Elemental Mapping Analysis Research Articles

Urea-dithiocarbamic acid functionalized magnetic nanoparticles modified with Ch-Cl: Catalytic application for the synthesis of novel hybrid pyridones via cooperative geminal-vinylogous anomeric-based oxidation

This investigation was focused on the novel magnetic nanoparticles anchored deep eutectic solvent namely Fe3O4@SiO2@(CH2)3-urea-dithiocarbamic acid/Ch-Cl as a heterogeneous catalyst. The formation of the catalyst was confirmed by several techniques including FT-IR spectroscopy, FE-SEM, TEM, EDX, elemental mapping, TGA/DTG and VSM analysis. Fe3O4@SiO2@(CH2)3-urea-dithiocarbamic acid/Ch-Cl was applied as environmentally sustainable and recoverable catalyst for the synthesis of novel hybrid pyridones containing triazole and sulfonamide moieties. X-ray crystallography was also used for the accurate determination of the structure of hybrid pyridones. In addition, based on revealed results, pyridone isomer was solely confirmed compared to its relevant tautomer (pyridine). In the current study, cooperative geminal-vinylogous anomeric-based oxidation concept has been used for suggesting a plausible mechanism for the synthesis of target molecules.

Carbonatitic footprints in the Bayan Obo REEs deposit as seen from pyrite geochemistry

The genesis of the Bayan Obo REEs deposit has been debated for a century. The most outstanding issue concerns the genesis of the ore-hosting dolomite and the contribution of the Paleozoic overprint events in the rare earth budget. Pyrite offers a unique window into those debates in that it is the only common fingerprinting mineral shared by both events. In this contribution, LA-ICP-MS trace element mapping, in-situ elemental and sulfur isotopic analyses on pyrite are integrated in order to constrain the genesis of ore-hosting dolomite and evaluate the contribution of the Paleozoic thermal events to enormous REEs resources. Five types of pyrite were distinguished in ore-hosting dolomites, various types of ore and skarns based on mineral paragenesis and geochemical signatures. The dolomites contain early euhedral pyrite (Py-1) overgrown by magnetite and euhedral pyrite (Py-2w in the West Open Pit and Py-2d in the deep boreholes) associated with pyrrhotite, monazite, dolomite and apatite. By contrast, pyrite in the banded ores (Py-3b) and the massive ores (Py-3 m) was co-precipitated with magnetite, aegirine, fluorite, riebeckite, REEs minerals and apatite. Pyrite in the vein ores (Py-4) usually coexists with barite, quartz, aegirine and calcite, and those (Py-5) in skarns associated with biotite and amphibole. Py-1 is enriched in Ti, Ni, Nb, Hf and REEs, with high Co/Ni and Y/Ho ratios (ca. 66), and high δ34S values from +8.6‰ to +13.8‰. In comparison, Py-2w and Py-2d have higher Co/Ni yet lower Y/Ho (ca. 11) ratios, but exhibit magmatic δ34S values (-1.0‰ to +3.0‰; −1.0‰ to +3.7‰). Py-3b and Py-3 m are relatively enriched in Cr, Mn, Zn and LREEs, and possess intermediate δ34S values (+5.7‰ to +7.7‰, and +0.2‰ to +2.4‰, respectively). Py-4 is generally depleted in trace elements with magmatic δ34S values (-2.0‰ to +2.7‰). Compared with Py-3 m and Py-3b, Py-5 is characterized by high Co yet low Ti, Cr, Mn, Cu and Zn with variable REEs, and is enriched in 34S (δ34S: +9.1‰ to +10.8‰). The high δ34S value and Y/Ho ratio in Py-1 indicate that the ore-hosting dolomite is an igneous carbonatite originated from partial melting of upper mantle contaminated by altered and subducted oceanic crust. The marked difference in trace elements and sulfur isotopes between Py-3, Py-4 and Py-5 implies that the Paleozoic thermal events contributed little to the primary REEs mineralization except remobilizing preexisting ore metals.

Sintering characteristics of plate-like bismuth titanate ceramics with preferred c - axis orientation for memory storage devices

Bismuth titanate (Bi4Ti3O12) (BIT) has been an attractive material due to its high Curie temperature, large remnant polarization and relatively low processing temperature, making it suitable for piezoelectric, pyroelectric and non-volatile random access memory storage devices. In this present work, polycrystalline textured bismuth titanate ceramics were synthesised by the cost-effective molten salt synthesis method. The effect of sintering conditions on the structural, morphological and dielectric properties have been carried out in detail. The X-ray diffraction studies reveal the formation of the monophasic structure of BIT ceramics with a preferential orientation along the c-axis. It is also noticed that the orientation along the c-axis increases with an increase in sintering temperature. Interestingly, the parameters like crystallite size and micro-strain calculated from the Williamson - Hall method could be tailored as a function of sintering temperature. The microstructural studies carried out using FESEM technique suggested the presence of plate-like morphology of BIT ceramics and subsequently, the elemental mapping analysis used to confirm the uniform distribution of the elements Bi, Ti and O present in the ceramic sample. The Fourier transform infrared and X-ray photoelectron spectroscopic studies have been done to identify the constituent chemical bonds and oxidation states of BIT ceramics. Interestingly, it is noted that the value of the dielectric constant increases with the increase in sintering temperature of BIT ceramics. Furthermore, the high dielectric constant value of 200 obtained at 100 kHz for 950 °C sintered sample could establish this material for the embedded capacitor in memory storage devices.

Effect of Gd doping on the microstructure and magnetocaloric properties of LaFe11.5Si1.5 alloy

NaZn13-type La(Fe,Si)13 alloys are one of the most promising magnetocaloric materials near room temperature. However, the impact of lanthanide doping on their magnetocaloric properties has not been thoroughly investigated. Here, a series of Gd-doped La1−xGdxFe11.5Si1.5 (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25) alloys were designed and synthesized by arc melting and annealing. The microstructure of different phases and their influence on magnetic properties were investigated. The Gd doping at La sites was confirmed by the lattice contraction revealed by X-ray diffraction and elemental mapping analysis. After saturation at around x = 0.1, extra Gd leads to formation of Gd-rich Gd2Fe16Si phase. Moreover, doping of extra Gd inhibits the formation of La(Fe,Si)13 phase, resulting in significantly increased amount of the impurity phases (α-Fe and LaFeSi phase). The change of microstructure and composition causes the magnetic transition to shift from first order to second order. Because of Gd doping, the Curie temperature of La1−xGdxFe11.5Si1.5 increases, and the maximum entropy change decreases. Understanding the effect of Gd on the microstructure and magnetic properties can help us develop more rare-earth-doped La(Fe, Si)13 alloys.

Investigation of vermiculite infiltration effect on microstructural properties of thermal barrier coatings (TBCs) produced by electron beam physical vapor deposition method (EB-PVD)

Thermal barrier coatings (TBCs) are protective coating systems that are mostly utilized to improve the thermal insulation and functional performance of gas turbine engines and other aircraft components that are both stable and movable. These coatings protect materials operating in harsh conditions from structural damage caused by corrosion, oxidation, the CaO-MgO-Al2O3-SiO2 effect (CMAS), thermal shock, volcanic ash, and vermiculite deposits at high temperatures. In this study, CoNiCrAIY metallic bond coatings were coated on Inconel 718 super alloy using a high velocity oxygen-fuel (HVOF) deposition technique. Then, single YSZ, Gd2Zr2O7 (GZ), and double YSZ/GZ based ceramic topcoats were applied to the bond coats by using the electron beam physical vapor deposition (EB-PVD) method. The produced TBC samples and the uncoated Inconel 718 superalloy substrate were subjected to vermiculite (VM) deposition at 1250 °C for 4 h, and then the coatings were characterized. To determine the phase structures, microstructural and mechanical properties of the TBCs, X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer elemental mapping analysis (EDS), stereo microscopy analyses, porosity, and hardness measurements were used. The obtained results were comparatively evaluated with the recent related studies in the literature.

Investigation of oxidation and hot corrosion behavior of molybdenum coatings produced by high-velocity oxy-fuel coating method

Thermal spray coatings methods are frequently used in automotive, aerospace, and marine vehicles. The most obvious damage mechanisms of coating systems, which are exposed to many damages during use, are high-temperature oxidation and corrosion. While the oxygen element coming from the atmosphere creates the high-temperature oxidation damage in the coating systems, the molten salts such as Na2SO4 and V2O5 coming from low-quality fuels constitute the high-temperature hot corrosion damage mechanism. In this study, its behavior against high-temperature oxidation and hot corrosion damage mechanisms was investigated by coating Molybdenum (Mo) on a 316 L stainless steel substrate with the High-Velocity Oxy-Fuel technique, which is an innovative thermal spray coating method. Both damage mechanisms were carried out isothermally at 650 °C. Oxidation tests were carried out for 5, 25, and 50 h, while hot corrosion tests were carried out for 1, 3, and 5 h. X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), Elemental mapping, and Energy Distribution Spectroscopy (EDS) analysis was performed on molybdenum-coated samples before and after both tests. The results obtained were evaluated and discussed in light of the literature.

Elemental Mapping and Characterization of Petroleum-Rich Rock Samples by Laser-Induced Breakdown Spectroscopy (LIBS)

The application of Laser-Induced Breakdown Spectroscopy (LIBS) is presented for the direct elemental analysis of hydrocarbon-rich solids. In recent years, LIBS has become a powerful tool for obtaining elemental information and mapping analysis of different petroleum-rich samples with minimal to no sample preparation and without the need to separate the organic matter from the inorganic matter. By selecting the most intense and representative lines, the element distribution in a 2D map can be accessed in less than ten hours. For this reason, two types of hydrocarbon-rich solids were chosen for examination, i.e., core and shale. Nineteen elements were identified in the samples, and 2D mapping for Ca, Mg, Fe, Ti, Ni, C, H, K, O, and S is presented here. A detailed distribution of the elements, and the main components of the hydrocarbons present in these samples, were determined using LIBS. The H/C molar ratio was determined by building H and C calibration curves using data obtained from classical elemental analysis via combustion. These calibration curves contained a high degree of linearity (R2 > 0.98) with the limits of detection for C (193 nm), C (247 nm), and H (656 nm) of 848 mg kg−1, 353 mg kg−1, and 3.5 mg kg−1, respectively. By combining all of this information, LIBS allowed us to determine how these elements were spatially distributed, which elements were dominant in a given sample, and how much hydrocarbon was present, as well as providing a quantitative determination of the H/C molar ratio, and its correlation with the source of origin.

Adsorption of diazinon using Cd-MOF nanoparticles before determination by UV-Vis spectrometer: isotherm, kinetic and thermodynamic study

In this work, Cd MOF has been prepared using a hydrothermal method and characterized by the SEM, elemental mapping, XRD, EDS, and BET analysis. The diazinon stability has been investigated in various pH (4-8) and temperature (298oK – 323oK) using UV-Vis spectrometer in the range of 230 – 280 nm, at its main absorption peak at 247 nm. Adsorption behaviors of diazinon on the Cd MOF were considered in different conditions. UV-Vis spectroscopy was used to monitor the removal of diazinon using the Cd MOF. The adsorption capacity of 138 mg g-1 was obtained. The effect of temperature (298 K -323 K), pH (4-8), adsorbent dose (1-7 mg), initial concentration (4-12 mg L-1), stirring speed (0-500 rpm), and adsorption kinetics were studied using batch rout. All the studied parameters have shown significant effects on the efficiency of removal of diazinon by the Cd MOF. The adsorption thermodynamic was investigated in the temperature range of 298 k to 323 K and it has shown the endothermic nature of adsorption of diazinon using prepared Cd MOF. The adsorption isotherm follows by the Langmuir isotherm model. It was demonstrated that synthesized adsorbent could be effectively used for the removal of diazinon from water.

Perovskite nanocomposite of defective yolk-shell BaHo2Co3O8-x for electrochemical sensing of ractopamine in pork meat sample

Since ractopamine (RPA) can increase high growth rates in cattle and swine, illegal RPA usage has been widespread in many farming enterprises. Owing to the possible damage to public health, RPA detection has become a critical issue in recent decades. As a result, in order to maintain food safety, an analytical tool for rapid, precise, portable, and sensitive monitoring of RPA in animal tissues is required. In this study, the electrochemical sensor is developed for the first time by the defective yolk-shell of BaHo2Co3O8-x nanocomposites (perovskite types), which are synthesized using a hydrothermal followed by a calcination process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FE-SEM), and high-resolution transmission electron microscope (HR-TEM) are used to investigate physicochemical characterizations. Moreover, the elements are confirmed by the energy dispersive X-ray spectrum (EDS) and elemental mapping analysis. Cyclic voltammetry (CV) and difference pulse voltammetry (DPV) are used to detect RPA by modified BaHo2Co3O8-x/SPCE. The electrochemical sensing ability of the modified BaHo2Co3O8-x/SPCE displays a broad linear response range (up to 200 μM) and an ultralow detection limit (0.029 μM). Furthermore, the BaHo2Co3O8-x/SPCE presents outstanding selectivity, good repeatability, long-term storage stability, and reproducibility for RPA detection in pork meat samples.

Construction of Synergistic Co and Cu Diatomic Sites for Enhanced Higher Alcohol Synthesis

Construction of Synergistic Co and Cu Diatomic Sites for Enhanced Higher Alcohol Synthesis

Tungsten mineralization process and oxygen fugacity evolution in the Weijia W deposit, South China: Constraints from the microstructures, geochemistry, and oxygen isotopes of scheelite, garnet, and calcite

Scheelite is a major (W)-bearing mineral enriched in rare earth elements (REEs) and is widely used to investigate the mineralization process, fluid source and redox environment of W deposits. In the Weijia skarn-type W deposit in South China, scheelite was formed during the greisen, retrograde skarn, oxidation, and sulfide-quartz vein stages. Various characteristics of cathodoluminescence (CL) images of scheelite grains (e.g., light to dark color, core-rim texture and oscillatory zonation) have recorded their detailed crystallization process. Scheelite grains formed in the greisen and retrograde skarn stages have similar LREE patterns, and the gradual fractionation in HREEs may be a result of the precipitation of garnet (And38-70Gr29-52Pr1-3) in the prograde skarn stage. In addition, the similar REE patterns of scheelite from the greisen stage and the granite porphyry pluton suggest a genetic relationship. The oxygen isotopic compositions of scheelite and quartz are all plotted near the edge of the magmatic fluid field, confirming their derivation from the same magmatic hydrothermal fluid. Elemental mapping and spot analyses using an electron probe microanalyzer indicated that extensive isomorphic substitution of W by molybdenum (Mo) occurs in scheelite, and the darker color in the CL images corresponds to a higher Mo content and lower W content. The Mo content of scheelite gradually increased from the greisen stage (mean = 0.46%), through the retrograde stage (mean = 2.89%), to the oxidation stage (mean = 19.8%), and then dropped sharply in the sulfide-quartz vein stage (mean = 0.20%), indicating a change in oxygen fugacity. Moreover, scheelite formed in the sulfide-quartz vein stage has an oscillating Mo content, thus implying a slight or periodical change in oxygen fugacity during the same mineralization stage.

Improvement of Physical Properties of Viscose using Nano GEO2 as Doping Material

Abstract The properties of viscose\TiO2 and viscose\TiO2\germanium dioxide (GeO2) are investigated and compared. The elemental mapping analysis using a field emission scanning electron microscope (FESEM) shows the excellent distribution of nanomaterials, while the energy dispersive X-ray (EDX) confirms its existence. The 500 s cycle of rubbing test indicates that the abrasion resistance of treated samples improves significantly. In addition, the doping of nano GeO2 enhances the strength of the treated samples. Furthermore, the thermal behavior of the treated samples, characterized by differential scanning calorimeter (DSC), results in a higher crystallization temperature and doping GeO2 increases the thermal properties of viscose in comparison with nano TiO2. The study of ultraviolet blocking indicates that doping GeO2 can improve the transmission of ultraviolet even from TiO2.

Stainless steel promoted the electrochemical oxidation of amines into imines

AbstractWe report the electrochemical oxidation of benzylamine (BA) into the imine by applying a bare stainless steel mesh (SSM) as an anode. Scanning electron microscopy (SEM) and energy‐dispersive X‐ray spectroscopy (EDX) elemental mapping analysis confirmed that there was no corrosion on the surface of SSM after an anodic electrolysis. Based on the gas chromatography (GC) analysis and electrochemical results, it was confirmed that conversion of BA with SSM was approximately 3.3 times higher than with Pt electrode. This work suggests that the anodic electrolysis with a bare SSM could be a promising route to electrochemical oxidation of BA in the absence of oxidizing agents.

Combined experimental and computational study on Ag-NPs immobilized on rod-like hydroxyapatite for promoting Hantzsch reaction

In this project, a bio-based heterogeneous catalyst is synthesized via multi steps process. First, nano-rod hydroxyapatite modified by silica compound is prepared, functionalized with of some nitrogen sources linkages such as, 4-aminoacetanilide and consequent immobilization of Ag nanoparticles by Sorbus aucuparia extract. The as-prepared catalyst, Ag@n-HA@SiO2-TAA, was successfully characterized by using FTIR, XRD, BET, SEM/EDX, TGA, TEM, ICP-AES and elemental mapping analysis. Furthermore, metal-ligand interactions in Ag@n-HA@SiO2-TAA complex models were assessed to interpret the immobilization behavior of Ag-NPs on the surface of nano-rod hydroxyapatite through quantum chemistry computations. The catalytic activity of the Ag@n-HA@SiO2-TAA was investigated in multi-component Hantzcsh reactions under mild conditions to furnish the corresponding products in high yields and short reaction times. Moreover, the recyclability study and Ag leaching of the Ag@n-HA@SiO2-TAA verified that the catalyst could be easily recovered and also recycled up to six runs with only slight loss of activity.

In‐Vitro Evaluation of Folic Acid Capped Gold Nanoformulations for Drug Delivery to Prostate Cancer

AbstractDevelopment of effective nanoformulations is one of the captivated attentions in the area of healthcare applications. Drug encapsulated metal nanoparticles (AuNPs) is an impressive nanoformulations, which reduces the side effects, enrich the pharmacokinetic and enables the targeted drug delivery. Gold nanoformulations (FA‐AuNFs) receiving much consideration in biomedical research, owing to their unique physical and chemical properties with beneficial features including ease of synthesize, relatively low‐toxicity, and good biocompatibility. Herein, we aimed to establish a simple, one‐step synthesis of gold nanoformulations by chemical reduction method using folic acid (FA) as a capping and stabilizing agent. Further, folic acid capped AuNPs were encapsulated with the docetaxel (Dtx) (an anticancer drug). The surface structural formation, chemical bonding with chemical constituents and surface morphology of the FA‐AuNFs were extensively demonstrated by various analytical techniques. Raman and FT‐IR spectra reveal that the formation of folic acid and Dtx on the surface of synthesized FA‐AuNFs. FE‐SEM and HR‐TEM results suggest that the particles are spherical in shape with an average dimension of 3 nm and nanoformulations at 6 nm. The encapsulation efficiency of Dtx encapsulated FA‐AuNFs was achieved 96 % evident from the elemental mapping, XRD and SAED pattern analysis. The drug release profile exhibited prolonged drug release kinetics at 72 h. The apoptotic quantification and binding affinity (IC50) of the FA capped FA‐AuNFs (FA‐AuNPs‐Dtx) were evaluated for the in‐vitro cytotoxicity and fluorescent staining analysis against prostate cancer cell line (PC3). The synthesized multifunctional nanoformulations could be comprehensively used for simultaneous imaging and therapeutic applications.

Green Synthesis and Pinning Behavior of Fe-Doped CuO/Cu2O/Cu4O3 Nanocomposites

Egg white-induced auto combustion has been used to synthesize undoped and Fe-doped CuO/Cu2O/Cu4O3 nanocomposites in a soft, secure, and one-pot procedure. X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) investigations have been used to identify functional groups and the structural properties of crystalline phases present in the as-synthesized composites. Scanning Electron Microscopy/Energy Dispersive Spectrometry (SEM/EDS) elemental mapping analyses and Transmission Electron Microscopy (TEM) techniques were used to explore the morphological and compositional properties of these composites. N2-adsorption/desorption isotherm models have been used to examine the surface variables of the as-prepared systems. Based on the Vibrating Sample Magnetometer (VSM) technique, the magnetic properties of various copper-based nanocomposites were detected due to being Fe-doped. XRD results showed that the undoped system was composed of CuO as a major phase with Cu2O and Cu4O3 as second phases that gradually disappeared by increasing the dopant content. The crystalline phase’s crystallographic properties were determined. The average particle size was reduced when the synthesized systems were doped with Fe. The construction of porous and polycrystalline nanocomposites involving Cu, Fe, O, and C components was confirmed by SEM/EDS and TEM measurements. In terms of the increase in magnetization of the as-manufactured nanocomposites due to Fe-doping, oxygen vacancies at the surface/or interfacial of nanoparticles, while also domain wall pinning mechanisms, were investigated. Finally, employing the investigated production process, Fe doping of CuO/Cu2O/Cu4O3 nanocomposite resulted in the development of a single phase (CuO) exhibiting “pinned” type magnetization. This is the first publication to show that CuO/Cu2O/Cu4O3.

Electrochemical monitoring of carbamazepine in biological fluids by a glassy carbon electrode modified with CuO/ZnFe2O4/rGO nanocomposite

This paper illustrates the modification of the glassy carbon electrode (GCE) with the synthesized ternary nanocomposite of graphene, zinc ferrite nanoparticles (ZnFe2O4), and copper oxide (CuO) for the determination of carbamazepine (CBZ) in the biological fluids. The large surface area of GO, the conductivity of CuO nanoparticles, and electron transfer sites of ZnFe2O4 provide a sensitive electrochemical sensor for the quantitative analysis of CBZ. The physicochemical and electrocatalytic characterizations of the constructed electro-catalysts were appraised by scanning electron microscopy, elemental mapping analysis, FT-IR, XRD, and voltammetry techniques. The superiority of the nanocomposite comprised of all synthesized components, GCE/CuO/ZnFe2O4/rGO, toward electrocatalytic oxidation of CBZ was confirmed. A sensitive oxidation peak was observed for CBZ at 1.2 V in a neutral solution. The LOD was deliberated to be 3 nM with a wide range of linearity in response (0.01 to 90 μM). The easy preparation, high stability, repeatability (RSD % < 3), and good antifouling activity of the GCE modified with the CuO/ZnFe2O4/rGO nano-composite indicated the synergistic effect of zinc ferrite, rGO, and CuO. The applicability of the sensor for CBZ monitoring in human serum and urine species was evaluated with satisfactory results.

Novel Urea-Functionalized Magnetic Nanoparticles as a Heterogeneous Hydrogen Bonding Catalyst for the Synthesis of New 2-Hydroxy Pyridines

A novel urea-functionalized silica-coated magnetic nanoparticle namely Fe3O4@SiO2@UBL was described as a reusable and recoverable heterogeneous hydrogen bonding catalyst. For characterization of the catalyst, varied techniques including Fourier-transform infrared (FT‐IR) spectroscopy, energy dispersive X‐ray (EDX) analysis, elemental mapping analysis, thermo gravimetric analysis/differential thermal analysis (TGA/DTG), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) were applied. Then, its catalytic performance was screened for the synthesis of new 2-hydroxy pyridine derivatives bearing sulfonate or sulfonamide moiety. Also, in a plausible mechanistic route, the stereoelectronic role of a cooperative vinylogous anomeric-based oxidation is suggested for the aromatization of targeted molecules.

Restricting lithium-ion migration via Lewis base groups in hole transporting materials for efficient and stable perovskite solar cells

• Lewis base groups are introduced into HTMs to restrict ion migration of Li + . • Phen-TPA effectively restricts ion migration of Li + by strong coordination effect. • PSC based on Phen-TPA achieves a PCE of 20.02% with negligible hysteresis effect. • PSC based on Phen-TPA exhibits preferable humid and thermal stability. • The performance of PSCs is promoted with enhanced coordination ability of HTMs. Li-TFSI as an indispensable dopant for hole transporting materials (HTMs) suffers from inherent hydrophilicity and ion migration, which seriously damages the stability of perovskite solar cells (PSCs). Herein, a facile design strategy is proposed to restrict ion migration of Li + by introducing different Lewis base groups (pyridine, 1,10-phenanthroline and pyrazine) into HTMs. Owing to the coordination effect of Lewis base groups to Li + , the doped HTMs (Pyrd-TPA, Phen-TPA and Pyra-TPA) exhibit significantly enhanced conjugation and hole mobility. Particularly, theoretical calculation and Fourier-transform infrared spectroscopy (FTIR) results demonstrate that Phen-TPA forms the strongest coordination with Li + due to the most negative electrostatic potential region existing around 1,10-phenanthroline group. The generated Li + -coordinated Phen-TPA contributes to preferable energy levels, morphology uniformity and hydrophobicity. Element mapping analysis shows that Li-ion migration in doped Phen-TPA is restricted effectively. In addition, Phen-TPA can also passivate the perovskite surface defects dramatically, which facilitates more efficient charge transfer to hole transporting layer. Consequently, PSCs based on Phen-TPA achieve promising power conversion efficiency (PCE) of 20.02% with negligible hysteresis effect. More importantly, it maintains over 88% of the initial PCE after 1056 h storage in ambient condition of 40–60% RH and about 81% of the original efficiency after 264 h storage at 60–70 °C. This work systematically revealed the relation between coordination ability of HTMs and the performance of PSCs for the first time, which provides new design strategies to develop efficient and stable PSCs.

Hydrothermal synthesis of glucose derived carbon surface on cupric oxide (C@CuO) nanocomposite for effective electro-oxidation of catechol

In this work, we prepared carbon surface on cupric oxide (C@CuO) utilizing facile hydrothermal with glucose as a carbon precursor and applied it in different annealing treatments (300, 400, and 500 °C). As-prepared materials were characterized by various physicochemical techniques such as FE-SEM, EDX, elemental mapping analysis, XRD, Raman, and EIS spectroscopy. The composite C@CuO annealed at 400 °C (C@CuO-2) shows a considerable amount of carbon surface on metal oxide (CuO) with a well-defined structure, high crystallinity, and low charge transfer resistance. The as-prepared composites were exploited to reduce the charge transfer resistance and enhance the electrocatalytic properties. Due to the promising properties of C@CuO-2, it is utilized as an active electrode modifier (C@CuO-2/GCE) for the electrochemical sensing of Catechol (CC). The electrochemical experiments were performed using cyclic voltammetry (CV) and amperometric (i-t) techniques. This C@CuO-2 composite shows an excellent activity towards the oxidation of CC compared to C@CuO-1 & 3 respectively. In addition, the C@CuO-2 modified GCE exhibits a substantial linear range (0.001 to 15.75 mM), sensitivity (259.19 µA mM−1 cm−2), and limit of detection (0.023 µM) respectively. Moreover, the C@CuO-2 composite also shows the perspective applications in real samples analysis.