CO2 Levels Research Articles

Modelling the impacts of future climate change on mixed farming system in southeastern Australia

Mixed farming systems play a crucial role in Australian agriculture, offering economic, social, and environmental advantages. However, these systems are vulnerable to climate change, characterized by rising temperatures and increased rainfall variability. We utilized the pre-calibrated AusFarm model, forced with daily climate data downscaled from 27 Global Climate Models, to simulate how climate change would affect mixed-farming systems at two sites, Condobolin and Wagga Wagga located in southeastern Australia. The results indicated that climate change had diverse effects on crop yields. The simulated yield for some crops, such as canola, was projected to decrease, while others, like field peas, were expected to increase. Elevated atmospheric CO2 levels were anticipated to boost pasture production, but the overall outcome would depend on how these changes interact with rising temperatures and changed rainfall patterns. The increase in pastures was associated with higher live sheep weights and increased fleece growth, with a more significant impact observed at the drier Condobolin site. Furthermore, we found that the gross margin was projected to rise at both sites, with Condobolin experiencing more variability under the influence of climate change. These modelling findings highlight the capacity of mixed-farming systems, which integrate both crops and livestock, to uphold or even improve farm profitability in the context of impending climate change. This underscores the crucial significance of mixed-farming systems in southeastern Australia.

Negative association of atmospheric pollutants with semen quality: A cross-sectional study in Taiyuan, China

BackgroundIn recent decades, the quality of male semen has decreased worldwide. Air pollution has been linked to lower semen quality in several studies. However, the effects of atmospheric pollutants on different semen characteristics have not always been consistent. The aim of this study was to investigate the association between the Air Quality Index (AQI) and six atmospheric pollutants (PM2.5, PM10, SO2, NO2, CO, and O3), semen quality, and their key exposure window periods. MethodsThis study included 1711 semen samples collected at the reproductive clinics of the First Affiliated Hospital of Shanxi Medical University in Taiyuan, Shanxi, China, from October 10, 2021, to September 30, 2022. We evaluated the association of AQI and six atmospheric pollutants with semen quality parameters throughout sperm development and three key exposure windows in men using single-pollutant models, double-pollutant models, and subgroup analyses of semen quality-eligible groups. ResultsBoth the single-pollutant model and subgroup analyses showed that PM, CO, and O3 levels were negatively correlated with total and progressive motility. At 70–90 d before semen collection, CO exposure and semen volume (β =-1.341, 95 % CI: −1.805, −0.877, P <0.001), total motility (β =-2.593, 95 % CI: −3.425, −1.761, P <0.001), and progressive motility (β =-4.658, 95 % CI: −5.556, −3.760, P <0.001) were negatively correlated. At 0–9 days before semen collection, CO was negatively correlated with normal morphology (β =-3.403, 95 % CI: −5.099, −1.708, P <0.001). Additionally, the AQI was adversely associated with total and progressive motility in subgroup analyses of the semen quality-eligible groups. ConclusionsDuring the entire sperm development process, multiple air pollutants were determined to have an adverse correlation with semen quality parameters. AQI was significant marker for the combined effects of various atmospheric pollutants on male reproductive health.

CO2 Breathing Prior to Simulated Diving Increases Decompression Sickness Risk in a Mouse Model: The Microbiota Trail Is Not Forgotten.

Decompression sickness (DCS) with neurological disorders is the leading cause of major diving accidents treated in hyperbaric chambers. Exposure to high levels of CO2 during diving is a safety concern for occupational groups at risk of DCS. However, the effects of prior exposure to CO2 have never been evaluated. The purpose of this study was to evaluate the effect of CO2 breathing prior to a provocative dive on the occurrence of DCS in mice. Fifty mice were exposed to a maximum CO2 concentration of 70 hPa, i.e., 7% at atmospheric pressure, for one hour at atmospheric pressure. Another 50 mice breathing air under similar conditions served as controls. In the AIR group (control), 22 out of 50 mice showed post-dive symptoms compared to 44 out of 50 in the CO2 group (p < 0.001). We found that CO2 breathing is associated with a decrease in body temperature in mice and that CO2 exposure dramatically increases the incidence of DCS (p < 0.001). More unexpectedly, it appears that the lower temperature of the animals even before exposure to the accident-prone protocol leads to an unfavorable prognosis (p = 0.046). This study also suggests that the composition of the microbiota may influence thermogenesis and thus accidentology. Depending on prior exposure, some of the bacterial genera identified in this work could be perceived as beneficial or pathogenic.

Tuning the active sites of polymeric palladium phthalocyanine with Ketjen Black for robust hydrogen evolution

Rising energy demands and the unchecked use of non-renewable sources have harmed the environment and increased the CO2 levels, prompting intensive research into clean, renewable energy technologies. Hydrogen-based energy is a promising method for converting and storing intermittent electricity from renewable sources in the form of chemicals. But the catalysts known for hydrogen production are costlier and in addition, their resources are meager. Hence, a simple, cost-effective, stable, and eco-friendly polymeric palladium ninhydrin phthalocyanine (poly-PdNPc) was synthesized, characterized, and assessed as a catalyst for the hydrogen evolution reaction (HER). The electrochemical activity of poly-PdNPc was enhanced by combining with conducting carbon material Ketjen-Black (KB) in an optimized ratio. The ratio of 3.5:1.5 (polymer to KB) organic hybrid exhibited an overpotential of -82 mV at -10 mA.cm−2 for HER in 0.5 M H2SO4, with a Tafel slope of 34 mV/dec and a mass activity of 3.1 mA/g comparable to Pt/C. Its superior activity and stability make it a viable electrocatalyst for practical HER applications. Enhanced conductivity, active surface area, π-π interactions, electronic density modulation, and a decreased d-band center contribute to its superior activity and stability, making it a feasible electrocatalyst for practical HER applications.

Fuel properties, performance, and emissions of water-emulsified diesel fuel in an IDI diesel engine

This paper aims to verify the possibility of utilising water-in-diesel emulsions (WiDE) as an alternative drop-in fuel for diesel engines. An 8% WiDE was produced to be tested in a four-stroke, indirect injection (IDI) diesel engine and compared to EN590 diesel fuel. An eddy current brake and an exhaust gas analyser were utilised to measure different engine parameters such as torque, fuel consumption, and emissions at different engine loads. The results show that the engine running on emulsified fuel leads to a reduction in torque and power, an increase in the specific fuel consumption, and slightly better thermal efficiency. The highest percentual increment of thermal efficiency for WiDE is obtained at 100% engine load, 5.68% higher compared to diesel. The emissions of nitric oxide (NO) and carbon dioxide (CO2) are reduced, but carbon monoxide (CO) and hydrocarbons (HC) emissions are increased, compared to traditional diesel fuel. The most substantial decrease in NO and CO2 levels was achieved at 75% engine load with 33.86% and 25.08% respectively, compared to diesel.

Efficacy of Fe-Mg-bimetallic biochar in stabilization of multiple heavy metals-contaminated soil and attenuation of toxicity in spinach (Spinacia oleracea L.)

Globally, soil contamination with heavy metals (HMs) pose serious threats to soil health, crop productivity, and human health. The present investigation involved synthesis and analysis of biochar with bimetallic combination of iron and magnesium (Fe-Mg-BC). Our study evaluated how Fe-Mg-BC affects the absorption of cadmium (Cd), lead (Pb), and copper (Cu) in spinach (Spinacia oleracea L.) and remediation of soil contaminated with multiple HMs. Results demonstrated the successful loading of iron (Fe) and magnesium (Mg) onto pristine biochar (BC) derived from peanut shells. The addition of Fe-Mg-BC (3%) notably increased spinach biomass, enhancing photosynthesis, transpiration, stomatal conductance, and intercellular CO2 levels by 22%, 21%, 103%, and 15.3%, respectively. Compared to control, Fe-Mg-BC (3%) suppressed metal-induced oxidative stress by boosting levels of superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) in roots by 40.9%, 57%, 54.8 %, and in shoots by 55.5%, 65.5%, and 37.4% in shoots, respectively. The Fe-Mg-BC effectively reduced the uptake of Cd, Pb, and Cu in spinach tissues by transforming their bioavailable fractions to non-bioavailable forms. The Fe-Mg-BC (3%) significantly reduced the mobility of Cd, Pb and Cu in soil and limited the concentration of Cd, Pb, and Cu in plant roots by 34.1%, 79.2%, 47%, and shoots by 56.3%, 43.3%, and 54.1%, respectively, compared to control. These findings underscore the potential of Fe-Mg-BC as a promising amendment for reclaiming soils contaminated with variety of HMs, thereby making a significant contribution to the promotion of safer food production.

Unraveling the mechanism and the role of hydrogen bonds in CO2 capture by diluent-free amine sorbents through a combination of experimental and theoretical methods

The utilization of water-lean and non-aqueous amine sorbents is regarded as an appealing approach to reduce the energy costs of CO2 capture via liquid sorbents. However, significant research is still needed to achieve the technological maturity required for industrial-scale implementation. Here, we present a detailed experimental and computational analysis at the molecular level of CO2 capture by dipropylamine (DPA) as a case study to deepen our understanding of the mechanisms governing CO2 absorption by liquid secondary amines that can be used without any additional diluent. CO2 uptake with pure DPA was investigated, and the species produced over time were determined by NMR and FT-IR spectroscopy. In particular, the NMR analysis revealed the formation of carbamic acid at high CO2/DPA ratios. A detailed DFT investigation explained the mechanism of the reaction revealing a dynamic evolution in product distribution as CO2 loading increases. At low CO2 loadings, adducts with at least four DPA molecules are formed, ultimately leading to the carbamate/ammonium ionic pair stabilized through H-bonding interactions with DPA moieties. Conversely, at higher CO2 levels some stabilizing DPA molecules of ionic pair are required for the CO2 activation, resulting in the formation of carbamic acid. A reasonable mechanism for the evolution of product distribution is provided, and the main steps of the mechanistic picture are depicted and commented on. The dependence of carbamate and carbamic acid on the availability of hydrogen bond donors and acceptors in solution is also highlighted.

Surface carbonate dynamics in a temperate coastal system in the Northern Yellow Sea, China

The carbon sink/source in estuaries and coastal seas may have significant implications for regional climate change. This study investigated seawater carbon dioxide partial pressure (pCO2), aragonite saturation state (Ωarag), and related carbonate parameters in the Yalu River estuary and the adjacent Northern Yellow Sea, China, in September 2023. The results indicate that seawater pCO2 ranged from 261 to 1121 μatm, while Ωarag ranged from 0.49 to 3.34 in the study area. High pCO2 were observed in the estuarine and northwestern areas, whereas low pCO2 were found in the southern offshore area. In the estuarine area, high pCO2 levels were attributed to the input of diluted water from the Yalu River. In the southern areas, low pCO2 were a result of primary production, while community respiration played an important role in increasing seawater pCO2 in the northwestern area. On the other hand, seawater Ωarag was extremely low in the estuarine area, and greater than 1.5 in the southern offshore area. Ωarag in the study area was mainly controlled by water mixing and temperature. The study area acted as a source of atmospheric CO2 with an average air-sea CO2 flux of 6.2 mmol m−2d−1 in autumn, which was relatively high compared with other marginal seas. The high pCO2 and low Ωarag associated with diluted water inputs and community respiration could weaken the ability of coastal oceans to uptake CO2. Therefore, it is crucial to explore ways to reduce CO2 levels in riverine and adjacent coastal seas.

Carbon Sequestration and Storage of Urban Trees in a Polluted Semiarid City

Cities play a critical role in anthropogenic CO2 emissions, which exacerbate climate change and impact urban populations. Urban green infrastructure, such as urban trees, provides essential ecosystem services, including reducing atmospheric CO2 levels. However, there is a significant knowledge gap regarding the impact of urban trees on climate change in semiarid, polluted cities like Tehran, the capital and largest metropolis of the Middle East. This study assesses the carbon sequestration and storage potential of Tehran’s urban infrastructure using the i-Tree Eco model. A randomized cluster sampling method was employed, collecting data on species composition, diameter at breast height (DBH), and total tree height. The results indicate that Tehran’s urban trees sequester approximately 60,102 tons of carbon per year, equivalent to 220,393 tons of CO2. The net carbon storage in urban trees is about 254,579 tons, equivalent to 933,455 tons of CO2. Parks and urban green spaces demonstrate the highest rate of carbon sequestration per hectare, followed by urban services land use. Prioritizing the planting of species with high sequestration rates like Cupressus arizonica (Arizona cypress) and Cupressus sempervirens L. var. horizontalis (Mediterranean cypress) could enhance carbon sequestration efforts in Tehran. These data provide valuable insights into the carbon sequestration potential and environmental impact of different land use types, and may aid in the development of effective environmental policies and land management strategies in semiarid urban areas and other cities in similar settings.

Enhanced erosion and silicate weathering of the West African craton during the late Cretaceous cooling evidenced by mineralogical and Hf[sbnd]Nd isotope proxies

The evolution of oceanic temperatures between the Turonian and the K/T boundary indicates a long-term cooling coincident with a decrease of atmospheric CO2 levels, yet the cause of climate cooling at that time still remains debated. In this study, we evaluated the possible implication of enhanced silicate weathering as a sink for atmospheric CO2 by applying paired NdHf isotope measurements to detrital clay records from the West African margin. The use of this novel proxy for chemical weathering intensity (ΔɛHf(t)clay) was complemented by additional mineralogical and major-trace element analyses in order to investigate the variability of mechanical erosion patterns and further explore potential linkages between tectonics, weathering and climate during the late Cretaceous.Our ΔɛHf(t)clay data suggest more intense silicate weathering on the West African Craton during the Santonian to the middle Campanian period, coincident with enhanced physical erosional inputs as inferred from higher Quartz/Clays and Feldspar/Clays ratios. This observation suggests that the shift towards intensified chemical weathering at that time was driven by enhanced mechanical erosion, possibly related to a moderate tectonic event on the West African craton. Evidence for increasing kaolinite contents and higher ΔɛHf(t)clay values during the Maastrichtian point towards more hydrolysing conditions, inducing either destabilization of older Mesozoic lateritic material or favouring the development of kaolinite-rich soils.Overall, this study was compared with several new data of chemical weathering evolution along the south Atlantic margins, adding new insights on tectonic-weathering-climate interactions during the late Cretaceous, suggesting a possible link between silicate weathering feedbacks and global cooling at that time.

Economic Growth, Industrialization, and CO2 Emissions in Pakistan: Insights from ARDL Modeling

This study explores how industrialization, economic growth (measured by GDP per capita), and CO? emissions have interacted in Pakistan over nearly five decades, from 1974 to 2022. It also considers the influence of population growth and foreign direct investment (FDI) on this relationship. To analyze the data, the ARDL model was used, ensuring the reliability of the results by confirming stationarity with the Augmented Dickey-Fuller (ADF) test. The results showed that in the long run, a 1% increase in GDP per capita and FDI inflows results in respective increases in CO? emissions of 0.33% and 0.061%. Still, a 1% rise in industrial activity lowers CO? emissions by 0.34%. In the short run, a 1% rise in GDP per capita and FDI reduces CO? emissions by 0.21% and 0.020%, respectively. Conversely, a 1% increase in industrial activity causes emissions of 0.29%. These findings are in line with the Environmental Kuznets Curve (EKC) theory, which holds that CO? emissions initially rises when a nation industrializes but as the technology advances and more rigorous rules are followed, the level of CO? emissions decreases. Based on these results, policies emphasizing investments in renewable energy, strict environmental rules enforced, and support of clean technologies and sustainable industrial practices are suggested.

Cobalt exposure and pulmonary function reduction in chronic obstructive pulmonary disease patients: the mediating role of club cell secretory protein

BackgroundCobalt (Co) is a metal which is widely used in the industrial production. The previous studies found the toxic effects of environmental Co exposure on multiple organs. However, the correlation of blood Co concentration with lung function was inconsistent in patients with chronic obstructive pulmonary disease (COPD).MethodsAll 771 stable COPD patients were recruited. Peripheral blood and clinical information were collected. The levels of blood Co and serum CC16 were measured.ResultsCross-sectional study suggested that the level of blood Co was inversely and dose-dependently related to lung function parameters. Each 1 ppm elevation of blood Co was related to 0.598 L decline in FVC, 0.465 L decline in FEV1, 6.540% decline in FEV1/FVC%, and 14.013% decline in FEV1%, respectively. Moreover, higher age, enrolled in winter, current-smoking, higher smoking amount, and inhaled corticosteroids prominently exacerbated the negative correlation between blood Co and lung function. Besides, serum CC16 content was gradually reduced with blood Co elevation in COPD patients. Besides, serum CC16 was positively correlated with lung function, and inversely related to blood Co. Additionally, decreased CC16 substantially mediated 11.45% and 6.37% Co-triggered downregulations in FEV1 and FEV1%, respectively.ConclusionBlood Co elevation is closely related to the reductions of pulmonary function and serum CC16. CC16 exerts a significantly mediating role of Co-related to pulmonary function decrease among COPD patients.

Assessment of Air Pollution Levels from a Building Construction Site on Lagos Island

The introduction highlights the challenges of air pollution from construction activities on a site in Lagos Island, Nigeria, emphasizing the need for comprehensive studies to assess air pollution levels and evaluate its implications for public health and environmental quality. The methodology outlines the monthly data collection process, using the Earth Sense Zephyr (equipped with electrochemical detectors for gases) to measure CO, NO, NO₂, O₃, and Optical light scattering for particles) to measure PM₂.₅, and PM₁₀, and the ARA n-FRM Sampler for additional data collection on PM₂.₅, and PM₁₀. The study found that CO, NO, and NO₂ levels were influenced by construction activities, vehicle emissions and industrial sources, with notable peaks in CO and NO concentrations during specific months. Ozone levels remained consistently low, likely due to the "titration effect," while particulate matter (PM₂.₅ and PM₁₀) showed significant seasonal variation, peaking during the dry season due to construction dust and dry weather conditions. The findings underscore the need for stringent regulatory measures and effective dust control practices, particularly during periods of increased construction activity and dry weather, to mitigate air pollution and protect public health. In conclusion, the study provides valuable insights into the dynamics of air pollution from a typical construction site in Lagos Island, emphasizing the urgency of sustainable interventions to safeguard public health and environmental integrity. The study proposes enhanced monitoring and surveillance, stringent regulatory measures, promotion of sustainable construction practices, and public awareness and education, to address the challenges associated with construction-related air pollution on Lagos Island.

Fluorinated metal-organic framework aerogels with enhanced moisture resistance and efficient gas diffusion for CO2 capture

Escalating CO2 levels in confined spaces threatens human well-being and safety, underscoring the urgent need for effective CO2 mitigation strategies. Metal-organic frameworks (MOFs), with their large surface areas and capacious pores, represent a promising avenue for CO2 capture. However, their application is often limited by susceptibility to moisture and lack of uniformity in mesopore distribution. Here, we present a novel approach involving ligand fluorination modification and pore reconstruction to fabricate ultralight, highly moisture resistant, and hierarchically porous UiO-66-NH2-F4 aerogels. This design ingenuity promotes the formation of an efficient gas transport network and generates an abundance of micropores decorated with hydrophobic units, effectively shielding CO2 adsorption from the interference of water molecules. The UiO-66-NH2-F4 aerogels exhibit an impressive CO2 adsorption capacity of 5.18 mmol/g (dry) and 4.48 mmol/g (70 % RH) at 298 K, a remarkable CO2/N2 selectivity of 29, and exceptional cyclability. Density functional theory (DFT) calculations further elucidate the robust binding interactions of these CO2-selective UiO-66-NH2-F4 aerogels, attributing them to the tailed pore environment created by fluorinated hydrophobic groups and the accessibility of adsorption sites. This work charts a promising course for developing moisture-resistant and hierarchically porous MOF aerogels, which are poised to revolutionize CO2 adsorption practices in confined environments.

Life Cycle Carbon Assessment of Mortars with Carbonated and Non-Carbonated Recycled Aggregates

Global warming is one of the most important issues that the world is currently facing. The cement industry accounts for around 7% of total global CO2 emissions. According to the 13th United Nations Sustainable Development Goals, cement plants must become carbon neutral by 2050. This neutrality may be achieved by a reduction in CO2 emissions complemented with carbon capture, utilization and storage (CCUS) technologies. In accordance with these sustainable goals, several approaches have been studied. This paper investigates life cycle carbon of mortars produced with carbonated recycled aggregates. In previous works, the carbon dioxide capture capacity of construction and demolition waste (CDW) was analysed, and mortars with CDW recycled aggregates submitted to high levels of CO2 were evaluated in terms of their mechanical performance. This paper focus on the life cycle carbon impact assessment (LCCA) of industrial mortar formulations in a cradle-to-gate boundary. This assessment is carried out through a global warming potential environment impact assessment, since it represents the amount of CO2 equivalent that is sent to the atmosphere and contributes to the “greenhouse effect”. This LCCA includes the impacts associated with the treatment and additional transportation routes of the recycled aggregates. With this work, it was found that mortars with carbonated recycled aggregates have a considerably lower global warming potential impact than mortars without recycled aggregates. The mortars with recycled aggregates presented lower CO2 emissions of up to 6.31% for 100% incorporation of non-carbonated recycled aggregates. These values were incremented with the carbonation of the recycled aggregates, achieving a reduction of CO2 emissions of up to 36.75% for 100% of incorporation.

Elevated CO2 and Nitrogen Supply Boost N Use Efficiency and Wheat (T. aestivum cv. Yunmai) Growth and Differentiate Soil Microbial Communities Related to Ammonia Oxidization.

Elevated CO2 levels (eCO2) pose challenges to wheat (Triticum aestivum L.) growth, potentially leading to a decline in quality and productivity. This study addresses the effects of two ambient CO2 concentrations (aCO2, daytime/nighttime = 410/450 ± 30 ppm and eCO2, 550/600 ± 30 ppm) and two nitrogen (N) supplements (without N supply-N0 and with 100 mg N supply as urea per kg soil-N100) on wheat (T. aestivum cv. Yunmai) growth, N accumulation, and soil microbial communities related to ammonia oxidization. The data showed that the N supply effectively mitigated the negative impacts of eCO2 on wheat growth by reducing intercellular CO2 concentrations while enhancing photosynthesis parameters. Notably, the N supply significantly increased N concentrations in wheat tissues and biomass production, thereby boosting N accumulation in seeds, shoots, and roots. eCO2 increased the agronomic efficiency of applied N (AEN) and the physiological efficiency of applied N (PEN) under N supply. Plant tissue N concentrations and accumulations are positively related to plant biomass production and soil NO3--N. Additionally, the N supply increased the richness and evenness of the soil microbial community, particularly Nitrososphaeraceae, Nitrosospira, and Nitrosomonas, which responded differently to N availability under both aCO2 and eCO2. These results underscore the importance and complexity of optimizing N supply and eCO2 for enhancing crop tissue N accumulation and yield production as well as activating nitrification-related microbial activities for soil inorganic N availability under future global environment change scenarios.

Effects of an extreme heat event on indoor conditions of social heritage housing in Mediterranean climate

Social heritage housing in Mediterranean historic cities is particularly vulnerable to climate change hazards as protection policies lead to its exclusion from energy retrofitting programmes, leaving their residents - at higher risk of fuel poverty and the heat-island effect – defenceless. Increasingly frequent heatwaves can potentially produce “overheating” in these buildings, a thermal state that impedes people's comfort with harmful consequences to their health. Other indoor air quality factors, like humidity and CO₂ levels, also affect residents' health. The objective of this research is to evaluate the actual indoor environmental quality of three occupied dwellings in social buildings of high heritage value located in two historic cities in Andalusia (Spain) during the extreme heat events that occurred in 2022. A monitoring campaign was conducted and the data collected over the summer was analysed and evaluated using existing metrics. Our results show that the CO2 concentration rates generally remained below the upper limit of 1000 ppm in all cases, probably due to the high air infiltration rates measured (5.83 h−1, 4.39 h−1 and 14.65 h−1). On the contrary, the relative humidity rates were outside the acceptable range (45–60 %) for 90 % of the occupied hours in all cases. In the warmest city, overheating was continuous and severe in all rooms, according to the metric adopted (CIBSE standards TM52 and TM59 under the adaptive thermal comfort model). The situation was particularly critical in the free-running bedroom, but the overheating index values in the living rooms, where air conditioning was installed and used about 50 % of the occupied time, also deviated significantly from the acceptable limits.

Activated Carbon for CO2 Adsorption from Avocado Seeds Activated with NaOH: The Significance of the Production Method.

The rise in atmospheric greenhouse gases like CO2 is a primary driver of global warming. Human actions are the primary factor behind the surge in CO2 levels, contributing to two-thirds of the greenhouse effect over the past decade. This study focuses on the chemical activation of avocado seeds with sodium hydroxide (NaOH). The influence of various preparation methods was studied under the same parameters: carbon precursor to NaOH mass ratio, carbonization temperature, and nitrogen flow. For two samples, preliminary thermal treatment was applied (500 °C). NaOH was used in the form of a saturated solution as well as dry NaOH. The same temperature of 850 °C of carbonization combined with chemical activation was applied for all samples. The applied modifications resulted in the following textural parameters: specific surface area from 696 to 1217 m2/g, total pore volume from 0.440 to 0.761 cm3/g, micropore volume from 0.159 to 0.418 cm3/g. The textural parameters were estimated based on nitrogen sorption at -196 °C. The XRD measurements and SEM pictures were also performed. CO2 adsorption was performed at temperatures of 0, 10, 20, and 30 °C and pressure up to 1 bar. In order to calculate the CO2 selectivity over N2 nitrogen adsorption at 20 °C was investigated. The highest CO2 adsorption (4.90 mmol/g) at 1 bar and 0 °C was achieved.

NH3/C2H6 and NH3/C2H5OH oxidation in a shock tube: Multi-speciation measurement, uncertainty analysis, and kinetic modeling

This study examines NH3, NO, and CO profiles during NH3/C2H6 and NH3/C2H5OH oxidation in a shock tube using laser absorption spectroscopy at 1317–1957 K and ∼2.8 bar, with 5–20% C2H6 or C2H5OH, equivalence ratios of 0.5/1.0/1.5, and a 0.9 argon dilution ratio. Metrological uncertainty analysis on mole fractions have been performed. A novel dynamic uncertainty methodology is proposed to time-resolved speciation profiles. From the experimental measurements, the promotional effect on ammonia ignition by C2H6 or C2H5OH is identical under investigated conditions. The multi-speciation profiles demonstrate reasonable relations among the consumption of NH3 and the formation of NO and CO, which show strong temperature and equivalence ratio dependence. An updated PTB-NH3/C2 1.1 mechanism accurately predicts ignition delay times and speciation profiles. Sensitivity analysis reveals NH3 chemistry’s significant control, with NH3+O2/H/OH and N2H2+M reactions being critical at >1300 K, and HO2 interactions being pivotal at 800–1200 K. The reactions related to N2H2 and N-C chemistries dominate for fuel-rich mixtures at high temperatures, resulting in a reverse equivalence ratio dependence on IDTs, namely fuel-rich mixtures exhibit the lowest reactivity. The N-C chemistries, particularly the pronounced reaction pathway of HCN→CN→NCO→HNCO→CO play a crucial role in maintaining the CO level constant after reaching its peak position under fuel-rich conditions·NH3 consumption pathways shift from NH2→H2NO→HNO→NO→NO2→N2O→N2 at intermediate temperatures to NH3→NH2→NH→N(HNO)→NO→(N2O)N2 at high temperatures. The C2-additives participate in the oxidation process by introducing additional OH/H/CH3 radicals, thereby facilitating the reactive radical pool and developing the N-C intersystem-crossing pathways. In summary, the extensive multi-speciation data, metrological uncertainty analysis, mechanism validation and development, together with comprehensive kinetic modelling can be valuable resources for further studies of ammonia combustion.

Unparalleled single-atom catalytic efficiency of TM@Al12P12 (TM = Fe, Co, Ni, Cu) nanoclusters toward oxygen evolution reaction (OER)

Global warming is an unparalleled challenge to the globe. The increased usage of fossil fuel has significantly increased the CO2 level in the environment. Thus, scientists have diversified their attention towards other energy resources. Hydrogen energy represents a sustainable resource of green energy, where hydrogen and oxygen gases are converted into high amounts of energy without emitting greenhouse gases. In this work, we evaluated the potential use of transition metal (TM) doped Al12P12 single atom catalysts (SACs) toward the oxygen evolution reaction (OER) on the basis of the density functional theory (DFT) calculations. Results have shown that the highest activity is realized by the Co@Al12P12 SAC. This study represents another milestone in our quest of exploring the applicability of different TM@Nanocage systems as SACs for water electrolysis. We hope that this study will assist in the full realization of the water splitting reaction to produce hydrogen energy fuel.