Transition Metal Oxide Nanomaterials Research Articles

Transition Metal Oxide Nanomaterials: New Weapons to Boost Anti-Tumor Immunity Cycle.

Semiconductor nanomaterials have emerged as a significant factor in the advancement of tumor immunotherapy. This review discusses the potential of transition metal oxide (TMO) nanomaterials in the realm of anti-tumor immune modulation. These binary inorganic semiconductor compounds possess high electron mobility, extended ductility, and strong stability. Apart from being primary thermistor materials, they also serve as potent agents in enhancing the anti-tumor immunity cycle. The diverse metal oxidation states of TMOs result in a range of electronic properties, from metallicity to wide-bandgap insulating behavior. Notably, titanium oxide, manganese oxide, iron oxide, zinc oxide, and copper oxide have garnered interest due to their presence in tumor tissues and potential therapeutic implications. These nanoparticles (NPs) kickstart the tumor immunity cycle by inducing immunogenic cell death (ICD), prompting the release of ICD and tumor-associated antigens (TAAs) and working in conjunction with various therapies to trigger dendritic cell (DC) maturation, T cell response, and infiltration. Furthermore, they can alter the tumor microenvironment (TME) by reprogramming immunosuppressive tumor-associated macrophages into an inflammatory state, thereby impeding tumor growth. This review aims to bring attention to the research community regarding the diversity and significance of TMOs in the tumor immunity cycle, while also underscoring the potential and challenges associated with using TMOs in tumor immunotherapy.

Fabrication of a Molybdenum Dioxide/Multi-Walled Carbon Nanotubes Nanocomposite as an Anodic Modification Material for High-Performance Microbial Fuel Cells.

A nanocomposite of multi-walled carbon nanotubes (MWCNTs) decorated with molybdenum dioxide (MoO2) nanoparticles is fabricated through the reduction of phosphomolybdic acid hydrate on functionalized MWCNTs in a hydrogen-argon (10%) atmosphere in a tube furnace. The MoO2/MWCNTs composite is proposed as an anodic modification material for microbial fuel cells (MFCs). MWCNTs have outstanding physical and chemical peculiarities, with functionalized MWCNTs having substantially large electroactive areas. In addition, combined with the exceptional properties of MoO2 nanoparticles, the synergistic advantages of functionalized MWCNTs and MoO2 nanoparticles give a MoO2/MWCNTs anode a large electroactive area, excellent electronic conductivity, enhanced extracellular electron transfer capacity, and improved nutrient transfer capability. Finally, the power harvesting of an MFC with the MoO2/MWCNTs anode is improved, with the MFC showing long-term repeatability of voltage and current density outputs. This exploratory research advances the fundamental application of anodic modification to MFCs, simultaneously providing valuable guidance for the use of carbon-based transition metal oxide nanomaterials in high-performance MFCs.

Remediation of Metal Oxide Nanotoxicity with a Functional Amyloid.

Understanding the environmental health and safety of nanomaterials (NanoEHS) is essential for the sustained development of nanotechnology. Although extensive research over the past two decades has elucidated the phenomena, mechanisms, and implications of nanomaterials in cellular and organismal models, the active remediation of the adverse biological and environmental effects of nanomaterials remains largely unexplored. Inspired by recent developments in functional amyloids for biomedical and environmental engineering, this work shows their new utility as metallothionein mimics in the strategically important area of NanoEHS. Specifically, metal ions released from CuO and ZnO nanoparticles are sequestered through cysteine coordination and electrostatic interactions with beta-lactoglobulin (bLg) amyloid, as revealed by inductively coupled plasma mass spectrometry and molecular dynamics simulations. The toxicity of the metal oxide nanoparticles is subsequently mitigated by functional amyloids, as validated by cell viability and apoptosis assays in vitro and murine survival and biomarker assays in vivo. As bLg amyloid fibrils can be readily produced from whey in large quantities at a low cost, the study offers a crucial strategy for remediating the biological and environmental footprints of transition metal oxide nanomaterials.

Common Transition Metal Oxide Nanomaterials in Electrochemical Sensors for the Diagnosis of Monoamine Neurotransmitter‐Related Disorders

AbstractMonoamine neurotransmitters are essential for learning, mental alertness, emotions, and blood flow, among other functions. Fatal neurological disorders that signal the imbalance of these biomolecules in the human system include Parkinson's disease, myocardial infarction, Alzheimer's disease, hypoglycemia, Schizophrenia, and a host of other ailments. The diagnosis of these monoamine neurotransmitter‐related conditions revolves around the development of analytical tools with high sensitivity for the four major monoamine neurotransmitters namely dopamine, epinephrine, norepinephrine, and serotonin. The application of electrochemical sensors made from notable metal oxide nanoparticles or composites containing the metal oxide nanoparticles for the detection of these monoamine neurotransmitters was discussed herein. More importantly, the feasibility of the application of the ZnO, CuO, and TiO2 nanoparticle‐based electrochemical sensors for a comprehensive diagnosis of monoamine neurotransmitter‐related conditions was critically investigated in this review.

Light-responsive functional nanomaterials as pioneering therapeutics: a paradigm shift to combat age-related disorders.

Aging, marked by dysregulated cellular systems, gives rise to a spectrum of age-related disorders, including neurodegeneration, atherosclerosis, immunosenescence, and musculoskeletal issues. These conditions contribute significantly to the global disease burden, posing challenges to health span and economic resources. Current therapeutic approaches, although diverse in mechanism, often fall short in targeting the underlying cellular pathologies. They fail to address the issues compounded by altered pharmacokinetics in the elderly. Nanotechnology emerges as a transformative solution, offering tissue-specific targeted therapies through nanoparticles. Functional nanomaterials (FNMs) respond to internal or external stimuli, with light-responsive nanomaterials gaining prominence. Harnessing the benefits of deep tissue penetration and ease of manipulation particularly in the near-infrared spectrum, light-responsive FNMs present innovative strategies for age-related comorbidities. This review comprehensively summarizes the potential of light-responsive FNM-based approaches for targeting cellular environments in age-related disorders, and also emphasizes the advantages over traditional treatment modalities. Specifically, it focuses on the development of various classes of light-responsive functional nanomaterials including plasmonic nanomaterials, nanomaterials as carriers, upconversion nanomaterials, 2D nanomaterials, transition metal oxide and dichalcogenide nanomaterials and carbon-based nanomaterials against age related diseases. We foresee that such advanced developments in the field of nanotechnology could provide a new hope for clinical diagnosis and treatment of age-related disorders.

Influence of aluminum incorporation and aqueous conditions on metal ion release of high-Ni transition metal oxide nanomaterials

Developing a materials perspective of how to control the degradation and negative impact of complex metal oxides requires an integrated understanding of how these nanomaterials transform in the environment and interact with biological systems.

Metal Oxides Nanomaterials and Nanocomposite-Based Electrochemical Sensors for Healthcare Applications.

Wide-ranging research efforts have been directed to prioritize scientific and technological inventions for healthcare monitoring. In recent years, the effective utilization of functional nanomaterials in various electroanalytical measurements realized a rapid, sensitive, and selective detection and monitoring of a wide range of biomarkers in body fluids. Owing to good biocompatibility, high organic capturing ability, strong electrocatalytic activity, and high robustness, transition metal oxide-derived nanocomposites have led to enhancements in sensing performances. The aim of the present review is to describe key advancements of transition metal oxide nanomaterials and nanocomposites-based electrochemical sensors, along with current challenges and prospects towards the development of a highly durable and reliable detection of biomarkers. Moreover, the preparation of nanomaterials, electrode fabrication, sensing mechanism, electrode-bio interface, and performance of metal oxides nanomaterials and nanocomposite-based sensor platforms will be described.

Ultrathin fan-like multimetallic oxide as a superior oxygen evolution electrocatalyst in alkaline water and seawater

Multimetallic systems exhibit high catalytic activity because of the flexibility to change the electronic and crystal structures of the materials. On the other hand, the preparation of homogeneous catalysts and the revelation of synergistic interactions in the catalytic process limit the further development of multimetallic catalysts due to the increase in chemical complexity. Here, atomically thin quinary CNWFVOx (CoNiWFeVOx) fan-like nanobelts are successfully synthesized as an OER electrocatalyst by a simple colloidal chemistry strategy. Compared with the ternary and quaternary systems, the quinary CNWFVOx shows more excellent catalytic performance, requiring only low overpotentials of 245 mV and 272 mV to achieve a current density of 10 mA cm−2 under alkaline conditions and simulated seawater, respectively, and a small Tafel slope of 47.17 mV dec−1 under alkaline conditions. Moreover, the electrode activity remained almost constant after more than 83 h of stability testing. The OER activity of the catalyst was significantly enhanced and the kinetics were accelerated thanks to the synergistic effect of the multi-metals and the amorphous ultra-thin structure. This work may provide opportunities for the design and study of atomically thin multinary transition metal oxide nanomaterials.

Scope and significance of transition metal oxide nanomaterials for next-generation Li-ion batteries

This article presents a comprehensive overview of the current state-of-the-art research on the use of nanomaterials in batteries and provides valuable insights into their potential applications.

Ultrasensitive detection of Hg(II) by small-sized Mn3O4 loaded on g-C3N4 nanosheets: Heterojunction facilitates electron transfer and Mn(II)/Mn(III)/Mn(IV) cycle

Transition metal oxides are widely used in electrochemical detection because of the promotion of redox of heavy metal ions (HMIs) by valence change behavior. However, it is challenging to favorably promote the valence change to achieve the improvement of detection sensitivity. Herein, a Mn3O4/g-C3N4 composite (named as MO-CN) with small-sized of Mn3O4 and high proportion of Mn(II) and Mn(III) was prepared, which reveals an excellent performance on detecting mercury ion (Hg(II)). It is discovered that Mn3O4 becomes small in size and well disperses on g-C3N4, which solves the adverse effect of agglomeration and also lead to a good conductivity. And g-C3N4 can provide more adsorption sites to enhance the adsorption on Hg(II). Heterojunction is proved to form in MO-CN and thus accelerates electrons to flow from g-C3N4 to Mn3O4. This results in transforming Mn(IV) to Mn(II) and Mn(III) in Mn3O4, thereby promoting the cycle of Mn(II)/Mn(III)/Mn(IV) and furthermore facilitating the redox of Hg(II). Simultaneously, the obtained sensitivity (473.43 μA μM−1 cm−2) and limit of detection (LOD, 0.003 μM) are as expected. The nanocomposites and heterojunction based on transition metal oxide and 2D nanomaterials is promising to boost the detection of HMIs.

Comprehensive analysis of the transition metal oxide nanomaterials role as catalysts in the low-temperature oxidation of adsorbed nC7-asphaltenes

Fe2O3, V2O5, NiO, MnO2, and MoO3 nanomaterials were synthesized and used as adsorbents as well as catalysts in low-temperature oxidation of asphaltenes. The acidity of the metal cations seems to be the predominant factor improving adsorption capability. Further, RTO, TGA and DSC techniques evinced catalytic properties for all the studied materials in the oxidation of asphaltenes.Particularly, a correlation between the adsorption affinity and the activation energy in the combustion process was experimentally evidenced for Fe2O3, MnO2, and MoO3 materials. Thus, the asphaltenes-surface interaction plays a key role for adsorptive and oxidative treatment of asphaltenes.Transition metal oxide crystalline phase and its corresponding redox properties proved to be relevant parameters for promoting oxygen addition reactions in the low temperature oxidation process.

Removal of pollutants via synergy of adsorption and photocatalysis over MXene-based nanocomposites

The MXene-based nanocomposites comprised by multi-layered Ti3C2-MXene (ML-Ti3C2) nanosheets and transition metal oxide (TMO) nanomaterials, i.e. zinc oxide (ZnO), bismuth molybdate (Bi2MoO6) and tin dioxide (SnO2), were prepared in this work. After loading ML-Ti3C2 MXene, the contact angle of oleophobic ZnO, Bi2MoO6, and SnO2 for oil drop decreases to 98°, 62°, and 75°, respectively. The improvement of lipophilicity of the composites is conducive to the adsorption of water-soluble organic pollutants. Coupling of MXene enhances the adsorption capacity of the composite catalyst for pollutants. The adsorption capacities of ZnO/ML-Ti3C2, SnO2/ML-Ti3C2 and Bi2MoO6/ML-Ti3C2 for methylene blue (MB) molecules are 155 mg/g, 163 mg/g and 152 mg/g, respectively. The adsorption of MB on ML-Ti3C2 based nanocomposites follows the Langmuir model, indicating that the monolayer covering of the nanocomposites is the main adsorption mechanism. Under visible-light irradiation, 150 mg/L of high concentration MB solution and 20 mg/L of 4-chlorophenol (4-CP) solution could be completely removed by adsorption and photocatalysis over ZnO/ML-Ti3C2 for 4 h. The electron spin resonance (ESR) trapping method and free radical scavenger experiments both show that hydroxyl radicals and superoxide free radicals are reactive species in the degradation process. The photoluminescence (PL) spectrum analysis shows that coupling TMO and MXene inhibits the recombination of photogenerated electron-hole pairs. The synergistic removal of pollutants by strong adsorption and visible photocatalysis of MXene-based nanocomposites provides a new idea for environmental pollution control.

Applications of Non‐precious Transition Metal Oxide Nanoparticles in Electrochemistry

AbstractNon‐precious transition metal oxide nanomaterials offer numerous opportunities for various cost‐effective electrochemical applications. This review article features the design and advancement of such nanomaterials with unique features applied for the fabrication of electrochemical devices. Also, it discusses various new syntheses of transition metal oxide nanoparticles (TMO NPs) via multiple chemicophysical and biological procedures. Further, the novel appliances of the TMO NPs with varying sizes and morphologies are appraised. The advantages and challenges of a number of investigations on the TMO NPs towards electrochemical applications are addressed with their standpoint of cost‐effectiveness, applicability, and the efficiency of the introduced nanostructures for the industrial applications.

A facile one-pot microwave assisted hydrothermal synthesis of hierarchical cobalt oxide/reduced graphene oxide composite electrode for high-performance supercapacitors

The composites composed of transition metal oxide and carbonaceous nanomaterials have been regarded as one of the promising electrode materials for high performance supercapacitors. How to develop effective hybridization of two components to deliver synergistic effect on electrochemical performance is a key question to be tackled. Herein, we successfully prepare three-dimensional hierarchical cobalt oxide (Co3O4)/reduced graphene oxide (rGO) composites via a facile, rapid and cost-effective one-pot microwave assisted hydrothermal process. The effects of rGO content on morphology, chemical and crystalline structure, electrode performance are systematically investigated. Interestingly, it is noticed that by changing the addition of graphene oxide (GO), the size of Co3O4 nanoparticles can be effectively controlled, which has a significant effect on the electrochemical properties of electrode materials. The as-prepared Co3O4/rGO with 23 wt% rGO exhibits an outstanding specific capacitance of 1031 F g−1 at 1 A g−1 and retains 78% of capacitance when current density increased to 10 A g−1, revealing that Co3O4/rGO composites prepared by this facile process can be an ideal candidate electrode for high performance supercapacitors.

Self-assembled MXene-based Schottky-junction upon Transition metal oxide for regulated tumor microenvironment and enhanced CDT/PTT/MRI activated by NIR irradiation

Transition metal oxide nanomaterials (TMOs) have been adopted to produce reactive oxygen species (ROS) and adjust tumor microenvironment (TME) in cancer therapy. However, mono-modal treatment and the incompatibility of biological enzyme both hampered the therapeutic effect. Herein, we developed a multimodal TMO-based nanoplatform that the ultrathin Ti3C2 nanosheets were attached onto the MnFe2O4 nanoparticles self-assembled by applying chitosan as a chemical crosslinker to construct an interfacial Schottky junction, Ti3C2@Chitosan-MnFe2O4 (TC@Ch-MFO), achieving improved ROS generation as well as optimized biocompatibility. This heterojunction can controllably catalyze hydrogen peroxide (H2O2) to generate O2 and deplete the overexpressed glutathione (GSH) levels in hypoxic TME, which realizes the chemodynamic therapy (CDT) by cyclized Fenton reaction under NIR excitation. TC@Ch-MFO also constructs a multimodal treatment nanoplatform by introducing available high-efficiency photothermal agent (PTA), Ti3C2, for phtotheraml therapy (PTT). In addition, it simultaneously integrates the visualization with T1- and T2-weighting magnetic resonance imaging (MRI). The toxicity of TC@Ch-MFO to normal tissue cells is negligible. This platform could provide new insights into the development of multimoded synergistic nanoplatform for biological applications, especially breaking the shackles of MXenes merely used as a photo-thermal agent, adopting it to bioimaging sensor and drug loading.

Transition metal oxide and chalcogenide-based nanomaterials for antibacterial activities: an overview

A new battle line is drawn where antibiotic misuse and mismanagement have made treatment of bacterial infection a thorny issue. It is highly desirable to develop active antibacterial materials for bacterial control and destruction without drug resistance. A large amount of effort has been devoted to transition metal oxide and chalcogenide (TMO&C) nanomaterials as possible candidates owing to their unconventional physiochemical, electronic and optical properties and feasibility of functional architecture assembly. This review expounds multiple TMO&C-based strategies to combat pathogens, opening up new possibilities for the design of simple, yet highly effective systems that are crucial for antimicrobial treatment. A special emphasis is placed on the multiple mechanisms of these nanoagents, including mechanical rupture, photocatalytic/photothermal activity, Fenton-type reaction, nanozyme-assisted effect, released metal ions and the synergistic action of TMO&C in combination with other antibacterial agents. The applications of TMO&C nanomaterials mostly in air/water purification and wound healing along with their bactericidal activities and mechanisms are also described. Finally, the contemporary challenges and trends in the development of TMO&C-based antibacterial strategies are proposed.

In situ synthesis of nanostructured Fe3O4@TiO2 composite grown on activated carbon cloth as a binder-free electrode for high performance supercapacitors.

Transition metal oxide (TMO) nanomaterials with regular morphology have received widening research attention as electrode materials due to their improved electrochemical characteristics. In this study we present the successful fabrication of an Fe3O4/TiO2 nanocomposite grown on a carbon cloth (Fe3O4/TiO2@C) used as a high-efficiency electrochemical supercapacitor electrode. Flexible electrodes are directly used for asymmetric supercapacitors without any binder. The increased specific surface area of the TiO2 nanorod arrays provides sufficient adsorption sites for Fe3O4 nanoparticles. An asymmetric supercapacitor composed of Fe3O4/TiO2@C is tested in 1 M Na2SO3 electrolyte, and the synergistic effects of fast reversible Faraday reaction on the Fe3O4/TiO2 surface and the highly conductive network formed by TiO2@C help the electrode to achieve a high areal capacitance of 304.1 mF cm−2 at a current density of 1 mA cm−2 and excellent cycling stability with 90.7% capacitance retention at 5 mA cm−2 after 10 000 cycles. As a result, novel synthesis of a binder-free Fe3O4/TiO2@C electrode provides a feasible approach for developing competitive candidates in supercapacitor applications.

Protein Fe-S Centers as a Molecular Target of Toxicity of a Complex Transition Metal Oxide Nanomaterial with Downstream Impacts on Metabolism and Growth.

Oxidative stress is frequently identified as a mechanism of toxicity of nanomaterials. However, rarely have the specific underlying molecular targets responsible for these impacts been identified. We previously demonstrated significant negative impacts of transition metal oxide (TMO) lithium-ion battery cathode nanomaterial, lithium cobalt oxide (LCO), on the growth, development, hemoglobin, and heme synthesis gene expression in the larvae of a model sediment invertebrate Chironomus riparius. Here, we propose that alteration of the Fe-S protein function by LCO is a molecular initiating event leading to these changes. A 10 mg/L LCO exposure causes significant oxidation of the aconitase 4Fe-4S center after 7 d as determined from the electron paramagnetic resonance spectroscopy measurements of intact larvae and a significant reduction in the aconitase activity of larval protein after 48 h (p < 0.05). Next-generation RNA sequencing identified significant changes in the expression of genes involved in 4Fe-4S center binding, Fe-S center synthesis, iron ion binding, and metabolism for 10 mg/L LCO at 48 h (FDR-adjusted, p < 0.1). We propose an adverse outcome pathway, where the oxidation of metabolic and regulatory Fe-S centers of proteins by LCO disrupts metabolic homeostasis, which negatively impacts the growth and development, a mechanism that may apply for these conserved proteins across species and for other TMO nanomaterials.

Two-Dimensional Molecular Sheets of Transition Metal Oxides toward Wearable Energy Storage.

Flexible and wearable electronics have recently sparked intense interest in both academia and industry because they can greatly revolutionize human lives by impacting every aspect of our daily routine. Therefore, developing compatible energy storage devices has become one of the most important research frontiers in this field. Particularly, the development of flexible electrodes is of great significance when considering their essential role in the performance of these devices. Although there is no doubt that transition metal oxide nanomaterials are suitable for providing electrochemical energy storage, individual oxides generally cannot be developed into freestanding electrodes because of their intrinsically low mechanical strength.Two-dimensional sheets with genuine unilamellar thickness are perfect units for the assembly of freestanding and mechanically flexible devices, as they have the advantages of low thickness and good flexibility. Therefore, the development of metal oxide materials into a two-dimensional sheet morphology analogous to graphene is expected to solve the above-mentioned problems. In this Account, we summarize the recent progress on two-dimensional molecular sheets of transition metal oxides for wearable energy storage applications. We start with our understanding of the principle of producing two-dimensional metal oxides from their bulk-layered counterparts. The unique layered structure of the precursors inspired the exploration of their interlayer chemistry, which helps us to understand the processes of swelling and delamination. Rational methods for tuning the chemical composition, size/thickness, and surface chemistry of the obtained nanosheets and how physicochemical properties of the nanosheets can be modulated are then briefly introduced. Subsequently, the orientational alignment of the anisotropic sheets and the origins of their liquid-crystalline characteristics are discussed, which are of vital importance for their subsequent macroscopic assembly. Finally, macroscopic electrodes with geometric diversity ranging from one-dimensional macroscopic fibers to two-dimensional films/papers and three-dimensional monolithic foams are summarized. The intrinsically low mechanical stiffness of metal oxide sheets can be effectively overcome by wisely designing the assembly mode and sheet interfaces to obtain decent mechanical properties integrated with superior electrochemical performance, thereby providing critical advantages for the fabrication of wearable energy storage devices.We expect that this Account will stimulate further efforts toward fundamental research on interface engineering in metal oxide sheet assembly and facilitate wide applications of their designed assemblies in future new-concept energy conversion devices and beyond. In the foreseeable future, we believe that there will be a big explosion in the application of transition metal oxide sheets in flexible electronics.

Synthesis of early transition metal oxide nanomaterials and their conversion to nitrides

The synthesis of nanorods and nanowires of early transition metal oxides by hydrothermal methods and the conversion of some bulk oxides to nitrides in NH3 flow are both well established. However, the conversion of such oxide nanostructures to nitrides is not as well explored but could be a valuable method of producing nanowires, nanorods, and other asymmetric or high aspect ratio nanoparticles of the highly conductive metal nitrides. In this work, nanostructures of TiO2, V2O5, MoO3, and WO3 and mixtures thereof were synthesized by hydrothermal reactions, and conversion into nitride was attempted by heating the oxide material under NH3 flow with or without N2 flow. It was found that slow heating produces the best shape retention, but the nitridized products are porous in even the most favorable cases. The products were characterized by X-ray powder diffraction and scanning electron microscopy. Two-point conductivity measurements were done on the nitride materials, and optical measurements to characterize the plasmon absorption were done in favorable cases.