ZnO Composites Research Articles

Ternary MXene/PANI/ZnO-based composite with a built-in p–n heterojunction for high-performance supercapacitor applications

Abstract Two-dimensional (2D) Ti3C2T x MXene-based materials have attracted widespread attraction in the field of energy storage owing to their high conductivity and accordion-like structure. However, challenges such as restacking and oxidative degradation of the Ti3C2T x MXene structure lead to poor stability, low conductivity, low specific capacitance and, consequently, a low specific energy, hindering their extensive adoption at an industrial scale. In this study, a ternary MXene/polyaniline (PANI)/ZnO (MPZ) composite has been synthesized via surface engineering of two-dimensional (2D) MXene using one-dimensional (1D) PANI nanowires and ZnO nanoparticles to enhance its specific energy and stability while sustaining its specific power. 1D PANI nanowires and ZnO nanoparticles act as spacers to prevent restacking, while also exposing the suppressed redox active sites of 2D MXene and preventing it from being oxidized by forming a porous conductive network all over the surface of the MXene. PANI and ZnO also provide additional electroactive redox sites by forming p–n heterojunctions, thus enhancing faradaic redox reactions and the specific capacitance of the MPZ composite. As a result, the overall electrochemical performance and stability of the ternary MPZ composite are enhanced due to the synergistic interactions among the individual components within the ternary MPZ composite. At a low current density of 0.1 A g−1, the ternary MPZ composite exhibited a maximum specific capacitance of 651.96 F g−1 and a highest specific energy of 32.59 Wh Kg−1 while maintaining a specific power of 60 W Kg−1 as compared to MXene and binary MP composite. Furthermore, it showcased exceptional cyclic stability over 10 000 cycles with 94.75% and 92.95% capacitive retention at 0.6 A g−1 current density and 40 mV s−1 scan rate, respectively. Thus, this current study highlights an effective strategy to enhance the specific energy of MXene-based supercapacitors through surface engineering and the construction of p–n heterojunctions within the composite.

A novel environmentally friendly linear thermistor in the xAl2O3-(1-x)ZnO composite

A novel environmentally friendly linear thermistor in the xAl2O3-(1-x)ZnO composite

Charge transport properties and photostability of microcrystalline cellulose derived from Gigantochloa scortechinii-supported ZnO for enhanced acetaminophen degradation

A facile chemical mixing procedure was utilized to fabricate microcrystalline cellulose (MCC) derived from Gigantochloa scortechinii-supported ZnO photocatalysts, with different MCC content. The successful incorporation of ZnO onto the MCC surfaces was characterized by multitudinous characterization techniques. The photocatalytic evaluation studies were carried out under a very low UVC light intensity (9 W) against acetaminophen (ACE) in the aqueous solution. The MCC-supported ZnO (0.5:1) composites photocatalyst demonstrated a rapid and enhanced performance within 180 min under normal conditions, with a two-time higher value of rate constant k (1.12 ×10−2 min−1) as compared to pristine ZnO. The improved efficiency under UVC irradiation was associated with the excellent separation capability of photoexcited charge carriers, ease of electron migration, and electrons’ mediators by the MCC in the composite photocatalyst, as demonstrated by the band gap and photoluminescence analyses. The major reactive species were found to be hydroxyl radicals (•OH) and photoexcited holes (h+). The best photocatalyst has high photostability since it can be recycled up to five times towards ACE degradation without any regeneration step.

Enhanced photoelectrochemical sensor for dopamine detection based on MOFs-derived ZnO and TpPa-1 heterostructure composite

This study used ZIF-8 metal–organic framework as a precursor to create a N-doped ZnO. Subsequently, covalent organic framework named TpPa-1 (Tp, 1,3,5-triformylphloroglucinol; Pa-1, p-phenylenediamine) with a ZnO heterostructure composite (ZnO/TpPa-1) was created through an in-situ synthesis approach. Due to its superior band structure and outstanding photocatalytic performance, the ZnO/TpPa-1 composite is a good candidate for the development of a new type of photoelectrochemical (PEC) sensor for the detection of dopamine (DA). According to experimental data, ZnO/TpPa-1/ITO had a photocurrent that was roughly 1.5 times higher than TpPa-1/ITO and 4.5 times higher than ZnO/ITO. The primary reason for this improvement was the synergistic effects brought about by effective light usage and charge transfer at the interface between the TpPa-1 π-conjugated backbone and ZnO porous structure. The determination ranges for DA demonstrated two linear ranges, 0.005–0.25 μmol/L and 0.25–1.00 μmol/L, and the detection limit was as low as 1.3 nmol/L. Moreover, the PEC sensor exhibited good stability, selectivity, repeatability, and suitability for real-world samples. This work provides important new understandings for covalent organic framework (COF)-based heterostructure design, which can be used to improve PEC sensor performance.

Biocompatible protein-based self-assembled nanocomposite as efficient drug nanocarrier and antibacterial agent

To fulfill diverse application-specific purposes, functional nanoparticles encapsulated into protein-based self-assemblies show promising advantages includes easy preparation, high biocompatibility and multiple properties. In this study, the model protein of BSA used for multi-component self-assembly, including hydrophobic Fe3O4 nanoparticles, nano-ZnO and curcumin, was constructed through hydrophobic interactions. The obtained composites of BSA-Fe3O4&ZnO and BSA-Fe3O4&ZnO&curcumin self-assemblies were tested for antibacterial and drug delivery, respectively. It was found that the multicomponents loaded into protein assembly confer a simple yet robust synthetic method resulting in the produced nanocomposites with high stability and desirable biocompatibility. Notably, the protein self-assemblies successfully increased the antibacterial efficacy of hydrophobic ZnO nanoparticles, and promote the intracellular delivery of poorly soluble curcumin to exert significant killing effects against cancer cells. Therefore, the constructed multi-component contained protein self-assembly that enables hydrophobic interactions of compositional nanoparticles holds promising potentials for the versatile uses in biomedical aspects.

Comprehensive study for radiation shielding features for Bi2O3–B2O3–ZnO composite using computational radioanalytical Phy-X/PSD, MCNP5, and SRIM software

The current study uses zinc oxide doping nanoparticles to investigate the radiation shielding properties of bismuth borate glass. Fourier transform infrared (FTIR) and X-ray diffraction (XRD) examined the structural characteristics of the current samples. In contrast, the optical properties were determined based on the absorption spectrum for current samples. Appraisal studies are carried out depending on the simulation capabilities of Phy-X/PSD software in conjunction with MCNP5 to achieve this goal. In addition, the neutron and charged particle shielding properties were evaluated theoretically. All glasses are amorphous, as confirmed by the XRD data, and the FTIR data showed several vibration bands and functional groups. The density showed rising from 5.981 to 6.433 g/cm3 with adding ZnO. The band gap values reduced from 2.831 to 2.091 eV for direct and 3.024 to 2.218 eV for indirect with adding ZnO. The investigations' findings demonstrate a strong agreement between the theoretical and simulation-derived estimates of the mass attenuation coefficient. The relative difference of MAC results lie in the range 0.106–2.941% for BBZ0, 0.105–4.348% for BBZ1, 0.105–3.398% for BBZ2, and 0.105–2.032% for BBZ3. The study's findings are valuable insights from thoroughly examining these parameters, which can potentially improve the radiation protection abilities of Bi2O3–B2O3–ZnO glasses. This study represents a significant step in developing more efficient and safer materials for gamma radiation shielding applications.

Enhanced acetone detection performance of mechanically-mixed WO3:ZnO composites

In recent years, the potential use of mixed metal oxide WO3:ZnO is widely sought in photocatalytic application due to its excellent electrical and optical properties, but is less explored for chemiresistive sensor. The heterojunction effect in WO3:ZnO is of particular interest to eradicate common issues suffered by the pristine metal oxide sensors, such as limited sensitivity, poor selectivity, and high operating temperature. In addition, the acetone detection study based on heterostructured WO3:ZnO is quite limited. Herein, we demonstrate that the mechanically-mixed WO3:ZnO sensor exhibits comparable reducing gas sensing performance as other doped WO3:ZnO and relative improvement compared with the undoped composites, without the need of catalyst. In this work, WO3:ZnO thin-film based chemiresistive sensors were fabricated through straightforward methods comprising mechanical mixing and drop casting of sensor materials onto gold interdigitated alumina substrates. Structural and morphological properties of the prepared WO3, ZnO, and WO3:ZnO composites were examined through the X-ray diffraction (XRD), Raman spectroscopy, photoluminescence spectroscopy (PL), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDX) analyses, respectively. Sensor performance parameters including operating temperature and response were determined. The sensing properties of WO3:ZnO composites with different weight compositions (1:1, 1:2, and 1:3) were evaluated against the pristine ZnO and WO3. The weight ratio of 1:2 was the optimal composition for the WO3:ZnO composite to achieve the highest sensor response of 53.8 % towards 300 ppm acetone at 200 ºC compared to the pristine ZnO with a response of 23.5 %. The WO3:ZnO (1:2) thin film displayed granular morphology with uniform particle dispersion and porosity, enhancing the gas diffusion. The WO3:ZnO (1:2) thin-film composite sensor exhibited improved sensing performance and good repeatability towards acetone compared with that of ZnO and WO3. The enhanced response to acetone was possibly contributed by the development of n-n heterojunctions, porous morphology, and surface defects in the WO3:ZnO composite. The underlying sensing mechanism of WO3:ZnO composite is also discussed extensively with the aid of energy band diagrams. This study presents a foundation for future development of cost-effective acetone sensors through mechanical mixing with great potential for practical and scalable implementation in various industries.

Evaluation of anti-microbial activity of biotite and biotite composite based on crystallographic parameters: Estimation of crystallite size employing X-ray diffraction data

This study dealt with naturally occurring biotite from the river sediment to synthesize biotite based composite to evaluate antimicrobial activities against gram positive bacteria, negative bacteria and fungi. Biotite mineral, and synthesized carbon aerogel –biotite (CBt) composite and carbon aerogel-biotite –ZnO (CBtZ) composites were considered for the antimicrobial study. The samples were characterized by X-ray diffraction technique and different crystallographic parameters were computed applying X-ray diffraction data. Also, FESEM was performed to understand the surface morphology of the samples. Crystal size of the biotite, CBt and CBtZ were computed 103.215, 57.567, and 36.496 nm respectively. Tabulated microstrain are 0.175, 0.499 and 0.935 for the biotite, CBt and CBtZ respectively. Various models and equations were used to justify crystallite size, including the Williamson-Hall plot, linear straight line model, Scherrer equation, Monshi-Scherrer model, Size-strain plot (SSP) model, Halder-Wagner method and Sahadat-Scherrer model. For the both composite samples, following models confirmrd the presence of nanocrystal with a range of 50.789–97.777 nm (CBt) and 36.496–105.843 nm(CBtZ). However, for the biotite, all mentioned models were proved invalid except scherrer equation, SSP model and Monshi-Scherrer model. Linear straight line model was found invalid to calculate crystallite size of the three samples. Moreover, different crystal parameters like dislocation density, volume of the unit cell, lattice parameters were computed. Zone of inhabitation estimation method was employed to estimate antimicrobial activity against Listeria monocytogenes, Staphylococcus aureus, Salmonella abony, Escherichia coli and Candida albicans. Required minimum inhibitory concentration (MIC) together with minimum bactericidal concentration (MBC) also estimated in this study. Crystal size effect on the antimicrobial activities of the samples were evaluated in this study.

Treatment of Paracetamol in Water with Different Salinities over Powder and Supported TiO2 and ZnO Photocatalysts

ABSTRACT. Paracetamol's (PCT) Paracetamol's (PCT) presence in water bodies poses a risk to both aquatic life and humans. This study aims to examine the effect of salinities on PCT removal in water using powder and supported photocatalysts. ZnO powder is a superior photocatalyst to TiO2, where the rate constant can be 18 times higher. Salinity boosted the PCT removal up to 2.7 times for TiO2 at lower concentrations but decreased the PCT removal for TiO2 and ZnO at higher values. Immobilizing the powder photocatalysts on a nonwoven polyester support (NPS) dropped the photocatalytic activity, especially for ZnO, whose performance was 36 times lower than its powder counterpart. The passivation of the photocatalysts by the silica binder necessary for attaching the photocatalyst to the support can be linked to the decline in the performance of TiO2 and ZnO composites. The silica and TiO2 formed homogeneous layers on the NPS, unlike the silica and ZnO layers. High salinity reduced the performance of TiO2 composites by 20 times but showed no significant effect on ZnO composites. The performance of the ZnO composite was further reduced when real seawater was used as feed. Keywords: Titanium dioxide, zinc oxide, polyester, paracetamol, salinity.

Fabrication and characterization of sustainable composites from animal fibers reinforced unsaturated polyester resin

The research involves developing eco-friendly polymer composites by combining synthetic unsaturated polyester resin (UPR) with treated and untreated leather fibers (LF), cow hair fibers (CHF), and chicken feather fibers (CFF). By using these natural fibers instead of synthetic polymer, we aim to reduce the environmental impact while finding new purposes for waste materials from the poultry and tannery industries which would otherwise end up in garbage. The fibers were incorporated into the resin matrix at various weight percentages such as 2, 5, 7, 10, 12, and 15 % (w/w). Additionally, the properties of composites were improved by the addition of different types of inorganic nanoparticles, like CaCO3, Al2O3, and ZnO to the UPR matrix. These composites where inorganic materials were added as filler revealed better results than the neat composites. The composites showed the maximum overall mechanical properties in the bending modulus (BM), bending strength (BS), tensile modulus (TM), and tensile strength (TS) when 5 % of cow hair and chicken feather mixed fiber was used and ZnO was added as filler compared to the other composites. The highest values 4400.415, 68.91, 1788.74, and 34.95 N/mm2 of BM, BS, TM, and TS respectively, were found for the CFF + CHF + UPR + ZnO composite. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) supported mechanical rather than chemical connections between fiber and UPR. Ionizing gamma radiation-modified fiber exhibited superior tensile characteristics when 5 % of cow hair and chicken feather mixed fiber was used.

UV-activated CH4 gas sensor based on Pd@Ni/ZnO microspheres

Developing methane (CH4) gas sensors with low working temperatures and high response has garnered substantial interest in reliably monitoring CH4 and achieving intrinsic safety. In this work, we combined photo-activation with bimetallic doping to explore CH4-sensing performance. ZnO, Pt/ZnO, and Pt@Ni/ZnO composites with different contents of Pt@Ni were synthesized. Their morphology, structure, and optical properties were characterized using various techniques. Subsequently, their CH4 sensing performance was systematically evaluated under ultraviolet (UV) illumination. The results show that the sensor based on 3Pt@Ni/ZnO composite demonstrated superior CH4 sensing performance among all sensors under UV illumination, presenting a low working temperature of 60 °C, a high response (904.04), which is approximately 60 times higher than pure ZnO (14.97) toward 5000 ppm CH4, and good response and recovery times of 4/174 s. The improved gas-sensing mechanism of the 3Pt@Ni/ZnO sensor was discussed and ascribed to the UV illumination, the synergistic effect of the bimetallic Pt@Ni, and the hollow structure of the ZnO. This study provides a promising gas-sensing material for CH4 detection at a low temperature assisted with UV illumination.

Designing innovative PAni-based adsorbents for CO2 capture via in-situ nitrogen plasma modification for sustainable development

Carbon dioxide (CO2) capture is a critical strategy in the fight against climate change. By implementing this innovative technology, CO2 emissions from diverse sources will be captured and neutralized, thereby mitigating global warming. For this purpose, novel sorbents were developed in this work by loading TiO2 and ZnO nanofillers into a polyaniline (PAni) system to form PAni–TiO2 (PT) and PAni–ZnO (PZ) composites. Following that, in-situ nitrogen (N2) plasma treatments were applied for 5 min to improve their surface nature and physiochemical properties. The CO2 capture qualities of modified PT and PZ sorbents were investigated, as well as physical assessments of their microstructure, nuclear magnetic resonance (NMR), morphology, contact angle, roughness, electrical optical, reactivity, stability, and adsorption capability, hardness, softness and electrophilicity properties. Bombardment of high-energy plasma species for 5 min was sufficient to optimize the crystallite size and crystallinity degree in both the PT5 and PZ5 systems. These enhancements may be related to the growth of protonated benzoid rings -NH+- as a result of plasma modifications to the structure of PAni and its transformation into emerald salt. In a similar vein, the SEM micrographs, porous topography and hydrophilic nature of the PAni composites varied with respect to the type of nanofillers and plasma level. The plasma treatment provided additional oxygen-containing functional groups as active sites for chemical interactions, including CO2 via chemisorption or physisorption, facilitating further reduction. Additionally, plasma activities assisted in shifting to a rougher surface (i.e.,Ra = 3.83 µm) as well as optimizing the energy band gap (1.57 eV), which can accommodate more CO2 molecules, thereby improving the capture efficiency. Moreover, the findings indicate that PZ5 is more desirable for CO2 adsorption since it possesses a 2.52-fold greater CO2 adsorption energy (-0.079 a.u) than pristine PZ0. In the future, our work opens up exciting new prospects to achieve desired performance from CO2 capturing compounds utilizing plasma technology.

Investigation of gamma radiation shielding and antimicrobial properties of PbO-doped ZnO and TiO2 composites

Gamma radiation is utilized in various fields, such as food shelf-life preservation, medicine, and industry. The protection against ionizing radiation, such as gamma radiation, is a crucial matter. Ionizing radiation is harmful to both the environment and living organisms, leading to cellular mutations, organ damage, equipment malfunctions, and other adverse effects. To achieve radiation protection, shielding methods are employed. Materials that prevent bacterial growth and contamination should also be developed in all areas. In our study, glass substrates were coated using the rotational coating method. In this study, the antimicrobial and radiation protection properties of glass coatings prepared with ZnPb (50% ZnO + 50% PbO) and TiPb (50% TiO2 + 50% PbO) ratios were investigated. For radiation protection properties, mass attenuation coefficient (MAC) values were calculated using the Geant4-GATE and XCOM simulations, and the results were compared with the experimental data. Calculations were performed at 511, 662, 1173, 1274, and 1332 keV energy levels. A colony counting method was employed to determine the antibacterial effectiveness of Pb-doped TiO2 and ZnO. The antibacterial efficacy of Pb-doped TiO2 and ZnO films was tested against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) bacteria. It was found that these films were effective only against Staphylococcus aureus bacteria. The antimicrobial efficiency of the nanocomposites was evaluated against various bacterial strains, highlighting significant inhibitory properties, particularly for TiO2 and ZnO nanocomposites against S. aureus. This emphasizes their potential as antimicrobial agents.

Anti-humidity and high sensitivity sensor for detecting acetone with Ce–ZnO nanosheets

Here, Ce-doped ZnO flower-like nanosheets are prepared by one-step hydrothermal method. The sensor based on Ce–ZnO composite exhibits excellent gas-sensing properties to acetone. Compared with pure ZnO, the response of Ce–ZnO composite is increased by 5.5 times, and the optimum operating temperature is reduced by 60 °C. The gas-sensing properties of the sensor to acetone under different humidity conditions are investigated. The redox reaction of Ce element increases the anti-humidity of Ce–ZnO sensor. Finally, the gas sensing mechanism of Ce–ZnO nanomaterial and anti-humidity principle are discussed in detail. The result can provide a new material for develop high sensitivity acetone sensor and a new anti-humidity strategy for designing gas sensing materials.

The role of Mg content in regulating microstructures and mechanical properties of Al–Mg–ZnO composites fabricated via in-situ reaction sintering

Al–Mg-oxides composite system exhibits great potential for achieving aluminum matrix composites (AMCs) with exceptional mechanical properties. However, the effects of Mg element on in-situ reaction mechanism and precipitation behavior remains largely unknown. In this work, Al–Mg–ZnO composite was successfully fabricated by using segmented ball milling, reaction sintering and heat treatment, resulting in an ultimate tensile strength of ∼760 MPa and fracture elongation of ∼3.5 %. The Mg content-dependent reaction pathway and precipitation evolution were systematically investigated through thermodynamic analysis and microstructural characterization. The results revealed that the relatively high Mg content promotes the in-situ generation of the hybrid reinforcements composed of MgAl2O4 and MgO. Additionally, the semi-coherent reinforcement-matrix interface facilitates interfacial precipitation by reducing the energy barrier for nucleation. Consequently, solute-rich/vacancy-rich Guinier-Preston (GP) zones are activated to form η′ and T′ precipitates. These high-density nano-sized secondary phases contribute to the considerable strengthening effect of the composite. The present work provides valuable theoretical insight into the effect of Mg content on the microstructure evolution of Al–Mg–ZnO composite system, which offers promising avenues for achieving AMCs with superior mechanical properties.

How do the non‐linear I–V curves of ZnO‐based adaptive composites behave with electrodes placed on the opposite sides with a series of horizontal distances?

AbstractRecently, ZnO‐based composites have been widely applied in the field of electric power. To meet the diverse application requirements, it is necessary to figure out the I–V characteristics of ZnO composites whose high‐voltage and ground‐voltage electrodes are arranged on the opposite sides with a certain horizontal distance. 30 vol%, 40 vol% and 50 vol% ZnO‐based silicone rubber composites were prepared. The horizontal distance between their electrodes was set as 50, 100, 500 μm, 1 and 2 mm, respectively. Results showed that with the increase of ZnO fillers volume fraction under a fixed horizontal distance of 100 μm, from 30 vol% to 50 vol%, the I–V curves shifted left, the leakage current increased and the switching voltage decreased. When the horizontal distance between electrodes increased from 50 μm to 1 mm under a fixed doping concentration of 40%, the I–V curves shifted to the right, the leakage current dropped and the switching voltage rose. The mathematical and physical models were established to explain the results. This work provides a referential significance for the practical application of ZnO composites, such as 5G folding mobile phones and power electronic modules.

Sustainable removal of organic pollutants using biochar based ZnO composites: Experimental and theoretical studies of remediation process

The tailoring of biochar to enhance its remediation efficiency for removal of pollutants from water has been a hot topic these days. Fabricating two different biochar materials using metal oxide nano particles in four ratios has been done in this work. The synthesized materials have been characterized by XRD, surface functional groups were analyzed using FTIR and XPS, band gap calculation were carried out using Tauc's method, recombination of charges was studied using photoluminescence spectroscopy, morphological, textural properties and elemental analysis was done using SEM, BET, TGA, EIS and EDX analysis. The removal of organic pollutants including phenol, dibutyl phthalate and gallic acid up to 91.6 %, 84 % and 95 % was observed employing these composites. The band gap reduction from 3.1 eV to 2.5 eV and 2.8 eV was observed in case of ZW(1–10) and ZP(1–10) respectively. The formation of Zn-O-C bond in the composite could be possible reasons for the band gap reduction and excellent performance exhibited by the composite. The results highlight the influence of functional groups on the efficiency of synthesized material. Furthermore, density functional theory (DFT) calculations were performed using Gaussian16 software to propose the adsorption mechanism for the observed results. The energy calculation for different binding modes were carried out. Theoretical findings agreed with the empirically demonstrated remediation mechanism.

Morphology modulation of ZnO microspheres and improvement of triethylamine detection performance by introducing carbon dots

Microspherical ZnO composites were prepared by introducing carbon dots (CDs) in situ by a one-step hydrothermal method. The effects of precursor and calcination treatments on the microstructure and morphology, compositional features and triethylamine (TEA) detection were carefully investigated. The results show that the addition of excess urea promotes the formation of CDs, the produced UC-ZnO composite presents microspheres with relatively smooth surface after calcination, and the retained CDs form heterojunctions with ZnO. TC-ZnO composite produced by adding excess trisodium citrate displays bowl-shaped depressions on the surface. After calcination, the porous structures with large specific surface area and carbon incorporation are achieved. The two composites show improved gas-sensitive response and reduced detection limit for TEA. The sensitivity for 100 ppm TEA at the optimal operating temperature of 350°C is 357 for UC-ZnO and 526 for TC-ZnO sensor, which are 21% and 80% higher than that of pure ZnO, respectively. The TC-ZnO sensor possesses an excellent low detection limit of 32 ppb. The introduction of CDs effectively modulates the morphology and interface state of ZnO microspheres, and improves the gas-sensitive performance.

Design and fabrication of Zeolite Socony Mobil-5 incorporated ZnO composite for enhanced visible light photocatalytic performance

In this study, a hydrothermal method was used to synthesize a ZSM-5/ZnO nanocomposite which was used to photocatalytic activity degrade methylene blue (MB) and Rhodamine B (RhB) dye in an aqueous solution. The structure, morphology, composition and optical and textural properties of the composites were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and UV– vis diffuse absorption spectroscopy (UV–vis DAS), photoluminescence (PL) and N2 adsorption/desorption, respectively. TEM images showed the ZnO nanorods were uniformly embroidered on the surface of ZSM-5 sphere surfaces, and the embroidered ZnO nanorods had an average size of 80 ± 20 nm. The presence of ZnO in ZSM-5 leading resulted in a increase in the surface area (125.6 m2/g) and pore size (21.3 nm) as confirming by nitrogen adsorption-desorption isotherm experiments. The ZnO/ZSM-5 composite was further used as a photocatalyst material in the dye (methylene blue: MB and Rhodamine B: RhB) degradation process, and the performance was compared with that of pure prepared ZnO. Moreover, the degradation efficiency of the ZSM-5/ZnO composite for MO degradation was found to be ∼92 after 180 min, which is higher than that of the pure ZSM-5. While, the degradation efficiency of ZSM-5/ZnO composite was found to be 98.5 % towards RhB dye under identical experimental conditions. The ZSM-5/ZnO composite was also extensively reused for five photo degradation cycles without experiencing any significant changes in its activity or crystalline characteristics.The improved mechanism was also discussed in detail.

Synthesis and characterization of highly sensitive ammonia sensor based on polyaniline/bismuth doped zinc oxide composites

AbstractHighly efficient gas sensors fabrication having low detection limits have been one of key research area due to the industrial, environmental and other technological applications. In this study, polyaniline/bismuth doped zinc oxide (PANI/Bi‐ZnO) was prepared via inverse emulsion polymerization and it was coated over a substrate with staggered electrodes to create a highly efficient ammonia (NH3) sensor. The UV/Vis investigation, fourier transformed infrared (FTIR), raman spectral analysis, and scanning electron microscopy (SEM) were used to describe the structure and morphology of prepared samples. At room temperature, the PANI/Bi‐ZnO sensor's sensitivity to various NH3 gas concentrations ranging from 20 to 100 ppm was examined. According to the experimental findings, the PANI/Bi‐ZnO film exhibits outstanding performance of response and selectivity. The response at 20 ppm NH3 was as high as ⁓100%. The response and recovery time was also calculated at 20 ppm and was 11/15 s. The contact between p‐n heterojunctions in the composite is responsible for the exceptional sensitivity of PANI/Bi‐ZnO towards NH3 sensing.Highlights Synthesis of Bi doped ZnO composites with PANI at room temperature Fabrication of highly sensitive and efficient resistive type ammonia sensor Selective and robust detection of ammonia by the fabricated sensor High sensitivity with low limit of detection offered by the sensor Response of the fabricated sensor at 20 ppm NH3 was as high as ⁓100%