In the present work we report the sol-gel synthesis of pure TiO₂ and (TiO₂)_1−x(Fe₂O₃)_x nanocomposites with different Fe₂O₃ contents (x = 0, 0.1, 0.5, and 1.0 for pure TiO₂, Fe₂O₃ incorporated 0.1, 0.5, and pure Fe₂O₃ which are denoted as PT, 0.1F, 0.5F, and PF, respectively). The structural, morphological, optical, and surface texture of the prepared nanocomposites were characterized using various techniques. The structural studies confirm the strong influence of Fe₂O₃ contents on the crystallite sizes and dislocation values. The size of the crystallites was increased by the increase in Fe₂O₃ contents. The bandgap values elucidated from DRS analysis were decreased from 3.15 eV to 1.91 eV with increasing Fe₂O₃ contents. The N₂-Physorption analysis has confirmed the mesoporous nature of the samples with a comparable specific surface area of 35 m²/g. The photoelectrochemical measurements (CV, CA and EIS) were performed to assess the photoelectric properties of the prepared materials. It was found that the PT samples have the highest catalytic activity and photocurrent response compared to other composites. The reduction in current density was as follows: 2.8, 1.65, 1.5 and 0.9 mA/cm², while the photocurrent response was ca. 800, 450, 45, 35 µA/cm² for PT, 0.1F, 0.5F and PF samples, respectively. The EIS results showed that the (TiO₂)_1−x(Fe₂O₃)_x nanocomposites exhibit lower charge transfer resistance than pure titania and hematite samples.

Fischer–Tropsch has become an indispensable choice in the gas-to-liquid conversion reactions to produce a wide range of petrochemicals using recently emerging biomass or other types of feedstock such as coal or natural gas. Herein we report the incorporation of novel Cu nanoparticles with two Fischer–Tropsch synthesis (FTS) catalytic systems, Fe/reduced graphene oxide (rGO) and Fe–Mn/rGO, to evaluate their FTS performance and olefin productivity in two types of reactors: slurry-bed reactor (SBR) and fixed-bed reactor (FBR). Four catalysts were compared and investigated, namely Fe, FeCu₇, FeMn₁₀Cu₇, and FeMn₁₆, which were highly dispersed over reduced graphene oxide nanosheets. The catalysts were first characterized by transmission electron microscopy (TEM), nitrogen physisorption, X-ray fluorescence (XRF), X-ray diffraction (XRD), and H-TPR techniques. In the SBR, Cu enhanced olefinity only when used alone in FeCu₇ without Mn promotion. When used with Mn, the olefin yield was not changed, but light olefins decreased slightly at the expense of heavier olefins. In the FBR system, Cu as a reduction promoter improved the catalyst activity. It increased the olefin yield mainly due to increased activity, even if the CO₂ decreased by the action of Cu promoters. The olefinity of the product was improved by Cu promotion but it did not exceed the landmark made by FeMn₁₆ at 320 °C. The paraffinity was also enhanced by Cu promotion especially in the presence of Mn, indicating a strong synergistic effect. Cu was found to be better than Mn in enhancing the paraffin yield, while Mn is a better olefin yield enhancer. Finally, Cu promotion was found to enhance the selectivity towards light olefins C2–4. This study gives a deep insight into the effect of different highly dispersed FTS catalyst systems on the olefin hydrocarbon productivity and selectivity in two major types of FTS reactors.

Rational design and fabrication of effective multi-component cocatalyst for high performance photocatalytic hydrogen production via water-splitting have been investigated. Herein, polyaniline-derived N-doped carbon encapsulated copper/copper phosphide nanoparticles (Cu/Cu_xP@NC) was facilely prepared by a single-step phosphorization-pyrolysis route. Homologous Cu/Cu_xP heterostructure with a diameter ∼ 20 nm was successfully wrapped with N-doped carbon layers. The resultant Cu/Cu_xP@NC is utilized as a cocatalyst of host photocatalysts like TiO₂ and g-C₃N₄ for H₂ generation. The optimal Cu/Cu_xP@NC/TiO₂ composites exhibited a hydrogen evolution rate (HER) of 12.45 mmol.h⁻¹ g⁻¹ which is 145-fold higher than TiO₂ alone. Interestingly, the Cu/Cu_xP@NC composite also improved the activity of g-C₃N₄ to produce 285 µmol.h⁻¹ g⁻¹ of H₂ under visible light where no H₂ was evolved over pure g-C₃N_4. The photocatalytic performance of the presented Cu/Cu_xP@NC/TiO₂ was superior than carbon-free Cu/Cu_xP/TiO₂ nanocomposite. Such improved activity is attributed to the N-doped carbon layer that plays a pivotal role in suppressing the recombination of the photogenerated electron-hole pairs. Thus, Cu/Cu_xP@NC cocatalyst composite can efficiently capture the photoexcited electrons from the conduction band of TiO₂ or g-C₃N₄, accelerating the charge separation process. This study provides a low-cost and competitive cocatalyst to substitute noble metals in photocatalytic reactions.

Photocatalytic Hydrogen production via water splitting is considered a sustainable ecofriendly pathway to replenish the current and future energy demands. In this study, the self-assembly synthesis of Cu nanospheres (∼8 nm) surrounded by a thin conductive layer of polyaniline (Cu@PANI) was rationally engineered via in˗situ polymerization. Afterward, it was successfully deposited onto the TiO₂ surface to improve the photocatalytic activities for hydrogen production. The optimal Cu@PANI/TiO₂ ternary photocatalyst produced a substantial hydrogen generation rate (HGR) of 17.7 mmol h⁻¹ g⁻¹, 207-fold higher than that of bare TiO₂. The performance was considerably improved compared with (Cu–TiO₂)/PANI and (PANI-TiO₂)/Cu composites prepared by changing the deposition sequence of Cu and PANI. Such an improved activity was because of multiple transferring paths of photogenerated electrons in the composite. Interestingly, the as-prepared ternary photocatalyst exhibited superior hydrogen evolution compared with the binary hybrids (Cu/TiO₂ and PANI/TiO₂). The exceptional performance of Cu@PANI/TiO₂ could be understood considering the distinctive electrical conductivity of PANI and heterojunction formed between PANI and TiO₂, as well as the merits of the Schottky junction constructed between Cu and PANI. These superior features could efficiently suppress the recombination rate of the photogenerated electron–hole pairs and maximize the photocatalytic activity. This study provides new insights for understanding the effect of electron transfer pathways on photocatalytic activities.

The charge simulation technique (CST) was applied for computing the electric field in long space-charge-free rod-to-plane gaps with G (=gap-spacing to rod-radius) ratio in the range of 50-500. In this article, a new formation of CST is proposed for computing the electric field in short positively stressed rod-to-plane gaps characterized by G in the range of 2-160 and gap spacing up to 8 cm, provided that the gap can accommodate space charges. This is a prerequisite for computing the inception voltage of different corona modes, including burst pulses (BP), onset streamers (OS), and positive glow (PG). The criteria developed before for computing the inception voltage of BP and OS are refined for short rod-to-plane gaps. However, the inception criterion for PG cannot be extended to short gaps. A method is proposed for calculating the inception voltage of PG in short rod-to-plane gaps in the air at room temperature. The initiatory electrons for burst avalanches are produced by photoionization inside the ionization zone rather than by detachment of negative ions as experienced in long gaps. The resulting BP merges in time to form the steady glow at the rod surface in conformity with Loeb's postulate. The computed inception voltage of BP, OS, and PG agreed reasonably with those measured experimentally for short rod-to-plane gaps.

This study targeted to examine the protective effects of acetovanillone (AV) against methotrexate (MTX)-induced hepatotoxicity. Thirty-two rats were allocated into four groups of eight animals; Group 1: Normal; Group 2: administered AV (100 ml/kg; P.O.) for 10 days; Group 3: challenged with MTX (20 mg/kg, i.p; single dose); Group 4: administered AV 5 days before and 5 days after MTX. For the first time, this study affords evidence for AV's hepatoprotective effects on MTX-induced hepatotoxicity. The underlined mechanisms behind its hepatic protection include counteracting MTX-induced oxidative injury via down-regulation of NADPH oxidase and up-regulation of Nrf2/ARE, SIRT1, PPARγ, and cytoglobin signals. Additionally, AV attenuated hepatic inflammation through down-regulation of IL-6/STAT-3 and NF-κB/AP-1 signaling. Network pharmacology analysis exhibited a high enrichment score between the interacting proteins and strongly suggested the intricate and essential role of the target proteins regulating MTX-induced oxidative damage and inflammatory perturbation. Besides, AV increased the in vitro cytotoxic activity of MTX toward PC-3, HeLa, and K562 cancer cell lines. On the whole, our investigation suggested that AV might be regarded as a promising adjuvant for the amelioration of MTX hepatotoxicity and/or increased its in vitro antitumor efficacy, and it could be used in patients receiving MTX.

Luminescent coatings have several exciting applications. Polymers have been reported as both corrosion inhibitors and luminescent materials. Mild steel corrosion is a major economic problem. Moreover, full-color luminescence from one material is a hot research topic due to the advantages of such materials. Here, some liquid crystal polymers (LCPs) have been checked as corrosion inhibitors of mild steel in an acidic medium (1.0 M H₂SO₄) through potentiodynamic polarization techniques. The LCPs showed high anticorrosion efficiency depending on their structure. These LCPs were confirmed as mixed-type inhibitors. Furthermore, the studied LCPs have aggregation-induced emission behavior with controlled emission colors (blue, white, and green) via adjusting the solution concentration. The molecular aggregation changed according to the solution concentration, and thus the relative emission intensity was …

n the present work, sulfacetamide (SFA)-modified glassy carbon electrode (MGCE) was successfully constructed by electrochemical modification applying simply cyclic voltammetry (CV) scans. It is well observed that the excellent electrocatalytic ability of SFA film led to much higher oxidation peak current responses compared with bare GCE for epinephrine (EP) oxidation. The EP oxidation takes place at a potential about 120 mV less positive compared with that of an unmodified GCE at the optimum pH 5.5 of phosphate buffer solution (PBS). Applying the anodic stripping differential pulse voltammetry (ASDPV) method and under the optimum conditions, the linear dependence of oxidation peak current on analyte concentrations was found to be (1.0 x10-7-1.5 x10-6) mol L-1, giving detection limit of 2.1 x10-8 mol L-1 and quantification limit of 6.9 x10-8 mol L-1 for EP. The proposed modified electrode exhibited excellent selectivity in the presence of ascorbic acid (AA), glucose (Glu) and uric acid (UA) species whereas dopamine (DA) interfere seriously at higher concentrations. The proposed method showed simplicity, reproducibility, high sensitivity and adequate selectivity. The modified electrode was successfully devoted to EP determination in pharmaceutical formulations and biological fluids; human plasma and urine with acceptable results.

A new method based on the charge simulation technique is proposed for computing the electric field in a short uniform field gap with space charge and without space charge of avalanches growing in the gap. The self-space-charge field of the avalanche is evaluated to result in field enhancement ahead of the avalanche due to electrons at its head and behind the avalanche due to positive ions in its wake. Also, a criterion is proposed for calculating the breakdown voltage and time-to-breakdown when the primary avalanche crosses the gap. The criterion is based on self-recurrence of the avalanche by secondary processes, and the most dominant one is the photoemission at the cathode. The condition of transition of the primary avalanche to anode- and cathode-directed streamers is formulated where the avalanche is chocked by its self-space-charge field. The number of electrons starting avalanche chains forming the streamers is evaluated in the gas ahead and behind the primary avalanche by photoionization and at the cathode by photoemitted electrons. The present computed values of the breakdown voltage of air at different pressures and N2 at atmospheric pressure as well as the time-to-breakdown in air at atmospheric pressure agree satisfactory with those recorded experimentally. The computed temporal variation of the size of the primary avalanche as influenced by its self-space-charge field agrees with that reported in the literature at different E/N values. The computed current waveforms of the primary avalanche and its successor chains agree reasonably with those measured and those calculated using a finite-element method.

Catalytic esterification of acetic acid with iso-amyl, benzyl, and cinnamyl alcohols in the liquid phase over unmodified natural silica catalyst has been studied. The virgin and calcined catalysts were characterized by thermal analyses (Thermogravimetry (TG) and diffrential thermal analysis (DTA)), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and N₂ sorption analyses. The acidity of natural silica catalysts was investigated using isopropyl alcohol dehydration and chemisorption of pyridine and dimethyl pyridine. The results indicated that most of the acidic sites are of Brϕnsted type and of intermediate strength. The effect of different parameters such as reaction time, molar ratio, catalyst dosage, and calcination temperature was studied. Natural silica catalyst exhibited excellent catalytic performance with a selectivity of 100% to acetate esters formation. The maximum yields of isoamyl, benzyl, and cinnamyl acetate esters obtained in the batch conditions were 80, 81, and 83%, respectively. Whereas on adopting a simple distillation technique, these yields were successfully improved to higher values of 97, 98, and 90%, respectively. Experimental results manifested that the reaction followed Langmuir–Hinshelwood mechanism. Finally, the catalyst could be completely recycled without loss of its activity after four cycles of the esterification reactions.