Gas Generation Research Articles

Prediction of quaternary SnGeS2As4 monolayer as a promising photocatalyst in water splitting: A DFT study

Abstract The SnGeS2As4 monolayer was studied by first-principles calculations to estimate its potential for used as photocatalyst in water splitting process. The stability of this structure is confirmed based on the analysis of its phonon dispersion and AIDM simulation. The electronic features including density of state (DOS), band structure, and Bader charge were calculated. These data show the role of each constitute element in the formation of covalent π− and σ−bonds, which play important role in stabilizing the buckled honeycomb structure. Besides, the DOS and band structure also provide information regarding to the high light absorption rate α(ω) of 105–105 cm−1. The positions of valence band maximum (VBM) and conduction band minimum (CBM) are suitable for generation of hydrogen and oxygen gases. The SnGeS2As4 monolayer also has optimal work function 5.16 eV for water splitting process and a rather high solar-to-hydrogen efficiency ηSTH = 13.11%. It is worth to note that SnGeS2As4 monolayers with strains ranging from −2% to 6% are still capable to trigger redox reactions in the water splitting process. Moreover, the tensile trains slightly increase the light absorption rates. Such characteristics not only make SnGeS2As4 monolayer a suitable photocatalyst for water splitting but also ensure its performance in wider range of applications

Nuclear Cogeneration to Support a Net-Zero, High-Renewable Electricity Grid

UK Government projections anticipate increasing electricity use, provided by variable renewables (i.e., wind and solar PV). A side effect of increasing the proportion of variable renewable generation is increased support costs, including curtailment, energy storage, and (most significantly) the cost of supplying electricity for periods of high demand when variable renewable generation is low. As the proportion of variable renewable capacity increases, demand for supporting capacity increases but the capacity factor of the support generation decreases, raising the support costs. Using nuclear power for dedicated baseload supply makes the situation worse. This paper explores in the UK context an original low-cost solution using nuclear cogeneration with hydrogen production as the main application. Electricity is diverted at low cost to the grid at times of high demand when renewables are not available. This ensures nuclear maintains a high capacity factor. When higher temperature advanced systems become available, using thermal energy storage will increase the nuclear electrical capacity. This “Flexible Nuclear” scenario substantially reduces support costs for accommodating variable renewables, saving GBP 14 bn/yr and leading to an 80% reduction in CO2 equivalent emissions, compared to a recent UK Government scenario utilising a large capacity of hydrogen and unabated gas generation at very low capacity factors.

Numerical Analysis of Gas Generation and Migration in a Radioactive Waste Disposal Cell of a Deep Geological Repository

Abstract In a deep geological repository (DGR) for the long-term disposal of radioactive waste, gases (e.g., hydrogen (H2), carbon dioxide (CO2) and methane (CH4)) can be generated through a number of processes, such as corrosion of various metals and alloys and degradation of organic materials. If gas induced pressure exceeds the containment capacity of the engineered barrier systems (EBS) or the host rock, the gases could migrate through these barriers and potentially expose people and the environment to radiation. Therefore, a good understanding on the long-term performance of these barriers against gas migration is an important component in DGR design and safety assessment. In the present work, a numerical model has been developed to simulate the diffusion of CO2 (one of the gas species) in the near field of a DGR with the generation from related chemical reactions. The generation of CO2 was investigated to determine if it is a critical factor to impact the DGR safety under Canadian geological formations. A commercial computational fluid dynamics (CFD) code, ANSYS Fluent was used for the calculations. The model considered pH and temperature effects on CO2 migration under Canadian DGR geochemistry conditions.

System Design and Launch of a Hybrid Rocket with a Star-Fractal Swirl Fuel Grain Toward an Altitude of 15 km

To achieve low-cost and on-demand launches of microsatellites, the authors have been researching and developing a micro hybrid rocket since 2014. In 2018, a ballistic launch experiment was performed using the developed hybrid rocket, where it reached an altitude of about 6.2 km. The rocket engine had a 3D-printed solid fuel grain made of acrylonitrile butadiene styrene (ABS) resin in combination with a nitrous oxide oxidizer. The fuel grain port had a star-fractal swirl geometry in order to increase the surface area of the port, to promote the laminar–turbulent transition by increasing the friction resistance, and to give a swirling velocity component to the oxidizer flow. This overcame the hybrid rocket’s drawback of a low fuel regression rate; i.e., it achieved a higher fuel gas generation rate compared with a classical port geometry. In 2021, the hybrid rocket engine was scaled up, and its total impulse was increased to over 50 kNs; it reached an altitude of 15 km. In addition to the engine, other components were also improved, such as through the incorporation of lightweight structures, low-shock separation devices, a high-reliability telemetry device, and a data logger, while keeping costs low. The rocket was launched and reached an altitude of about 10.1 km, which broke the previous Japanese altitude record of 8.3 km for hybrid rockets. This presentation will report on the developed components from the viewpoint of system design and the results of the ballistic launch experiments.

Magnetite–poly-1H pyrrole dendritic nanocomposite seeded on poly-1H pyrrole: A promising photocathode for green hydrogen generation from sanitation water without using external sacrificing agent

Abstract The Fe3O4 magnetite–poly-1H pyrrole dendritic nanocomposite seeded on additional poly-1H pyrrole film, denoted as Fe3O4-P1HP/P1HP, is synthesized by oxidative polymerization utilizing (Fe(NO3)3·5H2O for the pyrrole monomer. The resulting nanocomposite exhibits a notable bandgap of 1.97 eV and demonstrates broad optical absorption up to 625 nm. The structure of each particle consists of numerous smaller internal particles, which are composed of nanofibers of approximately 2.0 nm in length and porous structures of around 5.0 nm. These porous structures cluster together to form a larger configuration, with an overall diameter of ∼230 nm and a length of approximately 300 nm, giving the composite a nano-cactus-like appearance. The fabricated Fe3O4–P1HP/P1HP photocathode is inserted into a three-electrode cell to facilitate green hydrogen production from sanitation water without the need for any external sacrificial agent. The performance of H2 gas generation is assessed by measuring the photocurrent density (J ph) under light, which serves as an indicator of the efficiency of hydrogen production. The J ph value reaches −0.23 mA/cm² under light conditions. The highest J ph values of −0.164 and −0.158 mA/cm² are observed at wavelengths of 340 and 440 nm, respectively. However, as the wavelength reaches 540 nm, the J ph value decreases to −0.134 mA/cm² and drops to its lowest point of −0.128 mA/cm² at 730 nm, which is comparable to the dark current (J o). The fabricated photocathode demonstrates a promising hydrogen generation rate of 90 µmol/h cm², reflecting its potential for commercial applications. The combination of this impressive hydrogen production rate, along with the photocathode’s cost-effectiveness and straightforward fabrication process, suggests that this technology could be commercially viable for converting sanitation water into hydrogen gas.

Optimization of Parameters Responsible for the Rate of Gas Generation Through Mixed Anaerobic Digestion

Optimization of Parameters Responsible for the Rate of Gas Generation Through Mixed Anaerobic Digestion

Design and Implementation of a Cost-Effective, Safe, and Precise Lean-Rich Generating System for NOX Storage Reduction Catalyst Evaluation: Performance Analysis, Statistical Modeling, and Multiple Response Optimization – A Guideline for Future Research and Application

Mixing is a critical factor in chemical reaction engineering, particularly in the development of new catalysts for pollutant removal, such as NOx storage reduction catalysts. Comprehensive performance evaluation in laboratory experiments requires high-quality test gases. Several techniques have been developed for generating these gases, each with specific advantages and limitations. This research presents a simple, safe, and cost-effective gas generation system for laboratory applications, including evaluating adsorbents and catalysts, particularly NOx storage reduction catalysts, and for toxicological studies using precise dynamic methods like gas stream mixing and evaporation. Components of the dynamic system—including gas cylinders, connections, mixing chambers, rotameters, the quartz reactor with preheating chamber, bubbler systems, and tubular heaters—are comprehensively described. Statistical modeling and optimization were employed to determine the optimal operating conditions. The optimal conditions were identified as NO (924 ppm), O₂ (15%), CO (9999 ppm), and a space velocity of 105,921 h⁻¹. Additionally, the system's ability to generate various mixtures of gases (NO, O₂, and CO) and vapors (toluene and water) was assessed. The system was further evaluated under fan-on and fan-off modes to assess its performance under varying turbulent conditions. A detailed analysis was performed to determine the relative errors, time to reach steady-state conditions, and actual concentrations produced under different expected concentrations (NO: 100-200 ppm, O₂: 3-15%, CO: 500-10000 ppm, toluene: 64-8999 ppm, relative humidity: 0.14-22.69%), space velocity (70,000-140,000 h⁻¹), bubbler flow rates (10-600 mL/min), and saturator temperatures (5-20°C). Fundamental equations for calculating conversion, selectivity, and yield of a component of interest, carbon-messing, and carbon balance in the mixture are also provided.

Hydrogen-rich gas generation from enhanced catalytic cracking of biomass tar and related model compounds on Ni-Fe/ASA@HZSM-5 catalyst: Pathways and mechanisms

This study focused on the design of complex tar model compounds (CTMC) and synthesized a highly efficient aluminum dross (ASA) combined with HZSM-5 molecular sieve co-loaded bimetallic Ni-Fe catalyst (Ni-Fe/ASA@HZSM-5), comprehensively evaluated the catalytic cracking of real tar and its model compound by adjusting the injection amount and injection state of tar, and catalyst types to obtain hydrogen-rich gas with high H2 and low CO2 content. The results showed under the conditions of the injection amount of 0.6 mL/min, pyrolysis temperature of 600 °C, reforming temperature of 800 °C in the liquid phase, Ni-Fe/ASA@HZSM-5 displays excellent catalytic cracking performance with CTMC conversion efficiency of 87.80 % (79.46 % of gas yield and 34.20 vol% of H2 yield). The possible cracking paths between different components of CTMC in the Ni-Fe catalytic system were summarized by the experimental data and product distribution, the catalytic mechanism of Ni–Fe based catalysts can be attributed to the formation of a Ni-Fe alloy and the synergistic effect of ASA and HZSM-5 co-carrier. Further, the catalytic cracking pathway of CTMC was enhanced in the gas phase, the higher CTMC conversion efficiency of 93.68 %, gas yield (a mass fraction of 82.51 %) and H2 (a volume fraction of 33.59 %) were obtained from catalytic cracking of CTMC, the liquid yield decreased by 12.39 %, significantly improved the cracking degree and gas production capacity of CTMC. The real tar showed the same catalytic pyrolysis path and product distribution. Under the same cracking conditions, the yields of gas, liquid and char were 84.85 %, 12.00 % and 3.15 % respectively, and obtained the hydrogen yield of 55.29 mL/g. The CTMC simplifies the cracking process and reduces polymerization, provides insights into the cracking mechanisms of heavy components in biomass tar. Furthermore, the synergy of Ni and Fe contributed to greater activity for CTMC and real tar cracking, ASA combined with HZSM-5 molecular sieve co-loaded bimetallic Ni-Fe catalysts have a promising application potential as highly efficient catalysts for tar removal and reutilization.

Experimental study on the influence of CO2 injection on coal spontaneous combustion characteristics and molecular functional groups

The study aims to investigate changes in the spontaneous combustion characteristics of coal and its microscopic reaction mechanisms in a CO2 atmosphere. Programmed heating experiments and thermogravimetric analysis were conducted to examine index gas and combustion parameters in both air and CO2 atmospheres. Molecular functional group changes were analyzed via in situ infrared experiments, and their correlation with index gases was assessed using the grey correlation method. The results revealed that CO2 injection during the initial heating stage increased the production of CO, CH4, and C2H4. However, beyond 160 °C, CO2 effectively reduced the oxidation activity of functional groups and significantly inhibited the production of indicator gas. The characteristic temperature range of coal samples exhibited a 'lag' phenomenon under the influence of CO2, resulting in a prolonged combustion stage with reduced mass loss and heat discharge. Following CO2 injection, the -OH concentration significantly decreased, while C=O gradually increased. Additionally, the concentrations of -COOH, aliphatic hydrocarbons, and aromatic hydrocarbons initially increased with rising temperature and then declined. The contribution of these groups to gas generation followed the sequence of oxygen-containing functional groups > aliphatic hydrocarbons > -OH > aromatic hydrocarbons.

Easing extraction of spudcan foundations through electrokinetic phenomenon

Extraction of mobile jack-up rigs’ spudcan foundations in soft clay sediments is a time-consuming process. Suction at the base of an installed spudcan dictates the extraction resistance. Consequently, any reduction of the base suction will ease the extraction process and reduce offshore time and hence cost. This paper experimented the potential of using electrokinetic phenomena such as electrode reaction and electroosmosis for reducing the base suction. Two series of experiments were carried out. First series concentrated at observing hydroxyl (OH−) generation from a half-spudcan to assess the effectiveness of the new method of applying electric current in kaolin clay. Second series focused on observing gas generation around an installed full-spudcan and crack formation through the kaolin and Tokyo Bay clay deposits to evaluate the potential of reducing base suction. The results of the experiment showed that the new method is effective for applying current to the entire embedded spudcan, where the anode is set in the solution above the ground and the spudcan serves as the cathode. The results of X-ray micro tomography imaging indicated that gas and crack generated around the spudcan and shaft that could potentially reduce the base suction.

FORMULATION AND EVALUATION OF FLOATING BIOADHESIVE TABLET OF GLYBURIDE FOR DIABETES

The Floating tablets of Glyburide were prepared by granulation technique based on effervescent approach. HPMC and polyethylene oxide were used as polymer, for gas generation sodium bicarbonate was used. Talc, avicel, and magnesium stearate were used. In the present study, on the basis of results it was concluded that with increase in the concentration of polymers decrease the drug release profile. On the other hand there was no effect on release of drug by changing the HPMC viscosity grades. Increased sodium bicarbonate concentration can decrease the floating lag time and there is no significant change on drug release profile. So by using appropriate concentration of polymer and sodium bicarbonate can develop sustained release floating tablet.

Gas Content and Geological Control of Deep Jurassic Coalbed Methane in Baijiahai Uplift, Junggar Basin

Deep coalbed methane (CBM) resources are abundant in China, and in the last few years, the country’s search for and extraction of CBM have intensified, progressively moving from shallow to deep strata and from high-rank coal to medium- and low-rank coal. On the other hand, little is known about the gas content features of deep coal reservoirs in the eastern Junggar Basin, especially with regard to the gas content and the factors that affect it. Based on data from CBM drilling, logging, and seismic surveys, this study focuses on the gas content of Baijiahai Uplift’s primary Jurassic coal seams through experiments on the microscopic components of coal, industrial analysis, isothermal adsorption, low-temperature CO2, low-temperature N2, and high-pressure mercury injection. A systematic investigation of the controlling factors, including the depth, thickness, and quality of the coal seam and pore structure; tectonics; and lithology and thickness of the roof, was conducted. The results indicate that the Xishanyao Formation in the Baijiahai Uplift usually has a larger gas content than that in the Badaowan Formation, with the Xishanyao Formation showing that free gas and adsorbed gas coexist, while the Badaowan Formation primarily consists of adsorbed gas. The coal seams in the Baijiahai Uplift are generally deep and thick, and the coal samples from the Xishanyao and Badawan formations have a high vitrinite content, which contributes to their strong gas generation capacity. Additionally, low moisture and ash contents enhance the adsorption capacity of the coal seams, facilitating the storage of CBM. The pore-specific surface area of the coal samples is primarily provided by micropores, which is beneficial for CBM adsorption. Furthermore, a fault connecting the Carboniferous and Permian systems (C-P) developed in the northeastern part of the Baijiahai Uplift allows gas to migrate into the Xishanyao and Badaowan formations, resulting in a higher gas content in the coal seams. The roof lithology is predominantly mudstone with significant thickness, effectively reducing the dissipation of coalbed methane and promoting its accumulation.

Pore formation and pore inter-connectivity in plasma electrolytic oxidation coatings on aluminium alloy

The porosity and microstructure of plasma electrolytic oxidation (PEO) coatings are key factors in determining their properties and applications. Despite advances in understanding the PEO process, the mechanisms driving pore formation and their correlation with process parameters remain unclear due to the complex interplay between these variables. This study investigates the effects of treatment time and duty cycle on the microstructure of PEO coatings produced on an aluminium alloy in an alkaline electrolyte, with a particular focus on pore formation. Our findings reveal that longer treatment durations lead to the significant development of sub-surface pores at the interface between the inner and outer layers. Additionally, a lower duty cycle leads to an increase in sub-surface pores, while a higher duty cycle favours the formation of surface pores. Morphological, 3D microstructural mapping, and chemical analyses reveal that pore formation is driven by the micro-discharges, gas generation, and the preferred gas escape path within the micro-melt pools formed during the PEO formation process. The preferred gas escape path is closely linked to the characteristics and lifetime of local micro-melt pools, elucidating the mechanisms behind pore formation.

A Comprehensive Approach to Load Frequency Control in Hybrid Power Systems Incorporating Renewable and Conventional Sources with Electric Vehicles and Superconducting Magnetic Energy Storage

This study addresses the load frequency control (LFC) within a multiarea power system characterized by diverse generation sources across three distinct power system areas. area 1 comprises thermal, geothermal, and electric vehicle (EV) generation with superconducting magnetic energy storage (SMES) support; area 2 encompasses thermal and EV generation; and area 3 includes hydro, gas, and EV generation. The objective is to minimize the area control error (ACE) under various scenarios, including parameter variations and random load changes, using different control strategies: proportional-integral-derivative (PID), two-degree-of-freedom PID (PID-2DF), fractional-order PID (FOPID), fractional-order integral (FOPID-FOI), and fractional-order integral and derivative (FOPID-FOID) controllers. The result analysis under various conditions (normal, random, and parameter variations) evidences the superior performance of the FOPID-FOID control scheme over the others in terms of time-domain specifications like oscillations and settling time. The FOPID-FOID control scheme provides advantages like adaptability/flexibility to system parameter changes and better response time for the current power system. This research is novel because it shows that the FOPID-FOID is an excellent control scheme that can integrate these diverse/renewable sources with modern systems.

Biomass nanoarchitectonics for porous carbon materials with exceptionally high mesoporous ratio through urea-regulated co-activation strategy and their application in supercapacitors

The synthesis of porous carbon with a high mesoporous ratio is a significant challenge, particularly when utilizing heteroatom-enriched biomass precursors as feedstock. In this work, bio-based porous carbon with a 95 % mesoporous ratio was synthesized by using chitosan and lignosulfonates as biomass precursors, combined with a urea-regulated co-activation strategy. The high mesoporous formation of porous carbon can primarily be attributed to four factors: (1) the formation of a cross-linked 3D network, (2) the generation of nitrogen-containing gas resulting from urea decomposition, (3) the depolymerization of LS and (4) KOH-activated carbonization. Besides, the specific surface area and mesoporous ratio can be adjusted by varying the ratio of KOH to urea, ranging from 1793 m2 g−1 to 2876 m2 g−1 and from 22 % to 95 %, respectively. The application of density functional theory calculations reveals that the synergistic effect of N/S co-doping facilitates rapid ion adsorption reactions on carbon surfaces, further improving the electrochemical performance. As carbon electrode materials for supercapacitors in a three-electrode device, the capacitance reaches up to 263 F g−1 at 1 A g−1. The symmetric supercapacitors fabricated using CS@LS/C-800–1:0.5 achieved an impressive energy density of 17.8 Wh·kg−1 at a power density of 300.6 W kg−1, along with a remarkable capacitance retention rate of 96.6 %. This strategy provides a novel insight into enhancing the mesoporous ratio of bio-based porous carbon materials, thereby significantly broadening the application scope of biomass materials.

(Keynote) on the Challenges and Opportunities for Parameterizing Multi-Physics Battery Models with Expansion Measurements

Lithium-ion batteries are projected to reach cost targets making them competitive with internal combustion engines for light-duty transportation within the decade [1], which will help drive demand for EVs. Upcoming regulations in Europe, China, and the United States for automotive safety and durability will drive the design of battery systems, and the algorithms for battery management over the next decade. The Global Technical Regulation 20 (GTR20) describes the safety requirements for electric vehicle battery systems. In particular, the proposed regulation addresses the need for early detection and warning of occupants about battery faults and failures. The warning should allow for egress 5 minutes prior to the presence of a hazardous situation inside the passenger compartment caused by a battery cell thermal runaway. However, detecting the failure with enough time can be difficult using the current production battery sensor suites. Durability assessment for Lithium-ion batteries is also tricky because these systems are designed to live for more than 10-15 years, so testing under representative conditions could exceed multiple product development cycles. Accelerated aging tests can shorten the testing time to reach the product's end-of-life conditions, typically defined as 70 or 80% state of health, but a deep physical understanding of the degradation modes that are accelerated by the testing is required to project these results back to the real-world use case and warranty period. Due to the many possible definitions of battery State of Health (SoH) which can be related to both capacity loss and internal resistance growth, the Global Technical Regulation 22 (GTR22) defines their durability requirements in terms of two new related metrics: the State of Certified Energy (SOCE) and the State of Certified Range (SOCR). Both metrics represent a percentage of the certified battery energy or electric range remaining at a given point in time. The SOCE is based on the Society of Automotive Engineers (SAE) metric of Usable Battery Energy (UBE). The GTR22 will also require a way for the consumer to read battery health information and usage data from the vehicle. Physics-based battery models which include degradation mechanisms have great promise in addressing many of these challenges due to the relationship between modeled design parameters and the resulting device performance and durability. The models can enable virtual engineering to assess design tradeoffs before building the first prototype, however, parameterizing these models can be difficult due to the large number of parameters. In this presentation, we will explore the challenges of parameterizing physics-based battery models using conventional current, voltage, and temperature measurements. We will show how the measurement of the cell expansion in the laboratory setting and the fixtures that support the testing [2]. The augmentation of expansion data can inform model development and parameterization of a Single Particle Model with electrolyte dynamics (SPMe) implemented in the PyBaMM (Python Battery Mathematical Modelling) framework [3]. Next, we will demonstrate how the sensor data could be paired with the models to augment diagnostic algorithms to infer electrode-level aging phenomena, improve the state of charge estimation, and provide an early warning of gas generation before cell venting. Finally, we will discuss the practical implementation issues in packaging temperature and strain sensors in automotive battery modules and packs. [1] C. Shen, P. Slowik, A. Beach. “INVESTIGATING THE U.S. BATTERY SUPPLY CHAIN AND ITS IMPACT ON ELECTRIC VEHICLE COSTS.” Feb 2024, ICCT REPORT [2] S. Pannala, A. Weng, I. Fischer, J.B. Siegel, and A.G. Stefanopoulou, “Low-cost inductive sensor and fixture kit for measuring battery cell thickness under constant pressure.” 2022, IFAC-PapersOnLine, 55(37), 712-717. [3] Sravan Pannala et al 2024 J. Electrochem. Soc. 171 010532

A comprehensive analysis of preload force effects on the opening of safety valves and thermal runaway behavior in prismatic batteries

Lithium-ion batteries (LIBs) are typically assembled into battery packs under a preload force. Despite its significance, research on the impact of preload force on thermal runaway (TR), a critical safety concern for LIBs, remains deficient. Furthermore, few existing TR models incorporate preload force, highlighting a gap in current methodologies. In this work, a TR prediction model that integrates gas generation and mechanical responses is developed, aiming to incorporate the influence of preload force and enhance the accuracy of safety venting predictions. To validate the prediction model, TR experiments are conducted to examine the internal pressure and shell deformation of LiFePO4 (LFP) prismatic batteries under different preload forces. The experimental results reveal that an increased preload force leads to a higher internal pressure. The increase rate of internal pressure in the rapid rise stage is about 0.5 kPa/s, regardless of the preload force. Moreover, model results indicate that an excessively high preload force leads to a reduction in the opening pressure of the safety valve, due to the large stress concentration at the safety valve. Overall, this study can provide a comprehensive guide for the safety design of prismatic battery systems, advancing current standards.

Eco-Pozzolans as Raw Material for Sustainable Construction Industry: Comparative Evaluation of Reactivity Through Direct and Indirect Methods

A solution to reduce the consumption of raw materials and the generation of greenhouse gases is the partial replacement of clinker (the main constituent of cement) with supplementary cementitious materials. This study aimed to compare the reactivity of ten supplementary cementitious materials—synthetic/commercial ones and those from industrial and agricultural waste (eco-pozzolans). The characterization of the raw materials was carried out using X-ray fluorescence, the loss on ignition, X-ray diffraction, and the determination of the amorphous silica content and particle size distribution. The pozzolanicity assessment was carried out using the Frattini test (direct method) and electrical conductivity and pH tests (indirect method), with the latter presenting greater sensitivity and precision, enabling us to classify the pozzolan reactivity. Although synthetic/commercial pozzolans have higher silica content, the eco-pozzolans showed excellent reactivity results, thus indicating their use as sustainable pozzolans, presenting characteristics that enhance the performance of cement matrices and reduce the environmental impacts of production. Nyasil and rice leaf ash were the pozzolans that presented the greatest reactivity among those studied. The obtained results suggest that using industrial/agricultural waste like reactive pozzolans can help to mitigate the adverse impacts of cement production, address natural resource shortages, and promote a circular economy.

C/H isotope fractionation of hydrocarbon gases from hydrogenation of organic matter: Insights from hydrothermal experiments

It is widely accepted that organic–inorganic interactions involving hydrogen-rich fluids (H2O and H2) play a significant role in hydrocarbon (HC) generation in sedimentary basins, and the effects of hydrogenation of organic matter (OM) by H2O/H2 on C/H isotope fractionation remain poorly understood. This study investigates these effects through a series of pyrolysis experiments conducted at 330–420 °C and 50 MPa, encompassing three groups: (1) anhydrous pyrolysis with kerogen only (Group 1), (2) kerogen and H2O (Group 2), and (3) kerogen, H2O, and Fe1-xS (Group 3). Groups 2 and 3 were designed to simulate hydrogenation of OM by H2O and H2, respectively. Results show that HC gas yields in Group 3 experiments are 1.8 to 3.2 times of those in Group 1, while yields in Group 2 are lower than Group 1. Moreover, hydrogenation by H2 produces HC gases with smaller 13C fractionation and more negative δ2H values compared to hydrogenation by H2O. These findings suggest distinct mechanisms for HC gas generation during H2-OM and H2O-OM reactions. Further analysis demonstrates that the equilibrium isotope effect (EIE) governs 13C and 2H isotope fractionation during hydrogenation of OM by H2. Importantly, the EIE for 2H isotope fractionation of H2O-H2, CH4-H2, and OM-H2 is evaluated under both experimental and geological conditions. This study provides crucial insights into the significant influence of hydrogenation of OM by H2 on the generation and C/H isotopic fractionation of HC gases, as well as the evolution and preservation of H2 in organic-rich shales.

A catalytic approach for the dehydrogenative upgradation of crude glycerol to lactate and hydrogen generation.

The ambiguous nature of non-innocent ligand catalysts provides an excellent strategy for developing an efficient catalyst system featuring extended applicability in sustainable catalysis. In this study, we unveil the catalytic activity of an NNN-Ru catalyst for lactic acid synthesis from a mixture of glycerol, ethylene glycol, and methanol. The developed strategy was also implemented to synthesize lactate (up to 80% yield) with good selectivity via the dehydrogenative upgradation of a crude glycerol and ethylene glycol mixture. As an extended utility, the method was utilized for lactate synthesis from triglyceride directly with hydrogen gas generation.