The development of a mild, general, and green method for the C-H arylation of pyrazoles with relatively unreactive aryl halides is an ongoing challenge in organic synthesis. We describe herein a novel sonophotoreactor based on an ultrasonic cleaning bath and blue LED light (visible light) that induce copper-catalyzed monoarylation for pharmacologically relevant pyrazoles. The hybrid effect of ultrasonic irradiation and blue LED is discussed to interpret the observed synergistic action. A broad array of pyrazoles coupled with iodobenzene avoids expensive palladium metal or salts, and certain designed substrates were attained. Only comparatively inexpensive copper(I)iodide and 1,10-phenanthroline were used all together as the catalyst. The presented technique is a greener way to create C-H arylation of pyrazoles. It significantly reduces the amount of energy needed. Full article

Zileuton (ZLT) is an active oral inhibitor of enzyme 5-lipoxygenase, and long-term intake and overdose of ZLT cause adverse effects, leading to critical conditions in patients. This is a well-recognized issue that necessitates a better approach for ZLT sensing. Given the increasing interest in ZLT sensing and the limitations of previous techniques, there is a need for a highly sensitive, robust, and fast operation method that is inexpensive and easy to use. Thus, for the sensitive detection and determination of ZLT, an electrochemical sensor based on graphene was fabricated. Graphene has excellent properties, such as high surface area, low toxicity, conductivity, and electroactive conjugation with biomolecules, making it suitable for sensing. The electrocatalytic property of graphene promotes the redox-coupled reaction of ZLT. Electrochemical investigation of the modifier was carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). An optimization and analysis of the influence of different parameters on the electrochemical behavior of ZLT were carried out using the CV approach. The scan rate study aided in exploring the physicochemical properties of the electrode process, and two electrons with two protons were found to be involved in the electrooxidation of ZLT. The fabricated sensor showed a wide range of linearity with ZLT, from 0.3 µM to 100.0 µM, and the detection limit was evaluated as 0.03 µM under optimized conditions. The analysis of spiked urine samples, with good recovery values for percent RSD, provided support for the efficiency and applicability of the developed electrode. Full article

Highly ordered TiO₂ nanotubes (TNTs) decorated with a series of lanthanide ions (Ln³⁺ = Ho³⁺, Tb³⁺, Eu³⁺, Yb³⁺, and Er³⁺) were prepared through an electrochemical process and anodization. The composition, structure, and chemical bond of the as-prepared photocatalysts were characterized through scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and ultraviolet diffuse reflectance spectroscopy. Furthermore, the electrochemical characteristics of the catalysts were analyzed and photoelectrochemical properties were investigated through water splitting. All samples were prepared in the anatase phase without changing the crystal structure. The holmium-doped TNT photocatalyst exhibited the best performance with a hydrogen evolution rate of 90.13 μmol cm⁻²h⁻¹ and photoconversion efficiency of 2.68% (0 V vs. RHE). Photocatalytic efficiency increased because of the expansion of the absorption wavelength range attributed to the appropriate positioning of the band structure and reduced electron/hole pair recombination resulting from the unhindered electron movement. This study demonstrated the preparation of high-potential solar-active photocatalysts through the synergetic effects of the work function, band edge, and bandgap changes caused by the series of lanthanide combinations with TNTs. Full article

Single-phase oxygen stoichiometric LaMnO₃ and doped La_0.8A_0.2MnO₃ (A = Ca, Sr, Ba) perovskites have been prepared by a simple one-step auto-combustion method. Cation-deficient LaMnO_3+δ and La_0.8A_0.2MnO_3+δ were obtained by calcination of the former samples in air at 750 °C. The samples were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction, temperature-programmed oxygen desorption, and N₂ physisorption in order to apply them as catalysts in the complete catalytic oxidation of acetone as a model volatile organic compound. The studied phases show the expected orthorhombic and rhombohedral perovskite crystal structures. Catalytic experiments performed with all the samples show measurable activity already at 100 °C. At 200 °C, doped La_0.8A_0.2MnO₃ samples show higher activity than undoped LaMnO_3, with increasing conversion with larger A-cation size. Calcined samples also show higher activity than as-prepared ones making La_0.8Ba_0.2MnO_3+δ the best catalyst at this temperature. All doped samples show >95% acetone conversion at T ≥ 250 °C with a weak dependence on the sample processing or A cation doping. The collected evidence confirms that the most important factors for the catalytic activity of these oxides are the Mn⁴⁺/Mn³⁺ molar ratio on the surface of the samples and the cation-deficiency of the bulk perovskite structure. In addition, increasing the symmetry of the bulk crystal structure appears to have an additional favourable effect. Despite the observation of the presence of surface carbonates, we show that it is possible to use the as-prepared samples without further thermal treatment with good results in the oxidation of acetone. Full article

In propylene (C3) polymerization with Ziegler-Natta catalyst, not only internal donor but also external donor is very important to make isotactic polypropylene (PP) with higher yield. Most propylene-based polymers have been commercially produced with Ziegler-Natta catalysts combined with dialkyl-dialkoxy silane compounds (R₂Si(OR)₂) such as C-donor, P-donor, and D-donor as external donors. In this paper, we will introduce the propylene polymerization performance with aminosilane compounds, i.e., diethylamino triethoxy silane (U-donor) and bis(ethylamino) di-cyclopentyl silane (T01 donor), as external donor in Ziegler–Natta catalyst. The polymerization screening experiments were conducted using some triethoxyalkylsilanes compounds (1–7) and performances were compared with U-donor. The polymerization results of the binary donor system show improvement in stereoregularity. These aminosilane compounds exhibit high hydrogen response in propylene polymerization and high copolymerization performance of propylene (C3) and ethylene (C2) in ICP production compared with dialkyl-dialkoxy silane compounds. While using methanol as an additive along with external electron donor, as a serendipitous, the copolymerization activity, block ratio, EPR (ethylene-propylene rubber) content improve significantly for U-donor as compared with T01 donor and C-donor. Full article

Linear free−energy scaling relationships (LFESRs) and regression analysis may predict the catalytic performance of heterogeneous and recently, homogenous water oxidation catalysts (WOCs). This study analyses thirteen homogeneous Ru−based catalysts—some, the most active catalysts studied: the Ru(tpy−R)(QC) and Ru(tpy−R)(4−pic)₂ complexes, where tpy is 2,2’;6’,2”terpyridine, QC is 8−quinolinecarboxylate and 4−pic is 4−picoline. Typical relationships studied among heterogenous catalysts cannot be applied to homogeneous catalysts. The selected group of structurally similar catalysts with impressive catalytic activity deserves closer computational and statistical analysis of multiple reaction step energetics correlating with measured catalytic activity. We report general methods of LFESR analysis yield insufficiently robust relationships between descriptor variables. However, volcano−plot−based analysis grounded in Sabatier’s principle reveals ideal relative energies of the Ru^IV = O and Ru^IV−OH intermediates and optimal changes in free energies of water nucleophilic attack on Ru^V = O. A narrow range of Ru^IV−OH to Ru^V = O redox potentials corresponding with the highest catalytic activities suggests facile access to the catalytically competent high−valent Ru^V = O state, often inaccessible from Ru^IV = O. Our work incorporates experimental oxygen evolution rates into approaches of LFESR and Sabatier−principle−based analysis, identifying a narrow yet fertile energetic landscape to bountiful oxygen evolution activity, leading to future rational design. Full article

Copper- and cobalt-containing carbon composites were prepared by pyrolysis of an aniline-formaldehyde polymer (AFP) doped with the metal oxides, followed by the reduction of metal cations in an electrochemical cell. AFP + metal oxide nanocomposites were synthesized by introducing a metal salt during the polycondensation of aniline with formaldehyde and by alkaline precipitation of metal oxides into the polymer matrix. The heat treatment was carried out at 400, 500 and 700 °C. Microscopic studies revealed the formation of CuO crystallites in the shape of "stars" on the heat-treated carbon material. The resulting composites were saturated with hydrogen in an electrochemical system, which was accompanied by the reduction of copper and cobalt cations, and the appearance of the metals in zero-valence state. The so-prepared Cu + copper oxides/C and Co + Co(OH)₂/C composites were used as electrocatalysts in the electrohydrogenation of acetophenone (APh). Compared to the electrochemical reduction of APh on a copper cathode (without catalysts), an increase in the rate of this process (by 2–4 times) in the presence of the composites and an increase in the APh conversion with the selective formation of 1-phenylethanol were established. Full article

Noble metal nanoparticle-loaded catalytic membrane reactors (CMRs) have emerged as a promising method for water decontamination. In this study, we proposed a convenient and green strategy to prepare gold nanoparticle (Au NPs)-loaded CMRs. First, the redox-active substrate membrane (CNT-MoS₂) composed of carbon nanotube (CNT) and molybdenum disulfide (MoS₂) was prepared by an impregnation method. Water-diluted Au(III) precursor (HAuCl₄) was then spontaneously adsorbed on the CNT-MoS₂ membrane only through filtration and reduced into Au(0) nanoparticles in situ, which involved a “adsorption–reduction” process between Au(III) and MoS₂. The constructed CNT-MoS₂@Au membrane demonstrated excellent catalytic activity and stability, where a complete 4-nitrophenol transformation can be obtained within a hydraulic residence time of <3.0 s. In addition, thanks to the electroactivity of CNT networks, the as-designed CMR could also be applied to the electrocatalytic reduction of bromate (>90%) at an applied voltage of −1 V. More importantly, by changing the precursors, one could further obtain the other noble metal-based CMR (e.g., CNT-MoS₂@Pd) with superior (electro)catalytic activity. This study provided new insights for the rational design of high-performance CMRs toward various environmental applications. Full article

Facing greenhouse effects and the rapid exhaustion of fossil fuel, CO₂ electrochemical reduction presents a promising method of environmental protection and energy transformation. Low onset potential, large current density, high faradaic efficiency (FE), and long-time stability are required for industrial production, due to economic costs and energy consumption. This minireview showcases the recent progress in catalyst design and engineering technology in CO₂ reduction reaction (CO₂RR) on copper based-catalysts. We focus on strategies optimizing the performance of copper-based catalysts, such as single-atom catalysts, doping, surface modification, crystal facet engineering, etc., and reactor design including gas diffusion layer, membrane electrode assembly, etc., in enhancing target electroreduction products including methane, methanol, ethylene, and C₂₊ oxygenates. The determination of the correlation and the developed technology might be helpful for future applications in the industry. Full article

In this paper, DFT computations revealed the mechanisms of the asymmetric catalytic reactions of diisopropylzinc with pyrimidylaldehyde catalyzed by 1- and 2-aza[6]helicenes, which make them effective inductors of the autocatalytic chiral amplification Soai reaction. The generation of chirality takes place through the formation of adducts of aldehyde and helicenes stabilized via non-covalent disperse interactions strictly defining the orientation of the aldehyde molecule in the corresponding transition state. Full article

The Fenton reaction is a powerful method for removing refractory pollutants from water, yet it is restricted by shortcomings such as pH adjustments and generation of iron-containing sludge. In this study, a highly dispersed pyrite nanoplate supported on chitosan hydrochar was prepared through a simple one-pot hydrothermal method. The interactions between chitosan and Fe³⁺ suppressed the accumulation of FeS₂ in the crystal growth period and led to the formation of pyrite nanoplates with many exposed (210) facets. Thus, it showed excellent Fenton-like activity and the removal efficiency of AR 73 reached 99.9% within 60 min. The catalyst could be used in a wide pH range of 3~10. Hydroxyl radicals are the main reactive oxygen species in this catalytic system. The self-reduction of generated Fe(III) species by sulfur via inner electron transfer promoted the Fe(II)/Fe(III) redox cycle, and the presence of graphene facilitated the adsorption of pollutants. This catalyst also showed good reuse performances as well as stability, which has promising prospects for practical use in wastewater treatment. Full article

We compared the activity enhancement effect of noble metal deposited on TiO₂ in photocatalytic nitrogen oxides oxidation. Titanium dioxide was decorated with Ag, Au, Pt or Pd in the sol-gel process. Synthesized catalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller measurement (BET), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX). All catalysts together with pure TiO₂ obtained by sol-gel (SG) technique were tested for their photocatalytic activity towards nitrogen oxide oxidation (high concentrations of 50, 150 and 250 ppm). FTIR spectrometry was used to determine the gas phase composition and identify TiO₂ surface species. The Ag0.1 sample turned out to be deactivated within 60 min of UV/Vis irradiation. Photocatalytic oxidation rate towards NO₂ turned to be the highest over SG (photocatalyst without metal deposition). NO₂ formation was also observed for Au0.1, Au0.5, Pt0.1, Pt0.5 and Pd0.1. The best NO_x removal, i.e., conversion to final product HNO₃ was obtained with the Au0.5 photocatalyst. Full article

Legionella pneumophila (L. pneumophila) is the causative agent of Legionnaires’ disease and Pontiac fever, collectively known as legionellosis. L. pneumophila infection occurs through inhalation of contaminated aerosols from water systems in workplaces and institutions. The development of disinfectants that can eliminate L. pneumophila in such water systems without evacuating people is needed to prevent the spread of L. pneumophila. Photocatalysts are attractive disinfectants that do not harm human health. In particular, the TiO₂ photocatalyst kills L. pneumophila under various conditions, but its mode of action is unknown. Here, we confirmed the high performance of TiO₂ photocatalyst containing PtO₂ via the degradation of methylene blue (half-value period: 19.2 min) and bactericidal activity against Escherichia coli (half-value period: 15.1 min) in water. Using transmission electron microscopy, we demonstrate that the disinfection of L. pneumophila (half-value period: 6.7 min) by TiO₂ photocatalyst in water is accompanied by remarkable cellular membrane and internal damage to L. pneumophila. Assays with limulus amebocyte lysate and silver staining showed the release of endotoxin from L. pneumophila due to membrane damage and photocatalytic degradation of this endotoxin. This is the first study to demonstrate the disinfection mechanisms of TiO₂ photocatalyst, namely, via morphological changes and membrane damage of L. pneumophila. Our results suggest that TiO₂ photocatalyst might be effective in controlling the spread of L. pneumophila. Full article

Diesel soot particles are of concern for both the environment and health. To catalytically remove them, it is important to know their structure and composition. There is little described in the literature on how catalysts favor the combustion of different soot fractions. In this work, programmed temperature oxidation (TPO) experiments were carried out using Co,Ce or Co,Ba,K catalysts supported on ceramic papers. Soot particles were obtained by burning diesel fuel in a vessel (LabSoot) or by filtering exhaust gases from a turbo diesel engine in a DPF filter (BenchSoot), and compared with a commercial diesel soot: Printex U. Various characterization techniques were useful to relate the characteristics of both the soot particles and the catalysts with the TPO results. The maximum catalytic soot burn rate (T_M) temperatures were in the range of diesel exhaust temperatures that would facilitate in-situ regeneration of the DPF. The Co,Ba,K catalyst showed a higher catalytic effect in LabSoot, as the latter exhibited the largest primary particles and the higher order of graphene layers, for which the potassium-containing catalyst improves the contact between soot and catalyst and favors the combustion of soot, while the Co,Ce catalyst preferentially enhanced the combustion of commercial soot by supplying active oxygen. Full article

Enzyme immobilization on inorganic materials is gaining more attention with the potential characteristics of high-surface-area-to-volume ratios, increasing the efficiency of enzyme loading on the support. Metal oxide hybrid support was prepared by a wetness impregnation of five metal precursors, including CaO, CuO, MgO, NiO, and ZnO, on Al₂O₃ and used as a support for the immobilization of Candida rugosa lipase (CRL) by adsorption. Maximum activity recovery (70.6%) and immobilization efficiency (63.2%) were obtained after optimization of five parameters using response surface methodology (RSM) by Box–Behnken design (BBD). The biochemical properties of immobilized CRL showed high thermostability up to 70 °C and a wide range in pH stability (pH 4–10). TGA-DTA and FTIR analysis were conducted, verifying thermo-decomposition of lipase and the presence of an amide bond. FESEM-EDX showed the homogeneous distribution and high dispersion of magnesium and CRL on MgO-Al₂O₃, while a nitrogen adsorption–desorption study confirmed MgO-Al₂O₃ as a mesoporous material. CRL/MgO-Al₂O₃ can be reused for up to 12 cycles and it demonstrated high tolerance in solvents (ethanol, isopropanol, methanol, and tert-butanol) compared to free CRL. Full article