Thermal Decomposition Technique Research Articles

Phosphorus-doped carbon nitride for enhanced supercapacitor performance and energy storage applications

Exploiting the advantages of graphitic carbon nitride doped with phosphorus (xP-CN) electrodes were designed for high-performance hybrid asymmetric supercapacitor via facile hydrothermal and thermal decomposition techniques. The structural, surface chemistry, functional and morphological characterizations evidence depict successful phosphorus incorporation in Carbon Nitride (CN). X-ray photoelectron spectroscopy analysis shows that phosphorus (P) atoms have replaced corner carbon atoms in the CN structure. These findings clearly demonstrate that the presence of phosphorus doping improves the electrochemical activity of the electrodes. The designed three-electrode system has a specific capacitance of 189.36 F/g with a current density of 1 A/g. Phosphorus doping has been discovered to play a significant role in improving both specific capacitance and cycling stability. The capacitance retention of the two-electrode solid-state device has 97.2 % after 5000 cycles. These electrochemical evaluations reveal that the xP-CN electrode exhibits superior electrochemical performances than pristine CN. This doping strategy for CN presents a novel and efficient approach for crafting high-performance supercapacitors.

Agarose derived carbon based nanocomposite for hydrogen storage at near-ambient conditions

Nanocomposites of high surface area adsorption materials and nanosized transition metals have emerged as a promising strategy for hydrogen storage applications. However, their potential use in both transport and stationary applications depends on reaching the ultimate storage capacity at near-ambient conditions along with scalable synthesis protocols. Herein, a direct and simple thermal decomposition technique is reported to synthesize carbon-based nanocomposite, where nickel nanoparticles are dispersed in a porous carbon matrix. It is also demonstrated that the storage capacity can be enhanced at near-ambient conditions by effectively engineering the microstructure and synergistically combining the ‘physisorption’ and ‘spillover’ mechanism. The structure, composition and morphology of the samples were investigated using X-ray diffraction, energy dispersive spectroscopy, transmission and scanning electron microscopy. Sorption-desorption isotherms were obtained to study the hydrogen storage capacity at a moderate H2 pressure of 20 bar. The nanocomposite showed a promising storage capacity of 0.73 wt% at 298 K with reversible cyclability. It is shown that the uniform dispersion of catalytic nanoparticles leads to an increase in the spillover efficiency, which further helps in the enhancement of hydrogen storage capacity by a factor of 6.5 over pure carbon.

Synthesis of hydroxyapatite (HAp) from eggshells via thermal decomposition method for the application of dye adsorption

The study aims to synthesize hydroxyapatite (HAp) from eggshells and explore its potential for dye removal from wastewater streams. Calcium was derived from the disposed eggshells, through which CaO was acquired using the thermal decomposition technique. HAp synthesis was conducted via the direct precipitation method with the addition of diammonium hydrogen phosphate as the phosphorus source. The synthesized HAp was characterized using various techniques including XRD, SEM, FTIR, BET and UV–Vis Analysis. HAp appeared to be in a large form with tightly agglomerated rod-like nanometric particles with a surface area of 16.700 m2/g and pore volume of approximately 0.137 cm³/g, from which HAp was confirmed to have a porous structure. The synthesized hydroxyapatite showed a pure crystalline phase with a particle size in the nanometer range, according to the test results. The effectiveness of hydroxyapatite (HAp) in adsorbing methylene blue dye from wastewater was assessed using methylene blue as a representative dye. The results demonstrated that HAp exhibited a high adsorption capacity for methylene blue, indicating that the synthesized HAp was an effective adsorbent. Based on the studies conducted, it is evident that the hydroxyapatite synthesized from eggshells exhibits great potential as a cost-effective and efficient adsorbent for removing dyes from wastewater.

Efficacy of electrospun PAN/g-C3N4 nanofibers as a photocatalyst for the deterioration of hazardous azo dyes

PAN and PAN/g-C3N4 nanofibers were fabricated using the electrospinning technique. Meanwhile, g-C3N4 nanoflakes were synthesized using the thermal decomposition technique. The challenge of reusing powder catalysts was ultimately surmounted due to the use of dispersed g-C3N4. Characterization of the as-fabricated PAN/g-C3N4 NFs was performed employing wide-angle powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), UV–Vis spectrophotometry (UV–Vis), thermogravimetry analysis (TGA), N2 adsorption-desorption isotherms (BET) and X-ray photoelectron spectrometer (XPS). According to morphological studies, g-C3N4 nanoflakes get uniformly decorated over PAN fibers with a greater specific surface area and smaller band gap than g-C3N4, exhibiting maximal uniformity in dispersion. Under solar light irradiation, PAN (71%), g-C3N4 (84%), and PAN/g-C3N4 nanofibers (95%) showed excellent photocatalytic performances for the degradation of Methyl orange dye (MO) in 120 min with 95% degradation. Similarly, PAN (61%), g-C3N4 (72%), and PAN/g-C3N4 nanofibers (91%) showed photocatalytic performances for the degradation of Congo red dye (CR) in 160 min with 91% degradation. This effective degradation was due to a shift in band gap with high porosity of PAN/g-C3N4 NFs compared to pure materials such as PAN and g-C3N4.

Effect of Pr3+ concentration in luminescence properties & upconversion mechanism of triple doped NaYF4: Yb3+, Er3+, Pr3+

Lanthanide-doped fluoride nanocrystals (NCs) exhibit excellent optical features, including upconversion and downconversion luminescence (UCL and DCL), that can be utilized in a variety of applications. In this study, we have successfully demonstrated the photoluminescence behavior of triple-doped NaYF4: Yb3+, Er3+, Pr3+ NCs in the Vis-NIR region. Herein, highly monodisperse hexagonal phase NaYF4: Yb0.2, Er0.02, Prx nanocrystals in various Pr3+ (x = 0, 0.1, 0.5, and 1 mol %) concentration with ∼22 nm diameter synthesized by thermal decomposition technique. The photoluminescence studies for all samples were performed under 980 nm laser excitation. The luminescence intensity of Er3+ including blue (407 nm), green (520 and 540 nm), red (654 nm), and near-infrared (845 nm and 1530 nm) emissions was significantly quenched and Pr3+ emission intensity at 1290 nm (Pr3+:1G4→3H5) changes irregularly upon doping with Pr3+ ions. Furthermore, we performed the excitation power dependence and decay time analysis to investigate the energy transfer and upconversion mechanisms of samples. These findings indicate that the presence of praseodymium strongly reduces emission intensities due to abundant cross-relaxation channels. In addition, particle size is an efficient factor, shedding light on the influence of Pr3+ on the energy transfer and upconversion mechanisms of the fluorides.

QbD-driven development and characterization of superparamagnetic iron oxide nanoparticles (SPIONS) of a bone-targeting peptide for early detection of osteoporosis

Osteoporosis is a metabolic disorder that leads to deterioration of bones. The major challenges confronting osteoporosis therapy include early-stage detection and regular disease monitoring. The present studies employed D-aspartic acid octapeptide (-D-Asp-)8 as bone-targeting peptide for evaluating osteoporosis manifestation, and superparamagnetic iron oxide nanoparticles (SPIONs) as nanocarriers for MRI-aided diagnosis. Thermal decomposition technique was employed to synthesize SPIONs, followed by surface-functionalization with hydrophilic ligands. Failure mode effect analysis and factor screening studies were performed to identify concentrations of SPIONs and ligand as critical material attributes, and systematic optimization was subsequently conducted employing face-centered cubic design. The optimum formulation was delineated using desirability function, and design space demarcated with 178.70 nm as hydrodynamic particle size, –24.40 mV as zeta potential, and 99.89 % as hydrophilic iron content as critical quality attributes. XRD patterns ratified lattice structure and SQUID studies corroborated superparamagnetic properties of hydrophilic SPIONs. Bioconjugation of (-D-Asp-)8 with SPIONs (1:1) was confirmed using UV spectroscopy, FTIR and NMR studies. Cell line studies indicated successful targeting of SPIONs to MG-63 human osteoblasts, ratifying enormous bone-targeting and safety potential of peptide-tethered SPIONs as MRI probes. In vivo MRI imaging studies in rats showcased promising contrast ability and safety of peptide-conjugated SPIONs.

Degradation of toxic textile effluent rhodamine-B dyes using oxygen doped graphitic carbon nitride nanosheets

A metal-free oxygen-doped graphitic carbon nitride (O-gCN) is prepared by thermal decomposition techniques using urea and oxalic acid (OA). The O-gCN physio-chemical properties are obtained by using different analytical analyses. The O-gCN is utilized as a photocatalyst and applied to degrade rhodamine-B toxic environmental dye. The higher photocatalytic ability of O-gCN is ascribed to the nanostructure with a porous nature. In addition, the porous nature of prepared O-gCN initiated more reactive sites for the degradation of target pollutants. The dopant oxygen atoms in the gCN tri-s-triazine units have extended enormous light absorption capability in the visible range. Radical scavenging experiments exhibited that the reactive radicals played a key role in the photocatalytic degradation of rhodamine B (RhB). The treated waters' toxic and non-toxic nature is observed using mung bean seed germination. Hence, this present study portrayed a simple, eco-friendly, and cost-effective technique to prepare O-gCN nanosheets for environmental remediation applications.

Efficient sunlight-assisted degradation of organic dyes using V2O3/g-C3N4 nanocomposite catalyst

This study reports the synthesis of vanadium oxide (V2O3) and graphitic carbon nitride (g-C3N4) nanocomposite for simple sunlight-assisted degradation of Methylene Blue(MB) and Rhodamine B (RhB) dyes. Herein, the V2O3 and g-C3N4 are synthesized via hydrothermal and thermal decomposition techniques, respectively. X-ray diffraction (XRD) analysis confirms the formation of the rhombohedral and hexagonal structures of V2O3 and g-C3N4 in the nanocomposite, respectively, while scanning electron microscopy (SEM) reveals the sheet-like morphology of g-C3N4 and V2O3 nanoparticles. The optical band gap of the nanocomposite is estimated as 1.89 eV using a Tauc's plot generated from UV–Vis reflectance spectroscopy. The as-synthesized nanocomposite exhibits an excellent dye degradation efficacy displaying a 100 % degradation of RhB and 90 % degradation of MB dyes within 1 h of exposure to daylight. This performance is attributed to the synergistic effect of the V2O3/g-C3N4 nanocomposite wherein the composite benefits from the large surface area and high visible light adsorption of g-C3N4, combined with the active catalytic sites of the rhombohedral V2O3 structure, resulting in its high efficiency for photocatalytic dye degradation. Scavenger studies confirm the hydroxyl (.OH) radicals and oxygen (O2−.) radicals as the primary reactive species in the degradation process MB. Furthermore, the catalyst exhibited remarkable stability over three cycles of photocatalysis thus confirming its utility for real-time environmental remediation applications.

Physical properties with high specific loss power of magnetite (Fe3O4) synthesized via thermal decomposition technique

Magnetic iron oxide nanoparticles have versatile applications in biomedical science that require control over shape and size distribution. Thermal decomposition is one of the best methods for controlling the size and shape of produced nanoparticles (NPs). The size distribution can be tuned (5–30 nm) by varying the reaction environment such as precursor concentration, amount of solvent used, temperature ramp, and reflux time. Iron oleate was used as a precursor solution and heated up to reflux temperature (310 °C) for 10 min within the oxygen-free environment by applying N2 gas flow. The XRD pattern confirmed the formation of NPs with a crystallite size of 17 ± 2.45 nm. Transmission electron microscope images showed moderately cubic shapes with a mean particle size of 28.67 ± 7.12 nm. Magnetic properties such as saturation magnetization, coercivity, and remanence were calculated at 23.48 emu/gm, 33 Oe, and 0.6 emu/gm, respectively, which indicated the ferromagnetic nature of the NPs. The Verwey transition was identified from the magnetization vs temperature (FC-ZFC) plot. The bondings of the oleic acid surfactant with the produced NPs were confirmed from Fourier transformation infrared spectroscopy (FTIR) data analysis. For the application of hyperthermia, the hydrophobic phase was transferred to the hydrophilic phase using cetyltrimethylammonium bromide, which was assured by the FTIR data analysis. The hyperthermia heating of NPs was measured for different concentrations of NPs (0.25, 0.5, 1, 2, and 4 mg/ml), from which specific loss power (SLP) was calculated. Among them, 0.25 mg/ml produced the most prominent SLP (2149 ± 309 w/g) that can be applied for targeted cancer treatment.

3,4-Dihydroxiphenylacetic Acid-Based Universal Coating Technique for Magnetic Nanoparticles Stabilization for Biomedical Applications.

Magnetic nanoparticles based on iron oxide attract researchers' attention due to a wide range of possible applications in biomedicine. As synthesized, most of the magnetic nanoparticles do not form the stable colloidal solutions that are required for the evaluation of their interactions with cells or their efficacy on animal models. For further application in biomedicine, magnetic nanoparticles must be further modified with biocompatible coating. Both the size and shape of magnetic nanoparticles and the chemical composition of the coating have an effect on magnetic nanoparticles' interactions with living objects. Thus, a universal method for magnetic nanoparticles' stabilization in water solutions is needed, regardless of how magnetic nanoparticles were initially synthesized. In this paper, we propose the versatile and highly reproducible ligand exchange technique of coating with 3,4-dihydroxiphenylacetic acid (DOPAC), based on the formation of Fe-O bonds with hydroxyl groups of DOPAC leading to the hydrophilization of the magnetic nanoparticles' surfaces following phase transfer from organic solutions to water. The proposed technique allows for obtaining stable water-colloidal solutions of magnetic nanoparticles with sizes from 21 to 307 nm synthesized by thermal decomposition or coprecipitation techniques. Those stabilized by DOPAC nanoparticles were shown to be efficient in the magnetomechanical actuation of DNA duplexes, drug delivery of doxorubicin to cancer cells, and targeted delivery by conjugation with antibodies. Moreover, the diversity of possible biomedical applications of the resulting nanoparticles was presented. This finding is important in terms of nanoparticle design for various biomedical applications and will reduce nanomedicines manufacturing time, along with difficulties related to comparative studies of magnetic nanoparticles with different magnetic core characteristics.

Autonomous Materials Synthesis Strategies Towards Accelerated Discovery of Novel Functional Nanomaterials for Green Energy Production

Electrocatalysts designed by alloying two or more elements (e.g., transition metals) showed promising enhancement in catalytic activity and durability due to synergistic effects from alloying, such as strain engineering or electron exchange. The potential of the alloying approach is constrained by standard synthesis methods (e.g., wet chemistry and thermal decomposition techniques) due to the governing thermodynamics rules (e.g., miscibility of the different alloying elements). That renders the synthesis of high entropy alloys (HEA), with more than 3 elements, to be complicated and tedious to achieve by those conventional methods.In the presented talk we are presenting different strategies to synthesize metastable high entropy alloys (HEA) and their outstanding catalytic performance towards OER, in correlation to their unique chemistries and structures. Rapid cycling of temperature from room 25 °C to highly elevated levels (1700 °C), in conjunction with ultra-rapid cooling, within milli-second range have been demonstrated by different methods including rapid Joule heating, Intense light flashing, and microwave plasma shock. Our results show successful synthesis of non-noble metals HEA NPs, possessing higher catalytic activity than IrO2 catalyst for OER. The nature of the alloying elements dictates OER activity by promoting different oxidation states of the catalytically active transition metals (e.g., Fe, Ni and Co). In addition, a phenomenal in-situ chemical welding of HEA NP to carbon support, yielded HEA catalysts with two orders of magnitude longer durability than IrO2. Our developed techniques resulted in formation of super-strong metal-carbide bonds “chemically welding” HEA NP to the catalyst support.Synthesis of various HEA catalyst and their electrocatalytic performance screening has been carried out by using liquid handler robots and multi-axes robotic arm systems. Moreover, to optimize the design of materials (structure and chemistry), we are using active learning techniques to evaluate the achieved performance results by applying Gaussian process, followed by applying Bayesian Optimization techniques to propose novel chemistries and structures with a higher probability to achieve further improved performances. The presented the study does not open the door only towards developing novel catalysts for energy production. However, it presents a strategy with multiple successfully demonstrated platforms towards accelerated discovery of novel materials. The high-throughput nature of the synthesis protocols presented in this talk can produce tens of thousands of different novel chemistries, at the same time taken by conventional methods to synthesize just a few, at a minimal energy consumption, cost, and manpower.

High Entropy Oxides Synthesis by Rapid Plasma Generation with Applications Towards Electrocatalytic Hydrogen Generation

It has been challenging over the past three decades to find viable energy alternatives with higher efficiency and lower cost to beat the non-friendly and commercially dominant hydrocarbon energy sources. Hydrogen is deemed to be one of the most prominent candidates, as a green fuel. Hydrogen can be generated in abundance from water splitting. Utilization of hydrogen in fuel cells, with no doubt, produces no harmful gases. Nevertheless, the two parts of the technology: hydrogen production and reduction are cumbersome. Both processes rely on kinetically sluggish electrocatalytic reactions. Enormous research efforts have been spent, with thousands of studies presented in literature, despite the technology left with a dim light shed on from commercial and practical point of views. Many materials-related challenges are hindering the flourishing of green hydrogen technology, where poor catalyst durability is a major challenge, despite being made from very expensive elements (e.g., Ir, ru or Pt). Therefore, gigantic effort of research has been devoted to find inexpensive alternatives. Transition metals showed interesting performance towards water splitting (e.g., oxygen evolution (OER)).Recent research showed that electrocatalysts designed by alloying two or more elements (e.g., transition metals) showed promising enhancement in catalytic activity and durability due to synergistic effects from alloying, such as strain engineering or electron exchange. The potential of the alloying approach is constrained by standard synthesis methods (e.g., wet chemistry and thermal decomposition techniques) due to the governing thermodynamics rules (e.g., miscibility of the different alloying elements). That renders the synthesis of high entropy alloys (HEA), with more than 3 elements, to be complicated and tedious to achieve by those conventional methods.In the presented talk we are presenting the utilization of microwaves to generate plasma to synthesize metastable high entropy oxides (HEA) and their outstanding catalytic performance towards OER, in correlation to their unique chemistries and structures. Plasma generated enable temperature increase of the precursor substrate to elevated levels (~1000s °C), in conjunction with rapid cooling, within seconds range. Our results show successful synthesis of non-noble metals HEA NPs, possessing higher catalytic activity than IrO2 catalyst for OER. The nature of the alloying elements dictates OER activity by promoting different oxidation states of the catalytically active transition metals (e.g., Fe, Ni and Co). Our developed techniques resulted in formation of super-strong metal-carbide bonds “chemically welding” HEA NP to the catalyst support.

Reaction time-induced improvement in hyperthermia properties of cobalt ferrite nanoparticles with different sizes

Chemical reaction conditions involved in the formation of nanoscale materials can enormously affect their properties. However, the correlation between the reaction time (RT) and hyperthermia properties of magnetic nanoparticles (MNPs) is yet to be understood. Here, we synthesize cobalt ferrite magnetic nanoparticles (MNPs) using a thermal decomposition technique with different RT values. The variation in RT (70–180 min) is designed in such a way that the nucleation and growth process can be affected and improved considerably, achieving monodisperse spherical-like MNPs with superparamagnetic nature as confirmed by first-order reversal curve analysis. Hyperthermia properties are studied for cobalt ferrite MNP ferrofluids with different concentrations (1–5 mg/ml) at various magnetic field strengths (100–400 Oe). We obtain a maximum specific loss power (SLP) value of 510 W/g for MNPs synthesized using RT = 150 min. By extracting magnetic characteristic, we find a correlation between SLP and coercive field values as a function of RT, which can shed light on subtle changes in hyperthermia properties of MNPs.

Adsorption of organic dyes by Fe<sub>3</sub>O<sub>4</sub>@C, Fe<sub>3</sub>O<sub>4</sub>@C@C, Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub> magnetic nanoparticles

The Fe3O4@C, Fe3O4@C@C, and Fe3O4@SiO2 core-shell nanoparticles were synthesized using thermal decomposition and co-precipitation techniques and characterized by X-ray spectroscopy, transmission electron microscopy and magnetometry. It is shown that the magnetic core of all nanoparticles is nanocrystalline with crystal parameters corresponding to only one Fe3O4 phase, which is covered with a uniform shell of amorphous carbon or silicon oxide about 8 nm thick. The main attention was paid to the adsorption properties of nanoparticles with respect to four dyes: methylene blue, Congo red, eosin Y, and rhodamine C. The high selectivity of Fe3O4@C nanoparticles with respect to various dyes was revealed.

Synergistic effect in g-C3N4/CuO nanohybrid structures as efficient electrode material for supercapacitor applications

A facile thermal decomposition and hydrothermal techniques were used to fabricate g-C3N4/CuO nanohybrid electrode material. The pure g-C3N4, CuO and g-C3N4/CuO nanohybrid composites were confirmed by powder X-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and Fourier-transform infrared spectroscopy (FTIR). The g-C3N4/CuO electrode material exhibited a specific capacitance of 98F/g which is substantially higher than those using bare CuO (40F/g) and bare g-C3N4 electrodes (62F/g). Cycle-life data for over 2500 cycles reflect 19 % capacitance degradation for g-C3N4/CuO nanohybrid material. The energy density given by g-C3N4/CuO, CuO and g-C3N4 devices is 14.8 W h kg−1, 5 W h kg−1 and 6.3 W h kg−1 respectively. The enhanced electrochemical performance of the nanohybrid material is ascribed to synergistic effect and pseudo capacitive nature of the metal oxide nanoparticles incorporated in the g-C3N4 matrix.

2D-layered Bi-functional direct solid-Z-scheme heterogenous vanadium and oxygen doped graphitic carbon nitride single layered nanosheet catalysis for detection and photocatalytic removal of toxic heavy metal

In this Research, the “Get the two Mangoes with one stone” strategy was utilized to investigate the electrochemical detection and photocatalytic removal of mercury ions (Hg2+) using vanadium pentoxide doped graphitic carbon nitride (V2O5/gCN) nanosheets for the first time. The proposed materials can be better choice for environmental issues. In this research, a novel direct Z-scheme V2O5/gCN nanosheets were prepared through direct thermal decomposition techniques with the different (0.1–0.5 wt%) weight ratios of dopant materials. The prepared nanosheets physiochemical properties can be obtained through various characterizations techniques. Moreover, the prepared nanosheets exhibit an excellent electrochemical ability for the detection of Hg2+ ions with a limit of detection is 9.2 nM, linear range from 0.2 to 100 μM, and enormous sensitivity (9.9857 μA μM−1 cm−2), respectively. Furthermore, the higher photocatalytic removal efficiency was obtained in this optimized dopant (0.2 wt%) concentration of V2O5-doped gCN nanosheets. In addition, the complete removal was obtained within a short treatment time under the visible light irradiation. Furthermore, the target (Hg2+) ions removals are quantified by ICP-OES, and quantification values were found to be 2762 ppm and 101 ppm before and after treatments, respectively. Therefore, this research work will be beneficial for the design of direct Z-scheme photo-electrocatalytic systems for application in real-time detection and environmental remediation.

Production of biodiesel from waste cooking oil using mesoporous MgO-SnO2 nanocomposite

Mesoporous, bifunctional MgO-SnO2 nanocatalysts with enhanced surface area are used for producing biodiesel from waste cooking oil. Biodiesel with yield of 80% is achieved within the first 20 min when transesterification is carried out at an optimum condition of 18:1 methanol to oil ratio, 2 wt% of nanocatalyst, and at a reaction temperature of 60 °C. The conversion gives a maximum yield of 88% when transesterification is allowed to continue for 120 min. The waste cooking oil used in this work is dominated with linoleic acid and oleic acid, which during transesterification gets converted into methyl linoleate and 9-octadecenoic acid methyl ester. These nanocatalysts are fabricated using a composite of rutile (tetragonal) phase SnO2 and cubic phase MgO nanostructures with prominent crystal orientation along [211] and [200] plane respectively. The MgO-SnO2 nanocomposites with an enhanced surface area of 31 m2/g, basic sites of 2 mmol/g, and particle size of ~15 nm are synthesized by novel sequential thermal decomposition and sol-gel technique. The synthesized wide band gap nanocomposites have Mg and Sn in the ratio of 15:1 and do not have any impurity phases as observed in the X-ray diffraction pattern and EDS spectrum. The presence of surface oxygen states and Mg2+ and Sn4+ oxidative states is responsible for the catalytic activity and recyclability displayed by the composites. This work signifies the role of nanocomposites and their synthesis conditions in improving the rate of transesterification. These metal oxide nanocomposites which are nontoxic, stable, cost effective, and easier to synthesis are promising catalysts for large-scale transesterification of waste cooking oil to biodiesel.

Surface-engineered CuFeS2/Camptothecin nanoassembly with enhanced chemodynamic therapy via GSH depletion for synergistic photo/chemotherapy of cancer

Constructing the antitumor agents that are responsive to reactive oxygen species (ROS) have received considerable interest owing to their low drug resistance, high lethality of cytotoxic radicals such (•OH, •O2-, 1O2), and ease of combining with other therapeutic strategies. In this work, ROS-mediated therapies of quasi-spherical chalcogenide, CuFeS2 nanoparticles (NPs) were reported. Firstly, CuFeS2 NPs capped with oleylamine-capping agent were synthesized using the thermal decomposition technique, and surface modification was accomplished by micelles formation using an amphiphilic copolymer, pluronic 127 (PF127), to improve the water dispersibility of CuFeS2 NPs. The resulting material, CFS@PF nanoassembly, exhibited good dispersibility in an aqueous solution, which was attributed to the PF127 copolymer's hydrophilic property. Due to their strong absorption spectra in the near-infrared region (NIR), CFS@PF nanoassembly demonstrated remarkable photothermal conversion efficiency (PCE) of 63.3% upon NIR laser irradiation for photothermal therapy (PTT), which might induce hyperthermia in cancer treatment. Furthermore, CFS@PF nanoassembly could efficiently trigger not only singlet oxygen (1O2) under laser illumination for photodynamic therapy (PDT), but also cytotoxic hydroxyl radical (•OH) in the presence of peroxide solution (H2O2) for chemodynamic therapy (CDT) via Fenton reaction. Interestingly, the intracellular antioxidant, glutathione (GSH), could be effectively depleted via Cu–Fe-induced redox reaction, hence enhancing the efficacy of ROS-mediated therapeutics. In vitro experiments verified that CFS@PF NPs were more biocompatible with B16F1 and HeLa cells, but also exhibited substantial toxicity in the presence of laser and H2O2, resulting in 80% cell death through CDT/PDT/PTT synergistic effects. More crucially, CFS@PF micelles are employed in drug delivery for loading of Camptothecin (CPT), generating a CFS@PF/CPT nanoassembly for chemotherapy with a loading efficiency of 46.42%, and CPT release at various pH conditions was examined. The results of the cell experiments indicated that drug pairings boost tumor-killing performance by up to 90% due to the synergistic effect of CDT/PTT/chemotherapy. Overall, this study explored CFS@PF/CPT NPs, which might be potential anticancer agents for cancer therapy in the future of nanomedicine.

Impact of Sm2O3 onthe Morphological, Optical, Magnetic, and Pesticide Adsorption of Co3O4/PANI Hybrid Nanocomposites

Adsorption is one of the most favored procedures in advanced wastewater treatment. Magnetic hybrid materials have a great adsorption performance and excellent reusability in the industry. For this reason, the amazing roles of Sm2O3 doping on Co3O4/PANI hybrid nanocomposite materials were studied. Co3O4 nanoparticles were synthesized using the thermal decomposition technique where Sm2O3 doped Co3O4/ PANI hybrid nanocomposite materials were prepared via in situ oxidative polymerization. The X-ray analysis, technique results confirm the successful formation of neat Co3O4 nanoparticles with cubic phase and its presence in emeraldine phase of PANI matrix. X-ray reveals that the crystallinity of hybrid nanocomposite materials increases with increasing Sm2O3 doping ratio. HRTEM showed polycrystalline structure of Co3O4 nanoparticles and that the doped Sm2O3 was well incorporated and dispersed within the PANI matrix. The surfaces topography was studied by FESEM. UV–Vis diffuse reflectance spectrum revealed two characteristic bands of PANI that are shifted towards higher wavelengths with Sm2O3 doping ratio. The calculated indirect energy gaps were found to decrease from 2.83–2.56 eV which indicates a good response of the hybrid nanocomposite materials to the effect of the UV absorption. The magnetic properties of the investigated samples are measured by VSM. Ms was found to decrease with increasing Sm2O3, while Hc increase with Sm2O3 ratio which will hinder the domain walls motion. Adsorptive removal of chlorpyrifos could be ascribed as pseudo-second ordered and Langmuir model. The maximum adsorptive capacity was 36.9, 47.11, 63.8, and 83.03, 96.73 mg/g for PANI, Co3O4/PANI, Co3O4/PANI-2 wt% Sm2O3, Co3O4/PANI/−4 wt% Sm2O3, and Co3O4/PANI-6 wt% Sm2O3hybridnanocomposite materials, respectively.

Kinetic of the Oxygen and Chlorine Evolution Reaction on Platinum Electrodes at Neutral pH

The platinum anode modified by metal oxides electrodes degrades Abidjan wastewater which contains a high concentration of Cl-. During this degradation process, the organic polluants are oxidized, O2 and Cl2 are produced. The purpose of this study is to contribute to the understanding of these reaction mechanisms by studying the kinetics of O2 and Cl2 evolution at neutral pH on Pt. The study was performed by interpreting the voltammograms and Tafel slopes obtained. The voltammetric measurements were carried out using an Autolab Potentiostat from ECHOCHEMIE (PGSTAT 20) connected by interface to a computer. Pt electrode was prepared on titanium (Ti) substrate by thermal decomposition techniques at 400°C. The characterization of the surface of the prepared electrode by scanning electron microscopy and X-ray photoelectron spectrometry showed the presence of platinum on its surface. The results obtained show that the OH· are adsorbed on the active sites of Pt. Then they react to form PtO. Then by reaction between the surface oxygen and PtO, O2 is produced and the active sites are regenerated. In the presence of low Cl- concentration, there is a competition between the Cl2 and O2 evolution reactions. However, Cl2 only is produced for high Cl- concentrations. The kinetics of the evolution reaction of chlorine increases with the concentration of Cl- and remains constant for concentrations greater than 0.5 M. This study also showed that the chlorine reduction reaction produced in solution is a diffusion-controlled reaction for low scan rates.