CN catalytic system was found to be highly active in the RWGS reaction in comparison with the unsupported Mo2C, where CO2 conversion percentage was around 76 % at 700 °C, combined with high CO selectivity (87 %) and very reduced CH4 selectivity (2 %). The addition of potassium as a promoter enhanced CO selectivity (99 %). The active catalyst performance was stable during the catalysis process and for up to 100 h, which imposes the effect of the CN support in preventing the aggregation of Mo2C and keeping its active sites in direct contact with the reactant. This work presents an effective strategy for improving the active catalyst dispersion and reducibility in synergy with the promoter effect to optimize the RWGS reaction output.

Synthesis of Stable and Efficient Electrocatalysts for Hydrogen Evolution: Hierarchical NiMo-Based Hollow Nanotubes

Large-scale development of low-cost, efficient, and stable powder electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solutions is a key step toward commercial hydrogen production. Herein, a hierarchical NiMo-MoO3-x hollow nanotube (NiMo-MoO3-x-HNT) with bifunctional groups as an efficient HER electrocatalyst was strategically invented using an MoO3 nanorod (MoO3−NR) as the precursor. The synthesis mechanism of the NiMo-MoO3-x-HNT is established based on in-depth investigations using diffraction, spectral, and microscopy results. Experimental results suggest that the NiMo-MoO3-x-HNT exhibits excellent electrocatalytic HER performance in 1 M KOH, with a low overpotential of 26.5 mV@10.0 mA cm-2 and a small Tafel slope of 32.6 mV dec–1. These values are comparable to those of cutting-edge electrocatalysts based on platinum-group metals. Moreover, it exhibits an almost unaffected cyclic stability over 50,000 cycles and robust durability over 98 h. This remarkable performance is attributed to its bifunctional groups and the porous hierarchical hollow nanotubular morphology. In summary, this study proposes a novel, efficient, and cost-effective strategy for the development of noble metal-free, high-performance HER electrocatalysts.

Sonication supported green modulation of Fe:MoO3/g-C3N4 heterojunction as solar light sensitive photocatalyst for dye degradation and photoelectrochemical water splitting

The concerns of dye in an aquatic system associated with acute toxicity and carcinogenicity, and the increase in demand for hydrogen production has led to a keen interest in advancing solar driven methodologies utilizing potent photocatalysts to address environmental concerns through sustainable remediation practices. In this pursuit, we synthesized a heterostructure comprised of Fe doped MoO3 (Fe:MoO3), anchored on g-C3N4 sheet as a photocatalyst denoted as Fe:MoO3/g-C3N4, employing a sonication supported green synthesis method with the aid of Murraya paniculata leaf extract. We explored structural, morphological, and surface characteristics using various analytical techniques, including X-Ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–visible spectroscopy, Field emission scanning electron microscopy (FE-SEM) and High-resolution transmission electron microscopy (HR-TEM), X-Ray photoelectron spectroscopy, and BET for a comprehensive surface analysis. The outcomes highlighted the exquisitely oriented and interconnected arrangement of MoO3 nano rods ensconced within a piled layer of g-C3N4. The XRD patterns unveiled the coexistence of g-C3N4 and Fe:MoO3 within the heterojunction structure. FESEM and HRTEM image analysis of Fe:MoO3/g-C3N4 heterojunction reveals a g-C3N4 nanosheet wrapping the Fe:MoO3 nanoparticles with the formation of nanorods of MoO3 with an average thickness of 9.46 nm containing circular Fe nanoparticles with a mean diameter of 8.97 nm. This intricate configuration resulting in a decrease of the size of the nanoparticle caused by effective sonication-supported green modulation configuration facilitated an optimized charge flow, contributing to the elevated photo assisted catalytic performance of the heterojunction. The Fe:MoO3/g-C3N4 semiconductor heterojunction exhibited a considerable surface area and pore volume, inherently amplifying the sites of the activity on the surface and thereby enhancing photoactivity. As opposed to both g-C3N4 and the Fe:MoO3 nanoparticles, the Fe:MoO3/g-C3N4 semiconductor heterojunction showcased enhanced photocatalytic effectiveness in the degradation of dye Crystal violet (CV). Under optimized circumstances, the photo assisted degradation of dye CV by the semiconductor heterojunction adhered to pseudo-first-order kinetics. The active species responsible for the photo assisted degradation process is identified as •O2−. These findings not only emphasize the enhanced efficacy of the developed semiconductor heterojunction but also reveal its potential for addressing the environmental challenges posed by dye CV contamination through prolonged and efficient photocatalytic remediation practices. A marked improvement in both photo assisted catalytic and photoelectrochemical (PEC) water splitting activities under visible light exposure was showcased. The augmented performance of the Fe:MoO3/g-C3N4 semiconductor heterojunction in photodegradation and PEC water splitting activities can be attributed to the extended absorption of visible light. Additionally, the synergistic influence of g-C3N4, contributes positively to the separation of charges and expedites the transfer efficiency of photogenerated charge carriers. This synergy enhances the overall effectiveness of the nanoparticles in harnessing visible light for efficient water-related processes.

V-doped MoO3 nanorods for highly selective oxidation of 5-hydroxymethylfurfural to bio-monomer 2, 5-furandicarboxylic acid

2,5-Furanodicarboxylic acid (FDCA) is a significant chemical derived from biomass and holds the potential to replace traditional petrochemicals in the production of biodegradable polyester materials. In this study, a series of new-type V-doped MoO3 catalysts with different crystalline phases were prepared through the hydrothermal method. The V-doped α-MoO3 with growth along the [010] crystal plane demonstrated the most efficient catalytic activity in the selective oxidation of 5-hydroxymethylfurfural (HMF) to produce FDCA, potentially attributable to the [010] crystal plane's superior affinity for substrate interactions. The catalysts were analyzed using TEM, XPS, XRD, FT-IR, N2 adsorption isotherms and other characterization techniques. The Box-Behnken response surface method was utilized to investigate and successfully determine the optimal reaction conditions. A remarkable HMF conversion of 99.5% and a 97.4% selectivity toward FDCA were achieved at 80 °C after 10 h using tert-butanol as the solvent and tert-butyl hydroperoxide as the oxidant. Furthermore, the catalyst could be readily recovered conveniently and reused without any significant loss in catalytic activity.

Zn-doped MoO3 nanorods for dispersive solid phase extraction of trace Pb(II) from water and food samples

A rapid, and environmentally friendly dispersive solid phase extraction method based on Zn-doped MoO3 nanorods for efficient extraction of trace level of Pb(II) from water and food samples was established before high-resolution continuum source flame atomic absorption spectrometric detection. The sorbent characterization studies were carried out using BET, FE-SEM, XRD, and FT-IR techniques. To achieve effective phase separation and accurate analytical data, the adsorption and desorption procedures have been precisely adjusted. The presented approach demonstrated a wide working range (9.3–500 µg L−1), a relatively low detection limit (3.1 µg L−1), and very good extraction recoveries (90–104%) under optimum conditions. The matrix effect was investigated by the addition of interference ions. The presence of many different anions and cations in the environment did not lead to negative results and selectivity towards the analyte was observed. The method was validated by the analysis of certified reference materials (TMDA - 64.3 and INCT-OBTL-5). The enhancement factor has been determined as 10.9. The suggested method worked efficiently to extract and determine Pb(II) from water, tea, and oil samples.

Fabrication of MoO3/rGO/Au composite for increased photocatalytic degradation of methylene blue

Water line purification and wastewater treatment have become challenging in the fast-growing industry, infrastructure, textile, manufacturing world, etc. with this challenge, photocatalysis has gained substantial attention as an environmentally friendly process on which researchers are working aggressively and, in this progress, two-dimensional (2D) are in focus because of their good photocatalytic ability. Therefore, in this study, we present the synthesis of one such ternary composite material comprising molybdenum trioxide nanorods (MoO3NR), reduced graphene oxide (rGO) and gold nanoparticles (AuNR), with a specific focus on its enhanced photocatalytic performance. The ternary composite is prepared via a combination of in situ hydrothermal and laser ablation methods allowing for precise control over the growth and integration of the constituent materials. The structural and morphological properties of the MoO3 nanorods, rGO and Au ternary material were systematically characterized using various techniques, including UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The obtained results suggest the successful formation of a composite, revealing the presence of uniformly dispersed MoO3 nanorods on the rGO sheets and evenly distributed Au nanoparticles throughout the structure. Photocatalysis evaluations conducted to assess the material performance under visible light irradiation exhibited significantly enhanced methylene blue degradation efficiency of 85.91% in 90[Formula: see text]min in comparison with individual MoO3 nanorods and rGO counterparts. The improved efficiency can be attributed to the combined effects arising from the integration of MoO3 nanorods, rGO and Au nanoparticles, which facilitate efficient light absorption, charge separation and catalytic reactions, which in turn reduces electron–hole recombination and improve photocatalytic performance. Also, the tunable morphology and collective effects of MoO3 nanorods, rGO and Au offer new avenues for designing highly efficient and stable photocatalytic materials.

Trifunctional L-Cysteine Assisted Construction of MoO2/MoS2/C Nanoarchitecture Toward High-Rate Sodium Storage.

The volume collapse and slow kinetics reaction of anode materials are two key issues for sodium ion batteries (SIBs). Herein, an "embryo" strategy is proposed for synthesis of nanorod-embedded MoO2/MoS2/C network nanoarchitecture as anode for SIBs with high-rate performance. Interestingly, L-cysteine which plays triple roles including sulfur source, reductant, and carbon source can be utilized to produce the sulfur vacancy-enriched heterostructure. Specifically, L-cysteine can combine with metastable monoclinic MoO3 nanorods at room temperature to encapsulate the "nutrient" of MoOx analogues (MoO2.5(OH)0.5 and MoO3·0.5H2O) and hydrogen-deficient L-cysteine in the "embryo" precursor affording for subsequent in situ multistep heating treatment. The resultant MoO2/MoS2/C presents a high-rate capability of 875 and 420mAhg-1 at 0.5 and 10Ag-1, respectively, which are much better than the MoS2-based anode materials reported by far. Finite element simulation and analysis results verify that the volume expansion can be reduced to 42.8% from 88.8% when building nanorod-embedded porous network structure. Theoretical calculations reveal that the sulfur vacancies and heterointerface engineering can promote the adsorption and migration of Na+ leading to highly enhanced thermodynamic and kinetic reaction. The work provides an efficient approach to develop advanced electrode materials for energy storage.

Oriented lateral growth of monolayer MoS2 mediated by highly-oriented MoO2 nanorods on sapphire

Two-dimensional (2D) transition metal chalcogenides (TMDs) have demonstrated immense potential and broad prospects in advancing the fields of next-generation optoelectronics, spintronics, valley electronics, and traditional electronics. In recent years, significant...

Improved performance of triethylamine sensors through defect formation in La-doped MoO3 nanorods

The rod-like pure MoO3 and La-doped MoO3 (L-MoO3) sensitive materials were prepared by hydrothermal method. A series of structural analyses, including XRD, element mapping and XPS, revealed that La was uniformly doped into the crystal lattice of MoO3. Furthermore, the gas sensitive studies showed that La doping significantly improved the gas sensitive performance of the sensors to triethylamine. The response value of L-MoO3 sensor is 1148 to 50 ppm triethylamine, which is five times that of pure MoO3, and has outstanding stability and selectivity. Preliminary studies have shown that La doping enables the material to generate more active sites and larger baseline resistance, and the combination of these advantages contributes to structural sensitization and synergies to enhance the gas-sensitive performance of the L-MoO3 sensors. This work prepared a high response TEA gas sensors, and verified the improvement of MoO3 gas-sensitive performance by La doping.

Construction of carbon net supported heterostructure with enhanced mesoscale diffusion for hydrogen production

Construction of heterocatalyst with enhanced mass diffusion at mesoscale is an efficient approach for improving activity of the catalysts. Herein, a L-cysteine-assisted strategy was reported for synthesis of carbon net supported Mo/MoS2 heterostructure towards efficient hydrogen production. Specifically, the MoO3 nanorods were mixed with L-cysteine at room temperature and treated in Ar/H2 at high temperature to in situ prepare Mo/MoS2/C heterostructure. During the above process, L-cysteine played the roles of carbon and sulfur source to generate porous carbon and MoS2, and Ar/H2 was used to produce Mo. The resultant Mo/MoS2/C exhibited an overpotential of 151 mV (η10), which was much lower than the MoS2/C (213 mV) and Mo/C (245 mV). Additionally, the activity was also much better in comparison with the Mo-based catalysts reported in the literature. The finite element analysis results revealed that the nanorod-embedded porous structure of the Mo/MoS2/C was conducive to the mesoscale diffusion, which could facilitate the HER process.

Atomic layer deposition of aluminum-doped zinc oxide onto MoO3 nanorods toward enhanced lithium storage performance

An atomic layer deposition (ALD) of aluminum-doped zinc oxide (AZO) onto MoO3 nanorods (denoted as MoO3@AZO) was developed to enhance the lithium storage performance of MoO3 anode. Thanks to the highly conductive and robust AZO layer, the MoO3@AZO electrode demonstrated high pseudocapacitive contribution (76.2 % at 1.0 mV s−1), enhanced electron/ion transferability, outstanding rate performance (708 mAh g−1 at 2 A g−1) and excellent cycling stability (973 mAh g−1 after 100 cycles at 0.2 A g−1 with a high capacity retention of 92.8 %) when applied as an anode for lithium-ion batteries. Ex-situ transmission electron microscopy analysis revealed that the rod feature of MoO3@AZO was well retained with the protection of the AZO layer even after 100 cycles. Moreover, the ALD-AZO coating may also be commonly used for other metal oxides to enhance their electron conductivity and structural stability.

N-doped carbon-coated TiN nanotube as a sulfur host for Li-S battery

Shuttle effect and slow redox reactions in Li-S battery limit its commercial application. Herein, TiN nanotubes with N-doped carbon coating (TiN/N-C NT) were obtained via MoO3 nanorod template-assistant hydrothermal method and followed by polydopamine coating and carbonization/nitriding. When used as sulfur host, the tubular structure buffers the volume change in lithiation process and shortens Li+ transfer route. Consequently, the TiN/N-C NT cathode exhibits a high capacity of 1010.3 mAh g−1 over 100 cycles at 0.1 A g−1. It provides a low capacity decay rate of 0.057 % per cycle over 500 cycles at a high current density of 1.0 A g−1. This study provides a promising method for preparing high-performance Li-S battery.

Ppb-level detection of trimethylamine as biomarker in exhaled gas based on MoO3/V2O5 hierarchical heterostructure

The toxic gas trimethylamine (TMA) with fishy odor can not only be used as an indicator for evaluating seafood spoilage, but also as a biomarker for trimethylaminuria and kidney disease. This paper constructs a ppb-level trimethylamine gas sensor that operates at room temperature based on MoO3/V2O5 nanocomposites, which were fabricated by hydrothermal synthesis process. The adsorption energy of TMA on sensitive materials was calculated through the density functional theory, and the sensing mechanism was explored by simulating the adsorption process of TMA on the sensitive materials. The response (11.37%) of MoO3/V2O5 composites to ultra-low concentration (20 ppb) TMA was better than that of pure MoO3 nanorods (5.49%) and V2O5 nanospheres (6.36%) at room temperature. Compared with pure MoO3 sensors, an n-n heterojunction is formed between MoO3 and V2O5, which enhances the sensing performance of pure sensing material for TMA. In addition, the detection of exhaled gas in simulated kidney disease patients indicates that this sensor has great potential as an effective TMA detection tool in the field of non-invasive disease diagnosis.