Reaction Progress Research Articles

Development of small, cost-efficient scintillating fiber detectors for automated synthesis of positron emission tomography radiopharmaceuticals.

Radiolabeling is critical in complex chemical reactions involving positron emission tomography (PET) radiotracer production. The process is now automated within a synthesis module to enhance efficiency and reduce radiation exposure. The key to this automation is the use of radiation detectors to monitor radioactivity transfer and ensure the progression of reactions. However, the high cost of these detectors has motivated the need for a more affordablealternative. This study aimed to develop a compact and cost-efficient detector using scintillating fibers and silicon photomultipliers (SiPMs) to track radioactivity throughout PET radiotracerproduction. Monte Carlo simulations were performed with the Geant4-based M-TAG software for four detector geometries (single fiber, single fiber with bolus, 16-fiber bundle, and spiral) to optimize the detector construction for better detection efficiency. The simulations scored the energy deposited into the scintillating fibers per simulated particle, which was used to estimate the expected voltage pulse height from the SiPM considering the total light collection efficiency. Based on the simulation results, two detector configurations (16-fiber bundle and spiral fiber) were constructed using plastic scintillating fibers, optical fibers, a 6 mm 6 mm SiPM, and commonly available electronic components. The detectors were calibrated using a Fluorine-18 ( ) source with typical activity levels used in radiotracer production. Detector performances were subsequently evaluated through linearity tests and measurement uncertainty assessments. Errors up to were considered acceptable for troubleshootingpurposes. The calibration curves showed a linear response with changing activity for both detectors. The calibrated detectors offered real-time activity measurements ranging from 0.10 to 49.41 GBq, with a 3-s refresh rate. In the activity range above 0.145 GBq, the uncertainties were less than for both the 16-fiber and spiral configurations. The spiral detector recorded a signal with a half-life of min, closely aligning with the reference half-life of . Cost-efficient plastic scintillation fiber detectors were developed to facilitate the troubleshooting of automated synthesis of PETradiotracers.

One-pot Three-component Synthesis of Fully and Diversely Functionalized Pyrans and Spiropyrans Using Sodium Formate as Catalyst in Aqueous Ethanol at Room Temperature

Abstract: A convenient and general method has been developed for the synthesis of fully and diversely functionalized pyrans via one-pot three-component reactions of various aryl or heteroaryl aldehydes, malononitrile, and 1,3-dimethyl/1,3-diethyl-acetonedicarboxylates in the presence of a catalytic amount of sodium formate as an efficient organocatalyst in aqueous ethanol at room temperature. All the scaffolds were synthesized in excellent yields within 2.5 hours. Under the same reaction conditions, fully and diversely functionalized spiro-pyrans were also synthesized in excellent yields from the reaction of isatin, malononitrile, and 1,3-dimethyl/1,3-diethylacetonedicarboxylates. All the products were isolated pure just by simple filtration. Synthesis of fully and diversely functionalized biologically promising pyrans, excellent yields, use of organocatalyst, less toxic solvent, no column chromatographic purification, and energy efficiency are some of the major advantages of this newly developed protocol. method: In a clean test tube a magnetic stir bar, 0.5 mmol of aldehydes (1a-1i), 0.5 mmol of malononitrile (2; 0.033 g) and 0.5 mmol of 1,3-dimethylacetonedicarboxylate (3a; 0.087 g) or 1,3-diethylacetonedicarboxylate (3b; 0.101 g), 4 ml aqueous ethanol (1:1 v/v) and 20 mol% sodium formate were taken sequentially. The whole reaction mixture was stirred at room temperature for the time mentioned in Table 2. The progress of reaction was monitored by TLC. By using the same amount of catalyst and solvent the synthesis of methyl/ethyl-2'-amino-3'-cyano-6'-(2-meth/ethoxy-2-oxoethyl)-2-oxospiro[indoline-3,4'-pyran]-5'-carboxylate (6a/6b) was achieved from the reactions of 0.5 mmol of isatin (5; 0.0735 g), 0.5 mmol of malononitrile (2; 0.033 g) and 0.5 mmol of 1,3-dimethylacetonedicarboxylate (3a; 0.0871 g) or 1,3-diethylacetonedicarboxylate (3b; 0.1011 g). After the completion of each reaction, the desired products were isolated simply by filtration and subsiquent washing with aqueous ethanol (EtOH:H2O = 1:1).

Chemodivergent Parallel Kinetic Resolution of Paracyclophanes: Enantiomer Fishing with Different Substrates

AbstractAn unprecedented chemodivergent strategy for parallel kinetic resolution (PKR) is disclosed through which two planar chiral products bearing different structures were simultaneously afforded with opposite stereoselectivities. Two achiral esters are activated by one single chiral N‐heterocyclic carbene (NHC) catalyst to react with the different enantiomers of the racemic imine substrate in a parallel fashion. Two products bearing distinct structures and opposite stereoselectivities are respectively afforded from the same reaction system in good to excellent yields, enantio‐ and diastereoselectivities. Control experiments and kinetic studies are carried out to probe the kinetic and dynamic properties during the reaction progress. The planar chiral pyridine and lactam products show interesting applications in both asymmetric synthesis and pesticide development.

Chemodivergent Parallel Kinetic Resolution of Paracyclophanes: Enantiomer Fishing with Different Substrates.

An unprecedented chemodivergent strategy for parallel kinetic resolution (PKR) is disclosed through which two planar chiral products bearing different structures were simultaneously afforded with opposite stereoselectivities. Two achiral esters are activated by one single chiral N-heterocyclic carbene (NHC) catalyst to react with the different enantiomers of the racemic imine substrate in a parallel fashion. Two products bearing distinct structures and opposite stereoselectivities are respectively afforded from the same reaction system in good to excellent yields, enantio- and diastereoselectivities. Control experiments and kinetic studies are carried out to probe the kinetic and dynamic properties during the reaction progress. The planar chiral pyridine and lactam products show interesting applications in both asymmetric synthesis and pesticide development.

Investigation on the reaction progress of titanium and lead chloride in NaCl-KCl melt

The in-situ preparation of NaCl-KCl-TiClx molten salt electrolyte was investigated by replacement of PbCl2 and Ti in a NaCl-KCl melt at 750 ℃. The reaction progress of PbCl2(3.38 wt.%) with excess Ti was monitored in real-time by a series of electrochemical techniques such as cyclic voltammetry, square wave voltammetry, and open circuit chronopotentiometry. The thermodynamic calculation and electrochemical test results show that titanium ions are mainly generated in the form of Ti(III). The redox peak current of Pb(II) decreases rapidly and drops to below the detection limit of the electrochemical tests after 275 min. Simultaneously, the reduction peak current of Ti(III) increases rapidly from 0 to 75min, and reaches to the maximum value until 275 min. At this time, the replacement reaction has been completed, and the NaCl-KCl-TiClx(2≤x≤4) molten salt is obtained finally. Ti-Pb alloy was obtained by depositing at -1.0 V(vs. Ag/AgCl) for 30 min during the replacement process. Lead by-product of the replacement reaction was precipitated and collected. Electrolytic refining was carried out successfully using the NaCl-KCl-TiClx molten salt electrolyte prepared as described above. The results demonstrated that a stable NaCl-KCl-TiClx molten salt electrolyte can be obtained by the present method. The study provides a new thinking for the preparation of molten salt electrolyte containing titanium ions, and also provides theoretical references for the electrolytic refining of titanium and the preparation of titanium alloys by electrodeposition.

Determination of a normal orogenic palaeo-geothermal gradient with clay mineral and organic matter indices: a review

A collection of large data sets from different orogenic belts was compiled for a correlation between organic matter (OM) versus clay mineral (CM) indices calibrated with the vitrinite reflectance, (VR) vs Kübler-Indices (KI) method. Data selection was based on a normal geothermal gradient (25 to 35 °C/km) as determined in previous studies, e.g. by maturity modelling and clay mineral reaction progress calculations. In the Lower Austroalpine (Eastern Switzerland, European Alps) a 20 myr lasting metamorphic overprint caused an OM–CM thermal equilibrium among the indices used. The observed correlation enables to determine gradual changes in metamorphic factors such as pressure, temperature and time causing sensitive shifts of the gradient slope in the range of normal gradients. For New Caledonia, an identical correlation has been determined. Prior to re-equilibration of the VR/KI indices, sediments in New Caledonia of diagenetic to incipient metamorphic grade underwent a high-pressure subduction event. VR/KI indices are in or close to equilibrium, while slight differences in OM vs CM indices allow for a better understanding of polyphase conditions, especially with respect to pressure. Temperature estimations are identical despite of their poly-phase metamorphic history, which was mainly controlled by the last orogenic thermal event lasting > 5 to < 10 myr. In the eastern Helvetic Alps and Northern Calcareous Alps similar correlations were found with slightly different slopes. Comparison between different regions is possible when using KI standardization and same data discrimination. In both parts of the Alps a complex thermal history of short durations (< 5.0 myr for the Northern Calcareous Alps to 10 myr for the Helvetic Alps) caused similar VR/KI trends, but disequilibrium is suggested by weaker regression parameters. The following correlation is calculated for a moderate geotherm (55 to 74 mWm2, mean = 61 mWm2) and normal temperature gradient conditions (25 to 35 °Ckm−1): KI = 1.134e−0.305VR, (R2 = 0.880, n = 462) with VR given as %Rmax, KI as Δ°2θ (limited to values between 0.2 to 1.0 Δ°2θ). With increasing depth (z) a VR gradient of 1.4 ± 0.2%Rmaxkm−1 is determined and a KI gradient of 0.09 ± 0.002 Δ°2θ km−1 is observed. The study illustrates that a normal geotherm can be described by VR/KI correlation, even if different heating episodes may occur. For the detection of a poly-phase or plurifacial thermal history, several indices of clay minerals and organic matter with very different kinetics should be used, as e.g. demonstrated by strong differences in smectite content at equal VR/KI values versus structural depth. A specific interest is given to the correlation of vitrinite like solid bitumen reflectance as an alternative method to VR, the persistent preservation of liptinite macerals and the stability range of clay minerals and sub-greenschist facies critical minerals compared with VR/KI data. Until now, despite the Alps in this study, systematic liptinite maceral studies have not been published in other orogenic settings.

Dry reforming of toluene over Ni/pyrochlore catalysts with A-site Sr doping

Dry reforming with CO2 is one potential method for tar removal and further production of syngas in biomass gasification, but the crucial catalysts with good reaction characteristics are still being developed. In the work, Ni/pyrochlore was proposed to be utilized as catalysts in the dry reforming of tar, and thermodynamic calculation, reaction progress test, and materials characterization were conducted to reveal dry reforming characteristics over Ni/pyrochlore catalysts and the reaction mechanism behind. Results show that YS0.2C catalyst exhibits the best activity (toluene and CO2 conversion of 70.1% and 79.5%) and stability among all catalysts under the optimized conditions of 700 °C with a CO2/toluene molar ratio of 7. Analysis on physicochemical properties of the catalysts indicate Sr doping can effectively promote catalytic reforming by enhanced interaction between Ni and support, CO2 adsorption and oxygen mobility. The work offers a promising catalyst type in improving tar removal by dry reforming.

Effect of Temperature and Initiator Concentration on the Curing Reaction of an Epoxy/Amine System

AbstractEpoxy blends of diglycidyl ether of bisphenol A (DGEBA) and 2‐[2‐(dimethylamino) ethoxy] ethanol (DMAEE) were prepared. The effect of DMAEE concentration on the rheological properties of the epoxy blends were investigated through oscillatory rheometry under isothermal conditions. A novel technique was developed to study the rheological behavior of the epoxy blends by using a Rubber Process Analyzer (RPA). The rheological study enabled analyzing the variations in the storage modulus (G’), loss modulus (G’’) and torque during the progress of the curing reaction. Additionally, the theoretical cross‐linking density (νe) and the degree of conversión of the curing reaction (α). The gel time (tgel) was determined at different temperatures, and the activation energy (Ea) was calculated by using Arrhenius‐type equation based on the gel time results. The activation energy values found are 24.79 kJ/mol and 23.01 kJ/mol. The results obtained are consistent with the values described in the literature. It was demonstrated that the proposed methodology is valid and, the use of the tertiary amine DMAEE curing agent for epoxy resins was confirmed.

Oxyanion-Sensitive Catalytic Activity of Ni(II)/Oxyanion Systems for Heterogeneous Organic Degradation: Differential Oxidizing Capacity of Ni(III) and Ni(IV) as High-Valent Intermediates.

This study demonstrated that NiO and Ni(OH)2 as Ni(II) catalysts exhibited significant activity for organic oxidation in the presence of various oxyanions, such as hypochlorous acid (HOCl), peroxymonosulfate (PMS), and peroxydisulfate (PDS), which markedly contrasted with Co-based counterparts exclusively activating PMS to yield sulfate radicals. The oxidizing capacity of the Ni catalyst/oxyanion varied depending on the oxyanion type. Ni catalyst/PMS (or HOCl) degraded a broad spectrum of organics, whereas PDS enabled selective phenol oxidation. This stemmed from the differential reactivity of two high-valent Ni intermediates, Ni(III) and Ni(IV). A high similarity with Ni(III)OOH in a substrate-specific reactivity indicated the role of Ni(III) as the primary oxidant of Ni-activated PDS. With the minor progress of redox reactions with radical probes and multiple spectroscopic evidence on moderate Ni(III) accumulation, the significant elimination of non-phenolic contaminants by NiOOH/PMS (or HOCl) suggested the involvement of Ni(IV) in the substrate-insensitive treatment capability of Ni catalyst/PMS (or HOCl). Since the electron-transfer oxidation of organics by high-valent Ni species involved Ni(II) regeneration, the loss of the treatment efficiency of Ni/oxyanion was marginal over multiple catalytic cycles.

Composite Melt–Rock Interactions in the Lowermost Continental Crust: Insights from a Dunite–Pyroxenite–Gabbronorite Association of the Mafic Complex from the Ivrea–Verbano Zone (Italian Alps)

Abstract The processes leading to the building of the continental crust through magmatic underplating are fundamentally unknown, mainly because of the rare accessibility to deep level sections of the continental crust. The Italian Alps expose the Permian Mafic Complex, an 8-km-thick gabbronorite–diorite batholith that intruded the lower continental crust during the post-Variscan transtensional tectonics. We present here a petrological and geochemical study of a concentric dunite–pyroxenite–gabbronorite association, called Monte Mazzucco sequence, enclosed at deep levels of the Mafic Complex, thereby allowing us to provide new insights into the magmatic processes driven by emplacement of mantle melts in deep crustal continental areas. The studied sequence includes a ~ 60-m-thick dunite lens, in which olivine (82 mol % forsterite) is associated with accessory Cr-spinel including blebs and lamellae made up of magnetite. The dunite lens is permeated by mm- to cm-scale thick magmatic veins, which range in composition from hornblende lherzolite to olivine hornblendite and hornblende websterite. The lens is mantled by a m-scale ring consisting of amphibole-bearing (≤1 vol %) websterite, and the websterite ring is in turn enclosed by amphibole-free gabbronorites. Both magmatic veins within the dunites and mantling websterites typically include an oxide association of Al-spinel and magnetite. Remarkably, the hornblende websterite veins and the mantling websterites are typically plagioclase-free and include clinopyroxene and amphibole with chondrite-normalized rare earth element patterns characterized by negative Eu anomaly. The mantling websterites display a subtle, gradual outward decrease of Mg# for orthopyroxene, clinopyroxene and accessory olivine, coupled with an increase of the negative Eu anomaly in clinopyroxene and amphibole. The enclosing gabbronorites are amphibole-free and have a chemically evolved signature. We propose a petrogenetic scenario including two major events of melt–dunite interaction. The first resulted from focused reactive melt infiltration and formed the magmatic veins within dunites. The hornblende lherzolite and the olivine hornblendite veins were produced by focused reactive melt migration through dunite grain boundaries, involving dissolution of olivine and recrystallization of Cr-spinel into Al-spinel and magnetite, whereas the hornblende websterite veins crystallized from melts penetrating through narrow fractures and recording earlier plagioclase fractionation. Most likely, the infiltrating melts were overall derived from an evolving H2O-rich magma emplaced below the dunite body. The second event of melt–dunite reactive interaction developed the websterite ring around dunites. We envision that the outermost domain of the dunite body was replaced by websterites in response to reaction with an invading H2O-poor melt, which had previously undergone plagioclase fractionation. The dunite replacement occurred under dynamic conditions, which promoted the reaction progress, thereby leading to total or almost total dissolution of precursor olivine, and started to form the lens shape of the Monte Mazzucco ultramafic association. The gabbronorites closely adjacent to the websterite ring represent the crystallization products of the invading melt.

The effects of raw materials particle sizes on the solid-state reaction progress, morphology and magnetic properties of M-type strontium hexaferrites

In this work, the effects of SrCO3 and Fe2O3 particle size on the reaction process, morphology and magnetic properties of M-type strontium hexaferrites (SrM) have been further studied. Pure strontium hexaferrite magnetic sample based on SrCO3 and Fe2O3 molar ratio of 1:6 has been successfully prepared at 1150 °C. The results indicated that Fe2O3 particle size was the main factor of affecting the formation of SrM, a pure SrM phase magnetic sample was able to obtain at lower calcination temperatures by using fine Fe2O3 powder as raw material, and at the same calcination temperature, a sample using fine Fe2O3 powder as raw material was able to obtain pure SrM phase magnetic sample with shorter holding time. When the mean particle size of Fe2O3 was below 60 nm, a pure SrM phase magnetic sample was able to form at 1150 °C at a molar ratio of 1:6 of SrCO3 and Fe2O3. In this case, the magnetic parameters of the sample with the optimum magnetic parameters were saturation magnetization MS = 77.8 emu/g and coercive force HC = 4122 Oe. And the solid-state reaction process of the corresponding samples was slightly faster when the mean particle size ratio of Fe2O3 and SrCO3 was between 0.35 and 0.36. Assuming that a SrCO3 particle is surrounded by Fe2O3 particles, it can be inferred that the corresponding molar ratio of Fe and Sr of the nearest raw material particles is between 3.6 and 3.8.

Understanding the effect of reaction parameters on the production of levulinic acid from glucose

AbstractA significant and sustainable feedstock for many value added products is levulinic acid, which is basically a short‐chain fatty acid. The current study aims to comprehend how multiple factors affect the hydrothermal reactions that convert glucose to levulinic acid. Glucose can be readily obtained from lignocellulosic biomass and hence it is selected in the work as representative sustainable source. The effect of various operating parameters, including time (0–180 min), temperature (140–180°C), nitrogen pressure (0–25 bar), glucose concentration (3%–10%), agitation speed (100–300 RPM), and acid concentration (2%–6%); use of different salts (NaCl, AlCl3 6H2O, FeCl3); and different acids (HCl, H3PO4, H2SO4) on the reaction progress has been studied in a batch autoclave reactor. It was elucidated that pressure (only nitrogen purge was essential for reaction progress) or salt content changes did not affect sugar conversion significantly. The process was seriously influenced by the presence of acids, mostly in the form of homogeneous catalysts, and the most significant results were obtained for H2SO4. The highest levulinic acid yield (39.7 g/g) at 90 min, with nearly complete sugar conversion, was obtained under the ideal conditions of 160°C, 5% sugar loading, and 5% H2SO4 concentration. The current study indicates that the two primary operating parameters in this conversion process are temperature and time, with higher temperature and lower sugar concentration showing a rising tendency in sugar conversion. Overall, the study establishes a sustainable process for levulinic acid synthesis.

Classification of adsorbates in scanning tunneling microscopy images of Fe3O4(111) surfaces exposed to water and carbon monoxide

Understanding the structure of catalyst surfaces with adsorbed molecules is key to improving catalyst design. Scanning tunneling microscopy (STM) allows the observation of adsorption states and sites and provides insights into diffusion and desorption processes; however, the presence of multiple types of molecules on the surface presents challenges such as the identification of species and verification of reaction progress, particularly at room temperature or higher. In this study, we develop a protocol for the height classification analysis of STM images using the Watershed algorithm. This method is applied to a system involving the co-adsorption of H2O and CO on the Fe3O4(111) surface, which represents the beginning of the water-gas shift reaction. Water molecules and dissociated OH species were identified in STM images of the Fe3O4(111) surface following the adsorption of water. Furthermore, gradual changes in the types of surface species were observed upon exposure of the surface to CO, indicating reaction progression. Our observations suggest that CO may react with molecular water rather than with dissociated OH on Fe sites. Despite its simplicity, the height classification analysis effectively identifies changes in the adsorbates on the catalyst surface. This method can be extended to other catalyst surfaces with adsorbed gasses.

Green Molecular Reactor Boosting the Photocatalytic Aerobic Oxidation of Sulfides in Clean Solvent

AbstractThe synthesis of sulfoxides has long attracted considerable interest due to their pivotal role in organic synthesis, pharmaceutics and environmental protection. Oxidation of the corresponding sulfides is recognized as the most effective strategy. Traditional oxidation methods, however, fall short of the growing demands of green chemistry. Photocatalytic aerobic oxidation has thus garnered attention, employing the greenest and most sustainable oxidants—oxygen or air—and sunlight as the energy source. Nevertheless, these reactions are typically conducted in potentially pollutive organic solvents rather than in the greenest solvent, water. To facilitate this organic transformation in aqueous phase, molecular reactors that can encapsulate reactants within their confined pores and facilitate photocatalytic reactions have been developed recently. This Concept article summarizes the development of molecular reactors for the photocatalytic oxidation of sulfides and provides perspectives for the design and construction of effective photocatalytic molecular reactors.

Exploring photocatalytic tetracycline removal performance under simulated sunlight irradiation: Milling time effect on metallic reduction of MnO/ZrO2 mixed oxide

In the present research, it is reported that ball milling technique can be applied to enhance the photocatalytic properties of MnO and ZrO2 metal oxide powders (MZOx) furthermore the fabricated photocatalyst can be used for the degradation of tetracycline (TTC). XRD analyses revealed that increasing the milling time resulted in the formation of a pure metallic Mn crystal phase, which boosted the antibiotic degradation rate. It was confirmed by SEM technique that the morphological structures of the particles were generally small and uniform. The band gap energy was calculated as 3.70 eV for the hybrid metal oxide. Additionally, the adsorptive and photoluminescence features were illuminated via DRS and PL analyses. The effect of milling time had a major impact on the photodegradation rate of TTC, and the 8 h milling sample (MZOx-8h) exhibited the highest catalytic degradation activity (79.4 %). Low photocatalytic activity was obtained at acidic pHs and increased at alkaline pHs. The presence of H2O2 sharply decreased photocatalytic process time (60 min) and 94.3 % of the TTC was degraded at 7.5 mM H2O2. The photocatalytic degradation process proceeded through superoxide radicals and was supported by holes. The stability of MZOx-8h almost remained constant (70.02 %) even after seven cycles. It was determined that the presence of oxalic acid positively affected the progress of TTC degradation reactions. Further, practical application areas were investigated and MZOx-8h doped on support materials was found to be suitable for such applications in proportion to the doping ratio. Finally, it was demonstrated that MZOx-8h exhibited remarkable performance in photocatalytic reactions of different types of organic pollutants. The synergistic nature of MnO and ZrO2 with the contribution of ball milling time effect resulted in high photocatalytic activity.

Computational simulation of SE-SR of methane in a bench-scale circulating fluidised bed reactor: Insights into the effects of bed geometry design and catalyst-sorbent ratios

Operating sorbent-enhanced steam reforming (SE-SR) of methane in fluidised bed reactors presents a promising pathway for industrial low-carbon hydrogen production. However, further understanding of its complex multi-phase behaviours under certain operating conditions is still needed to guide reactor design and scale-up. This study developed a computational particle fluid dynamic (CPFD) reactor model to study cyclic SE-SR performance. The model was used to simulate scenarios representing potential reductions in catalyst activity and sorbent inventory levels over time by varying catalyst-sorbent ratios. Additionally, the effects of two different bed geometry designs were examined.Results indicate that varying solids ratios influenced reaction progress, with optimised methane conversion and CO2 capture observed at moderate ratios. Higher sorbent loadings enhanced thermal neutrality but risked increased calciner energy penalties. Bed geometry also influenced localised hydrodynamics. Detailed solids and gas concentration contours provided insight into segregation and spatial product distribution in the two designs.

Theoretical study on the electrochemical CO2 reduction performance of MoS2-supported Ni single atoms with transition metal substrate doping

In the context of increasing energy issues and climate change, the development of electrochemical CO2 reduction strategies using single atom catalysts (SACs) presents a viable solution by converting CO2 into high-value-added products. Transition metal dichalcogenides (TMDs) have emerged as the main candidates for SACs in electrocatalytic CO2 reduction reaction (CO2RR) catalysts. The regulation of the second coordination sphere of SACs is known to modulate their electronic structure and catalytic behavior. This study delves into the effect of transition metal-doped substrates on SACs. We employed spin-polarization density functional theory (DFT) to design a series of Ni/TM-MoS2 monolayer MoS2 materials, with transition metals (including Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt and Au) substituting the Mo atoms and anchoring single atom Ni. Among them, six Ni/TM-MoS2 catalysts doped with Mn, Fe, Co, Ru, Rh, and Ir demonstrate enhanced CO2RR activity and selectivity when compared to unmodified Ni/MoS2. The Ni/Ru-MoS2 SAC exhibits the best catalytic activity and selectivity for formic acid production, with a limiting potential (UL) of -0.06 V. The incorporation of the metal-doped substrate lowers the work function of the catalyst, facilitating electron transfer and reaction progression. Furthermore, a volcanic relationship was observed between the work function and UL. This study provides strategic insights into the design and development of SACs, highlighting the potential for future modifications and applications.

More than just smoke and mirrors: Gas-phase polaritons for optical control of chemistry.

Gas-phase molecules are a promising platform to elucidate the mechanisms of action and scope of polaritons for optical control of chemistry. Polaritons arise from the strong coupling of a dipole-allowed molecular transition with the photonic mode of an optical cavity. There is mounting evidence of modified reactivity under polaritonic conditions; however, the complex condensed-phase environment of most experimental demonstrations impedes mechanistic understanding of this phenomenon. While the gas phase was the playground of early efforts in atomic cavity quantum electrodynamics, we have only recently demonstrated the formation of molecular polaritons under these conditions. Studying the reactivity of isolated gas-phase molecules under strong coupling would eliminate solvent interactions and enable quantum state resolution of reaction progress. In this Perspective, we contextualize recent gas-phase efforts in the field of polariton chemistry and offer a practical guide for experimental design moving forward.

Re-designing nano-silver technology exploiting one-pot hydroxyethyl cellulose-driven green synthesis.

Re-designing existing nano-silver technologies to optimize efficacy and sustainability has a tangible impact on preventing infections and limiting the spread of pathogenic microorganisms. Advancements in manufacturing processes could lead to more cost-effective and scalable production methods, making nano-silver-based antimicrobial products more accessible in various applications, such as medical devices, textiles, and water purification systems. In this paper, we present a new, versatile, and eco-friendly one-pot process for preparing silver nanoparticles (AgNPs) at room temperature by using a quaternary ammonium salt of hydroxyethyl cellulose (HEC), a green ingredient, acting as a capping and reducing agent. The resulting nano-hybrid phase, AgHEC, consists of AgNPs embedded into a hydrogel matrix with a tunable viscosity depending on the conversion grade, from ions to nanoparticles, and on the pH. To investigate the synthesis kinetics, we monitored the reaction progress within the first 24h by analyzing the obtained NPs in terms of particle size (dynamic light scattering (DLS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM)), Z-potential (ELS), surface plasmon resonance (UV-VIS), crystallographic phase (XRD), viscosity, and reaction yield (inductively coupled plasma-optical emission spectrometry (ICP-OES)). To explore the design space associated with AgHEC synthesis, we prepared a set of sample variants by changing two independent key parameters that affect nucleation and growth steps, thereby impacting the physicochemical properties and the investigated antimicrobial activity. One of the identified design alternatives pointed out an improved antimicrobial activity in the suspension, which was confirmed after application as a coating on nonwoven cellulose fabrics. This enhancement was attributed to a lower particle size distribution and a positive synergistic effect with the HEC matrix.

Catalytic Ozonation of Low Concentration Toluene over MnFeOx-USY Catalyst: Effects of Interactions between Catalytic Components and Introduction of Gas Phase NOx.

A series of Mn and Fe metal oxide catalysts loaded onto USY, as well as single metal oxides, were prepared and characterized. The effects of interactions between the catalytic components and the introduction of gas phase NO on the catalytic ozonation of toluene were investigated. Characterization showed that there existed strong interactions between MnOx, FeOx, and USY, which enhanced the content of oxygen vacancies and acid sites of the catalysts and thus boosted the generation of reactive oxygen species and the adsorption of toluene. The MnFeOx-USY catalyst with MnOx and FeOx dimetallic oxides exhibited the most excellent performance of catalytic ozonation of toluene. On the other hand, the presence of NOx in reaction gas mixtures significantly promoted both toluene conversion and mineralization, which was attributed to the formation of nitrate species on the catalysts surface and thus the increase of both acid sites and toluene oxidation sites. Meanwhile, the reaction mechanism between O3 and C7H8 was modified in which the strong interactions between MnOx, FeOx, and USY accelerated the reaction progress based on the L-H route. In addition, the formation of the surface nitrate species not only promoted reaction progress following the L-H route but also resulted in the occurrence of the reaction via the E-R route.