Carbon nanomaterials as electrochemical sensors for theophylline: a review

Theophylline (TP) is a methylxanthine derivative, which serves as a valuable compound in treating respiratory disorders and acts as a bronchodilator agent. However, TP has a limited therapeutic range (20-100 μmol L-1), demanding precise monitoring to prevent potential drug toxicity even with slight level fluctuations during treatment. Thus, to overcome this limitation, electrochemical methods have been extensively used due to their efficacy in achieving sensitivity, selectivity, and accuracy. In the context of electrochemical sensors, nanocarbon-based materials have gained widespread recognition for their extensive applications. Therefore, this review aims to explore the latest advancements in carbon-based electrodes particularly used for the precise determination of TP through electrochemical methods. The results are expected to provide insights into the profound significance of the methods in enhancing the accuracy and sensitivity for the detection of TP.

A tungsten phosphide cocatalyst enhanced bismuth tungstate photoanode with the robust built-in electric field towards highly efficient photoelectrochemical water splitting

The use of low-cost and effective cocatalyst is a potential strategy to optimize the effectiveness of photoelectrochemical (PEC) water splitting. In this study, tungsten phosphide (WP) is introduced as a remarkably active cocatalyst to enhance the PEC efficiency of a Bi2WO6 photoanode. The onset potential of Bi2WO6/WP demonstrates a negative shift, while the photocurrent density demonstrates a significant 5.5-fold increase compared to that of unmodified Bi2WO6 at 1.23 VRHE (reversible hydrogen electrode). The loading of WP cocatalyst facilitates the rapid transfer of holes, increasing the range of visible light absorption, the water adsorption ability as well as promoting the separation of photogenerated electrons and holes via the built-in electric field between Bi2WO6 and WP. This study proposes a strategy to hinder the recombination of electron-hole pairs by using WP cocatalyst as a hole capture agent, improve the photoelectric conversion efficiency, and enhance the overall photoelectrochemical properties of Bi2WO6 photoanode.

Innovations in WO3 gas sensors: Nanostructure engineering, functionalization, and future perspectives

This review critically examines the progress and challenges in the field of nanostructured tungsten oxide (WO3) gas sensors. It delves into the significant advancements achieved through nanostructuring and composite formation of WO3, which have markedly improved sensor sensitivity for gases like NO2, NH3, and VOCs, achieving detection limits in the ppb range. The review systematically explores various innovative approaches, such as doping WO3 with transition metals, creating heterojunctions with materials like CuO and graphene, and employing machine learning models to optimize sensor configurations. The challenges facing WO3 sensors are also thoroughly examined. Key issues include cross-sensitivity to different gases, particularly at higher temperatures, and long-term stability affected by factors like grain growth and volatility of dopants. The review assesses potential solutions to these challenges, including statistical analysis of sensor arrays, surface functionalization, and the use of novel nanostructures for enhanced performance and selectivity. In addition, the review discusses the impact of ambient humidity on sensor performance and the current strategies to mitigate it, such as composite materials with humidity shielding effects and surface functionalization with hydrophobic groups. The need for high operating temperatures, leading to higher power consumption, is also addressed, along with possible solutions like the use of advanced materials and new transduction principles to lower temperature requirements. The review concludes by highlighting the necessity for a multidisciplinary approach in future research. This approach should combine materials synthesis, device engineering, and data science to develop the next generation of WO3 sensors with enhanced sensitivity, ultrafast response rates, and improved portability. The integration of machine learning and IoT connectivity is posited as a key driver for new applications in areas like personal exposure monitoring, wearable diagnostics, and smart city networks, underlining WO3's potential as a robust gas sensing material in future technological advancements.

Caffeine derived graphene-wrapped Fe3C nanoparticles entrapped in hierarchically porous FeNC nanosheets for boosting oxygen reduction reaction

It is a vital requirement to explore high-efficiency and stable electrocatalysts for oxygen reduction reaction (ORR) to further relieve energy depletion. However, it is a critical challenge to develop low cost and high-quality carbon-based catalysts. Herein, a caffeine chelation-triggered pyrolysis approach was developed to construct graphene-wrapped Fe₃C nanoparticles incorporated in hierarchically porous FeNC nanosheets (G-Fe₃C/FeNC). The present Fe salt and its content as well as the pyrolysis temperature were carefully investigated in the control groups. The G-Fe₃C/FeNC catalyst showed a more positive onset potential (E_onset = 1.09 V) and half-wave potential (E_1/2 = 0.88 V) in a 0.1 M KOH solution, which outperformed commercial Pt/C (E_1/2 = 0.83 V, E_onset = 0.95 V), showing the excellent catalytic performance for the ORR activity, coupled with remarkable stability (only 0.18 mV negative shift in E_1/2 after 2000 cycles). This work provides some valuable insights for developing advanced electrocatalysts for energy storage and conversion related research.

One-step and room-temperature fabrication of carbon nanocomposites including Ni nanoparticles for supercapacitor electrodes

With the increasing importance of power storage devices, demand for the development of supercapacitors possessing both rapid reversible chargeability and high energy density is accelerating. Here we propose a simple process for the room temperature fabrication of pseudocapacitor electrodes consisting of a faradaic redox reaction layer on a metallic electrode with an enhanced surface area. As a model metallic electrode, an Au foil was irradiated with Ar+ ions with a simultaneous supply of C and Ni at room temperature, resulting in fine metallic Ni nanoparticles dispersed in the carbon matrix with local graphitization on the ion-induced roughened Au surface. A carbon layer including fine Ni nanoparticles acted as an excellent faradaic redox reaction layer and the roughened surface contributed to an increase in surface area. The fabricated electrode, which included only 14 μg cm-2 of Ni, showed a stored charge ability three times as large as that of the bulky Ni foil. Thus, it is believed that a carbon layer including Ni nanoparticles fabricated on the charge collective electrode with an ion-irradiation method is promising for the development of supercapacitors from the viewpoints of the reduced use of rare metal and excellent supercapacitor performance.

Potential of graphene based photocatalyst for antiviral activity with emphasis on COVID-19: A review

Coronavirus disease-2019 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been one of the most challenging worldwide epidemics of recent times. Semiconducting materials (photocatalysts) could prove effectual solar-light-driven technology on account of variant reactive oxidative species (ROS), including superoxide (^•O₂ ^- ) and hydroxyl (^•OH) radicals either by degradation of proteins, DNA, RNA, or preventing cell development by terminating cellular membrane. Graphene-based materials have been exquisitely explored for antiviral applications due to their extraordinary physicochemical features including large specific surface area, robust mechanical strength, tunable structural features, and high electrical conductivity. Considering that, the present study highlights a perspective on the potentials of graphene based materials for photocatalytic antiviral activity. The interaction of virus with the surface of graphene based nanomaterials and the consequent physical, as well as ROS induced inactivation process, has been highlighted and discussed. It is highly anticipated that the present review article emphasizing mechanistic antiviral insights could accelerate further research in this field.

Facile design of a WO3 nanorod-decorated graphene oxide 1D–2D nanocatalyst for the synthesis of quinoline and its derivatives

Graphene oxide supported WO3 nanorod as an efficient and recyclable catalyst for synthesis of Quinoline and its derivatives under solventless condition.

Black Tungsten Oxide Nanofiber as a Robust Support for Metal Catalysts: High Catalyst Loading for Electrochemical Oxygen Reduction

Black valve metal oxides with low oxygen vacancies are identified to be promising for various industrial applications, such as in gas sensing, photocatalysis, and rechargeable batteries, owing to their high reducibility and stability, as well as considerable fractions of low-valent metal species and oxygen vacancies in their lattices. Herein, the nanofiber (NF) of black oxygen-deficient tungsten trioxide (WO_{3- x} ) is presented as a versatile and robust support for the direct growth of a platinum catalyst for oxygen reduction reaction (ORR). The nonstoichiometric, poorly crystallized black WO_{3- x} NFs are prepared by electrospinning the W precursor into NFs followed by their low-temperature (650 °C) reductive calcination. The black WO_{3- x} NFs have adequate electrical conductivity owing to their decreased bandgap and amorphous structure. Remarkably, the oxygen-deficient surface (surface O/W = 2.44) facilitates the growth of small Pt nanoparticles, which resist aggregation, as confirmed by structural characterization and computational analysis. The Pt-loaded black WO_{3- x} NFs outperform the Pt-loaded crystalline white WO_{3- x} NFs in both the electrochemical ORR activity and the accelerated durability test. This study can inspire the use of oxygen-deficient metal oxides as supports for other electrocatalysts, and can further increase the versatility of oxygen-deficient metal oxides.

Engineered two-dimensional nanomaterials: an emerging paradigm for water purification and monitoring

Water scarcity has become an increasingly complex challenge with the growth of the global population, economic expansion, and climate change, highlighting the demand for advanced water treatment technologies that can provide clean water in a scalable, reliable, affordable, and sustainable manner. Recent advancements on 2D nanomaterials (2DM) open a new pathway for addressing the grand challenge of water treatment owing to their unique structures and superior properties. Emerging 2D nanostructures such as graphene, MoS₂, MXene, h-BN, g-C₃N₄, and black phosphorus have demonstrated an unprecedented surface-to-volume ratio, which promises ultralow material use, ultrafast processing time, and ultrahigh treatment efficiency for water cleaning/monitoring. In this review, we provide a state-of-the-art account on engineered 2D nanomaterials and their applications in emerging water technologies, involving separation, adsorption, photocatalysis, and pollutant detection. The fundamental design strategies of 2DM are discussed with emphasis on their physicochemical properties, underlying mechanism and targeted applications in different scenarios. This review concludes with a perspective on the pressing challenges and emerging opportunities in 2DM-enabled wastewater treatment and water-quality monitoring. This review can help to elaborate the structure-processing-property relationship of 2DM, and aims to guide the design of next-generation 2DM systems for the development of selective, multifunctional, programmable, and even intelligent water technologies. The global significance of clean water for future generations sheds new light and much inspiration in this rising field to enhance the efficiency and affordability of water treatment and secure a global water supply in a growing portion of the world.

Designing a Rare DNA-Like Double Helical Microfiber Superstructure via Self-Assembly of In Situ Carbon Fiber-Encapsulated WO3-x Nanorods as an Advanced Supercapacitor Material

Double helical DNA structure is one of the most beautiful and fascinating nanoarchitecture nature has produced. Mimicking nature's design by the tailored synthesis of semiconductor nanomaterials such as WO₃ into a DNA-like double helical superstructure could impart special properties, such as enhanced stability, electrical conductivity, information storage, signal processing, and catalysis, owing to the synergistic interaction across helices. However, double helical WO₃ synthesis is extremely challenging and has never been reported earlier. This investigation presents the first-ever report on a facile synthesis route for designing a DNA-like double helical WO_3-x/C microfiber superstructure via self-assembly of in situ carbon fiber-encapsulated WO_3-x nanorods. This innovative design strategy is completely template-free and does not require predesigned helical templates or hydro/solvothermal treatment. Detailed spectroscopic material characterization and electrochemical studies confirmed that the double helical structure with carbon fiber-WO_3-x heterostructures enabled effective induction and distribution of oxygen vacancies along with W⁵⁺/W⁶⁺ redox surface states. Furthermore, faster electrode-electrolyte interfacial kinetics, improved electrical conductivity, and cycling stability has been observed in the carbon fiber-WO_3-x heterostructures which resulted in a high area specific capacitance of 401 mF cm^-2 at 2 mA cm^-2 with excellent capacitance retention of >94% for more than 5000 cycles. Additionally, the carbon fiber-WO_3-x heterostructures demonstrated promising performance when fabricated in a solid-state asymmetric supercapacitor device with the power density of 498 W kg^-1 at an energy density of 15.4 W h kg^-1. Therefore, the rare DNA-like double helical WO_3-x/C superstructure synthesized in this study could open new doorways toward in situ, facile fabrication of double helical superstructures for energy and environmental applications.

Quaternary type IV deep eutectic solvent-based tungsten oxide/niobium oxide photochromic and reverse fading composite complex

An excellent photochromic material based on a WO3/Nb2O5 complex with the fast fading property for promising application in optical glasses/lenses and color display devices.

Breakthroughs in the Design of Novel Carbon-Based Metal Oxides Nanocomposites for VOCs Gas Sensing

Nowadays, the detection of volatile organic compounds (VOCs) at trace levels (down to ppb) is feasible by exploiting ultra-sensitive and highly selective chemoresistors, especially in the field of medical diagnosis. By coupling metal oxide semiconductors (MOS e.g., SnO₂, ZnO, WO₃, CuO, TiO₂ and Fe₂O₃) with innovative carbon-based materials (graphene, graphene oxide, reduced graphene oxide, single-wall and multi-wall carbon nanotubes), outstanding performances in terms of sensitivity, selectivity, limits of detection, response and recovery times towards specific gaseous targets (such as ethanol, acetone, formaldehyde and aromatic compounds) can be easily achieved. Notably, carbonaceous species, highly interconnected to MOS nanoparticles, enhance the sensor responses by (i) increasing the surface area and the pore content, (ii) favoring the electron migration, the transfer efficiency (spillover effect) and gas diffusion rate, (iii) promoting the active sites concomitantly limiting the nanopowders agglomeration; and (iv) forming nano-heterojunctions. Herein, the aim of the present review is to highlight the above-mentioned hybrid features in order to engineer novel flexible, miniaturized and low working temperature sensors, able to detect specific VOC biomarkers of a human's disease.

Metal Oxide Nanoparticle-Decorated Few Layer Graphene Nanoflake Chemoresistors for the Detection of Aromatic Volatile Organic Compounds

Benzene, toluene, and xylene, commonly known as BTX, are hazardous aromatic organic vapors with high toxicity towards living organisms. Many techniques are being developed to provide the community with portable, cost effective, and high performance BTX sensing devices in order to effectively monitor the quality of air. In this paper, we study the effect of decorating graphene with tin oxide (SnO₂) or tungsten oxide (WO₃) nanoparticles on its performance as a chemoresistive material for detecting BTX vapors. Transmission electron microscopy and environmental scanning electron microscopy are used as morphological characterization techniques. SnO₂-decorated graphene displayed high sensitivity towards benzene, toluene, and xylene with the lowest tested concentrations of 2 ppm, 1.5 ppm, and 0.2 ppm, respectively. In addition, we found that, by employing these nanomaterials, the observed response could provide a unique double signal confirmation to identify the presence of benzene vapors for monitoring occupational exposure in the textiles, painting, and adhesives industries or in fuel stations.

Porous reduced graphene oxide (rGO)/WO3 nanocomposites for the enhanced detection of NH3 at room temperature

Incorporation of reduced graphene oxide (rGO) modifies the properties of semiconducting metal oxide nanoparticles and makes it possible to tune the surface area and pore size to optimum values, which in turn improves their gas sensing properties. In this work, to improve the ammonia (NH₃) gas sensing characteristics, reduced graphene oxide (rGO) was incorporated into tungsten oxide (WO₃) nanospheres using a simple ultrasonication method. The rGO-WO₃ nanocomposites exhibited porous nanosheets with nanospherical WO₃ as observed with field-emission scanning electron microscopy (FE-SEM). The oxidation state of the rGO-WO₃ nanocomposite was determined using X-ray photoelectron spectroscopy (XPS). Three ratios of (1, 5 and 10% rGO/WO₃) nanocomposites and pure WO₃ showed good selectivity towards NH₃ at 10-100 ppm, and more remarkably at room temperature in the range of about 32-35 °C and at a relative humidity (RH) of 55%. The limit of detection (LOD) of the synthesized rGO-WO₃ nanocomposites was 1.14 ppm, which will highly favour low detection ranges of NH₃. The sensor response was 1.5 times higher than that of the bare WO₃ nanospheres. The sensors showed excellent selectivity, ultrafast response/recovery times (18/24 s), reproducibility and stability even after one month of their preparation. We believe that metal oxides using the rGO modifier can improve the sensitivity and reduce the LOD towards NH₃ and can be used effectively in real-time environmental monitoring.

WO3/p-Type-GR Layered Materials for Promoted Photocatalytic Antibiotic Degradation and Device for Mechanism Insight

Graphene enhanced WO₃ has recently become a promising material for various applications. The understanding of the transfer of charge carriers during the photocatalytic processes remains unclear because of their complexity. In this study, the characteristics of the deposited WO₃/graphene layered materials were investigated by Raman spectroscopy, UV-vis spectroscopy, and SEM. According to the results, p-graphene exhibits and enhances the characteristics of the WO₃/graphene film. The photocatalytic activities of WO₃/graphene layered materials were assessed by the photocatalytic degradation of oxytetracycline antibiotics as irradiated by UV light. Here, a higher current of cyclic voltammetry and a higher resistance of impedance spectra were obtained with the as-grown WO₃/graphene directly synthesized on Cu foils under UV light using an electrochemical method, which was different from traditional WO₃ catalysts. Thus, it is urgent to explore the underlying mechanism in depth. In this study, a large layered material WO₃/graphene was fabricated on a Si substrate using a modified CVD method, and a WO₃/graphene device was developed by depositing a gold electrode material and compared with a WO₃ device. Due to photo-induced doping effects, the current-voltage test suggested that the photo-resistance is larger than dark-resistance, and the photo-current is less than the dark current based on WO₃/graphene layered materials, which are significantly different from the characteristics of the WO₃ layered material. A new pathway was developed here to analyze the transfer properties of carriers in the photocatalytic process.

Efficient degradation of 2,4-dichlorophenol in aqueous solution by peroxymonosulfate activated with magnetic spinel FeCo2O4 nanoparticles

Magnetic spinel FeCo₂O₄ nanoparticles (NPs) were synthesized and proposed as a catalyst of peroxymonosulfate (PMS) for the degradation of 2,4-dichlorophenol (2,4-DCP). The catalyst was characterized by XRD, TEM, XPS, nitrogen adsorption-desorption isotherms, and magnetization curve. In addition, the effects of parameters, such as initial pH, PMS dosage, FeCo₂O₄ addition, and initial concentration of 2,4-DCP were studied. The results showed that FeCo₂O₄ NPs exhibit good properties for the degradation and mineralization of 2,4-DCP, achieving 95.8% and 44.7% removal of 2,4-DCP and TOC, respectively, within 90 min under reaction conditions of 4 mM PMS, 0.06 g L^-1 FeCo₂O₄, 100 mg L^-1 2,4-DCP, pH = 7.0, and T = 30 °C. Furthermore, SO₄^- and HO were main radical species in the reaction system was explored. The 2,4-DCP degradation efficiency could reach 91.8% even after FeCo₂O₄ NPs were used for the fifth run. Moreover, the degradation efficiencies of metronidazole (MNZ), methylene blue (MB), and rhodamine B (RhB) could reach 74.8%, 86.7%, and 96.1% under the same reaction conditions, respectively. Results revealed that the FeCo₂O₄/PMS system shows potential for degrading contaminants in the environment.

Activation of Peroxymonosulfate by CuNi@C Derived from Metal–Organic Frameworks Precursor

Calcined Cu-based metal–organic frameworks impregnated with nickel nitrate catalysts (CuNi@C) were synthesised. X-Ray diffraction, scanning electronic microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy techniques were applied for the characterisation of the synthesised catalyst, which revealed an octahedral particle shape, rough surface, and metallic copper (Cu, CuO) and nickel (Ni, NiO) particles. CuNi@C was fabricated as a novel peroxymonosulfate (PMS) activator for the oxidative degradation of Acid Orange 7 (AO7) in aqueous media. Results showed that the CuNi@C/PMS system can efficiently degrade nearly 100 % of 0.02 mmol L−1 AO7 within 60 min. In addition, the trapping experiments confirmed the participation of sulfate radicals (SO4•−) and hydroxyl radicals (HO•) as reactive species in the system. Furthermore, the effects of parameters including catalyst and PMS dosages, initial concentration of AO7, and pH were studied. Results showed that the decolourisation efficiency increased with the increase of catalyst dosage, but decreased with the increase of AO7 concentration. The optimal PMS concentration was 0.675 mmol L−1, and initial pH showed no significant effect on the degradation of AO7. Moreover, the CuNi@C could be reused four times with good activity and reusability. Findings revealed that the CuNi@C/PMS system shows potential for degrading contaminants in the environment, due to its catalytic activity and non-negligible adsorption.

Scalable Fabrication of Photochemically Reduced Graphene-Based Monolithic Micro-Supercapacitors with Superior Energy and Power Densities

Micro-supercapacitors (MSCs) hold great promise as highly competitive miniaturized power sources satisfying the increased demand of smart integrated electronics. However, single-step scalable fabrication of MSCs with both high energy and power densities is still challenging. Here we demonstrate the scalable fabrication of graphene-based monolithic MSCs with diverse planar geometries and capable of superior integration by photochemical reduction of graphene oxide/TiO₂ nanoparticle hybrid films. The resulting MSCs exhibit high volumetric capacitance of 233.0 F cm^-3, exceptional flexibility, and remarkable capacity of modular serial and parallel integration in aqueous gel electrolyte. Furthermore, by precisely engineering the interface of electrode with electrolyte, these monolithic MSCs can operate well in a hydrophobic electrolyte of ionic liquid (3.0 V) at a high scan rate of 200 V s^-1, two orders of magnitude higher than those of conventional supercapacitors. More notably, the MSCs show landmark volumetric power density of 312 W cm^-3 and energy density of 7.7 mWh cm^-3, both of which are among the highest values attained for carbon-based MSCs. Therefore, such monolithic MSC devices based on photochemically reduced, compact graphene films possess enormous potential for numerous miniaturized, flexible electronic applications.

Synthesis of graphene-transition metal oxide hybrid nanoparticles and their application in various fields

Single layer graphite, known as graphene, is an important material because of its unique two-dimensional structure, high conductivity, excellent electron mobility and high surface area. To explore the more prospective properties of graphene, graphene hybrids have been synthesised, where graphene has been integrated with other important nanoparticles (NPs). These graphene-NP hybrid structures are particularly interesting because after hybridisation they not only display the individual properties of graphene and the NPs, but also they exhibit further synergistic properties. Reduced graphene oxide (rGO), a graphene-like material, can be easily prepared by reduction of graphene oxide (GO) and therefore offers the possibility to fabricate a large variety of graphene-transition metal oxide (TMO) NP hybrids. These hybrid materials are promising alternatives to reduce the drawbacks of using only TMO NPs in various applications, such as anode materials in lithium ion batteries (LIBs), sensors, photocatalysts, removal of organic pollutants, etc. Recent studies have shown that a single graphene sheet (GS) has extraordinary electronic transport properties. One possible route to connecting those properties for application in electronics would be to prepare graphene-wrapped TMO NPs. In this critical review, we discuss the development of graphene-TMO hybrids with the detailed account of their synthesis. In addition, attention is given to the wide range of applications. This review covers the details of graphene-TMO hybrid materials and ends with a summary where an outlook on future perspectives to improve the properties of the hybrid materials in view of applications are outlined.

Magneto-optically active magnetoplasmonic graphene

Two-dimensional nanocomposites with magnetic and optical properties were investigated for novel magneto-optical (MO) applications.

Fabrication of WO2.72/RGO nano-composites for enhanced photocatalysis

WO_2.72/RGO nano-composites exhibit remarkable photocatalytic activity in both oxygen evolution from water splitting and selective oxidation of benzyl alcohol due to the synergetic effects between WO_2.72 and RGO.

Two-dimensional nanomaterial-based field-effect transistors for chemical and biological sensing

This review highlights the recent progress in graphene-, 2D transition metal dichalcogenide-, and 2D black phosphorus-based FET sensors for detecting gases, biomolecules, and water contaminants.

Graphene in Photocatalysis: A Review

In recent years, heterogeneous photocatalysis has received much research interest because of its powerful potential applications in tackling many important energy and environmental challenges at a global level in an economically sustainable manner. Due to their unique optical, electrical, and physicochemical properties, various 2D graphene nanosheets-supported semiconductor composite photocatalysts have been widely constructed and applied in different photocatalytic fields. In this review, fundamental mechanisms of heterogeneous photocatalysis, including thermodynamic and kinetics requirements, are first systematically summarized. Then, the photocatalysis-related properties of graphene and its derivatives, and design rules and synthesis methods of graphene-based composites are highlighted. Importantly, different design strategies, including doping and sensitization of semiconductors by graphene, improving electrical conductivity of graphene, increasing eloectrocatalytic active sites on graphene, strengthening interface coupling between semiconductors and graphene, fabricating micro/nano architectures, constructing multi-junction nanocomposites, enhancing photostability of semiconductors, and utilizing the synergistic effect of various modification strategies, are thoroughly summarized. The important applications including photocatalytic pollutant degradation, H₂ production, and CO₂ reduction are also addressed. Through reviewing the significant advances on this topic, it may provide new opportunities for designing highly efficient 2D graphene-based photocatalysts for various applications in photocatalysis and other fields, such as solar cells, thermal catalysis, separation, and purification.

Formation of tungsten trioxide with hierarchical architectures arranged by tiny nanorods for lithium ion batteries

WO₃ with hierarchical flower-like architectures has been obtained by calcination of WO₃·0.33H₂O, which is initially prepared via a hydrothermal method with formic acid as a structure directing agent.

Greatly enhanced photocatalytic activity of semiconductor CeO2 by integrating with upconversion nanocrystals and graphene

A novel nanocomposite photocatalyst of NaLuF₄:Gd,Yb,Tm@SiO₂@CeO₂:Tm/GN has been developed. The designed structure takes advantage of a synergetic effect from UCNCs, GN, and Tm-doping, which improves the photocatalytic activity of CeO₂ significantly.

Graphene Hybrid Materials in Gas Sensing Applications

Graphene, a two dimensional structure of carbon atoms, has been widely used as a material for gas sensing applications because of its large surface area, excellent conductivity, and ease of functionalization. This article reviews the most recent advances in graphene hybrid materials developed for gas sensing applications. In this review, synthetic approaches to fabricate graphene sensors, the nano structures of hybrid materials, and their sensing mechanism are presented. Future perspectives of this rapidly growing field are also discussed.

Preparation of zinc oxide nanoparticle–reduced graphene oxide–gold nanoparticle hybrids for detection of NO2

A novel NO₂ gas sensor bas been fabricated using ZnO–rGO–Au hybrids as sensing materials, which exhibit excellent sensing performances operated at 80 °C.

Introduction of α-MnO2nanosheets to NH2graphene to remove Cr6+from aqueous solutions

The planar structure of the designed α-MnO₂–NH₂–RGO hybrid was prepared and characterized and used to remove hexavalent chromium ions (Cr⁶⁺) from aqueous solutions.

A facile hydrothermal synthesis of MnO2 nanorod–reduced graphene oxide nanocomposites possessing excellent microwave absorption properties

MnO₂ nanorod/reduced graphene oxide nanocomposites synthesized by a simple one-step hydrothermal method significantly improved the electromagnetic wave absorption performance and widened the effective absorption bandwidth.

Rh-catalyzed WO3 with anomalous humidity dependence of gas sensing characteristics

An anomalous humidity dependence of gas sensing characteristics is found for a Rh-loaded WO₃ sensor, where the resistance and gas response increased in humid atmospheres.

Modification of tungsten trioxide with ionic liquid for enhanced photocatalytic performance

Ionic liquid (IL) modification endows the surface of WO₃ with a stronger electron-trapping capability, which effectively inhibits the recombination of electron–hole pairs and thus enhances photocatalysis.

A universal strategy for the hierarchical assembly of functional 0/2D nanohybrids

We report a universal strategy for the hierarchical assembly of nanoparticles on various 2D materials, resulting in functional 0/2D nanohybrids holding great promise in catalysis, energy storage, and chemical and biological sensing.