Increase In Reaction Rate Research Articles

Factors affecting iron and manganese dissolution in groundwater: treatments with simultaneous oxidation and precipitation methods

ABSTRACT This study explores variations in groundwater (GW) pH, conductivity, ammonium, iron, and manganese parameters to reveal prospective interactions having an impact on the dissolved metal concentrations. To this end, bivariate and partial correlation procedures were applied to the data to obtain incisive evaluation. Besides characterisation efforts, photocatalytic iron and manganese removal experiments were also carried out with Ni-doped TiO2 nano-composite thin films (TFs) on real GW samples. UV-A (365 nm) An LED array was used as the illumination source. The experimental setup was based on three treatment routes including photocatalytic oxidation (PCO), NaOH-aided precipitation and PCO with simultaneous precipitation (SPCO-P). The main statistical analysis and treatment efforts have been performed on data and samples of a single well, respectively (N = 15). However, extended statistical analysis has also been performed on larger data groups (N = 1366) obtained from different GW sources as well. Analytical results have revealed that about 90% of iron and manganese were in oxidised forms which do not precipitate by simple pH regulation. Statistical analysis has also revealed significant interactions between metal concentrations and observed parameters depending on the level of pH and conductivity. Furthermore, the SPCO-P strategy has provided a four-fold increase in reaction rate (pseudo-first-order, kobs: 0.04 min−1). Removal efficiencies of iron and manganese also increased from 10% to 96% – 85%, respectively.

Molecular dynamics study on the effect of pressure on the combustion of NEPE propellant

The impact of pressure on the combustion micro-processes of NEPE propellant was studied through employing molecular dynamics simulation. A rational core–shell nanoparticle model (Al/Al2O3/NEPE) was established and simulated, we found the system temperature increased with rising pressure. Furthermore, the heightened pressure results in an advanced generation and increased yield of final products such as N2 and H2O, alongside an accelerated production and disappearance of intermediate molecules. For instance, with the pressure rising from 3 to 16 MPa, the yield of the final products increases from 30 to 75. Through in-depth analysis, the rapid increase in reaction rate can be attributed to the promotion of key exothermic reactions by elevated pressure. Specifically, the reactions (NO + NH2 = N2 + H2O and OH + HNO = H2O + NO) release a total heat of approximately 850 KJ/mol at 3000 K, leading to an increase in system temperature. This study holds significant promise in informing the regulation of combustion performance of NEPE propellant.

Dual Activation Modes Enable Bifunctional Catalysis of Aldol Reactions by Flexible Dihydrazides.

Hydrazides are known to catalyze reactions of α,β-unsaturated aldehydes via transient iminium formation. The iminium intermediate displays enhanced electrophilicity, which facilitates conjugate additions and cycloadditions. We observed that a hydrazide embedded in a seven-membered ring catalyzes homoaldol condensation of a simple aldehyde in a process that displays an approximate second-order dependence on the hydrazide. This finding suggests a dual activation mechanism involving both iminium and enamine intermediates. The unexpected nucleophilic activation mode led us to examine a series of simple dihydrazides for bifunctional catalysis of the aldol condensation. The two cyclic hydrazide units were connected via linear polymethylene linkers, which are inherently flexible. Substantial increases in initial reaction rate, relative to a monohydrazide, were observed for polymethylene linkers of sufficient length, with a maximum at 10 methylenes. Reactions promoted by this dihydrazide displayed an approximate first-order dependence on catalyst concentration, which suggested a bifunctional catalytic mechanism. Even for a dihydrazide with an 18-methylene linker, a substantial increase in relative initial rate was observed. These observations show that significant coordination can be achieved between two catalytically active moieties even when these moieties are connected via many flexible bonds.

ABO incompatibility and component irradiation are independently associated with platelet transfusion reaction rate.

Allocating incompatible platelet components to avoid product wastage must be balanced against the risk of reduced efficacy and adverse outcomes. The impact of platelet compatibility in association with product irradiation or pathogen reduction is unknown. This study aims to determine the combined and independent impact of platelet compatibility and component modification on transfusion reaction rate. A retrospective review of all adult platelet transfusions from 2020 to 2022 was performed, including all reported reactions. Logistic regression was performed to evaluate the significance of ABO compatibility and unit modification for reaction rate. Out of 21,330 transfusions to 3450 patients, 285 (1.33%) reactions were reported and 178 (0.83%) were diagnosed as related to transfusion, predominantly febrile nonhemolytic (n = 59) and allergic (n = 102). The compatibility of transfusion was 67.7% ABO identical, 13.8% ABO minor incompatible, 17.2% ABO major incompatible, and 1.4% ABO bidirectionally incompatible. Irradiated, unmodified, and pathogen-reduced single-donor platelets were transfused in 70.9%, 21.8%, and 7.3% of cases, respectively. Univariable regression demonstrated increased odds of reaction for major incompatibility vs. ABO identical (OR: 1.92; 95% CI: 1.36-2.71) and irradiated vs. unmodified (OR: 2.34; 95% CI: 1.45-3.91), which were confirmed by multivariable analysis. The effect of compatibility and unit modification were independent in all analyses. The results demonstrate a trend of increasing reaction rate associated with major incompatibility and product irradiation. This study provides additional data to inform institutional policies guiding product selection for individual patients.

Comparative analysis of the efficiency of catalytic methane pyrolysis technology for hydrogen production based on DEA method

This paper presents a comprehensive analysis of the efficiency of methane pyrolysis technologies and various catalysts using the DEA method. The study is based on an extensive set of experimental data obtained under laboratory conditions. Application of DEA method allowed to identify key factors affecting the pyrolysis process performance, including costs, process parameters and catalyst properties. Particular attention is paid to the role of catalysts in the methane pyrolysis process. Highly efficient catalysts show significant increases in reaction rate and decreases in energy costs. The DEA method allowed the identification of key factors affecting process efficiency, including the choice of catalyst carrier, temperature conditions and composition of active components. The analysis revealed that catalyst stability and its ability to maintain high activity over the reaction time were particularly important for industrial applications. The results of the analysis allowed us to evaluate the relative efficiency of each catalyst and identify the most optimal combinations of reaction conditions. It was found that catalysts with high nickel content (more than 80%) on Al₂O₃ carrier show the highest efficiency at about 750 ℃, achieving high values of methane conversion and hydrogen yield. SiO₂ based catalysts show high initial activity, but tend to deactivate or carbonize with time, which in turn markedly reduces their efficiency in long-term processes. The results highlight the importance of optimal catalyst composition and reaction conditions to improve the efficiency and economic viability of the methane pyrolysis process. The study demonstrates the potential of DEA method as a tool for comprehensive assessment and optimization of technological processes of hydrogen production and emphasizes the prospects for further development and implementation of methane pyrolysis technology in industrial hydrogen production as a component of the transition to low-carbon energy production.

Evaluating the Potential of Microdroplet Flow in Two-Phase Biocatalysis: A Systematic Study.

Two-phase biocatalysis in batch reactions often suffers from inefficient mass transfer, inconsistent reaction conditions, and enzyme inactivation issues. Microfluidics offer uniform and controlled environments ensuring better reproducibility and enable efficient, parallel processing of many small-scale reactions, making biocatalysis more scalable. In particular, the use of microfluidic droplets can increase the interfacial area between the two phases and can therefore also increase reaction rates. For these reasons, slug flow has been extensively used in two-phase biocatalysis in recent years. However, microdroplet flow has been largely neglected for this application despite its great potential. In this work, we performed biphasic biocatalysis in microfluidic droplets, both in microdroplets and slugs, as well as in batch, and systematically investigated the effect of various reaction parameters on the outcome of the reaction. We show that microdroplet flow outperforms the more commonly used batch and slug flow configurations for most reaction conditions by providing shorter substrate diffusion paths and larger interfacial area for the reaction. The potential trade-off between maximized mass transfer and possibly higher enzyme inactivation rates in small droplets with large surface-to-volume ratios was also investigated for the first time, and a pipeline was established to allow evaluation in other reactions. Finally, the effect of surfactant necessary for microdroplet stabilization was also investigated in all reaction setups for the first time, and it was shown that a properly selected surfactant can have a positive effect at low concentrations by creating more stable emulsions and smaller droplets, thus increasing the interfacial area between the two phases.

Impact of partial regeneration method on the reduction of CO2 desorption energy

Amine-functionalized solid materials have shown efficacy for low-concentration CO2 environments; however, their regeneration is often hindered by slow desorption kinetics at low temperatures. To address this, an innovative approach termed “The Partial Regeneration Method” is introduced as a driving method to enable low-temperature regeneration of CO2 adsorbents at low concentration levels. Analysis of desorption kinetics mechanisms reveal that at low temperatures, CO2 molecules exhibit reduced kinetic energy and intraparticle diffusion coefficients. Furthermore, as it approaches chemical equilibrium temperature, the re-adsorption reaction rate increases. The partial regeneration method which selectively targets CO2 molecules with low re-adsorption rates could be more effective in a such low temperature conditions. This method involves intentionally halting regeneration midway and proceeding to the next adsorption process. Experimental application of specific energy requirements and scenario analysis demonstrated a 50.7% decrease in energy consumption compared to the conventional methods. By optimizing amine loading to reduce excessive re-adsorption, the shortened cycle period compensates for the decreased adsorption per cycle. Increasing the number of cycles led to a 97.5% improvement in CO2 adsorption capacity over a one-month period. Thus, when faced with unavoidable inefficient low-temperature regeneration conditions, the proposed partial regeneration method emerges as a promising solution for minimizing energy consumption.

Spatially Preorganized Hybridization Chain Reaction for the Prompt Diagnosis of Inflammation

Biological systems utilize precise spatial organization to facilitate and regulate information transmission within signaling networks. Inspired by this, artificial scaffolds that enable delicate spatial arrangements are desirable to increase the local concentration of reactants, expedite specific interactions, and minimize undesired interference. In this study, we presented an integrated biosensing nanodevice, termed TRI‐HCR, in which hybridization chain reaction (HCR) probes were precisely organized on a triangular DNA origami nanostructure (TRI) with finely‐tuned distance, quantity, and pattern. Compared to traditional HCR in the free form, this nanodevice demonstrated increased reaction rate and signal level. We further employed the optimized TRI‐HCR for in vivo imaging of a nucleic acid biomarker of inflammatory diseases. In both acute gouty arthritis (AGA) and sepsis‐associated acute kidney injury (SA‐AKI) model mice, TRI‐HCR was capable of diagnosing inflammation in the early stages, significantly earlier than histological examination. We anticipate that this precise spatial preorganization strategy for HCR holds promise for broader applications in early disease detection and monitoring.

Spatially Preorganized Hybridization Chain Reaction for the Prompt Diagnosis of Inflammation.

Biological systems utilize precise spatial organization to facilitate and regulate information transmission within signaling networks. Inspired by this, artificial scaffolds that enable delicate spatial arrangements are desirable to increase the local concentration of reactants, expedite specific interactions, and minimize undesired interference. In this study, we presented an integrated biosensing nanodevice, termed TRI-HCR, in which hybridization chain reaction (HCR) probes were precisely organized on a triangular DNA origami nanostructure (TRI) with finely-tuned distance, quantity, and pattern. Compared to traditional HCR in the free form, this nanodevice demonstrated increased reaction rate and signal level. We further employed the optimized TRI-HCR for in vivo imaging of a nucleic acid biomarker of inflammatory diseases. In both acute gouty arthritis (AGA) and sepsis-associated acute kidney injury (SA-AKI) model mice, TRI-HCR was capable of diagnosing inflammation in the early stages, significantly earlier than histological examination. We anticipate that this precise spatial preorganization strategy for HCR holds promise for broader applications in early disease detection and monitoring.

Kinetics of reduction of m‐iodonitrobenzene by aqueous ammonium sulfide under liquid–liquid phase transfer catalysis

AbstractHydrogen sulfide generated during hydrotreatment of sour crude oil fractions could be absorbed into aqueous ammonium hydroxide to produce ammonium sulfide. This ammonium sulfide can then be utilized to produce commercially valuable aromatic amino compounds by reducing the corresponding nitro compounds. In this work, the reduction of m‐iodonitrobenzene (m‐INB) to m‐iodoaniline (m‐IA) was performed by aqueous ammonium sulfide using a phase transfer catalyst, tetrabutylammonium bromide (TBAB). The study scrutinized the influences of various parameters such as concentrations of TBAB and m‐INB, as well as initial sulfide and ammonia concentrations, on the rate of reaction of m‐INB. An 11‐fold increase in reaction rate was obtained with only 0.09 kmol of catalyst TBAB per cubic meter of the organic phase. The selectivity of m‐IA was found to be100%. The reaction was found to be kinetically controlled with an activation energy of 40.0 kJ/mol. The rate of reaction of m‐INB was observed to be directly proportional to the concentrations of m‐INB, initial sulfide, and catalyst. A pseudo‐first order kinetic model was developed to correlate the conversion versus time data and an excellent agreement between observed and predicted reaction rates was obtained. The present work has very high commercial importance as it could be a viable alternative to the traditional Claus process to arrest H2S released by petroleum refineries.

Autonomous and Closed-Loop Exploration and Optimization of Bioelectrocatalytic Systems

Automated electrochemistry platforms provide a pathway for speeding up the discovery and optimization of electrochemical systems, especially when a broad range of molecules and reaction conditions must be explored.1-3 Additionally, incorporation of machine learning enables closed-loop optimization campaigns, where the obtained experimental data guides the selection of the next set of experimental parameters to test. This type of autonomous exploration is ideally suited for the study of enzyme electrocatalysis, as the combinatorics of different enzymes, substrates, and redox mediators creates a prohibitively large parameter space. Even within a single enzyme class, mutations to the amino acid sequence can significantly impact rate, function, and selectivity of the catalyzed reaction. Thus, an automated electrochemical platform that enables rapid sampling both reaction parameters and amino acid sequence space would enable discovery of new, non-native enzymatic reactions.In this work we use an open source and modular automated electrochemistry platform to study enzyme electrocatalysis in several common bioelectrocatalytic systems, such as glucose oxidase, glucose dehydrogenase, and aldehyde dehydrogenase. We use automated cyclic voltammetric substrate titration experiments (Figure 1) to gain insight into the kinetics of the redox-mediated enzymatic catalysis and demonstrate the reaction conditions in which traditional mechanistic simplifications, like Michaelis-Menten, break down. Additionally, the automated electrochemistry platform allows for the rapid screening of different substrate molecules, enabling the quantification of substrate promiscuity in these enzymatic catalysts. We show how Bayesian Optimization can be incorporated into our workflow to autonomously tune solution parameters to promote increased reaction rates. These studies demonstrate the power of autonomous electrochemistry for understanding and screening biocatalytic systems and represent a significant step towards totally machine-guided biocatalyst evolution.[1] Oh, I. ; Pence, M. A.; Lukhanin, N.; Rodriguez, O.; Schroeder, C. M.*; Rodriguez-Lopez, J.*, “The Electrolab: An open-source, modular platform for automated characterization of redox-active electrolytes” Device, 2023, 1, 5, 100103[2] Rodriguez, O.; Pence, M. A.; Rodriguez-Lopez, J.*, “Hard Potato: An Open Source Python Library to Control Commercially Available Potentiostats and Automate Electrochemical Experiments” Anal. Chem., 2023, 95, 4840–4845[3]Pence, M. A.; Rodriguez, O.; Lukhanin, N.; Schroeder, C. M.*; Rodriguez-Lopez, J.*, “Automated Measurement of Electrogenerated Redox Species Degradation Using Multiplexed Interdigitated Electrode Arrays”, ACS Meas. Sci. Au, 2023, 3, 62–72 Figure 1

Unraveling the role of EPOC during the enhancement of RWGS reaction in a Pt/YSZ/Au single chamber reactor

The hydrogenation of CO2 remains one of the most intriguing and effective strategies for addressing the continuous increase of CO2 emissions in the atmosphere. At the same time, it serves as an effective pathway for the formation of value-added products. This work explores the Electrochemical Promotion of Catalysis (EPOC) phenomenon on the CO2 hydrogenation reaction, utilizing a single chamber reactor with a Pt/YSZ/Au electrochemical cell. Experiments were conducted under ambient pressure conditions, within a temperature range of 200–400 °C, for a reactant flow rate of 100 cm3/min under reducing (PCO2: PH2 = 1:7) and oxidizing (PCO2: PH2 = 2:1) conditions. The effect of reactant ratio, reactor temperature, and applied current/potentials on the reaction rate were thoroughly investigated. The only observed product was carbon monoxide through the Reverse Water Gas Shift Reaction (RWGS). Under purely catalytic operation of the cell (open circuit), reducing conditions were found to be more favorable for the RWGS reaction as compared to oxidizing ones. The imposition of negative potential values under reducing environment resulted in a 2.3-fold increase in the RWGS reaction rate (rCO = 21 × 10−9 mol/s) as compared to open circuit values (rCO = 9 × 10−9 mol/s). On the other hand, application of positive potentials had no profound effect on the catalytic rate, which was attributed to competing electrochemical and surface processes taking place on the catalyst electrode. The kinetic results are discussed in conjunction with the physicochemical and the morphological characteristics of the catalytic film.

Enhanced sintering resistance of NiFe‐based RWGS catalysts through Cu doping

AbstractThe reverse water‐gas shift (RWGS) reaction offers an effective method for mitigating CO2 emissions. Due to its affordability and physicochemical stability, iron has garnered significant attention as a potential catalyst for RWGS. The incorporation of nickel and copper promoters can enhance CO2 conversion and CO selectivity in Fe‐based catalysts. This study focuses on modifying the strength of the Strong Metal‐Support Interaction (SMSI) through particle size optimization. Doping Cu into NiFe‐based catalysts restricts particle size, which influences the curvature of the Ni0@FeOx interface. This curvature enhances the electron coupling between Ni0 and FeOx, promoting the formation of a denser and thicker Ni0 and FeOx layer. This results in a nearly 90% increase in the CO2 reaction rate during the sintering resistance test by anchoring Ni0 and facilitating electron transfer to active sites. Such morphological evolution improves high‐temperature resistance to sintering during RWGS. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

OXIDATIVE DESTRUCTION OF AMOXICILLIN IN PHOTO-FENTON-LIKE OXIDIZING SYSTEM USING SOLAR IRRADIATION

The kinetic regularities of oxidative destruction of β-lactam penicillin antibiotics are studied using amoxicillin as example in Fenton-like iron-persulfate system under solar irradiation. The effect of Fe2+ and persulfate concentrations on the antibiotic degradation rate and mineralization in terms of total organic carbon (TOC) decay in combined {Solar/Fe2+ /S2O82-} system was examined. With the increase of oxidant concentration from 0.5 mM to 1.5 mM, the initial reaction rate of amoxicillin degradation increased to 2.5-fold, and the conversion of target compound and TOC mineralization reached 90% and 19%, respectively, after 120 min of solar exposure. Increasing the Fe2+ concentration from 0.1 mM to 0.3 mM resulted in a 1.5-fold increase in the initial reaction rate of amoxicillin oxidation and up to 21% for TOC mineralization. A comparative evaluation of different oxidizing systems was given. It was experimentally established that the efficiency of amoxicillin destruction process increases in the order: {S2O82-} < {Solar} < {Solar/S2O82-} < {Fe2+/S2O82-} < < {Solar/Fe2+/S2O82-}. It should be noted that TOC mineralization was observed only in combined {Solar/Fe2+/S2O82-} system, which indicates to deep oxidation of intermediates and, consequently, increasing biodegradability of the final reaction products. It was found that in the real water matrix, in the natural surface water of Selenga River, inhibition of amoxicillin degradation and TOC mineralization were observed, due to a greater extent to bicarbonate ions presented in it. The obtained results demonstrate the prospect of using solar irradiation for effective degradation of β-lactam penicillin antibiotics in the combined {Solar/Fe2+/S2O82-} oxidation system. For citation: Alekseev K.D., Sizykh M.R., Batoeva A.A. Oxidative destruction of amoxicillin in photo-fenton-like oxidizing system using solar irradiation. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 12. P. 123-130. DOI: 10.6060/ivkkt.20246712.7082.

A study on the thermal behavior of coal gangue mountains under airflow influence based on MD and CFD simulations

The long-term accumulation of coal gangue can lead to an increase in internal temperature. If the temperature becomes excessive, it can cause spontaneous combustion, posing serious environmental risks. The process is significantly influenced by external airflow. This study analyzes the thermodynamic properties and oxidation heat release rate of coal gangue samples through laboratory experiments. Subsequently, molecular dynamics (MD) simulations are used to investigate the mechanism of oxidation heat release during the heating process of coal gangue under varying oxygen supply conditions. Based on these findings, a coupled three-field model for the heating process of coal gangue mountains is developed. Using computational fluid dynamics (CFD) methods, transient simulations are conducted to analyze the internal thermal behavior of coal gangue mountains under the influence of external airflow, clarifying the risks of spontaneous combustion. The results indicate that after reaching T2 (295.16 °C), coal gangue enters an accelerated oxidation phase, with an increased heat release rate, heightening the risk of spontaneous combustion. The oxidation heat release rate of coal gangue accelerates with rising temperature and oxygen concentration, entering a rapid reaction phase after 300 °C, with a sharp increase in reaction rate. Compared to N2, coal gangue surfaces exhibit stronger adsorption of O2, and temperature changes affect N2 diffusion more sensitively (O2 diffusion coefficient increases by 0.312 Å2/ps, N2 diffusion coefficient increases by 0.334 Å2/ps). The isosteric heat of O2 adsorption in coal gangue decreases significantly with increasing adsorption amount, and higher temperatures hinder competitive adsorption of O2. The temperature in the deep and foot areas of the coal gangue mountains is lower, while the middle and upper areas near the slope surface exhibit higher temperatures, indicating a higher risk of spontaneous combustion in these regions. When environmental wind speed is too high or too low, both the internal temperature of the coal gangue mountains and the area of spontaneous combustion risk zones decrease. At a wind speed of 3 m/s, the spontaneous combustion risk zone reaches its maximum area of 73.47 m2, but when the wind speed increases to 7 m/s, the risk area decreases to 65.72 m2.

Enhanced photo-oxidation of hormones in water using biomass waste-derived hydrochar composites as photocatalysts

This study introduces a green chemistry approach to enhance the catalytic efficiency of metal oxides in photocatalytic reactions using agro-industrial waste. Specifically, rice husks and spent coffee grounds were utilized as carbon sources to produce hydrochars, which served as sustainable supports for ZnO and ZnFe₂O₄ oxides. This method promotes waste minimization and circularity by repurposing agricultural byproducts, reducing the environmental impact of traditional catalyst production. The hydrochars were synthesized through mild hydrothermal carbonization (250 °C for 4 h) and characterized by various physicochemical analyses. Their photocatalytic performance was evaluated using a 20 mg L−1 solution of conjugated estrogens under ultraviolet light (120 W cm−2) for 30 min. Composites with ZnO exhibited a significant increase in oxidation reaction rates due to enhanced porosity and an oxygen-rich structure. Reactive oxygen species (ROS) analysis revealed hydroxyl radicals (OH) as the primary agents, with photocatalytic efficiencies exceeding 83 % after eleven cycles. In toxicity tests, 4 mL of treated solution was applied to 20 Lactuca sativa (lettuce) seeds, kept in the dark at 25 °C for 7 days. Seeds exposed to treated solutions showed improved radicle elongation and germination rates compared to controls, except for those with coffee hydrochar and ZnO. This indicates effective degradation of toxic estrogens without harmful by-products. Overall, this work highlights the advantages of integrating green chemistry principles and circular economy practices, transforming waste into valuable materials to enhance environmental sustainability and catalytic performance.

S-scheme3D/3D Bi0/BiOBr/P Doped g-C3 N4 with Oxygen Vacancies (Ov) for Photodegradation of Pharmaceuticals: In-situ H2O2 Production and Plasmon Induced Stability.

Complications accompanying photocatalyst stability and recombination of exciton charges in pollutants degradation has been addressed through the construction of heterojunctions, especially S-scheme heterojunction with strong and distinctive redox centres. Herein, an S-scheme BiOBr (BOR) and g-C3N4PO4 (CNPO) catalyst (BORCNPO) with oxygen vacancy (Ov) was synthesized for levofloxacin (LVX) and oxytetracycline (OTC) photodegradation under visible light. The 3D/3D BORCNPO catalyst possessed C-O-Br bridging bonds for efficient charge transfer during the fabrication of S-scheme heterojunction. In-situ H2O2 formation affirmed by potassium titanium (IV) oxalate spectrophotometric method improved the mineralization ability of BORCNPO7.5 catalyst. Bi0 surface plasmon resonance (SPR) enhanced formation and involvement of ⋅O2 - and the stability of the catalyst which increased reaction rate with increasing cycling experiments. XPS and radical trapping experiments supported the S-scheme charge transfer mechanism formation with high degradation rate of LVX which was 3 times higher than OTC degradation rate. Mineralization of pollutants and their intermediates were demonstrated with florescence excitation and emission matrix (FEEM) and quadruple time of flight high performance liquid chromatography (QTOF-HPLC). This work advances development of highly stable and efficient catalysts for photodegradation of pollutants through the formation of S-scheme heterostructure.

Sustainable Sulfur-Carbon Hybrids for Efficient Sulfur Redox Conversions in Nanoconfined Spaces.

Nanoconfinement is a promising strategy in chemistry enabling increased reaction rates, enhanced selectivity, and stabilized reactive species. Sulfur's abundance and highly reversible two-electron transfer mechanism have fueled research on sulfur-based electrochemical energy storage. However, the formation of soluble polysulfides, poor reaction kinetics, and low sulfur utilization are current bottlenecks for broader practical application. Herein, a novel strategy is proposed to confine sulfur species in a nanostructured hybrid sulfur-carbon material. A microporous sulfur-rich carbon is produced from sustainable natural precursors via inverse vulcanization and condensation. The material exhibits a unique structure with sulfur anchored to the conductive carbon matrix and physically confined in ultra-micropores. The structure promotes Na+ ion transport through micropores and electron transport through the carbon matrix, while effectively immobilizing sulfur species in the nanoconfined environment, fostering a quasi-solid-state redox reaction with sodium. This translates to ≈99% utilization of the 2e- reduction of sulfur and the highest reported capacity for a room temperature Na-S electrochemical system, with high rate capability, coulombic efficiency, and long-term stability. This study offers an innovative approach toward understanding the key physicochemical properties of sulfurcarbon nanohybrid materials, enabling the development of high-performance cathode materials for room-temperature Na-S batteries with efficient sulfur utilization.

Temperature sensitivity of the mineral permafrost feedback at the continental scale.

Oxidative weathering of sulfide minerals in sedimentary rocks releases carbon dioxide (CO2) into the atmosphere. In permafrost zones, this could be a positive feedback on climate change if it increases with warming, yet sulfide oxidation rates and their temperature response remain unknown over large spatial and temporal scales. We analyze a 60-year sulfate concentration dataset from catchments across the Mackenzie River Basin. Sulfate fluxes increased by 45% in the mainstem with 2.3°C of warming, and the temperature sensitivity suggests that continental-scale CO2 fluxes could double by 2100. The largest increases occur in catchments with geomorphic settings which act to rapidly expose rocks through physical weathering and thermokarst processes. Comparisons with a weathering model suggest that warming can increase reaction rates, and changes in the exposure of minerals with warming are also required. Future warming across vast Arctic landscapes could further increase sulfide oxidation rates and affect regional carbon cycle budgets.

In situ thermal-assisted photocatalytic decarboxylation of high-concentration biomass-derived fatty acids to alkanes

Heating is a straightforward method to increase reaction rates to meet industrial production, yet photocatalysis seldom incorporates it because their intrinsic driving force depends on the separation of photogenerated carriers, which is rarely affected by temperature. Here, we report a temperature-dependent photocatalytic decarboxylation strategy for producing long-chain n-alkanes from biomass-derived fatty acids using only the photothermal effect of the SnS catalyst. Under concentrated light irradiation without any external heating, and by employing high boiling-point solvents to reach optimal reaction temperatures (∼254 °C), Cn-1 n-alkane allows a very high concentration output (∼0.5 M for stearic acid to n-heptadecane) in a single operation, which is far beyond the capacity limit of conventional photocatalysis, typically no more than the mM levels. Mechanistic studies suggest that the in-situ heat brings the standing C-chain at low temperature down onto the SnS surface, increasing strain on the C-COO- bonds and facilitating reaction with photo-induced hole-electron pairs. We demonstrate that the majority of the incident light energy, when converted to heat, accelerates the photocatalytic decarboxylation.