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This paper presents a critical review of laser pyrolysis. Although this technology is almost 60 years old, in literature many researchers, both from academia and industry, are still developing and improving it. On the contrary industrial applications are struggling to take off, if not in very restricted areas, although the technology has undoubted advantages that justify future development. The aim of this work consists in analysing a representative pool of scientific papers (230) and patents (121), from the last 20 years, to have an overview about the evolution of the method and try to understand the efforts spent to improve this technology effectively in academia and in industry. This study is important to provide a complete review about the argument, still missing in the literature. The objective is to provide an overview sufficiently broad and representative in the sources and to capture all the main ways in which laser pyrolysis has been used and with what distribution. The main focuses of the study are the analyses of the functions carried out by laser technologies, the application fields, and the types of used laser (i.e. models, power and fluence). Among the main results, the study showed that the main use of laser pyrolysis is to produce nanoparticles and coatings, the main materials worked by laser pyrolysis are silicon and carbon dioxide and the main searched properties in the products of laser pyrolysis are catalysts activity and electrical conductivity. CO2 lasers are the most used and the have high versatility compared to others. In conclusion, the study showed that laser pyrolysis is a consolidated technology within its main application fields (nanoparticles and coatings) for several years. Within this context, the technology has been developed on very different sizes and processes, obtaining a very wide range of results. Finally, these results may also have stimulated new areas of experimentation that emerged mainly in recent years and which concern biomedical applications, additive manufacturing, and waste disposal. [ABSTRACT FROM AUTHOR]

In the global ecosystem, wetlands are vital carbon sinks, playing a crucial role in absorbing greenhouse gases such as carbon dioxide and mitigating global warming. Accurate estimation of wetland carbon content is essential for research on wetland carbon sinks. However, the carbon cycle of wetlands is complex, and the carbon sinking of wetlands is affected by climate, topography, water level conditions, vegetation types, soil types, and other factors. This has caused significant challenges in the estimation of wetland carbon sinks. In current studies, most research has focused on the impact of individual factors on wetland carbon sinks, often ignoring the interaction between various factors, which further leads to uncertainty in wetland carbon measurements. This paper aims to elucidate the process of the wetland carbon cycle, summarize the factors affecting wetland carbon sinks, and explore the interplay between various factors and their influence on wetland carbon sinks, aiming to provide theoretical support for the study of wetland carbon sinks. Additionally, this paper reviews the advantages and disadvantages of current wetland carbon measurement methods, proposes research directions for combining machine learning methods, identifies existing difficulties in current wetland carbon measurement, and offers suggestions to serve as a reference for future wetland carbon sink estimation and wetland management.Highlights: The potential and significance of wetland carbon sinks are explained. The advantages and disadvantages of current wetland carbon measurement techniques are summarized. The prospective method for integrating machine learning into integrated wetland carbon measurement is proposed. [ABSTRACT FROM AUTHOR]

Near miscibility widely exists in carbon dioxide (CO2) injection development projects. However, there is no existing approach to quantify the effect of near miscibility on oil recovery. In this paper, slim tube experiments were conducted to study near miscible region. The oil displacement efficiency curve is divided into immiscibility, near miscibility and miscibility. And three linear function is obtained, respectively. Then, the space between production well and CO2 injection well is discrete to characterize the effect of near miscibility on oil recovery. Then, a new approach is proposed to calculate oil recovery of CO2 displacement in tight oil reservoirs. This approach can calculate oil recovery considering near miscibility. It is found that minimum miscibility pressure (MMP) without considering near miscibility is 4 MPa lower than considering near miscibility. The near miscible pressure range is from 0.77 times to 1 time MMP considering near miscibility. Oil displacement efficiency difference reaches to be the maximum when the pressure is the minimum miscibility pressure without considering near miscibility. The maximum of the oil displacement efficiency difference is 3.4%. The optimal formation pressure considering near miscibility is 5 MPa larger than that without considering near miscibility. The oil recovery considering near miscibility is from 0.9 to 1.3% lower than that not considering near miscibility. It reaches to be the maximum when the pressure is the optimal formation pressure level without considering near miscibility. The maximum of the oil recovery difference is 1.3%. [ABSTRACT FROM AUTHOR]

Utilizing carbon dioxide in chemical processes is one of the suggested remedies for reducing its atmospheric concentration. In this paper, the simulation of the propylene carbonate production process using 1,2-propanediol and carbon dioxide has been performed. The impact of temperature was examined between 75 and 400°C. It has been found that as temperature rises, reaction conversion increases. Additionally, the impact of recycling ratio was examined in the range of 0.1–0.5, which demonstrates that a rise in the recycle ratio results in a fall in conversion. Furthermore; it was observed that the pressure initially increases the solubility of carbon dioxide in 1,2-propanediol and improves the conversion of the reaction, but when enough carbon dioxide is supplied in the reaction, increasing the pressure does not affect the corresponding reaction. The effect of all studied parameters depends on the residence time of the reactants in the reactor. Investigating the interaction of parameters and optimizing the process has shown several optimal point of the process such as temperature of 295 °C, a recycle ratio 0.1, feed ratio 0.8 and a residence time of 12.61 h, with the related conversion being 59.6%. [ABSTRACT FROM AUTHOR]

This paper investigates whether carbon dioxide (CO2) intensity of gross domestic product (GDP) matters for environmental deregulations in Southern European countries over the period of 1990–2018 while controlling economic growth, globalization, and energy consumption. The present study uses the second generation panel based techniques, namely cross-sectional dependency test, cross-sectional unit-root test, Westerlund cointegration test, augmented mean group and common correlated effects mean group estimators, and Dumitrescu–Hurlin causality test to measure the effect of CO2 intensity of GDP, economic growth, globalization, and energy consumption on environmental degradation. The empirical finding of the present study reveals that the CO2 intensity of GDP is an important factor in determining environmental degradation in South European countries, as the outcomes show that a 1% boost in CO2 intensity of GDP is causing a 1.7728% increase in CO2 emissions. Moreover, a 1% increase in economic growth caused a 0.2568% boost in CO2 emissions. The result is crucial for policy decision-making and can perhaps be applied to take decisive policy actions to mitigate environmental issues. [ABSTRACT FROM AUTHOR]

Carbon Integration methods help identify the appropriate allocation of captured carbon dioxide (CO2) streams into CO2-using sinks, and are especially useful when a number of CO2 sink options are present simultaneously. The method helps identify CO2 allocation scenarios when subjected to an emission target on the CO2 overall network. Many carbon dioxide sink options are costly, and more often than not, require a high purity carbon dioxide source to satisfy the sink demand. Hence, it is imperative to effectively incorporate treatment units in such networks, to obtain high-purity CO2 streams. In fact, it has been previously reported in many studies that the most expensive step in Carbon Capture, Utilization and Sequestration (CCUS) is the treatment system. As a result, this paper focuses on reassessing the performance of carbon integration networks using a more rigorous cost model for the treatment design stage. The effect of utilizing different treatment operating conditions on the overall cost of the treatment stage of CO2 (before allocation) is first captured using a detailed cost model. Subsequently, this information is then fed into a network design problem that involves a CO2 source-sink allocation network problem, and different CO2 net capture targets within the network. For this, an enhanced treatment model that captures all necessary treatment design parameters has been utilized alongside the original model. The original carbon integration formulation has been adopted from previous work. Many of the cost items have been lumped into single parameters in the original formulation, and lack the necessary depth required to carry out the necessary investigations for this work. Hence, the treatment model introduced in this paper is more rigorous, as it accounts for important technical performance constraints on the system to be assessed. Utilizing a more detailed cost model was found to be very helpful in understanding several effects of varying parameters on the overall source-sink allocations, when subjected to different CO2 net emission reduction targets. The cost of the carbon network increases when the solvent temperatures are increased. However, there was a noticeable linear trend at lower temperatures compared to higher temperatures, where the increase became non-linear. Furthermore, it was discovered that for net capture targets of 20% and 25%, no revenue from carbon storage could be generated beyond a solvent temperature of 25 °C. Additionally, the optimal diameter of the treatment column was more responsive to changes in solvent temperature for cases with low net capture targets (below 10%), while its sensitivity decreased for higher capture targets (above 10%). [ABSTRACT FROM AUTHOR]

Catalytic synthesis of urea is a bright substitutable to Haber–Bosch progression and industrial urea synthesis. Electrochemical C–N coupling of carbon dioxide and nitrogen oxides under environmental conditions is a newly developed method, which also provides a novel opinion for solving nitrate contamination. Conjugated organic frameworks (COFs) have been used as prospective electrocatalysts for nitrogen reduction reactions and carbon dioxide reduction reactions (CO2RR) as a result of their regulate structure and multihole properties, resulting in efficient electron transfer. This paper reports the efficient synthesis of urea from carbon dioxide and nitrate over MoM1S-Pc-M2PPs COF (M as a transition metal) electrocatalyst. According to the calculation of DFT, it was found that it was difficult for carbon dioxide and nitrogen oxide to coadsorb on MoM1S-Pc to synthesize urea, so we chose to synthesize CO on the metal porphyrin (M2PPs) structural unit, and then overflow on the bimetallic phthalocyanine and nitrogen oxide to synthesize urea. The possibility of nitrate adsorption on different catalysts was verified by calculation. We screened the stability, nitrate adsorption strength, and catalytic activity of MoM1S-Pc candidates, and the results showed that the most promising candidate catalyst was MoFeS-Pc. At the same time, the CO2RR M2PPs substrate was also screened, and the VPPs structure was selected as the best. In the study of coupling between different nitrogen-containing intermediates and *CO, the C–N coupling mechanism shows that *NOH and *CO are two possible C–N coupling nitrogen intermediates, which are shown to be thermodynamically spontaneous and have an inferior activation barrier. This study not only provisions novel perceptions into urea synthesis by coupling nitrogen oxides with carbon dioxide under environmental conditions, but also paves the way for boosting the sustainable production of carbon and nitrogen-coupled products. [ABSTRACT FROM AUTHOR]

ZnZrOx has been used in large quantities for the preparation of light olefins from CO2, but the relationship between structure and performance remains unclear at present. In this paper, ZnZrOx were prepared by co-precipitation method, and a series of oxides with different sizes were prepared by varying the calcination temperatures. Subsequently, these oxides were combined with SAPO-34 to create a composite bifunctional catalyst for the synthesis of light olefins by CO2 hydrogenation, in which the impact of nanocrystal size effect was examined. The catalytic performance significantly increased as the nanocrystal size reduced from 18 to 12 nm. However, when the nanocrystal size was further decreased to 8 nm, the catalytic performance decline. Characterizations revealed a gradual increase in the number of oxygen vacancies with decreasing nanocrystal size. However, the oxide with the smallest nanocrystal size, prepared by varied calcination temperatures, did not yield the optimal catalytic performance due to sintering occurring during the reaction process. The results show that the assumption that smaller nanocrystal sizes inherently equate to improved catalytic performance is not universally valid, and stability must be considered when the nanocrystal size is decreased. The bifunctional catalysts used in this paper for the prepared light olefins from CO2 in yield as high as 13.8%, which is higher than most previous reports. [ABSTRACT FROM AUTHOR]

It has been a crucial challenge for countries worldwide to reduce carbon dioxide (CO2) emissions. China is developing policies among various industries to peak CO2 emissions as soon as possible and expects the reduction of CO2 emissions through financial development. This paper explores the influencing mechanism of financial development on CO2 emissions based on panel data from provinces in China, considering constraints of technological innovation and fossil energy dependence among provinces and periods. Empirical results consistently indicate that the effect of China's financial development on CO2 emissions per capita is significantly negative, and it also presents an inverted U-shaped pattern. In those provinces or periods witnessing lower technological innovation and higher fossil energy dependence, the financial development has more significant effect on carbon emission reduction. This result suggests that regions with deficiencies in the development of technology industries, lower proportions of the tertiary industry, and a higher percentage of the secondary industry need to focus more on the value of financial development. [ABSTRACT FROM AUTHOR]

The paper presents the results of impregnation of dried common pine (Pinus sylvestris) specimens with propiconazole using a supercritical fluid CO2 impregnation process carried out at a temperature of 338 K in the pressure range of 10–30 MPa. Within the framework of the formation of a database on the properties of the impregnation material required for the stages of modeling, optimization, and scaling of the impregnation process, an investigation was conducted of some thermodynamic properties of a propiconazole–carbon dioxide mixture in the supercritical fluid region of the state. The isomeric composition of propiconazole has been investigated, and it has been established that it represents a mixture of two isomers. The methods of thermogravimetric analysis and differential scanning calorimetry have been used to study the thermal characteristics of propiconazole. The paper presents the results of an experimental investigation of propiconazole solubility in supercritical carbon dioxide on the isotherms T = 338, 358, and 378 K in the pressure range of 10–30 MPa. The experimental data on solubility have been described using the Peng–Robinson equation of state and providing the pressure of saturated propiconazole vapors with the status of the second adjustable parameter in the calculation algorithm. The paper presents the results of an experimental investigation of the isobaric heat capacity of propiconazole at atmospheric pressure in the temperature interval of 313–573 K and of propiconazole–carbon dioxide mixture in the timperature interval of 313–473 K and the pressure range of 0.098–25.0 MPa. [ABSTRACT FROM AUTHOR]

Agriculture has a main impact on increasing the economy of most developing countries, and energy policies in fighting climate change have a vital role in strengthening economic growth. This paper studies the impact of agriculture, trade openness and green energy on CO2 emissions in Rwanda during 1990–2022. Phillips- Peron and Augmented Dickey fuller unit root test affirmed the stationary of data, and autoregressive distributed lag (ARDL)-bound testing confirmed a long-run relationship among variables. The study employed an ARDL approach. Findings from long-run elasticities showed that 1% increase in agriculture productivity increased carbon dioxide emissions by 1.94%; 1% increase in trade openness increased carbon dioxide emissions by 0.16%; whereas 1% increase in renewable energy consumption and GDP per capita decreased carbon dioxide emissions by 2.71% and 2%, respectively. The result confirmed the induced environment curve and the pollution haven hypothesis in Rwanda. Moreover, green energy consumption and GDP per capita decreases CO2 emissions eventually, which supports the validity of environment Kuznets curve in Rwanda. The findings recommend that an increase in renewable energy usage and trade reforms accompanied by strong environmental policies to reduce CO2 emissions will develop the agriculture sector and regional economy. Highlights: • Rapid emission reduction is essential for achieving sustainable growth in Rwanda. • An Auto regressive distributed lag approach was employed by using time series data. • The results added new insights on renewable energy, agriculture, trade openness, and CO2 emission in Rwanda. • This article offers policy suggestions to reduce carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

Despite the efforts to transition to a low carbon economy, greenhouse gas emissions are surging to critical levels. Carbon dioxide removals (CDR) methods, such as direct air capture (DAC), have been gaining substantial public attention in the last few years. DAC is essential in curbing CO2 concentrations and achieving climate targets. It is said that DAC can be deployed at anywhere, but a throughout life cycle assessment (LCA) is imperative to prove its viability. Therefore, this paper aims to explore the feasibility of constructing a 1 MT CO 2 plant in Ireland, using Kinsale and Corrib gas fields as storage points. The results showed that the country is an ideal candidate for scaling up this emerging industry. The efficiency is primarily influenced by the construction of the pipeline section, given a reliable sources of heat and electricity. The study highlights the significant impact of distances to the storage points on feasibility, favouring counties near of the gas fields. In conclusion, Ireland has the potential to establish its own DAC industry. [ABSTRACT FROM AUTHOR]

The heat and mass transfer behavior of droplet transfer in the CO2 welding process plays a decisive role in weld formation, joint microstructure, and service performance. Studying the process of droplet transfer is of great significance for welding metallurgical analysis, stress deformation analysis, process control, and process optimization. In recent years, welding scholars have devoted themselves to the theoretical analysis of the dynamic information of droplet transfer through numerical simulation and combined with experimental research, so that the welding process has changed from qualitative analysis to quantitative analysis, and the theoretical research and experimental research have been upgraded to scientific research. Based on the available data, this paper takes the CO2 welding process as the object and finds that in recent years, the numerical simulation field of CO2 welding droplet transfer has developed in the direction of arc-droplet-pool integration. However, there are still some problems in the existing mathematical model, such as insufficient model accuracy, too much calculation, too many assumptions, and too large gap between the actual and other problems. It can be predicted that the future development direction of the numerical simulation of the droplet transfer will be towards refinement and high efficiency. [ABSTRACT FROM AUTHOR]

Pore fluids control the diagenetic processes and storage spaces of deep clastic rock reservoirs and have become a major area of interest within the fields of sedimentology and petroleum geology. This paper aims to relate the diagenetic processes of the Oligocene Zhuhai sandstones in the Baiyun Sag to pore fluids varying with burial depth. The types and distribution patterns of authigenic minerals are investigated through analysis of petrographic, mineralogical, and geochemical features to illustrate the origin and flow patterns of pore fluids and their influences on reservoir diagenesis. Strong cementation of eogenetic carbonate cement near the sandstone–mudstone interface was a consequence of material migration from adjacent mudstones on a large scale. The pore fluids were mainly affected by microbial methanogenesis and carbonate mineral dissolution in adjacent mudstones during eogenesis. The pore fluids were diffusively transported in a relatively open geochemical system within a local range. Support for this model is provided by the heavier stable isotopic values present in eogenetic calcite and dolomite. Feldspar dissolution during early mesogenesis was spatially accompanied by the precipitation of authigenic quartz and ferroan carbonate cement. Pore fluids in this period were rich in organic acids and CO2, and their migration mechanism was diffusive transport. The obviously lighter carbon and oxygen isotopic compositions of the ferroan calcite support this inference. During late mesogenesis, the input of deep hydrothermal fluid might have been partly responsible for the precipitation of ankerite, barite and authigenic albite. Oil charging may have inhibited carbonate cementation and compaction, accordingly preserving porosity, and together with authigenic kaolinite, might have promoted the transition of the reservoir from water wet to oil wet to the benefit of oil entrapment. The findings reported here shed new light on the evaluation and prediction of sandstone reservoirs that have experienced multiple periods of fluid flow. [ABSTRACT FROM AUTHOR]

Evaluation, prediction, and measurement of carbon dioxide (CO2) solubility in different polymers are crucial for engineers in various chemical applications, such as extraction and generation of novel materials. In this paper, correlations based on gene expression programming (GEP) were generated to predict the value of carbon dioxide solubility in three polymers. Results showed that the generated correlations could represent an outstanding efficiency and provide predictions for carbon dioxide solubility with satisfactory average absolute relative errors of 9.71%, 5.87%, and 1.63% for polystyrene (PS), polybutylene succinate-co-adipate (PBSA), and polybutylene succinate (PBS), respectively. Trend analysis based on Henry's law illustrated that increasing pressure and decreasing temperature lead to an increase in carbon dioxide solubility. Finally, outlier discovery was applied using the leverage approach to detect the suspected data points. The outlier detection demonstrated the statistical validity of the developed correlations. William's plot of three generated correlations showed that all of the data points are located in the valid zone except one point for PBS polymer and three points for PS polymer. [ABSTRACT FROM AUTHOR]

Analyzing the geographical distribution of carbon dioxide (CO2) is essential for understanding the influence and structural nature of area-specific sectoral emissions in the total carbon budget. In this practice, the implementations of specific accounting and spatial attribution methods are criticized for multiple sources of uncertainties. Therefore, estimated emissions may bring forth unreliable conclusions to analyze and understand the spatial variation and associated hypothesized anthropogenic sources in this gas' biophysical cyclical process. This paper examined the relations among the observed atmospheric phenomenon of column-averaged CO2 (XCO2) and the hypothesized major anthropogenic emissions and sources to understand their influences on the spatial variation of annual XCO2 concentration at the county-level contiguous USA (CONUS). Specifically, this paper explored the spatial distribution of XCO2 in the CONUS by processing the Orbiting Carbon Observatory-2 (OCO-2) satellite-based observed database of XCO2. The study found that observed XCO2 and interpolated data can represent the annual spatial variation of XCO2 at the county level of CONUS. The study established that industrial locations and emissions play a major role in the spatial variation of XCO2 in the CONUS regardless of the direct emissions from other anthropogenic sources (i.e., transport, residential) and the urban and rural nature of the counties. The study found that in 2017, 2634.92 Million Tons (MTons) industrial emissions increased the level of XCO2 by 0.0621 ppm in the CONUS. [ABSTRACT FROM AUTHOR]

This paper continues the work of Kang and Larsson Theoretical and Applied Climatology 116:537–548 (2014) What is the link between temperature and carbon dioxide levels? A Granger causality analysis based on ice core data. Theoretical and Applied Climatology 116:537-548, by adding methane to the study of causality between temperature and carbon dioxide. The data used goes 800,000 years back in time which is possible due to it being extracted from ice cores located at Dome C in Antarctica. First we use linear interpolation to make the three data sets equidistant to be able to employ statistical methods. We adjust for a deterministic trend and find the best model fit to be an autoregressive model with lag two and a piecewise quadratic trend. By employing multivariate Granger causality tests we find strong evidence that temperature, carbon dioxide and methane all Granger cause each other in both directions i.e. carbon dioxide Granger causes temperature and temperature Granger causes carbon dioxide, etc. This is in accordance with the findings of Kang and Larsson, with the extension that we can add methane to establish a trivariate feedback system between temperature, carbon dioxide and methane. [ABSTRACT FROM AUTHOR]

Because port operations have rapidly been extending, air pollution resulted from ports has been increased and become a persistent concern for environmentalist and policy makers. The objective of this paper is to measure the environmental efficiency of ports in Korea. The main characteristic of the environmental efficiency assessment problem is that undesirable output of carbon dioxide (CO2) emissions and exogenous fixed input of the terminal area of ports should concurrently be considered. By analysing the impacts of the exogenous fixed input and undesirable outputs on decision making units (DMUs) performance, a super efficiency slacks-based measure in data envelopment analysis (SE-SBM-DEA) approach is proposed. The proposed approach consists of two models: slacks-based measure (SBM) model and super efficiency SBM (SE-SBM) model. The models effectively discriminate between efficient and inefficient ports, and rank their efficiencies. To restrict any decreases or increases in the fixed input levels, the slacks of fixed inputs are removed from the target functions and their relevant constraints of the proposed approach. In addition, the undesirable outputs are formulated according to the weak disposability assumption, so that they can only be reduced with the reduction of certain desirable outputs. Hence, its slack should also be removed from the SBM and SE-SBM models. As a result, the scalar measures of the models only deal with the discretionary inputs and desirable outputs of a DMU being evaluated. We examine the applicability of the proposed approach, using real data, for 19 ports in Korea. [ABSTRACT FROM AUTHOR]

Neuronal activity consumes cellular energy and generates carbon dioxide (CO2). To counter this metabolic challenge, synaptic signalling communicates with nearby microvasculature to increase local blood flow. Is this process solely based on feedforward synaptic signalling, or is the generated CO2 also involved? This question was addressed in mice in a new Nature Communications publication by Tournissac and colleagues where they showed that neurovascular coupling is not affected by exogenous CO2 or its associated acidification. [ABSTRACT FROM AUTHOR]

The Soybean Free Air Concentration Enrichment (SoyFACE) facility is the longest running open-air carbon dioxide and ozone enrichment facility in the world. For over two decades, soybean, maize, and other crops have been exposed to the elevated carbon dioxide and ozone concentrations anticipated for late this century. The facility, located in East Central Illinois, USA, exposes crops to different atmospheric concentrations in replicated octagonal ~280 m2 Free Air Concentration Enrichment (FACE) treatment plots. Each FACE plot is paired with an untreated control (ambient) plot. The experiment provides important ground truth data for predicting future crop productivity. Fumigation data from SoyFACE were collected every four seconds throughout each growing season for over two decades. Here, we organize, quality control, and collate 20 years of data to facilitate trend analysis and crop modeling efforts. This paper provides the rationale for and a description of the SoyFACE experiments, along with a summary of the fumigation data and collation process, weather and ambient data collection procedures, and explanations of air pollution metrics and calculations. [ABSTRACT FROM AUTHOR]

Solar energy is the most sustainable alternative to fossil fuels. The production of solar thermochemical fuels from water/carbon dioxide not only overcomes the intermittent nature of solar energy, but also allows for flexible transportation and distribution. In this paper, the challenges for solar thermochemical H2/CO production are reviewed. New perspectives and insights to overcome these challenges are presented. For two-step cycles, the main challenges are high temperatures, low conversions and the intensive oxygen removal work. Theoretically feasible temperature and pressure ranges are needed to develop reactant materials. The fundamental mechanism to reduce the temperature and the potential to improve the efficiency by minimizing the oxygen removal work need be revealed. Various material modification strategies and advanced reactors are proposed to improve the efficiency by reducing the temperature and enhancing heat transfer process. But the oxygen removal work required has not been minimized. For multi-step cycles, the main challenges are the separation of corrosive acid and insufficient reaction kinetics. For the separation of acids, many methods have been proposed. But these methods require extra energy and causes undesired side reactions or byproducts. The reaction kinetics have been enhanced by improving catalysts with noble materials or complex fabrication methods. Developing novel multi-step cycles using metal oxides, hydroxides and carbonates may be promising. [ABSTRACT FROM AUTHOR]

The assurance of a stable and appealing foam on beer requires an understanding and application of several physical and chemical principles and these are reviewed in this paper. In terms of physics, it is essential that the foam is produced efficiently, the presence of nucleation sites being important, with major determining factors being temperature and carbonation level. The principle driving force for foam instability is disproportionation, wherein bubble collapse is caused by the passage of carbon dioxide from smaller to larger bubbles. As nitrogen does not readily make this passage, this gas allows for much more stable foams. The stability of foam depends on the balance of foam-positive foaming components (polypeptides, hop bitter acids, metal ions, melanoidins) over foam-negative entities (ethanol, lipids, detergents). The principal foam-stabilizing proteins contributed by malted barley are Protein Z4 and Lipid Transfer Protein (LTP1), but the fragments of hordein produced by proteolysis in malting and perhaps mashing have a greater ability to enter into the foam but display less ability to stabilize the bubbles. They compete with Protein Z and LTP1 which display less foamability but greater foam stability. Carbohydrate complexed with protein may have a significant role to play, and this is potentially the reason for the benefits to foam afforded by wheat. Kinetic models analogous to those employed in the study of enzyme kinetics are useful in terms of interpreting foaming systems, as are model systems. [ABSTRACT FROM AUTHOR]

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Masks are the primary tool used to prevent the spread of COVID-19 in the current pandemic. The use of masks may result in some discomfort, which may be caused by the accumulation of carbon dioxide in the inner space of the mask. This paper presents tests of carbon dioxide concentration in the inner space of the mask during work at a computer, for various flat and convex masks. Five different masks were used in the tests. Convex masks showed a greater accumulation of carbon dioxide than flat masks. The concentration of carbon dioxide was also higher for masks made of more layers. The dependence of the average values of carbon dioxide concentrations under the masks for selected people depending on the BMI and the type of mask was determined, as well as the measurements of carbon dioxide concentrations without the mask. An increase in carbon dioxide concentration was observed with increasing BMI. The development of effective self-defense tools against the virus, including masks, is essential to contain the spread of COVID-19. [ABSTRACT FROM AUTHOR]

To provide health services, hospitals consume electrical power and contribute to the CO2 emission. This paper aims to develop a modelling approach to optimize hospital services while reducing CO2 emissions. To capture treatment processes and the production of carbon dioxide, a hybrid method of data mining and simulation–optimization techniques is proposed. Different clustering algorithms are used to categorize patients. Using quality indicators, clustering methods are evaluated to find the best cluster sets, and then patients are categorized accordingly. Discrete-event simulation is applied to each patient category to estimate performance measures such as number of patients being served, waiting times, and length of stay, as well as the amount of CO2 emission. To optimize performance measures of patient flow, metaheuristic searches have been used. The dataset of Bushehr Heart Hospital is considered as a case study. Based on K-means, K-medoid, Hierarchical clustering, and Fuzzy C-means clustering methods, patients are categorized into two groups of high-risk and low-risk patients. The number of patients being served, total waiting time, length of stay, and CO2 emitted during care processes are improved for both groups. The proposed hybrid method is an effective method for hospitals to categorize patients based on care processes. The problems and the proposed solution approach reported in this study could be applicable to other hospitals, worldwide to help both optimize the patient flow and minimize the environmental consequences of care services. [ABSTRACT FROM AUTHOR]

Rhenium(I)-carbonyl-diimine complexes have emerged as promising photocatalysts for carbon dioxide reduction with covalent organic frameworks recognized as perfect sensitizers and scaffold support. Such Re complexes/covalent organic frameworks hybrid catalysts have demonstrated high carbon dioxide reduction activities but with strong excitation energy-dependence. In this paper, we rationalize this behavior by the excitation energy-dependent pathways of internal photo-induced charge transfer studied via transient optical spectroscopies and time-dependent density-functional theory calculation. Under band-edge excitation, the excited electrons are quickly injected from covalent organic frameworks moiety into catalytic RheniumI center within picosecond but followed by fast backward geminate recombination. While under excitation with high-energy photon, the injected electrons are located at high-energy levels in RheniumI centers with longer lifetime. Besides those injected electrons to RheniumI center, there still remain some long-lived electrons in covalent organic frameworks moiety which is transferred back from RheniumI. This facilitates the two-electron reaction of carbon dioxide conversion to carbon monoxide. Re complexes within covalent organic frameworks have emerged as promising photocatalysts for CO2 reduction. Here, authors identify a high-energy electron transfer pathway during CO2 reduction that results in longer-lived excited states than a low-energy electron transfer pathway. [ABSTRACT FROM AUTHOR]

Dimethyl sulfoxide (DMSO) and acetone are frequently used in supercritical antisolvent (SAS) processes, since they have very different physical properties and have complex phase behavior. This paper reports experimental phase equilibrium data for {CO2 + DMSO} and {CO2 + acetone + DMSO} systems. The static synthetic method was employed to obtain phase equilibrium behavior in pressures up to 12.1 MPa, temperature range between 313.15 and 343.15 K, the concentration of 5.5 mol·kg−1 (solute: DMSO; solvent: acetone) on a CO2-free basis, and CO2 mole fractions between 0.652 and 0.953. The experimental data measured here presented transitions of VLE (vapor–liquid equilibrium) and LLE (liquid–liquid equilibrium) phases. In this work, the effects of association between molecules are considered. Thus, the PC-SAFT EoS was used to model the experimental data and phase transitions, and the pressure deviation between experimental and calculated data for the binary and ternary system was 0.81% and 0.51%, respectively. The percentage average absolute relative deviation (%AARD) for {CO2 + DMSO}, {CO2 + acetone} and {DMSO + acetone} system was 0.57, 0.89 and 0.29, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a technological study aimed at growing buried-channel heterostructures for single-mode semiconductor lasers operating in the spectral range 1600–1610 nm. We have produced laser diodes with an emission wavelength corresponding to an overtone in the absorption band of carbon dioxide and assessed the effect of temperature on their optical emission spectra. It has been shown that their emission spectra can be tuned over the range from 1559 to 1620 nm. We have demonstrated the feasibility of producing intelligent fiber-optic systems for remote carbon dioxide concentration monitoring. [ABSTRACT FROM AUTHOR]

Climate change is introducing more risks and uncertainties into the economy and the financial system, but information failures limit the understanding of its financial impact on companies. To create the necessary conditions for transparency regarding these risks, the Financial Stability Board (FSB) has set up an international working group, the Task Force on Climate-related Financial Disclosures (TCFD), with the aim of enhancing climate-related corporate disclosures. In this paper, we build a novel composite index to assess firms' compliance with the TCFD recommendations: the Climate Risks and Opportunities Reporting Index (CRORI). We also perform an empirical analysis of French CAC 40 companies over the period 2015–2018 to i) test the robustness of the calculation of the CRORI and ii) provide an initial assessment of the level of compliance of companies with the recommendations of the TCFD. Our results reveal a trend toward improved voluntary disclosure of climate-related information, particularly in the case of CO 2 -intensive companies. [ABSTRACT FROM AUTHOR]

The present paper describes the effects of hydrogen addition and carbon dioxide dilution in the natural gas on the velocity profiles and on the turbulent quantities (integral scale and Kolmogorov scale) in a cylindrical burner. The hydrogen content in the fuel is varied from 0 to 20% in volume, and the volume of carbon dioxide is varied between 0 and 50%. The velocity fields and the root mean square value of velocity are determined by the particle image velocimetry technique in the reacting flow. The concentrations of CO and NO are found using the corresponding analyzers. The turbulent quantities are determined by a numerical method. The results show that the absence of hydrogen and the carbon dioxide content greater than 20% lead to flame blow-out. Therefore, the flame is hooked to the burner if hydrogen is added. In this study, with hydrogen addition, the difference in the maximum velocity () along the bio-hythane jet is less important far from the burner due to the low density and high molecular diffusivity of hydrogen. The studies of the root mean square values of two velocity components ( and ) indicate that turbulence is more important for the component. [ABSTRACT FROM AUTHOR]

Reduction gases are widely used in the metallurgical, chemical and other industries. In this paper, the possibility of higher-quality reduction gas production using a two-stage technology is considered. It is proposed to use air conversion of natural gas with cooling and drying of the obtained products at the first stage. At the second stage, gas mixture is heated, treated in the catalyst bed, quenched and dried. It is established that the temperature of heat treatment of the gas mixture at the second stage should be at least 850–950 °C. This allows to increase the ratio (CO − H2)/CO2 in the resulting reduction gas. The minimum gas treatment temperature at the second stage is calculated depending on the pressure in the system. By overheating the gas before it enters the catalyst bed in the second stage, it is possible to compensate for the heat required for chemical reactions in temperatures above 850 °C, the total thermal effect of chemical reactions is determined. The total heat effect of chemical reactions depending on the temperature of gas heat treatment at different pressure is defined. [ABSTRACT FROM AUTHOR]

Carbon dioxide phase transition fracturing is a safe rock-breaking technique. Its vibration effect cannot be ignored. It is valuable for fracturing safety control to investigate its ground vibration characteristics. In this paper, a single-hole test was implemented, and several vibration curves in jet direction and vertical jet direction were monitored to explore the ground vibration difference in these two directions. The attenuation laws of the peak particle velocity (PPV) and the Fourier dominant frequency were obtained. Moreover, based on the Hilbert–Huang transform method, the time–frequency–energy characteristics for the fracturing vibration were evaluated. The test results indicated that the PPV in jet direction is higher than that of the vertical jet direction, and the PPV obeys the power attenuation function in these two monitoring directions. When the explosion center distance increases from 2.193 to 6.067 m, the Fourier dominant frequency fluctuates slightly around 2 Hz in jet direction, but it decays from 12.5 to 1.6 Hz in the vertical jet direction. The vibration signal energies in jet direction and vertical jet direction are both distributed within 0–48 Hz. In addition, it is indicated that the vibration signal energy converses from a high-frequency band to a low-frequency band as the explosion center distance rises from 2.193 to 6.067 m. Due to the significant difference between the ground vibrations in the diverse directions, when this fracturing technique is carried out near the buildings, it is suggested that the installation direction of the fracturing pipe should be considered. [ABSTRACT FROM AUTHOR]

This review highlighted the current ongoing research in plasma technology and why this process needs to be explored in synergy with the other available/researched technologies worldwide. It provides a broad outlook to study the various elements of non-thermal plasma for CO2 conversion. Most commonly used reactors such as dielectric barrier discharge (DBD) plasma, microwave (MW) plasma, and gliding arc (GA) plasma are described with their operational challenges. It covers the laboratory-scale reactor designs, characterization, the overall efficiencies, the physical and chemical interplay between plasma and catalysis, as well as many of the recent efforts to improve the reaction efficiency. Multiple configurations of plasma reactors along with the effect of operating parameters such as gas flow rate, power input, diluting gas, and others on conversion and energy efficiency are reviewed in this paper. Different catalytic materials and their effect on conversion and energy efficiency are also explored. This review outlines the state-of-the-art development of the plasma catalysis process for CO2 conversion, including CO2 splitting and briefly discussing the mechanistic insights into CO2 hydrogenation and reforming. Additionally, the role and need for the intrinsic rational design of catalyst composition and structure in determining the selectivity of CO2 conversion is also deliberated. A perspective on current bottlenecks and opportunities for the advancement in development of next-generation novel catalysts for plasma catalysis for industrial applications is also presented. [ABSTRACT FROM AUTHOR]

In China, urbanization has been rapidly developing since the country began its economic reform in 1978. With the expansion of the urban population size and the corresponding urbanization and industrialization, the rapid increase in CO2 emissions has become a major restraint on China's economic growth. However, current studies have not paid sufficient attention to the impact of the urban population size on CO2 emissions in China due to poor data availability. In this paper, we apply index decomposition analysis (IDA) to decompose CO2 emissions into five elements, and we investigate both the direct and indirect impacts of the urban population size on total CO2 emissions and per capita CO2 emissions in China. Additionally, we empirically study the impact on 175 Chinese cities at the prefecture level and above for the first time. The results show that the urban population size significantly promotes total CO2 emissions but curbs per capita CO2 emissions in cities in China. A 1% increase in the urban population size will lead to a nearly 1% increase in total CO2 emissions and a 0.3% decrease in per capita CO2 emissions. Regarding heterogeneity, the expansion of the urban population size in the large city group drives a greater increase in CO2 emissions than the expansion of the urban population size in other city groups. The main transmission pathways are through population density, economic agglomeration and energy intensity. Regarding the mechanism variables, high economic agglomeration leads to more CO2 emissions, while an increase in population density and energy efficiency results in carbon mitigation. Moreover, public green areas, foreign direct investment (FDI) and technology innovation are conducive to reducing CO2 emissions. [ABSTRACT FROM AUTHOR]

In this paper, we propose a simple oligopoly game model to represent the interactions between coalitions of countries in deploying carbon dioxide removal (CDR) strategies in a steady-state net-zero emission climate regime that could take place by the end of the twenty-first century. The emission quotas and CDR activities obtained in the solution of this steady-state model could then be used as a target for end-of-period conditions in a dynamic integrated assessment analysis studying the transition to 2100. More precisely, we analyze a steady-state situation where m coalitions exist and behave as m players in a game of supplying emission rights on an international emission trading system. The quotas supplied by a coalition must correspond to the amount of CO2 captured through CDR activities in the corresponding world region. We use an extension of the computable general equilibrium model GEMINI-E3 to calibrate the payoff functions and compute an equilibrium solution in the noncooperative game. [ABSTRACT FROM AUTHOR]

This paper presents results obtained from a modified perfusion bioreactor designed to form tissue equivalents in conditions of long-term cultivation with the capacity to oxygenate the medium. The design of the device permits the morphology of cellular engineering structures to be studies at four cultivation time points under flow conditions and also provides for constant monitoring of culture medium pH, O2 and CO2 contents, and major metabolite contents throughout the experiment. The functional effectiveness of the bioreactor is confirmed by the example of "growing" the tissue equivalent of cartilage for 25 days with maintenance of cell culture viability, with constant values for the main culture medium parameters and sterility. [ABSTRACT FROM AUTHOR]

Background: Silage emits climate- and environment-relevant gases during fermentation and feed-out periods. This trial aimed to determine the unknown carbon dioxide (CO2), methane, nitrous oxide, ethanol, and ethyl acetate emissions of constant maize silage material over both periods. The results will be published in two consecutive articles (Part A: anaerobic fermentation period, Part B: aerobic storage period). Methods: The untreated control (CON) was compared with the chemical additive treatment (CHE; 0.5 g sodium benzoate and 0.3 g potassium sorbate per kg fresh matter) and the biological additive treatment (BIO; 108 colony-forming units (CFU) Lentilactobacillus buchneri and 107 CFU Lactiplantibacillus plantarum per kg fresh matter). Barrel silos (n = 4) were connected to gas bags to quantify gas formation during anaerobic fermentation (30 or 135 ensiling days). Glass jar silos (n = 12) were used for laboratory silage analysis. Results: CHE produced significantly (p < 0.05) less gas (6.7 ± 0.3 L per kg dry matter ensiled material (kgDM) until ensiling day 14.0 ± 0.0) and ethanol (8.6 ± 1.5 mg kgDM–1) than CON did (8.5 ± 0.2 L kgDM–1 until ensiling day 19.5 ± 6.4; 12.2 ± 1.5 (mg ethanol) kgDM–1). BIO indicates prolonged gas formation (9.1 ± 0.9 L kgDM–1 until ensiling day 61.3 ± 51.9; 12.0 ± 2.1 mg kgDM–1). CO2 is the main component of the gas formed. All treatments formed methane and nitrous oxide in small quantities. CON emitted significantly more CO2eq emissions than BIO and less than CHE (p < 0.05). Additives had no effect on ethyl acetate gas emissions. For BIO, ethanol concentrations in the material (rS = 0.609, p < 0.05) and gas quantities (rS = 0.691, p < 0.05) correlate with ethyl acetate gas quantities. All the treatments exhibited decreasing gas and CO2 quantities, and the dry matter mass increased between ensiling days 14 and 30 (− 0.810 ≤ rS ≤ 0.442; p < 0.05 to p = 0.20). Conclusion: Silage generates climate- and environmental-relevant gases during fermentation and silage additives affect this pattern. Gas formation exceeds the fixation potential, and the carbon footprint of silage fermentation is negative. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of carbon dioxide to produce high-value ethylene is often limited by poor selectivity and yield of multi-carbon products. To address this, we propose a cyanamide-coordinated isolated copper framework with both metallic copper (Cu0) and charged copper (Cu1+) sites as an efficient electrocatalyst for the reduction of carbon dioxide to ethylene. Our operando electrochemical characterizations and theoretical calculations reveal that copper atoms in the Cuδ+NCN complex enhance carbon dioxide activation by improving surface carbon monoxide adsorption, while delocalized electrons around copper sites facilitate carbon-carbon coupling by reducing the Gibbs free energy for *CHC formation. This leads to high selectivity for ethylene production. The Cuδ+NCN catalyst achieves 77.7% selectivity for carbon dioxide to ethylene conversion at a partial current density of 400 milliamperes per square centimeter and demonstrates long-term stability over 80 hours in membrane electrode assembly-based electrolysers. This study provides a strategic approach for designing catalysts for the electrosynthesis of value-added chemicals from carbon dioxide. This study reports a cyanamide-framework stabilized multivalent copper catalyst for efficient electrochemical reduction of carbon dioxide to ethylene with 77.7% selectivity at 400 mA cm−2, offering a rational strategy for CO2 conversion. [ABSTRACT FROM AUTHOR]

Metal hydrides are crucial intermediates in numerous catalytic reactions. Intensive efforts have been dedicated to constructing molecular metal hydrides, where toxic precursors and delicate mediators are usually involved. Herein, we demonstrate a facile pressure-induced methodology to generate a cost-effective heterogeneous electrocatalytic metal hydride surface for sustainable hydrogen transfer. Taking carbon dioxide (CO2) electroreduction as a model system and zinc (Zn), a well-known carbon monoxide (CO)-selective catalyst, as a model catalyst, we showcase a homogeneous-type hydrogen atom transfer process induced by heterogeneous hydride surfaces, enabling direct hydrogenation pathways traditionally considered "prohibited". Specifically, the maximal Faradaic efficiency for formate is enhanced by ~fivefold to 83% under ambient conditions. Experimental and theoretical analyses reveal that unlike the distal hydrogenation route for CO2 to CO over pristine Zn, the Zn hydride surface enables direct hydrogenation at the carbon site of CO2 to form formate. This work provides a promising material platform for sustainable synthesis. The authors demonstrate a facile pressure-induced methodology to generate a cost-effective heterogeneous electrocatalytic metal hydride surface for sustainable hydrogen transfer. [ABSTRACT FROM AUTHOR]

Calculating the minimum miscibility pressure (MMP) between crude oil and carbon dioxide (CO2) is critical for optimizing injection parameters, designing schemes, and predicting production capacity in CO2 injection projects for enhancing oil recovery. However, an accurate approach for obtaining this parameter is not yet established. In order to tackle this issue, a novel approach is suggested, based on the original cell-to-cell model, to determine the MMP and the 97% oil recovery rate as the standard. Using the volume-transformed Peng-Robinson equation of state enhances the precision of fluid volume estimation, as it mainly relies on predicting fluid volume within each cell. Furthermore, to ensure a precise estimation of the ultimate oil recovery rate, it is imperative to employ a total cell count of 500 in all simulations to avoid the problem of numerical dispersion. Finally, a second-order polynomial equation more accurately predicts the infinite-cell oil recovery factor. The accuracy of the modified model is verified by comparing MMP values from five oil and gas systems in the literature. The computational results of the modified multiple-mixing-cell (MMC) approach exhibit a higher level of concordance with the MMPs in the literature. The average relative error is less than 3.96%. The improved MMC algorithm can quickly determine the miscibility mechanism and visually represent the dynamic miscibility process involving multiple oil-gas contacts in a slim tube. This study provides a theoretical and practical basis for addressing the critical scientific issues of CO2-safe storage technology. [ABSTRACT FROM AUTHOR]

Highlights: Developing surface-functionalized catalysts with exceptional activity and selectivity for the electrocatalytic CO2RR to C2+ products under neutral electrolyte. A remarkable C2+ FE of nearly 90% at an unprecedented current density of 300 mA cm−2 and maintain high FE (> 80%) at the wide current density performance (100–600 mA cm−2) in neutral environments using a flow cell as well as MEA electrolyzer. Mechanical study reveals that reducing the coverage of coordinated K·H2O water increased the probability of intermediate reactants (CO) interacting with the surface, thereby promoting efficient C–C coupling and enhancing the yield of C2+ products. Surface functionalization of Cu-based catalysts has demonstrated promising potential for enhancing the electrochemical CO2 reduction reaction (CO2RR) toward multi-carbon (C2+) products, primarily by suppressing the parasitic hydrogen evolution reaction and facilitating a localized CO2/CO concentration at the electrode. Building upon this approach, we developed surface-functionalized catalysts with exceptional activity and selectivity for electrocatalytic CO2RR to C2+ in a neutral electrolyte. Employing CuO nanoparticles coated with hexaethynylbenzene organic molecules (HEB-CuO NPs), a remarkable C2+ Faradaic efficiency of nearly 90% was achieved at an unprecedented current density of 300 mA cm−2, and a high FE (> 80%) was maintained at a wide range of current densities (100–600 mA cm−2) in neutral environments using a flow cell. Furthermore, in a membrane electrode assembly (MEA) electrolyzer, 86.14% FEC2+ was achieved at a partial current density of 387.6 mA cm−2 while maintaining continuous operation for over 50 h at a current density of 200 mA cm−2. In-situ spectroscopy studies and molecular dynamics simulations reveal that reducing the coverage of coordinated K⋅H2O water increased the probability of intermediate reactants (CO) interacting with the surface, thereby promoting efficient C–C coupling and enhancing the yield of C2+ products. This advancement offers significant potential for optimizing local micro-environments for sustainable and highly efficient C2+ production. [ABSTRACT FROM AUTHOR]

The exchange of trace gases between the atmosphere and the ocean plays a key role in the Earth's climate. Fluxes at the air-sea interface are affected mainly by wind blowing over the ocean and seawater temperature and salinity changes. This study aimed to quantify the use of CO 2 partial pressure (pCO 2 ) measurements at different depths (1, 5, and 10 m) in ocean surface layers to determine CO 2 fluxes (FCO 2 ) and to investigate the impacts of wind-sheltered and wind-exposed regions on the carbon budget. Vertical profiles of temperature, salinity, and pCO 2 were considered during a daily cycle. pCO 2 profiles exhibited relatively high values during sunny hours, associated with relatively high sea temperatures. However, the largest FCO 2 corresponded with higher wind speeds. Estimated fluxes between measurements at 1 and 10 m depths decreased by 71% in the sheltered region and 44% in the exposed region. According to the SOCAT dataset, at a depth of 5 m, the Atlantic basin emits approximately 0.29 Tg month - 1 of CO 2 to the atmosphere; nevertheless, our estimates suggest that FCO 2 at the surface is 12.02 Tg month - 1 , which is 97.6% greater than that at 5 m depth. Therefore, future studies should consider sampling depth to adequately estimate the FCO 2 . [ABSTRACT FROM AUTHOR]

As a result of electrochemical conversion of carbon dioxide (CO2), value-added chemicals like as synthetic fuels and chemical feedstocks can be produced. In the current state of the art, copper-based materials are most widely used being the most effective catalysts for this reaction. It is still necessary to improve the reaction rate and product selectivity of CuOx for electrochemical CO2 reduction reaction (CO2RR). The main objective of this work was synthesized and evaluate the copper oxide electrocatalyst combined with silver (CuO 70% Ag 30%) for the conversion of carbon dioxide into synthetic fuels. The catalysts have been prepared by the oxalate method and assessed in a flow cell system. The results of electrochemical experiments were carried out at room temperature and at different potentials (-1.05 V–0.75 V vs. RHE in presence of 0.1 M KHCO3) and gas and liquid chromatographic analysis are summarized. The CuOx-based electrodes demonstrated the selective of ~ 25% at -0.55 V for formic acid (HCOOH) and over CuO -Ag and selective of ethylene at ~ 20% over CuOx at -1.05 V. Other products were formed as ethylene, ethanol, and propanol (C2H4, EtOH, PrOH) at more positive potentials. On the other hand, carbon monoxide, acetate, ethylene glycol, propinaldehyde, glycoaldehyde and glyoxal (CO, CH3COO, C2H6O2, C3H6O, C2H4O2, C2H2O2) have been formed and detected. Based on the results of these studies, it appears that the formation of synthetic fuels from CO2 at room temperature in alkaline environment can be very promising. [ABSTRACT FROM AUTHOR]

Methanogenic hydrocarbon degradation can be carried out by archaea that couple alkane oxidation directly to methanogenesis, or by syntrophic associations of bacteria with methanogenic archaea. However, metagenomic analyses of methanogenic environments have revealed other archaea with potential for alkane degradation but apparent inability to form methane, suggesting the existence of other modes of syntrophic hydrocarbon degradation. Here, we provide experimental evidence supporting the existence of a third mode of methanogenic degradation of hydrocarbons, mediated by syntrophic cooperation between archaeal partners. We collected sediment samples from a hot spring sediment in Tengchong, China, and enriched Hadarchaeota under methanogenic conditions at 60 °C, using hexadecane as substrate. We named the enriched archaeon Candidatus Melinoarchaeum fermentans DL9YTT1. We used 13C-substrate incubations, metagenomic, metatranscriptomic and metabolomic analyses to show that Ca. Melinoarchaeum uses alkyl-coenzyme M reductases (ACRs) to activate hexadecane via alkyl-CoM formation. Ca. Melinoarchaeum likely degrades alkanes to carbon dioxide, hydrogen and acetate, which can be used as substrates by hydrogenotrophic and acetoclastic methanogens such as Methanothermobacter and Methanothrix. Methanogenic hydrocarbon degradation can be carried out by archaea either by coupling alkane oxidation directly to methanogenesis, or in syntrophic associations with bacteria. Here, the authors provide experimental evidence supporting that methanogenic degradation of hydrocarbons can also be mediated by syntrophic cooperation between archaeal partners. [ABSTRACT FROM AUTHOR]

Although several studies examine the convergence of per capita carbon dioxide (CO2) at the country level, research at the regional level is scarce except in countries like China and the USA. This study bridges this research gap by considering India's regional-level CO2 emissions convergence. In particular, this study proposes to undercover the convergence patterns of carbon emissions towards designing effective carbon reduction policies in the future at the regional level in India. Addressing this research is vital since this question is closely allied with fairness in the distribution of per capita emissions. In order to achieve the stated objective, this study first computes per capita CO2 emissions. Then, it uses the convergence notion to analyse the CO2 emissions in the case of 16 Indian states from 2003–04 to 2018–19. By employing Phillips and Sul's clustering procedure, this study supports the presence of overall divergence when all 16 Indian states are considered as a group. This suggests that all states together are not forming a single steady state rather, they are forming multiple steady (or club convergence) due to heterogeneity in per capita CO2 emissions. Moreover, 16 states cluster into three clubs which have distinct transition paths. From the policy perspective, it is important for the government of India to target reducing per capita CO2 emissions by focusing on clusters of states in a phase-wise manner. [ABSTRACT FROM AUTHOR]

For ocean afforestation (lower illustration), a proportion of the nutrient inventory, which controls the magnitude of all carbon pools and fluxes, are diverted to the corresponding seaweed carbon pools and fluxes. Also, it assumes linearity between the baseline and the ocean afforestation scenario although the implementation of ocean afforestation may have synergistic/antagonistic effects on phytoplankton carbon sequestration. This statement is remarkable because Wang et al. swiftly convert ocean afforestation into a sub-category of ocean nutrient fertilisation in which carbon sequestration is enabled by the supply of additional nutrients and then supposed to be boosted by seaweeds. [Extracted from the article]

The direct co-conversion of methane and carbon dioxide into valuable chemicals has been a longstanding scientific pursuit for carbon neutrality and combating climate change. Herein, we present a photo-driven chemical process that reforms these two major greenhouse gases together to generate green methanol and CO, two high-valued industrial chemicals. Isotopic labeling and control experiments indicate an oxygen-atom-graft occurs, wherein CO2 transfers one O into the C–H bond of CH4 via photo-activated interfacial catalysis with AuPd nanoparticles supported on GaN. The photoexcited AuPd/GaN interface effectively orchestrates the CH4 oxidation and the CO2 reduction producing 13.66 mmol g−1 of CH3OH yield over 10 h. This design provides a solid scientific basis for the photo-driven oxygen-atom-grafting process to be further extended to visible light region. The direct co-conversion of CH4 and CO2 into valuable chemicals has been a longstanding scientific pursuit. Here, the authors present a photo-driven process that reforms these greenhouse gases together to generate CH3OH and CO over AuPd/GaN. [ABSTRACT FROM AUTHOR]

Existing studies indicate that future global carbon dioxide (CO2) removal (CDR) efforts could largely be concentrated in Asia. However, there is limited understanding of how individual Asian countries and regions will respond to varying and uncertain scales of future CDR concerning their energy-land-water system. We address this gap by modeling various levels of CDR-reliant pathways under climate change ambitions in Asia. We find that high CDR reliance leads to residual fossil fuel and industry emissions of about 8 Gigatonnes CO2yr−1 (GtCO2yr−1) by 2050, compared to less than 1 GtCO2yr−1 under moderate-to-low CDR reliance. Moreover, expectations of multi-gigatonne CDR could delay the achievement of domestic net zero CO2 emissions for several Asian countries and regions, and lead to higher land allocation and fertilizer demand for bioenergy crop cultivation. Here, we show that Asian countries and regions should prioritize emission reduction strategies while capitalizing on the advantages of carbon removal when it is most viable. Global future carbon removal efforts could largely be concentrated in Asia. Here, this study shows that multi-gigatonnes expectation of carbon removal could have adverse impact on the energy-land-water system of countries and regions within the continent. [ABSTRACT FROM AUTHOR]

Photoionization can initiate structural reorganization of molecular matter and drive formation of new chemical bonds. Here, we used time-resolved extreme ultraviolet (EUV) pump – EUV probe Coulomb explosion imaging of carbon dioxide dimer ion C O 2 2 + dynamics, that combined with ab initio molecular dynamics simulations, revealed unexpected asymmetric structural rearrangement. We show that ionization by the pump pulse induces rearrangement from the slipped-parallel (C2h) geometry of the neutral C O 2 dimer towards a T-shaped (C2v) structure on the ~100 fs timescale, although the most stable slipped-parallel (C2h) structure of the ionic dimer. Moreover, we find that excited states of the ionized C O 2 dimer can exhibit formation of a CO 3 moiety in the C 2 O 4 + complex that can persist even after a suitably time-delayed second photoionization in a metastable C 2 O 4 2 + dication. Our results suggest that charge asymmetry plays an important role in the ionization-induced dynamics in such dimers that are present in C O 2 rich environments. In a time-resolved Coulomb explosion imaging study using ultrafast extreme ultraviolet pulses, combined with theoretical simulations, authors reveal unexpected asymmetric rearrangement of carbon dioxide dimer ion, including a CO3 moiety formation. [ABSTRACT FROM AUTHOR]

Highlights: Ordered intermetallic pallium-zinc (PdZn) electrocatalyst comprising a high density of PdZn pairs is synthesized for achieving co-adsorption and co-activation carbon dioxide and nitrate. Both operando measurements and theoretical calculations reveal that the PdZn pairs provide a dual-site geometric structure conducive to the key C–N coupling with a low kinetical barrier. The intermetallic PdZn displays excellent performance for the co-reduction of nitrate (NO3–) and carbon dioxide (CO2) toward urea, with a maximum FEurea of 62.78% at a small potential of – 0.4 V versus RHE. Electrochemical co-reduction of nitrate (NO3–) and carbon dioxide (CO2) has been widely regarded as a promising route to produce urea under ambient conditions, however the yield rate of urea has remained limited. Here, we report an atomically ordered intermetallic pallium-zinc (PdZn) electrocatalyst comprising a high density of PdZn pairs for boosting urea electrosynthesis. It is found that Pd and Zn are responsible for the adsorption and activation of NO3– and CO2, respectively, and thus the co-adsorption and co-activation NO3– and CO2 are achieved in ordered PdZn pairs. More importantly, the ordered and well-defined PdZn pairs provide a dual-site geometric structure conducive to the key C–N coupling with a low kinetical barrier, as demonstrated on both operando measurements and theoretical calculations. Consequently, the PdZn electrocatalyst displays excellent performance for the co-reduction to generate urea with a maximum urea Faradaic efficiency of 62.78% and a urea yield rate of 1274.42 μg mg–1 h–1, and the latter is 1.5-fold larger than disordered pairs in PdZn alloys. This work paves new pathways to boost urea electrosynthesis via constructing ordered dual-metal pairs. [ABSTRACT FROM AUTHOR]