Gaseous Products Research Articles

The Synergistic Effects of Expandable Graphite and Ammonium Polyphosphate on the Properties of Flame-Retardant Nitrile Butadiene Rubber

This paper, investigated the effects of expandable graphite and ammonium polyphosphate on the flame-retardant properties of nitrile butadiene rubber. Several formulations of NBR were prepared by combining different ratios of expandable graphite and ammonium polyphosphate to evaluate their synergistic flame-retardant effects. The results show that the combination of expandable graphite and ammonium polyphosphate significantly enhances the flame-retardant effects of nitrile butadiene rubber, as evidenced by improved limiting oxygen index values, horizontal burning rates decreased and passed the UL-94 V1 when the ratio of expandable graphite and ammonium polyphosphate as (2/1). Results from TGA demonstrated that the ammonium polyphosphate/expandable graphite combination could retard the degradation of rubber by promoting the formation of a compact char layer on the condensed phase surface. This char layer effectively protects the matrix from heat penetration and the diffusion of flammable gas products, resulting in better flame-retardant performance. The effect of flame retardant on the mechanical properties of nitrile butadiene rubber was also evaluated. The results showed that the mechanical properties decreased with increasing flame retardant content.

Reaction Pathway Regulation for Gaseous and Liquid Products of Electrocatalytic CO2 Reduction under Adsorbate Interactions

AbstractHalide anion adsorption on transition metals can improve the performance of electrochemical CO2 reduction reaction (CO2RR), while the specific reaction mechanisms governing selective CO2RR pathways remain unclear. In this study, we reveal for the first time the distinct pathway switching between gaseous (CO) and liquid products (formate and ethanol) on the well‐defined Ag−Cu nanostructures with controlled chlorination. We show that CO2 conversion to CO on Ag/AgCl can be tuned by adjusting the thickness of AgCl layer, achieving a high selectivity over a broad potential range in a 0.5 M KHCO3 using flow cell. In contrast, the optimized Cl−Ag/Cu system enables the conversion of CO2 into liquid products including formate and ethanol with a total Faradaic efficiency (FE) nearing 100 %, delivering high current densities of 136.3 and 20.8 mA cm−2 at −1.3 V, respectively. In situ infrared experiments and theoretical calculations indicate that the lateral adsorbate of *OCHO intermediate facilitates the thermodynamics of both the CO pathway on Cl−Ag(111) and the formate pathway on Cl−Ag/Cu(111) by reducing Gibbs free energy barriers of each potential‐limit step. This work uncovers the role of chlorination in the tuning of C‐bound or O‐bound intermediates during CO2RR on Ag−Cu catalysts, determining the reaction pathway under lateral adsorbate effects.

Green villages by Wind + Solar + Hydrogen

This paper describes 5 steps on the move to cost-effective green villages, powered mainly by Solar, Wind and Hydrogen. In Britain, there are around 6000 villages comprising almost half the total population. These village dwellers wish to reduce their expensive energy bills, achievable by profitably going green with local Wind and Solar generation of electricity plus Hydrogen energy storage. The first step is to measure the total energy usage in the village. This defines the size of the required renewable private wire energy installations. The second step calculates savings on grid bills for electricity, natural gas and petroleum transport products, to ensure rapid payback for the renewables to be installed. A third concern is the planning permission for Wind/Solar installations that may take months to approve. Perhaps the most important requirement is to attract investment in the fourth step. Finally, the fifth step is to procure and commission the equipment needed in the village to prove that local energy can beat the present centralized grid energy systems, using Hydrogen as the vital energy storage molecule to fill gaps in Wind/Solar supply.

Spatial resolution of a velocity-selected ion imaging microscope for surface reaction kinetics mapping.

Experimental validation of complex microkinetic models derived from quantum chemistry is crucial for the advancement of bottom-up approaches to heterogeneous catalysis. State-of-the-art velocity-resolved kinetics experiments have made tremendous progress in this arena but integrate reactivity over centimeter-scale single-crystal catalytic surfaces even when complex spatial phenomena may perturb the kinetic results. We report a new design, optimization, and analysis of an ion imaging microscope that can collect spatially resolved kinetic data from a catalytic surface. In its simplest configuration, gaseous reaction products are ionized by a laser line or sheet above a catalytic surface. The resulting ions are extracted and strongly lensed to an intermediate velocity-mapped plane where a pinhole of radius r only transmits ions produced from reaction products with desorption velocities within a narrow solid angle centered on the surface normal. Transmitted ions re-expand through an electrostatic zoom lens to form a spatial image of the initial reaction product distribution with reduced blur from desorption velocity components parallel to the surface. The ion hits that define the magnified and deblurred spatial image can be used to determine spatiotemporal flux and speed-distributions of gas leaving the catalyst surface. Electrostatic trajectory simulations are performed and verify that transmission is ∝r2/TSurface. However, calculated global point spread functions acting on the magnified image have a width that is ∝r and largely independent of TSurface. Thus, velocity-filtered ion imaging microscopy can deliver a consistent resolution as the TSurface is varied, which is a great advantage because many catalytic reactions require elevated temperatures.

Reaction Pathway Regulation for Gaseous and Liquid Products of Electrocatalytic CO2 Reduction under Adsorbate Interactions.

Halide anion adsorption on transition metals can improve the performance of electrochemical CO2 reduction reaction (CO2RR), while the specific reaction mechanisms governing selective CO2RR pathways remain unclear. In this study, we demonstrate for the first time the distinct pathways for gaseous (CO) and liquid products (formate and ethanol) on the well-defined Ag-Cu nanostructures with controlled chlorination, respectively. We show that CO2 conversion to CO on Ag/AgCl can be tuned by adjusting the thickness of AgCl layer, achieving a Faradaic efficiency (FE) near 100% over a broad potential range in a 0.5 M KHCO3 using flow cell. In contrast, the optimized Cl-Ag/Cu system enables the conversion of CO2 into liquid products including formate and ethanol with a total FE nearing 100%, delivering high current density under similar conditions. In situ infrared experiments and theoretical calculations reveal that the lateral adsorbate of *OCHO intermediate facilitates the thermodynamics of both the CO pathway on Cl-Ag(111) and the formate pathway on Cl-Ag/Cu(111) by reducing Gibbs free energy barriers of each potential-limit step. This work uncovers the role of chlorination in the tuning of C-bound or O-bound intermediates during CO2RR on Ag-Cu catalysts, determining the reaction pathway under lateral adsorbate effects.

Developing Heterogeneous Catalysts for Reverse Water–Gas Shift Reaction in CO2 Valorization

Abstract Carbon dioxide capture and utilization (CCU) in chemical processes is vital for achieving sustainable and economically viable solutions in the context of climate change mitigation. This review focuses on the reverse water–gas shift (RWGS) reaction as a promising pathway for converting CO₂ into carbon monoxide (CO), which can subsequently be used as a precursor for the synthesis of various hydrocarbon compounds. The discussion centers on catalyst design strategies aimed at enhancing the low-temperature activity of the RWGS reaction, emphasizing the roles of catalyst supports and active sites. Key approaches include increasing surface area, introducing defect sites, and improving the redox properties of the catalysts. Methods for controlling the adsorption strength of gas reactants and products to enhance CO selectivity are explored, with particular attention to the use of ligands, promoters, doping, and advanced structures such as single-atom or core–shell configurations. Considerations regarding catalyst durability in reducing environments and the development of economically feasible catalysts are also addressed. Well-designed catalysts for the RWGS reaction offer significant advantages in CO₂ valorization, as the conversion of CO₂ to hydrocarbons is more readily achieved starting from CO.

Sulfite Pretreatment Enhances Tobacco Stalk Deconstruction for Cellulose Saccharification and Lignin Pyrolysis

Sulfite-catalyzed acid pretreatment to overcome the inherent recalcitrance of biomass offers a significant advantage in terms of obtaining high glucose conversion. However, the residual lignin after enzymatic hydrolysis has not been fully exploited. Herein, this study introduced a joint approach using sulfite-catalyzed acid pretreatment (SPROL) and pyrolysis to upgrade tobacco stalk to produce fermentable sugar, and the resulting lignin is used to produce bio-oil and bio-char. The results suggest that SPROL pretreated tobacco stalk yields a high cellulose-based glucose selectivity of 75.9% with 15 FPU/g substrate enzyme dosage at 50 °C after 72 h of enzymolysis. Lignin characterization reveals that sulfonation occurred during SPROL pretreatment, and as the dosage of sulfonating agent increased, the thermal stability of the residue lignin decreased. After sample pyrolysis at 600 °C for 30 min, approximately 22%, 33%, and 45% of the lignin undergoes conversion into bio-oil, bio-char, and gas products, respectively. The bio-oil analysis results demonstrated that acetic acid is the most abundant identified GC-MS component at around 69.91% at the optimal condition, which implied that it could be of high value when utilized for pyroligneous acid. This research provides a synthetic approach using the SPORL technique to process tobacco stalk into fermentable sugar, bio-oil, and bio-char, which is significant for the commercial utilization of agricultural waste into value-added products.

The Conversion of Ethanol to Syngas by Partial Oxidation in a Non-Premixed Moving Bed Reactor

An experimental investigation into the conversion of ethanol to syngas by partial oxidation in a non-premixed counterflow moving bed filtration combustion reactor was carried out. Regimes of conversion depending on the mass flow rates of fuel and air (separate feeding), as well as a granular solid heat carrier, were studied. Depending on the mass flow rate of the heat carrier, two combustion modes were realized—reaction trailing and intermediate—with different temperature patterns in the gas preheating, combustion, and cooling zones along the reactor. The product gas composition is far from the predictions of the equilibrium model; it contains substation fractions of methane and ethylene. Combustion temperature and conversion are limited by the relatively high level of heat loss from the laboratory-scale reactor. The effect of the heat loss can be reduced by enhancing the absolute flow rate of the reactants.

The suppression and CO elimination performance of Co3O4 dust cloud for methane-air mixture explosion

This paper experimentally studied the effect of Co3O4 dust clouds on the methane-air mixture explosion characteristics and post-explosion CO concentration, aiming to propose a novel method for simultaneously suppressing explosion and eliminating CO product. The Co3O4 catalyst was synthesized utilizing the co-precipitation method. We varied the methane concentration and Co3O4 dust cloud concentration to investigate their effects on the flame propagation behavior, maximum explosion overpressure (Pm), flame combustion time (tc), and the gaseous product concentration. The hazard of the gaseous product was evaluated by the effective escape time (te) based on the Fraction Effective Dose (FED) mathematical model. The results demonstrated that the Co3O4 dust cloud could significantly reduce the explosion severity and CO concentration. Furthermore, the higher the concentration of Co3O4 dust clouds, the more significant the explosion suppression and CO elimination performance, which was as a result of the significant increase in the contact area and collision probability between the Co3O4 particles and the reaction components increased. Compared to traditional inhibitors that only reduce the severity of an explosion, Co₃O₄ could not only significantly reduce the explosion severity, but also quickly eliminate post-detonation CO. The method proposed in this paper could effectively reduce the hazard of methane-air mixture explosion, which was of great practical significance for ensuring the safety of personnel involved in the risk.

Insights into polymer electrolyte stability and reaction pathways: A first-principle calculations study.

To identify suitable polymer candidates for electrolytes in solid-state batteries, this study investigates the electrochemical behavior and decomposition pathways of four monomers involving esters, ethers, and carbonates via first-principles calculations. In particular, we determine the oxidation and reduction potentials of these monomers near different ions (Li+, TFSI-, and [Li]+[TFSI]-) and the corresponding reorganization energies. The latter quantity is central to Marcus theory of electron transfer and, therefore, provides additional kinetic information. Our results reveal notable sensitivity of the monomers to reduction in a Li+-rich regime and to oxidation in a TFSI--rich regime. Additionally, the reactivity and decomposition pathways of the monomers were investigated for various electrochemical environments, focusing on the quantification of gaseous and ionic products during the initial stage of formation of interphasial layers. Based on the electrochemical windows and spontaneous Ab initio molecular dynamics calculations, we observe that monomers containing carbonate groups exhibit greater stability against decomposition caused by reduction, especially in different regimes, when compared to monomers with ester and ether groups.

Pyrolysis kinetics and reaction mechanism of waste medical masks by sectional heating process

The COVID-19 epidemic has led to a significant upsurge in the accumulation of waste medical masks. This work focuses on the detailed examination of waste medical masks’ pyrolysis kinetic and reaction mechanism, employing a sectional heating process. The degradation properties were analyzed via thermal gravimetric analysis and pyrolysis reactor. The comprehensive kinetic process was studied using model-free and model-fitting methods, which determined the apparent activation energy and pre-exponential factor. The calculated average value for these parameters was 221.32 kJ/mol and 2.6 × 1014 min−1, respectively. The pyrolysis process was carried out at three distinct temperatures: 380, 470, and 490 ℃, corresponding to the initial peak degradation rate and final degradation temperatures determined by TGA results. The total yield of oil, gas and tar was 88.6 %, 11.3 % and 0.1 %, respectively. The identification and quantification of pyrolysis products were achieved through GC–MS and FTIR. It was observed that higher pyrolysis temperature facilitated the generation of alkanes and hydrocarbons with lower carbon chain lengths in oil products and propylene monomers in gas products. The dominant pyrolysis products in oil under 380 ℃, 470 ℃ and 490 ℃ were C20, C20 and C12 with the yield of 36.17 %, 48.96 % and 43.35 %, respectively. And the corresponding dominant products in gas all were propylene with the yield of 34.74 %, 53.02 % and 54.55 %, respectively. Furthermore, a reaction mechanism was postulated to elucidate the pyrolysis process under varying temperature conditions.

Experiment investigation and multiscale modeling of biomass oxidative fast pyrolysis in a fluidized bed reactor

Experiments were conducted in a fluidized bed reactor to study the oxidative fast pyrolysis of biomass. The pressure drops along the bed height were measured, and the yield and composition of gas, liquid, and solid products were analyzed at various O2 concentrations. It was found that with the increase in oxygen concentration, the yield of biogas increased, especially CO2 and CO, while yields of bio-oil and biochar decreased. Under oxidative conditions, the fraction of tar in bio-oil was significantly reduced. A multiscale model was developed in the open-source code MFiX by integrating the reactor model based on the coarse-grained DEM-CFD, the intraparticle model, and the biomass oxidative fast pyrolysis kinetics. The model was verified by comparison with experimental data. As the oxygen concentration increases, the mixing and separation of biomass particles decreases, the residence time increases, the axial distribution moves upward, and the Lacey mixing index decreases. This study established experimental and theoretical foundations for designing and scaling up oxidative fast pyrolysis of biomass in fluidized beds.

ИССЛЕДОВАНИЕ ПРОДУКТОВ ГОРЕНИЯ ЭПОКСИДНЫХ ПОЛИМЕРОВ, МОДИФИЦИРОВАННЫХ ФОСФАТАМИ МЕДИ И АММОНИЯ

The paper presents the data reflecting the influence of copper (II) solutions of orthophosphate hydroxide in the mixture H3PO4: (NH4)2HPO4 = 10 : 1 (wt.) on the combustion process of polymers based on epoxydian resin ED-20 and hardener triethylenetetramine. It was found that during the combustion of the designated objects carbonized phosphates and (poly)oxonitrides of phosphorus are formed. Copper plays the role of a catalyst in the processes of coke layer formation, the structure of which is largely determined by the amount of gaseous products.

New insights into typical biodegradable plastics in rapid pyrolysis: Kinetics, product evolution and transformation mechanism

Biodegradable plastics (BP) have undergone rapid development in the field of replacing traditional packaging plastics. However, their recycling and disposal systems are unclear, and the standards are different, causing new environmental pollution. The rapid and appropriate disposal of BP has become a worthy direction of exploration. Here, rapid pyrolysis technology was used to explore the recycling of BP, and the product evolution and transformation mechanism of typical BP (BP1∼BP4) were analyzed. The results show that the main reaction stages of BP pyrolysis are concentrated at approximately 260∼450 °C. Most of the heat treatment stages of BP conform to the random nucleation and nuclear growth model An (n = 1.5, 2, 2.5. 3). The gaseous products of BP pyrolysis were mainly 1, 3-butadiene. The top four pyrolysis components are the same for the liquid products of BP1, BP2, and BP4, which are mainly benzoic acid (42.54%–44.67%). However, the proportion of polycyclic aromatic substances in the products of the BP3 pyrolysis solution was as high as 63.85%. For the transformation mechanism, BP containing polylactic acid (PLA) and polybutylene terephthalate-adipate (PBAT) is mainly composed of C–O bond fractures at the ester group and intramolecular hydrogen transfer to form a carboxyl group and CC. This study of BP pyrolysis provides an important scientific basis and theoretical reference for its rational and rapid treatment and product recovery and reuse.

Electrochemical Liquid Phase TEM in Aqueous Electrolytes for Energy Applications: the Role of Liquid Flow Configuration.

Electrochemical liquid phase transmission electron microscopy (EC-LPTEM) is an invaluable tool for investigating the structural and morphological properties of functional materials in electrochemical systems for energy transition. Despite its potential, standardized experimental protocols and a consensus on data interpretation are lacking, due to a variety of commercial and customized electrical and microfluidic configurations. Given the small size of a typical electrochemical cell used in these experiments, frequent electrolyte renewal is crucial to minimize local chemical alterations from reactions and radiolysis. This study explores the effects of modifying the flow configuration within the liquid cell under experimental conditions relevant for energy applications in aqueous-based electrolytes, revealing how changes in mass transport dynamics drastically influence the electrochemical response of the cell. Two different cell designs are compared: convection- and diffusion-governed. Ex situ and in situ comparative flow experiments show that the diffusion cell mitigates gas bubbles formation and improves removal of gaseous products. The electrodeposition of Zn nanostructures and the characterization of a Cu-based catalyst are presented as proof-of-concept experiments for energy storage and CO2 reduction reaction (CO2RR) applications, respectively. The reported findings demonstrate that controlling mass transport in the liquid cell setup is crucial to obtain reliable operando experimental electrochemical conditions.

Pyrolysis characterization and mechanism studies of different structural plastics: A comparative study at optimal temperatures

Thermal conversion technology is an effective means to transform waste plastics into high-value-added products. This study explored the thermal decomposition characteristics and cracking mechanism of four different types of plastics (polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET)) for thermal conversion technology. The findings revealed that PP exhibited the highest hydrogen yield, reaching 3.56 mmol/g at 510°C. PET's gas production was predominantly comprised of carbon monoxide and carbon dioxide. PVC gas products contained a significant amount of HCl, followed by hydrogen and methane. For solid products, the carbon yield followed the order PET > PVC > PS > PP, with the carbon content of PET accounting for 35.63% of the total products. PP and PS demonstrated higher oil yields for liquid products than PET and PVC. The oil yield of PP was 94.38%. Further analysis of the cracking mechanism found that during the thermal decomposition process, plastics underwent random fragmentation, leading to reactions such as β-scission, intramolecular and intermolecular hydrogen transfer, rearrangement, cyclization, etc., due to structural variations. This work provided foundational data for the thermal decomposition studies of different types of plastics.

Thermal characteristics and recycling of bolus – a polyurethane-based material used in radiotherap

The thermal resistance was investigated and the potential for recycling of a polyurethanebased polymer material (bolus) in the form of a gel constituting medical waste after irradiation with ionizing energy was indicated. The same gel, which was not subjected to radiotherapy, was used asa reference material. Thermal stability, the course of oxidative decomposition and the type of volatile substances released during heating in an oxidizing atmosphere were examined using the TG/FT-IR method. The glass transition temperature (Tg) of the tested materials before and after irradiation was determined using the DSC method. It was found that irradiation caused a slight change in Tg and increased thermal stability. However, the irradiation time had no effect on the type of gaseous decomposition products released during heating in an oxidizing atmosphere. The used polyurethane material (bolus)was recycled to obtain new composite materials with different physicochemical properties.

Pemanfaatan Hukum Internasional dalam Penyelesaian Sengketa Laut China Selatan: Analisis dengan Pendekatan Doktrinal

The South China Sea is a strategic region of global significance, both economically and geopolitically. It serves as a major global trade route, with over 30% of global trade passing through it annually. Additionally, the South China Sea is rich in natural resources, including oil, gas, and abundant marine products. However, overlapping territorial claims among countries such as China, the Philippines, Vietnam, Malaysia, Brunei, and Indonesia have triggered prolonged geopolitical tensions. This study aims to analyze the role of international law, particularly UNCLOS 1982, as the primary framework for resolving these disputes. Using a doctrinal approach, the study examines primary legal documents, such as UNCLOS 1982, the 2016 Arbitration Award, and ASEAN agreements. Data shows an average of 15 annual conflicts in the South China Sea over the past decade, with a significant increase from 5 cases in 2014 to 25 cases in 2023. While UNCLOS 1982 provides a clear legal framework, non-compliance with arbitration rulings, such as China's refusal to adhere to the 2016 ruling, highlights weaknesses in enforcement mechanisms and sanctions. This study emphasizes that multilateral approaches based on international law, supported by regional mechanisms like ASEAN, have yet to achieve full effectiveness. The findings offer strategic recommendations, including reforming international sanction mechanisms and strengthening ASEAN frameworks to support conflict resolution and ensure sustainable stability in the region

Effects of the mixing ratios of n-decane/methylcyclohexane binary fuel on the thermal cracking and carbon deposition propensity

The development of high-performance fuels for high-speed vehicles requires attention to the effects of interactions between different components of the fuels as coolant on cracking and carbon deposition. Pyrolysis and coking of n-decane and methylcyclohexane (MCH), which represent the n-alkane and cycloalkane classes, respectively, were conducted with electrical heating under supercritical conditions. The gas and liquid products were analyzed by GC–MS, while the coking properties were obtained by characterization methods including programmed temperature oxidation (TPO), scanning electron microscopy (SEM), and Raman spectroscopy. The results demonstrate that at the mixing ratio of 8:2, the gas yield is highest reaching about 41.8 % at 700 °C, while a smaller amount of coking precursors are produced, exhibiting excellent anti-coking performance. Meanwhile, the coke is gradually transformed from filamentous carbon to spherical carbon with a lower graphitization degree and higher oxidation activity. The addition of MCH mainly promotes the generation of ethylene to improve the degree of cracking of the fuel while reducing the generation of propylene and 1,3-butadiene, thereby reducing coke deposition. The regulation of fuel composition can achieve the effect of increasing the cracking depth and inhibiting coking simultaneously. The results can provide theoretical guidance for the adjustment of advanced fuel composition.

Minor theft committed from oil, oil product and gas pipelines

Relevance. The article deals with the issues of insignificance of the act, stipulated by item. "b" part 3 part 3 of article 158 of the Criminal Code of the Russian Federation. The grounds and conditions of the grounds and conditions of insignificance of thefts. On the basis of the study of judicial practice are outlined peculiarities of application of the provisions on insignificance to theft of hydrocarbon raw materials from the pipeline raw materials.Purpose: to study the possibility and conditions of applying the provisions of part 2 of article 14 of the Criminal Code of the Russian Federation to the theft committed from an oil pipeline to theft committed from an oil pipeline, oil product pipeline and gas pipeline (item "b", part 3, article 158 of the Criminal Code of the Russian Federation).Objectives: study and identification of conditions of application of insignificance of a deed to the theft from pipelines on the basis of analysis of modern judicial practice and provisions of doctrine of criminal law. Methodology. The methodological basis of the study was the general dialectical method of scientific cognition. of scientific cognition. The author used such private methods as: Formal-legal, sociological and method of legal modelling.Results. The authors analyzed and summarized the conditions, distinguished in the theory of criminal law, under which a specific socially dangerous act can be recognized as insignificant and projected on theft committed from an oil pipeline, petroleum product pipeline, petroleum product pipeline. oil, oil product and gas pipelines, and studied the materials of materials of judicial and investigative practice on the termination of criminal cases on theft of raw materials from the thefts of raw materials from pipelines due to insignificance, the author's conditional criteria were singled out criteria under which the theft of oil, oil products or gas can be considered a low-value act. as an insignificant act.Conclusion: the individual danger of a specific fact of theft from pipelines in some situations may not correspond to the level of criminal danger, which the legislator has laid down in the relevant act as a result of its criminalization. The conducted research allows us to determine the approximate mandatory and optional signs for recognizing theft from pipelines as insignificant.