Doping Percentage Research Articles

Zirconium-doped lead dioxide anodes prepared by sol-gel method for ampicillin removal from simulated pharmaceutical polluted wastewater.

New anodes consisting of zirconium-doped PbO2 coating, growth on titanium dioxide interlayer, were deposited on titanium substrates using spin coating method and have been tested for the removal of ampicillin, a β-lactam antibiotic, from water. Morphological, structural, and electrochemical properties of the prepared coatings were characterized by scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), and electrochemical impendence spectroscopy (EIS). Results showed that the incorporation of zirconium dopant had a noticeable modification in the morphology of anodes. An increase in the surface roughness and the specific active area were observed with Ti/TiO2/PbO2- 10% Zr electrode compared to other anodes. The electrochemical measurements indicated that the anode doped with 10% Zr showed a more protective coating performance than the undoped and 20% Zr-doped PbO2 electrodes. The experiments on ampicillin degradation revealed that doped lead dioxide anodes have excellent electrocatalytic activity. The major byproduct generated during anodic oxidation treatment has been identified as ampicilloic acid by liquid chromatography-mass spectroscopy (LC-MS) analysis. Results demonstrated that Ti/TiO2/PbO2- 10% Zr anode presents the best removal rate of ampicillin with a minimum intermediate amount, which leads to conclude that 10% is the optimum percentage of zirconium dopant for antibiotic wastewater treatment.

Structural and Optical Properties of SnS2:Cu Thin films prepared by chemical Spbay Pyrolysis

Thin filis have been prepared from the tin disulphide (SnS2 ), the pure and the doped with copper (SnS2:Cu) with a percentages (1,2,3,4)% by using ahemical spray pyrolysis techniqee on substrate of glass heated up to(603K)and sith thicknesses (0.7±0.02)?m ,after that the films were treated thermally with a low pressure (10-3mb) and at a temperature of (473K) for one hour. The influence of both doping with copper and the thermal treatment on some of the physical characteristics of the prepared films(structural and optical) was studied. The X-ray analysis showed that the prepared films were polycrystalline Hexagonal type. The optical study that included the absorptance and transmitance spectra in the weavelength range (300-900)nm demonstrated that the value of absorption coefficient (?) was greater than (104 cm-1) for the pure and doped films and that the electronic transitions at the fundamental absorption edge were of the indirect kind whether allowed or forbidden and the value of the optical energy gap in the case of the indirect transition, the allowed decreased from (2 eV) to (1.8,1.7,1.5,1.2)eV at the doping percentages (1,2,3,4)% respectively, also it was found that the value of energy gap for the pure and doped films increased after annealing. Tthe absorption and transmission spectra were used to find the optical constant including refractive index(n), extinction coefficient (k), imaginary and real part of dielectric constant (?1 &?2) , and it was found that all the optical constant was affected by changing the doping percentages; in addition to being affected after treating the films thermally

Analysis of semiconductor properties of fabricated graphene materials

Introducing dopant elements into graphene is a crucial process for creating bandgaps, which will have significant importance in developing nanoelectronic devices in the future. In this study, we provide an analysis of the electrical and carrier mobility properties of graphene doped with BN in ratios of 1 %, 3 %, and 5 %, graphene 95 %, ZnO-3 %, and BN2 %, graphene-95 %, Al2O3-3 % and BN-2 %, graphene-95 %, TiO2-3 % and BN-2 % by using a sintering process. Upon analyzing the band structure, it was determined that the mentioned materials demonstrate a bandgap in graphene. The resistivity values for fabricated graphene materials doped with different nanoparticles are estimated using the Source-meter Unit (SMU) at room temperature (25°C), 100°C and 200°C. The conductivity of graphene is 8.93E+07 Ω−1cm−1 and reduced gradually with the doping percentages. The resistivity of graphene is measured at 1.12 E-08 Ω.cmand increases with the doping percentages, and carrier mobility is measured to be 9239 cm2V−1s−1 and gradually reduced with the doping percentages. The temperature-dependent conductivity is determined using electrical conductivity under the constant relaxation time approximation.

Observation of anomalous excitonic emission in V-doped WS2 QDs synthesized by hydrothermal method and subsequent mechanical exfoliation

This study focuses on synthesizing vanadium (V) doped 2H phase WS2 via a facile hydrothermal method and subsequent liquid phase mechanical exfoliation of the material into QD-like nanostructures. An increment in dopant percentage from 1 % to 7 % red shifted the band gap of WS2 from 4.15 eV to 3.78 eV. The nanostructures show electronic transition due to B, A, and defect-bound excitons and demonstrate modulation of excitonic behavior with V doping. Low V doping provides the WS2 material with a reduced B/A excitonic peak intensity ratio because of the nonradiative pathways favoring the relaxation of high energy B excitons to A excitons. High V doping results in anomalous emission behavior marked by an increased B/A ratio, attributed to positive trion formation as a result of excess free hole concentration due to the p-type vanadium. The study suggests that V-doped WS2 nanostructures hold potential for technological applications, particularly in spintronics and photonics, emphasizing the importance of engineering exciton dynamics in two-dimensional materials using p-type substitutional dopants.

Hydrothermal synthesis, characterization of Co3Sb4O6F6 and carbon doped Co3Sb4O6F6 and their application towards photocatalytic dye degradation, adsorption, catalytic Knoevenagel condensation and bacterial disinfection

Single crystals of Co3Sb4O6F6 have been grown by employing hydrothermal techniques. Table sugar was utilized to prepare carbon-doped Co3Sb4O6F6. The objective was to employ Co(II)-based metal oxyfluoride comprising a stereochemically active lone pair element (Sb3+) and its carbon-doped analogues for the multifunctional applications. The impact of carbon doping on Co3Sb4O6F6 has been evaluated towards the changes in photocatalytic, catalytic, and adsorbent efficiency. The changes in carbon percentage affect the physical and chemical properties of the host material. A larger percentage of carbon doping turns the photocatalytic ability of the host material into an adsorbent for the removal of dye. The single crystal X-ray diffraction study reveals that Co3Sb4O6F6 crystallizes into cubic symmetry. However, powder X-ray diffraction study reveals the structural transformation in the carbon-doped Co3Sb4O6F6. It also reduces the band gap energy of the host material, and 4 wt% C@Co3Sb4O6F6 turns out to be an efficient photocatalyst. Large-scale carbon doping (15 wt%) appears to be an effective strategy to increase the surface charge and BET surface area, as consequences adsorption property develops in 15 wt% C@Co3Sb4O6F6/H2O2 for the elimination of methylene blue (MB). This favourable chemical adsorption process occurs with large maximum adsorption capacity (qmax = 58.41169 mg g-1), as evident from the Langmuir adsorption isotherm. Scavenger experiment confirms that the photocatalytic activities of the as-synthesised compounds were triggered by the active participation of the hydroxyl radical (.OH). The catalytic efficiencies of both parent and doped compounds are also established for the solvent-free Knoevenagel condensation reaction with 90 % yield at moderate temperature. Bacterial disinfection studies by the ‘Disc diffusion method’ confirm that Co3Sb4O6F6 shows better efficiency than the carbon doped compound against both Gram-positive and Gram-negative bacteria.

Synthesis of PPy-MnO2 Nanocomposite for Utilization in Supercapacitor Applications

Polypyrrole (PPy) nanocomposites were prepared using chemical oxidation and were combined with manganese oxide (MnO2) nanoparticles. The PPY-MnO2 nanocomposite was synthesized by integrating PPy nanofibers with varying volume ratio percentages of MnO2 dopant (10, 30, and 50% vol. ratio). The structural features of the PPy and PPy-MnO2 nanocomposite were investigated using X-ray diffraction (XRD). Fourier transfor infrared (FTIR) spectroscopy was used to demonstrate the molecular structures of primary materials and the final product of PPy, MnO2, and PPy- MnO2 nanocomposites. Field Emission Scanning Electron Microscopy (FESEM) showed that the morphology of PPy consisted of a network of nanofibers. Increasing the volume ratios of manganese oxide added to the PPY nanofiber led to the increase of manganese oxide nanoparticles on the surface of the PPY nanofiber network. This resulted in a noticeable alteration in the structure of the nanocomposite. It has been observed that the nanocomposites demonstrate a significant level of pseudocapacitive activity. The highest capacitance of 236 F/g was observed when pure PPy was doped with 30% MnO2 compared to 125 F/g of the pure PPy.

Zn2-xGeO4-GeO2:(x)Mn2+ films with long persistence, intense brightness and high quantum efficiency, deposited by ultrasonic spray pyrolysis

This work shows the synthesis and characterization of the Zn2-xGeO4-GeO2:(x)Mn2+ (x = 0.10, 0.25, and 0.50 at.%) films using the Ultrasonic Spray Pyrolysis (USP) technique. These films were deposited at 500 °C and heat treated at 800 °C for 13 h. X-ray diffraction (XRD) measurements showed the rhombohedral and hexagonal phases of Zn2-xGeO4 (78.8 %) and GeO2 (21.2 %), respectively. SEM micrographs exhibited the surface morphology of these films. The STEM and HAADF show Ge, Zn, and O atomic layers. In addition, XPS was carried out to observe the oxidation states of Mn2+ (75.4 %) and Mn3+ (24.6 %) for the films doped with Mn ions (0.10 at.%). Incorporating manganese ions into the Zn2-xGeO4-GeO2 host lattice generated an extremely green emission, exciting at 250 nm. The photoluminescence and persistence luminescence properties were studied in accordance with the manganese doping concentration. For photoluminescence, it was found that the optimal doping percentage was 0.25 at.%, and for persistence luminescence, it was 0.10 at.% Mn with λex = 250 nm. Quantum efficiency measurements gave a result of 100 %. In addition, preliminary CL measurements were exhibited.

Energy-saving synthesis of wurtzite ZnS nanoparticles using Yttrium as a defect regulator by hydrothermal method

In this work, Y-doped ZnS nanoparticles were synthesised using the hydrothermal method with doping percentages of 0.5%, 1%, 2.5%, and 5%. XRD study revealed that doping caused a phase transition from cubic to hexagonal, further confirmed by Raman analysis and TEM images. Morphological studies conducted by SEM and TEM provided insights into the structural changes. Diffused reflectance studies were used to evaluate the band gap, with values obtained as 3.33eV, 3.45 eV, 3.45 eV, 3.44 eV, and 3.37 eV for pure, 0.5%, 1%, 2.5%, and 5% Y-doped ZnS, respectively. Photoluminescence analysis revealed the presence of defect states in ZnS nanoparticles, indicated by peaks at 362 nm, 383 nm, and 390 nm in both pure and doped samples. The intensity of these peaks increased with Y doping, attaining its highest at 1% Y doping, while concentration quenching was observed at higher doping percentages. The EDAX analysis confirmed the successful integration of Y as a dopant in the ZnS lattice. These findings highlight the importance of optimizing the doping concentration to achieve the desired luminous features and provide valuable insights into the doping-dependent luminescence behaviour of Y-doped ZnS nanoparticles. The visible light photocatalytic activity of the nanoparticles was investigated, and it was revealed that the photocatalytic efficiency increased initially and then declined with the doping concentration increased. It was found that the ideal doping concentration for 93% degradation efficiency was 1%. The novelty of this work lies in developing a simple and energy-saving method for synthesizing hexagonal ZnS at low temperatures, which avoids the need for high temperatures and advanced anti-oxidation apparatus.

Dopant Activation Comparison in Phosphorus and Nitrogen Implanted 4H-Silicon Carbide

Bulk mobility and dopant activation of implanted species into 4H-SiC plays a crucial role in the carrier conduction, blocking behavior, and channel properties of a 4H-SiC vertical power MOSFET. Nitrogen and phosphorus ion implantation became the norm as n-type dopants for 4H-SiC. Therefore, the doping and temperature behavior of both species in 4H-SiC needs to be well characterized. In this study, we report a comparison in electrical characteristics between nitrogen and phosphorus implanted 4H-SiC as a function of temperature for various doping levels. For this purpose, 4-point van der Pauw samples are prepared, resistivity and Hall measurements are conducted. We found that resistivities drop as temperature increases from 140 K with phosphorus having higher resistivities at all implanted doping concentrations. The carrier concentrations increase with increase of temperature, indicating incomplete ionization of dopants. Mobilities drop at low temperature due to increased impurity scattering, reaches a peak near 300 K and drops at higher temperature due to increased phonon scattering. From the obtained data, using a two-level charge neutrality equation, the activation percentage and ionization energies of dopants in hexagonal and cubic sites for both species are extracted and compared.

Mg‐ZnO/CNT Nanocomposite as Electrode Materials with Enhanced Electrochemical Performance for Supercapacitor Applications

AbstractThe present research work reported the study of nanocomposites of undoped and Mg‐doped ZnO with CNT as electrode materials for supercapacitor application. The undoped ZnO/CNT and Mg‐doped ZnO/CNT nanocomposites (i.e., 10 % Mg‐doped and 20 % Mg‐doped) were synthesized using a cost‐effective blending‐assisted hydrothermal method. The morphological (FESEM & TEM) studies revealed that the diameter of CNT was ~7 nm and the ZnO nanoparticles were spherical in shape with an average particle size of ~5 nm. In addition, it was also found that 10 % Mg‐ZnO and 20 % Mg‐ZnO had a sheet‐like structure. XRD and FTIR studies further confirmed the successful doping of Mg in ZnO and CNT nanocomposites. BET analysis showed that the value of specific capacitance increased with the increase in surface area. Further, the electrochemical performance of these nanocomposites revealed that the higher doping percentage, 20 % Mg‐ZnO/CNT nanocomposite achieved the highest specific capacitance value i.e., 458.5 F/g at 0.1 A/g current density in 3M H2SO4 electrolytic solution, having a retention of 99.8 % after 12,00 long cycles. In addition, the charge storage mechanism revealed that the as‐synthesized nanocomposites showed both the diffusion‐controlled and capacitive‐controlled behaviors. Thus, a higher value of specific capacitance with excellent cyclic stability indicated the higher efficiency of Mg‐doped ZnO/CNT nanocomposite for future supercapacitor applications.

Atomic insight into residual stress and microstructure evolution of amorphous carbon heterostructured films induced by multi-stage phase transformation of high-entropy alloys

The residual stress has significant effects on the microstructure and service performance of films. With good toughness and low stacking fault energy, high-entropy alloy (HEA) can act as dopant to reduce the residual stress of films via self-plastic deformation. Nevertheless, the microscopic mechanism buried deep under the surface is difficult to study by experiments and the dynamic evolution cannot be observed, which the biggest obstacle to investigate the corresponding solutions is. In this paper, diamond-like carbon (DLC) models with different CoCrFeNi HEA doping ratios (1:2, 1:4, 1:6, and 1:8) were designed by molecular dynamics method. The effects of CoCrFeNi doping percentage on the structure and residual stress of this heterostructured films were investigated, and the mechanism of residual stress reduction was revealed. The results show that the phase transformation of HEA causes stress fluctuations in DLC films. The stress fluctuations at different orientations of the heterostructured films is gradually shifted to the right with the increase of HEA percentage, and the difference in stress level between the initial and final strain is significantly decreased. Meanwhile, when the doping ratio is 1:2, the compressive stresses inside the films is lower and the generation of stacking faults is later. With the increase of the HEA doping ratio, the proportion of C atoms with sp3 and sp2 hybridization structures is decreased significantly, and the percentages of the distorted C–C bond length and distorted C–C-C bond angle are also reduced. Therefore, HEA doping affects the number of hybrid atoms and the distribution of bond characteristics in DLC films, which leads to the decrease of the residual stress of the heterostructured films.Graphical

A comprehensive study of laser irradiated hydrothermally synthesized 2D layered heterostructure V2O5(1−x)MoS2(x) (X = 1–5%) nanocomposites for photocatalytic application

Abstract It has been studied that both two-dimensional (2D) MoS2 and V2O5, which are classified as transition metal dichalcogenides and transition metal oxides, are good photocatalyst materials. For this purpose, the hydrothermal method was practiced to synthesize V2O5(1−x)MoS2(x) (X = 1–5% w/w) nanocomposites with different 1–5% w/w weight percent of MoS2 as a prominent photocatalyst under laser irradiation for 2, 4, 6, 8, and 10 min to tune photocatalytic degradation of industrial wastage water. The surface of the 2D molybdenum nanolayered matrix was efficaciously decorated with V2O5 nanoparticles. The crystal phase and layered structures of the V2O5(1−x)MoS2(x) (X = 1–5% w/w) nanocomposites samples were verified by X-ray diffraction and scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy respectively. In the range of the UV visible spectrum, the increment in light absorption from 3.6 to 14.5 Ω−1 cm−1 with an increase of active surface from 108 to 169 μ m 2 {{\rm{\mu }}{\rm{m}}}^{2} with increased MoS2 doping percentage. Furthermore, dielectric findings like the complex dielectric function, tangent loss, electrical conductivity, quality factors, and impedance of V2O5(1−x)MoS2(x) (X = 1–5% w/w) nanocomposites are studied. According to photoluminescence studies, the intensity of peaks decreases when laser irradiation time and doping percentages of MoS2 are increased. As a result, a small peak indicates a decrement rate of electron–hole pair recombination, which increases the capacity for separation. Thermo-gravimetric analysis and differential thermal analysis results revealed that weight loss decreased from 0.69 to 0.35 mg and thermal stability increased with increased doping concentrations. Methylene blue was degraded in 150 min, proving that the prepared MoS2-doped V2O5 material was a stable and economically low-cost nanocomposite for photocatalytic activity.

Enhanced hydrogen gas sensing performance with Ag-doped WO3 thin film

The paper reports the fabrication of a device, based on the thin film of Ag-doped WO3 nanoparticles, to enhance the hydrogen gas sensing performance. The synthesis of thin films of pristine and Ag-doped WO3 nanoparticles were carried out using the single-step hydrothermal method, followed by the spin coating deposition process. The characterization of the samples was carried out with XRD, FESEM, TEM, FTIR and UV–vis spectroscopy. The consistent pattern observed from the microstructure analysis of data from XRD, UV–vis spectrometer and FTIR validates effective incorporation of Ag into the WO₃ structure. The XRD patterns confirmed the formation of the monoclinic phase of WO3 nanoparticles. The crystallite size and the value of band gap decreased on increasing the Ag doping percentage in WO3. This reduction with Ag-doping could be attributed to the proper substitution of the W with Ag due to their similar sizes. The gas sensing performances of the fabricated sensing devices were analyzed by exposing different concentrations of hydrogen gas ranging from 12.5 ppm to 75 ppm. The device based on the thin film of Ag-doped WO3 performed much better than the device based on the thin film of pristine WO3 nanoparticles. The device with 4% Ag-doped WO3 showed the best sensor response of 98 % for 75 ppm H2 gas concentration with response and recovery time of 76 and 100 s, respectively at 100 °C. The improved response of the device with Ag doping compared to the pristine device could be attributed to the better charge transfer, more defect creation, and the ability of Ag to work as a catalyst to make reaction kinetics faster. The selectivity of the device was tested using the oxidizing and reducing gasses of NO2, H2, and NH3 at 100 °C for 75 ppm gas concentration. The recorded response of the device for NO2, H2, NH3 were 38%, 98%, and 43%, respectively.

Investigation of mechanical behavior of porous carbon-based matrix by molecular dynamics simulation: Effects of Si doping

Understanding the mechanical properties of porous carbon-based materials can lead to advancements in various applications, including energy storage, filtration, and lightweight structural components. Also, investigating how silicon doping affects these materials can help optimize their mechanical properties, potentially improving strength, durability, and other performance metrics. This research investigated the effects of atomic doping (Si particle up to 10 %) on the mechanical properties of the porous carbon matrix using molecular dynamics methods. Young's modulus, ultimate strength, radial distribution function, interaction energy, mean square displacement and potential energy of designed samples were reported. MD outputs predict the Si doping process improved the mechanical performance of porous structures. Numerically, Young's modulus of the C-based porous matrix increased from 234.33 GPa to 363.82 GPa by 5 % Si inserted into a pristine porous sample. Also, the ultimate strength increases from 48.54 to 115.93 GPa with increasing Si doping from 1 % to 5 %. Silicon doping enhances the bonding strength and reduces defects in the carbon matrix, leading to improved stiffness and load-bearing capacity. This results in significant increases in mechanical performance. However, excess Si may disrupt the optimal bonding network, leading to weaker connections within the matrix. Also, considering the negative value of potential energy in different doping percentages, it can be concluded that the amount of doping added up to 10 % does not disturb the initial structure and stability of the system, and the structure still has structural stability. So, we expected our introduced atomic samples to be used in actual applications.

Influence of cobalt doping on structural, optical, and electrical properties of zinc oxide nanoparticles prepared by polymeric precursor method

Cobalt-doped ZnO nanoparticles at different compositions have been obtained by the polymeric precursor method. The nanoparticles were obtained at the working pH from 8.3 to 8.5 and synthesized at 550 °C. The properties were studied using X-ray diffraction (XRD), vibrational spectroscopy (FTIR/Raman), diffuse reflectance absorbance spectroscopy (DR UV–Vis), photoluminescence spectroscopy (PL), scanning electron microscopy (SEM/EDS), and impedance spectroscopy. The lattice parameters were determined at room temperature by Rietveld refinement, confirming single-phase composition with a hexagonal wurtzite structure. FTIR and Raman analyzes identified the characteristic vibrations of the synthesized system and the typical deformations of the wurtzite-type hexagonal structure, corroborating the results obtained from XRD. A redshift in the optical energy band gap (Egopt) was observed with increasing cobalt content compared to the ZnO sample. Considering the doping percentage, Egopt value varied between 3.13 eV and 3.04 eV for pure ZnO and Co-doped ZnO with 5 at. %., indicating that the optical properties of the nanoparticles were affected by dopant concentration. PL and SEM/EDS characterization were used to determine the associated defects for each sample and the morphology and composition of the nanoparticles. PL results showed a strong blue emission at around 439 nm (2.83 eV), which is redshift with cobalt content (ΔE between 0.05 eV and 0.01 eV), attributed to the surface defects present in the doped samples. Conductivity analysis to temperature revealed a semiconductor behavior for all samples, and their respective activation energies determined. The results provide an easy method to obtain Co-doped ZnO nanoparticles with interesting properties for optoelectronics devices.

Robust ferromagnetic V0.05-XCoxZn0.95O (x = 0.01, 0.02, 0.03, 0.04, 0.05) nano-compounds: New dilute magnetic-semiconductors with tailored optical activity

The development of diluted magnetic semiconductors (DMS) that combine magnetic properties with semiconducting behavior is a promising area of research that could lead to the creation of entirely new types of devices that are faster, more efficient, and potentially cheaper. In this investigation, DMS nanocompositions represented by V0.05-XCoxZn0.95O, (x = 0.01, 0.02, 0.03, 0.04, 0.05) were synthesized via a modified Pechini-sol-gel process. X-ray analysis showed a successful incorporation of V and Co ions into ZnO structure. The size and shape of the nanoparticles changed depending on the V/Co doping percentage. The addition of the blend of 2 wt% V and 3 wt% Co ions significantly reduced the particle size from 21 nm to 14 nm. The X-ray photoelectron analysis identified complex interactions between vanadium/cobalt dopants and the surrounding ZnO lattice with significant influence of cobalt incorporation on vanadium's oxidation state. It further revealed a significant influence of cobalt incorporation on vanadium’s oxidation state. Vanadium primarily exists as V3+ upon vanadium-mono doping (ZV5). However, co-doping with Co/V leads to a shift towards the V5+ state. Enhanced absorption extending into the visible light region was observed in either mono or (V/Co) co-doped samples. Notably, the band gap energy decline was more pronounced in the 5 mol% Co-doped ZnO, recording a value of 2.58 eV. An additional band gap around 1.8 eV appeared in Co-doped samples, potentially due to transitions in Co2+ ions. The combination of V and Co induced a ferromagnetic behavior with fully saturated order. The ZV3C2 composition exhibits the most promising characteristics, boasting the highest saturation magnetization (1.037 emu/g). Accordingly, robust ferromagnetism of V0.05-XCoxZn0.95O, (x = 0.01, 0.02, 0.03, 0.04, 0.05) nano-particles is a promising approach for spintronic applications.

The effect of solvent type and composition on the synthesis of boron-doped ordered mesoporous carbons

Boron-doped ordered mesoporous carbons (B-OMCs) were synthesized using different solvent types and compositions to study the effect of the solvent medium on the physical properties and oxygen reduction activities of the resultant structures. Materials were synthesized by a one-pot self-assembly method, using resorcinol and formaldehyde as carbon source, boric acid as boron source and triblock copolymer Pluronic F127 as the structure directing agent. Different solvents, namely ethanol, n-propanol, isopropanol and acetone were used as solvent media along with water as the cosolvent. Among different solvents, ethanol and n-propanol gave better-ordered structures and also had higher surface areas. At this stage, the highest boron doping percentage was obtained as 1.38 % with n-propanol. In the second stage, B-OMCs were synthesized with n-propanol in different water/n-propanol (W/N) molar ratios varying between 2.5 and 4.75. The orderliness was observed to be better in samples with low W/N ratios of 2.5 and 3.25 and the morphologies shifted from 2D to 3D interconnected type with the increase of water content. The average pore sizes of samples varied between 7.9 and 9.7 nm. On the other hand, the highest surface area (729 m2/g) and the highest boron doping percentage (1.53 %) were obtained with the W/N ratio of 4. XPS analysis showed that 23 % (w/w) of doped boron in this sample was in substitutional state while the remaining boron was found in mixed B–C and B–O states. Cyclic voltammetry measurements for the samples with W/N ratios of 2.5, 3.25 and 4 showed significant oxygen reduction activities at −0.28 and −0.29 V. Results showed that the properties of solvent play an effective role in the orderliness, pore structure and surface composition of B-OMCs, which in turn affect their electrochemical properties. Among different types of solvents, n-propanol can be used as an alternative to ethanol with the W/N ratio of 4 giving the highest surface area and boron doping percentage.

Study the Influence of Tin Oxide SnO2 Doping on the Optical and Structural Properties of Titanium Oxide TiO2

Titanium dioxide thin films, along with varying tin oxide ratios, were applied onto quartz substrates through pulsed laser deposition. The samples included pure TiO2 and doped versions ranging from 5% to 25%. The deposition parameters were kept constant at an energy level of 1000 mJ and a frequency of 6 Hz. Analysis via atomic force microscopy revealed that higher doping percentages correlated with increased surface roughness and grain diameter, indicating larger particle growth. Additionally, the absorption coefficient rose with higher doping ratios, peaking at 25% SnO2. This increase in absorption coefficient accompanied a decrease in the optical energy gap due to thicker film deposition, leading to higher absorbance and lower transmittance.

Temperature and humidity effects on the acetone gas sensing of pristine and Pd-doped WO3 clusters: A transition state theory study.

The performance of pristine and Pd-doped WO3 acetone gas sensors is calculated theoretically and compared with available experimental results. Temperature, humidity, and acetone concentration variation are considered in the present work. Transition state theory calculates Gibbs free energy of transition, including its components enthalpy and entropy of transition or activation. The variation of Pd doping concentration is used to obtain the maximum response and lowest response time for the optimum performance of the gas sensor. The present theory considers the reduction of acetone gas concentration as acetone reaches its autoignition temperature. Acceptable agreement between theory and experiment is obtained. The acceptance includes the decrease of Gibbs free energy with doping percentage, variation of temperature exponent to the power twelve in the considered reactions, and reduction of response time with the increase of temperature. Density functional theory at the B3LYP level is used. 6-311G** basis set (for O atoms) and SDD (for heavy Pd and W atoms) are used to optimize the structures examined in the present work. The Gaussian 09 program and accompanying software were used to perform the current tasks.

Structural and dielectric characteristics of doped nickle oxide polyaniline composites

ABSTRACT The PANI-NiO composites were synthesized by employing an in situ chemical polymerization technique, with varying weight percentages of NiO dopant (PANI-5%NiO and PANI-10%NiO). Additionally, AC conductivity, dielectric constant and dielectric loss were investigated within a frequency range from 20 Hz to 1 MHz. XRD confirmed the phase purity and high crystallinity. SEM reveals the granular shape with a porous surface. In addition, the incorporation of NiO with different concentrations influences the composite’s dielectric properties. All samples exhibited frequency-dependent dielectric properties in line with the Maxwell–Wagner model. Notably, the AC conductivity of PANI-10% NiO composite increased as the frequency increased, this behaviour was certified with Jonscher’s power law. The I–V characteristics confirm the ohmic nature of all synthesized samples. Therefore, the potential of PANI and PANI-NiO composites, as efficient dielectric materials, has been explored and can be useful for device applications in diverse fields.