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Theoretical developments in our understanding of leaf gas exchange processes and carbon isotope composition (δ13C) mean that it should now be possible to model their responses to global environmental change. Such a model would be of use for process-based interpretations of historical changes in leaf δ13C and for understanding the global stable carbon isotope balance. This paper describes the development and validation of a model towards this aim. The resulting model is used to simulate changes in leaf photosynthesis, stomatal conductance and δ13C of limber pine (Pinus flexilis) in response to the past 30000 y of global environmental change. The predictions of needle δ13C are in line with reported measurements of δ13C from fossilized Pinus flexilis needles preserved in packrat middens in western USA. Leaf gas exchange predictions show that the increased water use efficiency (WUE) of these trees growing in present-day environments, relative to the past, was brought about through an increase in photosynthetic rates and a decrease in stomatal conductance. This contrasts with the explanation of the recent (past 200 y) increase in the WUE of temperate and Mediterranean ecosystems inferred from δ13C measurements which are predicted by the model to have arisen largely by a decrease in stomatal conductance in response to increases in the concentration of atmospheric CO2 since the pre-industrial era. The model as described offers the potential to contribute to our understanding of vegetation effects on the global carbon isotope balance during the glacial periods, and therefore to provide a further constraint on the carbon cycle models used to explain the low concentrations of atmospheric CO2 at these times. [ABSTRACT FROM AUTHOR]

Because of their prominent role in the global carbon balance and their possible carbon sequestration, trees are very important organisms in relation to global climatic changes. Knowledge of these processes is the key to understanding the functioning of the whole forest ecosystem which can be modelled and predicted based on the physiological process information. This paper reviews the major methods and techniques used to examine the likely effects of elevated CO2 on woody plants, as well as the major physiological responses of trees to elevated CO2. The available exposure techniques and approaches are described. An overview table with all relevant literature data over the period 1989-93 summarizes the percent changes in biomass. root/shoot ratio, photosynthesis, leaf area and water use efficiency under elevated CO2. Interaction between growth, photosynthesis and nutrition is discussed with a special emphasis on downward regulation of photosynthesis. The stimulation or reduction found in the respiratory processes of woody plants are reviewed, as well as the effect of elevated CO2 on stomatal density, conductance and water use efficiency. Changes in plant quality and their consequences are examined. Changes in underground processes under elevated CO2 are especially emphasized and related to the functioning of the ecosystem. Some directions for future research arc put forward. [ABSTRACT FROM AUTHOR]

Thus far all attempts to isolate CO2 fixing chloroplasts from pine have failed. In this paper it is proposed that resin acids present in pine needles partition into membranes during chloroplast isolation and interfere with specific reactions of the Calvin cycle. CO2 fixation by isolated spinach chloroplasts was strongly inhibited by the introduction of a suspension of chloroplasts isolated from Pinus sylvestris L. A partially purified organic extract obtained from chloroplasts of this pine species also strongly inhibited CO2 fixation by the spinach chloroplasts. The major inhibitory compounds from the organic extract were identified as a mixture of resin acids by gas-liquid chromatography and mass spectrometry. Two resin acids, abietic acid and dehydroabietic acid, were tested for inhibitory activity. Both resin acids were potent inhibitors of photosynthetic CO2 fixation, with dehydroabietic acid being about three times more potent than abietic acid. [ABSTRACT FROM AUTHOR]

In saturating irradiances of red light, photosynthesis of Laminaria saccharina (L.) Lamouroux was stimulated by low irradiances of continuous blue light only when the supply of dissolved inorganic carbon (DIC) was limiting. The degree of this stimulation was inversely proportional to the logarithm of the concentration of free CO2, whether this was adjusted by varying the total DIC or the pH at a given DIC concentration. The final pH reached in a closed system was higher in blue light than in red light. Both acetazolamide and ethoxyzolamide suppressed the responses to blue light almost completely, but reduced photosynthesis in red light by only 30%. Buffering the pH of the seawater also suppressed the stimulation of photosynthesis by blue light without affecting the photosynthetic rate in red light. The transient stimulation of O2 evolution by a blue light pulse was not accompanied by a corresponding increase in CO2 consumption. These observations could be explained if, in analogy to the mechanism proposed for Ectocarpus (Schmid, Mills & Dring 1996, Plant Cell and Environment 19, 373-382, this issue, accompanying paper), photosynthesis was supported by a blue- light-activated release of CO2 from an internal store. We suggest that the store is located in the vacuoles of the cortical tissue of the blades. The main photosynthetic tissue, however, is in the overlying meristoderm, and blue-light- activated mobilization of the store could stimulate O2 evolution only if periplasmic carbonic anhydrase was available to facilitate CO2 uptake from the cortex. [ABSTRACT FROM AUTHOR]

In order to parametrize a leaf submodel of a canopy level gas-exchange model, a series of photosynthesis and stomatal conductance measurements were made on leaves of white oak (Quercus alba L.) and red maple (Acer rubrum L.) in a mature deciduous forest near Oak Ridge, TN. Gas-exchange characteristics of sun leaves growing at the top of a 30 m canopy and of shade leaves growing at a depth of 3-4 m from the top of the canopy were determined. Measured rates of net photosynthesis at a leaf temperature of 30 °C and saturating photosynthetic photon flux density, expressed on a leaf area basis, were significantly lower (P = 0.01; n = 8) in shade leaves (7.9 μmol m-2 S-1) than in sun leaves (11.5 μmol m-2 S-1). Specific leaf area increased significantly with depth in the canopy, and when photosynthesis rates were expressed on a dry mass basis, they were not significantly different for shade and sun leaves. The percentage leaf nitrogen did not vary significantly with height in the canopy; thus, rates expressed on a per unit nitrogen basis were also not significantly different in shade and sun leaves. A widely used model integrating photosynthesis and stomatal conductance was parametrized independently for sun and shade leaves, enabling us to model successfully diurnal variations in photosynthesis and evapotranspiration of both classes of leaves. Key photosynthesis model parameters were found to scale with leaf nitrogen levels. The leaf model parametrizations were then incorporated into a canopy-scale gas-exchange model that is discussed and tested in a companion paper (Baldocchi & Harley 1995, Plant, Cell and Environment 18, 1157-1173). [ABSTRACT FROM AUTHOR]

This paper describes the construction and performance of branch bags and a CO2 control system used to fumigate branches of mature Sitka spruce trees with air enriched in CO2 (700 μmol mol-1). It contains some examples of results obtained using the system over the course of the first two growing seasons. The branch bags have run continuously for 2 years with very few problems. CO2 concentrations were within 20 μmol mol-1 of the target concentration for more than 90% of the time. Temperatures within the bags were slightly higher than ambient (1-2 °C) and this had some effect on phenology. Attenuation of quantum flux density (photosynthetically active radiation) was 10-45%. The branch bag system has enabled investigation into the effects of elevated CO2 on mature tissue without the problems and expense of fumigating whole trees, Growth in elevated CO2 resulted in an increase in starch and a decrease in soluble protein content of needles, Stomatal conductance was higher in elevated CO2 grown needles, and there was some evidence of an increase in photosynthetic capacity. [ABSTRACT FROM AUTHOR]

The experiments and simulations reported in this paper show that, for stomata sensitive to both CO2 and water vapour concentrations, responses of stomatal conductance (gsw) to boundary layer thickness have two components, one resulting from changes in intercellular CO2 concentration (χic) and another from changes in leaf surface water vapour saturation deficit (Dsw). The experiments and simulations also show that the boundary layer conductance (gbw) can significantly alter the apparent response of gsw) to ambient air CO2 mole fraction (χac) and water vapour mole fraction (χ aw). Because of the feedback loop involved the responses of gsw) for χac) and χaw) each include responses to both χic) and Dsw), The boundary layer alters the state of the variables sensed by the guard cells-i.e. χic) and Dsw)-and so it is a source of feedback, Thus, when scaling up from responses of stomata to the response of gsw) for a whole leaf, the effect of the boundary layer must be considered. The results indicate that, for given responses of gsw) to χic)and Dsw), the apparent responses of gsw) to Daw and χac) depend on the size of the leaf and wind speed, showing that this effect of the boundary layer should be considered when comparing data measured under different conditions, or with different methods. [ABSTRACT FROM AUTHOR]

While photosynthesis of C3 plants is stimulated by an increase in the spheric CO2 concentration, photosynthetic capacity is often reduced after tong-term exposure to elevated CO2. This reduction appears to be brought about by end product inhibition, resulting from an imbalance in the supply and demand of carbohydrates. A review of the literature revealed that the reduction of photosynthetic capacity in elevated CO2 was most pronounced when the increased supply of carbohydrates was combined with small sink size. The volume of pots in which plants were grown affected the sink size by restricting root growth. While plants grown in small pots had a reduced photosynthetic capacity, plants grown in the field showed no reduction or an increase in this capacity. Pot volume also determined the effect of elevated CO2 on the root/shoot ratio: the root/shoot ratio increased when root growth was not restricted and decreased in plants grown in small pots. The data presented in this paper suggest that plants growing in the field will maintain a high photosynthetic capacity as the atmospheric CO2 level continues to rise. [ABSTRACT FROM AUTHOR]

The CO2 partial pressure in the chloroplasts of intact photosynthetic C3 leaves is thought to be less than the intercellular CO2 partial pressure. The intercellular CO2 partial pressure can be calculated from CO2 and H2O gas exchange measurements, whereas the CO2 partial pressure in the chloroplasts is unknown. The conductance of CO2 from the inter-cellular space to the chloroplast stroma and the CO2 partial pressure in the chloroplast stroma can be calculated if the properties of photosynthetic gas exchange are compared with the kinetics of the enzyme ribulose 1 ,5-bisphosphate carboxylase/ oxygenase (RuBPCO). A discrepancy between gas exchange and RuBPCO kinetics can be attributed to a deviation of CO2 partial pressure in the chloroplast stroma from that calculated in the intercellular space. This paper is concerned with the following: estimation of the kinetic constants of RuBPCO and their comparison with the CO2 compensation concentration; their comparison with differential uptake of 14CO2 and 12CO2 and their comparison with O2 dependence of net CO2 uptake of photosynthetic leaves. Discrepancy between RuBPCO kinetics and gas exchange was found at a temperature of 12.5 °C, a photosynthetic photon flux density (PPFD) of 550 μmol quanta m-2 s-1, and an ambient CO2 partial pressure of 40 Pa. Consistency between RuBPCO kinetics and gas exchange was found if CO2 partial pressure was decreased, temperature increased and PPFD decreased. The results suggest that a discrepancy between RuBPCO kinetics and gas exchange is due to a diffusion resistance for CO2 across the chloroplast envelope which decreases with increasing temperature. At low CO2 partial pressure, the diffusion resistance appears to be counterbalanced by active CO2 (or HCO3-) transport with high affinity and low maximum velocity. At low PPFD, CO2 partial pressure in the chloroplast stroma appears to be in equilibrium with that in the intercellular space due to low CO2 flux. [ABSTRACT FROM AUTHOR]

The paper reports the results of the comprehensive study of crassulacean acid metabolism in two epiphytic tropical ferns, Drymoglossum piloselloides and Pyrrosia longifolia. The plants were investigated under different light, temperature and water status. It was found that both species are obligate CAM plants. The diurnal acidity rhythm is due to the fluctuation in malic acid concentration, which accounts for the change in titratable acidity. Besides malic acid, shikimate and oxalate are found to be present, but not contributing to the CAM acid rhythm. The diurnal rhythm of malic acid content results in a corresponding rhythm in leaf water relations. Both ψπ and ψtotal were lowest at the end of the night, i.e. when the level of malic acid was highest. The effects of temperature on CO2 exchange were inverse to those observed in other CAM plants. In both ferns studied, dark CO2 fixation increased when the night temperature was increased. Increase in day temperature reduced CO2 uptake during phase IV and during the following night. The observed responses of the ferns to temperature changes suggest that the in situ environmental conditions are optimal for their CAM performance. In weak light, the plants showed net CO2 output during the midday deacidification period. Increases in light intensity reduced such CO2 output. Under drought conditions, the CO2 exchange in the ferns was reduced to zero within 5-6d, indication that the ferns studied are more susceptible to water deficiency than other CAM plants. This could be due to a higher cuticular conductance for water. The results are discussed, in particular, in relation to CAM performance of epiphytes growing in the wet tropics. [ABSTRACT FROM AUTHOR]

This Paper presents an efficient computational algorithm for selecting the optimal generation mix considering CO 2 emission. To demonstrate the effectiveness and feasibility of the proposed method, a fundamental study of the evaluation of the optimal generation mix for controlling CO2 emissions is indicated, Futhermore, by using parametric analysis which considers load characteristics as parameters, a general trend for the optimal generation mix which is affected by controlling CO2 can be derived. The proposed method is based on an optimization method know as simulated. In the method, solution in a generation mix problems are equivalent to states of physical system, and the cost of a solution is equivalent to a state. The proposed method can easily accommodate not only CO2 emission but also many practical constrains of generation expansion planning, such interger solutions of unit capacities, condition of existing units, and so on. Case studies various annual load patterns (combinations of annual factors and the shapes of annual load duration curve) are presented and discussed. Consequently, a general trent for selecting generation technologies that should be added to a power system is derived, i.e., a useful guideline for studying generation expansion planning under controlling CO2 emission can be provided. [ABSTRACT FROM AUTHOR]

This paper discusses potential impacts of a climate change on forests ecosystems. Climate change can be defined as the long-term fluctuations in temperature, precipitation, wind and all other aspects of the Earth's climate. One of the most important factors determining the Earth's climate is the greenhouse effect. This popular term describes the roles of water vapor, carbon dioxide, methane, man-made chlorofluorocarbons and other trace gases in keeping the Earth's surface warmer than it would be otherwise. These radioactively active gases are relatively transparent to incoming short-wavelength sunlight radiation, but are opaque to longer wavelength infrared radiation which arises from the Earth's surface.

A study was made of the influence of SO2 at concentrations 0.25, 0.50 and 0.75 ppm for 5 h on the 14CO2 assimilation and 14C transport in SO2-sensitive and SO2-tolerant seedlings of Scots pine and on the regeneration of the above mentioned processes depending on the duration of tune from the end of fumigation (i. e. after 24 h or 48 h). Immediately after treating the seedlings with SO2 or 24 h later they were exposed to an atmosphere with 14CO2 for 20 min and then after a further 24 h the incorporation of 14C into the general ethanol-soluble fraction, the total sugar fraction and its various components was investigated using ion-exchange, paper chromatography and radioautography. SO2 inhibited the 14C-translocation more than 14CO2 uptake. Also the regeneration of 14C-transport was slower than the regeneration of photosynthesis, which was particularly obvious in the SO2-sensitive plants. The inhibitive effect of SO2 on the transport of 14C-sugars was characterized by a significant lowering of the level of sugars exported from the needles to the roots but not by any qualitative changes. [ABSTRACT FROM AUTHOR]

This paper describes the characteristics and construction of a coal-gas-burned high efficiency power plant which emits no carbon dioxide (CO2) into the atmosphere. In a plant, CO2 gas and superheated steam are used as the main and the secondary working fluids, respectively, of a closed dual fluid regenerative gas turbine power plant. Since coal gas composed of CO, H2, CO2 and CH4 is burned in a combustor using oxygen, the exhaust gas let into a condenser includes only CO2 and H2O. Hence, CO2 gas can be easily separated at the condenser outlet from condensate. In the plant, the combustion gas is first used to generate power by driving a turbine. High-temperature turbine exhaust gas is next utilized at a regenerator to heat the main working fluid of CO2 gas flowing into the combustor, and then is utilized at a waste heat boiler to produce the superheated steam injected into the combustor. It is estimated that the power can be generated with gross thermal efficiency of 54.4 percent, and that the power generating efficiency is 46.7 percent. Generating efficiency is calculated by subtracting the power required for producing the high-pressure oxygen used for combustion from the generator output. It is shown that the estimated efficiency is higher by 18.1 percent than that of a conventional boiler steam turbine power generating plant into which a process for removing and recovering CO2 from the stack gas by utilizing alkanolamine-based solvent is integrated. [ABSTRACT FROM AUTHOR]

The TCDC/CO, hypothesis is that slowly changing potentials, source resistances and source currents, measured between electrodes placed over specific diploic/emissary vein distributions on the scalp, largely reflect regional differences in subelectrode CO[sub2] concentrations which are in equilibrium with subjacent conical differences in metabolism and CO[sub2] production. Studies on humans show that TCDC parameters do show the expected relationships with the effects of regional differences in CO[sub2] concentration. An explicit quantitative formulation of the hypothesis is developed based on the best available measures of all essential parameters, and it is shown that this model permits the correct computation of all TCDC empirical norms under essentially all conditions of measurement. Although it now appears that TCDC studies have a substantial theoretical foundation it must be emphasized that the analysis in this paper is based on normative -- i.e. averaged -- values and cannot yet be applied to isolated TCDC measurements on single subjects. [ABSTRACT FROM AUTHOR]

The after-effect of wind on photosynthesis and transpiration of Festuca arundinacea Schreb., was determined. Following a period of exposure in a controlled environment wind tunnel the wind-treated plants showed reduced rates of photo-synthesis when compared with the controls under standard conditions. Evaporation from paper model tillers was measured and the boundary layer resistance was shown to be low in all but very low wind speeds. Analysis of CO2 and H2O diffusion pathways indicated that mesophyll resistance in wind-treated plants was higher whilst leaf surface resistance was lower than in the controls. The high mesophyll resistance in the wind-treated plants was attributed to reduced water content. [ABSTRACT FROM AUTHOR]

The article discusses the findings of the paper "Hybrid Neurons in a MicroRNA Mutant Are Putative Evolutionary Intermediates in Insect CO2 Sensory Systems," by P. Cayirlioglu and colleagues. In this study, researchers found out that a population of hybrid CO2 neurons, that usually acts to inhibit the transcription factor Nerfin-1, can be uncovered with the disruption of a single microRNA gene, miR-279, in the Drosophila maxillary palp.

Keywords: carbon dioxide; hydrogenation; Cu-based catalyst; hydrogen enrichment; ethylene carbonate EN carbon dioxide hydrogenation Cu-based catalyst hydrogen enrichment ethylene carbonate 3599 3599 1 07/23/20 20200721 NES 200721 The Cover Feature shows a nanoflower-like Cu/SiO SB 2 sb catalyst of H SB 2 sb -enrichment capacity used for the hydrogenation of ethylene carbonate (EC) derived from CO SB 2 sb to produce methanol and ethylene glycol. In their Full Paper, M. Zhang, Y. Yang et al. synthesized the nanoflower-like copper catalysts with open-ended fibers and well-dispersed active species via one-step hydrolysis precipitation method. Carbon dioxide, hydrogenation, Cu-based catalyst, hydrogen enrichment, ethylene carbonate. [Extracted from the article]

Catalytic hydrogenation of carbon dioxide to methane can not only achieve the recycling of carbon resources, but also effectively meet the increasing demand for natural gas. In this paper, Ni‐based catalysts on different supports including ZrO2, CeO2 and Al2O3 were synthesized using citric acid complexation method and their CO2 methanation performances were tested. Among these catalysts, the Ni/ZrO2 catalyst achieved the best CO2 methanation activity. The catalysts were characterized by N2‐physisorption, XRD, H2‐TPR and H2‐TPD. The results indicate that the superiority of the Ni/ZrO2 catalyst can be mainly ascribed to its not only high Ni dispersion but also high reduction degree. Since the reduction degree of Ni/Al2O3 is low, it exhibits poor activity. The preparation condition for the Ni/ZrO2 catalyst was further optimized. The result shows that at molar ratio of citric acid to Ni ions of 3, the catalyst exhibits the best activity owing to the highest Ni dispersion, the largest Ni surface area, an appropriate metal‐support interaction and the most moderate basic sites. [ABSTRACT FROM AUTHOR]

The Front Cover shows the production of formic acid from CO2 and H2 by a ternary hybrid catalyst composed of an Ir complex, poly(ethyleneimine) and titanate nanotubes (TNTs).In their Full Paper, Y. Kuwahara et al. demonstrate that immobilization of a poly(ethyleneimine)‐tethered Ir complex catalyst inside the cavity space of TNTs can afford efficient catalysts with both improved activity and reusability, owing to the CO2 adsorption capacity of poly(ethyleneimine) and stabilizing effect of TNTs. This study can potentially offer a generalized method to capture and convert CO2, which is particularly desirable for sustainable formic acid production. More information can be found in the Full Paper by Y. Kuwahara et al. on page 1906 in Issue 11, 2017 (DOI: 10.1002/cctc.201700508). [ABSTRACT FROM AUTHOR]

The highlights of papers published in this issue are presented including one on the transfer hydrogenation of nitroarenes, one on the role of gold nanoneedles as catalyzer of carbon dioxide, and one on herbicidal ionic liquids.

The front cover artwork for Issue 10/2019 is a collaboration between the O'Hair group (University of Melbourne, Australia) and the Bonačić‐Koutecký group (University of Split, Croatia). The image shows how gas‐phase studies of model systems can be used for the design of MOF based catalysts for the selective decomposition of formic acid into hydrogen and carbon dioxide, a reaction of considerable interest for hydrogen storage applications. See the Full Paper itself at https://doi.org/10.1002/cctc.201900346. [ABSTRACT FROM AUTHOR]

A new dephosphorization technology with introduction of partial CO2 into O2 is proposed in this paper. Thermodynamic characteristics and dephosphorization mechanism by introduction of CO2 are analyzed and the results show that using CO2 as partial dephosphorization oxidant can change the selective oxidation condition of steelmaking system, control the temperature of bath, strengthen the stirring ability, and finally obtain a high efficiency of dephosphorization. Meanwhile, the relationship between selective oxidation temperature T of C and P, partial pressure of CO gas, slag activity, and compositions of melt is obtained as follows. T=(PCO/P0)0.0401a4CaO·P2O50.0080·exp(−0.0403[%C]−0.0030[%Si]+0.0011[%Mn]+0.3515[%P]+7.3986) Furthermore, dephosphorization trails are carried out in a 30t steelmaking converter and a 300t special dephosphorization converter, respectively. It is concluded that the new technology of injecting CO2–O2 mixture is beneficial to reduce phosphorus content in liquid steel, increase the partition ratio of phosphorus, and reduce iron loss of slag. A new dephosphorization technology with introduction of partial CO2 into O2 is proposed during steelmaking process. Through the an alysis of thermodynamics and kinetics, it is found that CO 2 can participate in dephosphorization, strengthen s tirring ability, and control the bath temperature. Furthermore, industrial experiments are performed in a 30t steelmaking converter and a 300t special dephosphorization converter, respectively, which obtains good dephosphorization results. [ABSTRACT FROM AUTHOR]

Single nickel atoms are uniformly formed over graphene sheets with the assistance of tris(2‐benzimidazolylmethyl)amine (NTB) ligands. Strong interactions of NTB ligands between graphene oxide (GO) sheets and nickel ions facilitates the homogenous dispersion of nickel atoms over the GO sheets. Homogeneously dispersed Ni(NTB)–GO sheets were then chemically transformed into highly active single‐atom nickel sites that show high faradaic efficiency and selectivity for electrochemical CO2 to CO reduction reaction. For more information, see the Full Paper by K. T. Nam et al. on page 18444 ff. [ABSTRACT FROM AUTHOR]

The image illustrates the operation mechanism of the photothermal activation of Ru/Au nanoparticles deposited on Siralox. Upon absorption of light by Au nanoparticles, the photon energy is thermalized, leading to the heating of smaller Ru nanoparticles located on the Au surface. This local heating serves to promote the selective methanation of CO2 by H2. For more information, see the Full Paper by H. García et al. on page 18436 ff. [ABSTRACT FROM AUTHOR]

In this study, the densities of carbonated aqueous solution of amines (ethanolamine, methylethanolamine, aminoethylethanolamine, and N‐methyldiethanolamine with piperazine) in various concentration and CO2 loadings were measured with temperatures ranging from 20°C to 60°C. The measured densities are in good agreement with those reported in the literature. The density experimental data were correlated with temperature and CO2 loading. Additionally, in case of the monoethanolamine, amine concentration was included into the correlation. Furthermore, an obtained correlation for density prediction of carbonated monoethanoloamine solutions was compared with Jouyban–Acree model. The fitted models are able to predict the density of carbonated amine solutions with a satisfactory precision. Presented correlations can be used either to predict the density of carbonated amine solutions or to determine CO2 loading of the investigated solution, if the density is known. The results of this paper may have an industrial application as a tool for process control of CO2 capture systems. [ABSTRACT FROM AUTHOR]

Abstract: The increasing emission of carbon dioxide (CO2) caused by the unrestrained consumption of fossil fuels in recent hundreds of years, has caused global environmental and social problems. Meanwhile, CO2 is a cheap, abundant and renewable C1‐feedstock, which can be converted into alcohols, ethers, acids and other value‐added chemicals. Compared with the thermal reactions, electrochemical reduction of CO2 is more attractive because of its advantages by using the seasonal, geographical and intermittent energy (tide, wind and solar) under mild conditions. In recent years, taking ionic liquids (ILs) as electrolytes in the CO2 electrochemical reduction reaction has been paid much more attention due to the advantages of lowering the overpotential of CO2 electroreduction and improving the Faradaic efficiency. In this paper, we summarized the recent progresses of electrochemical reduction of CO2 in ILs electrolytes, and analyzed the reaction mechanism of CO2 reaction in the electrode‐electrolyte interface region by experimental and simulation methods. Finally, the research which needs to be highlighted in this area was proposed. [ABSTRACT FROM AUTHOR]

Abstract: The front cover artwork for issue 9/2018 is provided by Prof. Jin‐Ook Baeg's artificial photosynthesis research group from Korea Research Institute of Chemical Technology (KRICT), Republic of Korea. The image shows a light harvesting 3D aromatic polymer (3DAP) derived from triptycene that can efficiently and selectively convert CO2 to formic acid. See the Full Paper itself at https://doi.org/10.1002/cctc.201701730. [ABSTRACT FROM AUTHOR]

The front cover artwork for Issue 18/2017 is provided by the Fritz-Haber-Institut der Max-Planck-Gesellschaft, Department of Inorganic Chemistry, Berlin (Germany). The image shows the proposed network of consecutive and parallel reactions in oxidation of propane over vanadium oxide catalysts. Detailed understanding of the complex system is necessary to advance catalyst and process design in terms of high selectivity to desired olefins and oxygenates, prevention of CO2 formation, and sustainable use of resources. See the Full Paper itself at . [ABSTRACT FROM AUTHOR]

Caging carbon dioxide: Self ‐ assembled discrete palladium(II) [Pd2(L)4]4+ cages with 2,6 ‐ bis(pyridin ‐ 3 ‐ ylethynyl)pyridine) ligands (L) have cavities, which bind guests containing carbonyl groups through hydrogen bonding interactions. In the solid state these cages have now been shown to bind up to four CO2 molecules, with selectivity over N2. Long ‐ range order in the packing of the molecules in powdered samples of the compound does not appear to be necessary for their activity, making their preparation easy. Additionally, the cages can be readily functionalized, opening up avenues for selective guest binding and gas separations. More information can be found in the Full Paper by B. F. Abrahams, J. D. Crowley et al. on page 10559. [ABSTRACT FROM AUTHOR]

Hydrogenation of CO2 to methanol is one of the most attractive ways for carbon dioxide recycle and hydrogen storage. Our computationally designed Fe, Co, and Mn cyclopentadienone complexes are promising low‐cost catalysts for hydrogenation of CO2 to methanol. Density functional theory calculations also reveal a methanol‐ or water‐mediated proton‐transfer mechanism for H2 cleavage and a direct C−O bond‐breaking process for the formation of formaldehyde as key steps in the catalytic reaction. More information can be found in the Full Paper by X. Yang et al. on page 8850. [ABSTRACT FROM AUTHOR]

Mn(bpy)‐type complexes bearing local proton source catalyse the electrochemical reduction of CO2. Depending on the strength of the Brønsted acid added to the solution, CO or formate are produced. Spectroelectrochemical studies under Ar and CO2 atmospheres show fast solvolysis and the dimer formation is suppressed, providing an atypical reduction mechanism of MnI catalysts. Spectroscopic evidence of Mn hydride formation supports the existence of different electrocatalytic CO2 reduction pathways. For more information, see the Full Paper by R. Gobetto, C. Nervi et al. on page 4782 ff. [ABSTRACT FROM AUTHOR]

The Cover shows a state‐of‐the‐art aluminum porphyrin‐based hyper‐crosslinked polymer for the chemical fixation of CO2 into cyclic carbonates under mild conditions.In their Full Paper, Y. J. Chen et al. demonstrate the outstanding catalytic activity and excellent reusability of aluminum porphyrin‐based heterogeneous catalysts in the solvent‐free synthesis of cyclic carbonates from epoxides and CO2 in the presence of tetrabutylammonium bromide as cocatalyst. [ABSTRACT FROM AUTHOR]

Electrocatalysis The Ru complex is set on its path, along which it must cross either a high mountain (EEC pathway) or a smaller hill (ECE pathway) to reach the glittering green palace where it can fulfill its goal of converting CO2 to CO. The sun shines brighter on the ECE path, which is alluring and less energy‐demanding. The complex can tread that path provided that its Ru heart has electrons (e−) pumped in (tBu on terpyridine), and that the CH3CN is easily removed. This is achieved by a CH3 group at the bipyridine, which pushes the bipyridine into the CH3CN with the force of a bull, thereby facilitating CH3CN dissociation from the complex. More information can be found in the Full Paper by S. Ott, S. Maji et al. on page 14870 ff. [ABSTRACT FROM AUTHOR]

A graphical abstract for the paper "Copper-Catalyzed N-Formylation of Amines with CO2 under Ambient Conditions," is presented.

The front cover artwork for Issue 13/2016 is provided by researchers from the Catalysis Engineering group, Chemical Engineering Department, Delft University of Technology (The Netherlands). The image shows the formation of covalent triazine framework (CTF) based spheres by using commercially available polyimide as a binder. See the Full Paper itself at . [ABSTRACT FROM AUTHOR]

The inside cover picture, provided by Arjan W. Kleij and co ‐ workers, illustrates an example of regio ‐ directing: a general route towards the regio ‐ selective formation of carbamates derived from substituted cyclic organic carbonates and amines is reported using a readily available organocatalyst (TBD; 1,5,7 ‐ triazabicyclo[4.4.0]dec ‐ 5 ‐ ene) under attractively mild reaction conditions. The carbonate substitution pattern and the presence of a ternary intermediate dictate the carbonate bond scission process giving preferentially rise to highly functional carbamates with tertiary alcohol functions. The easy and regio ‐ selective formation of di ‐ carbamates/urethanes shows the potential of this process to become valuable in the context of the preparation of regio ‐ regular oligo/polyurethanes. Details can be found in the full paper on pages 2172 – 2178 (S. Sopeña, V. Laserna, W. Guo, E. Martin, E. C. Escudero ‐ Adán, A. W. Kleij, Adv. Synth. Catal.­ 2016, 358, 2172 – 2178; DOI: 10.1002/adsc.201600290). [ABSTRACT FROM AUTHOR]

The front cover picture, provided by Arjan Kleij and co ‐ workers, illustrates oxetane ‐ based carbamates: oxetane ‐ based carbamate scaffolds are formed using an efficient aluminium catalyst. The process combines three reagents (CO2, oxetanes and amines) in a one ‐ pot approach towards a wide diversity of carbamate structures. The methodology has been applied in the formal synthesis of drug ‐ relevant molecules such as Carisoprodol and the mono ‐ carbamate of Felbatol showing the utility of the new catalytic procedure. The work also illustrates the potential of oxetanes as versatile reagents in pharma ‐ organic synthesis. Details can be found in the full paper on pages 1602 – 1607 (W. Guo, V. Laserna, J. Rintjema, A. W. Kleij, Adv. Synth. Catal.­ 2016, 358, 1602 – 1607; DOI: 10.1002/adsc.201500895). [ABSTRACT FROM AUTHOR]

Porphyrinoids CO2 is a cheap, abundant, and nontoxic C1 source, and the chemical conversion of CO2 into useful organic compounds has become increasingly important. In their Full Paper on page 6556 ff., C. Maeda, J. Hasegawa, T. Ema et al. describe the synthesis of bifunctional metalloporphyrins with quaternary ammonium bromides at the meta, para, or ortho positions of the meso‐phenyl groups and investigated their catalytic activities in the formation of cyclic carbonates from epoxides and CO2 under solvent‐free conditions. [ABSTRACT FROM AUTHOR]

The front cover picture, provided by Qing ‐ Wen Song and Liang ‐ Nian He, illustrates a silver ‐ catalyzed carboxylative cyclization of propargylic alcohols/propargylic amines with CO2 for the synthesis of α ‐ alkylidene cyclic carbonates/oxazolidinones under ambient conditions without employing any additional organic base and ligand. The synergistic effect of Lewis basic and Lewis acidic species in conjunction with the bulkier counterion, via the alkyl carbonate intermediate, leads to the excellent efficiency. The picture shows an outline of exhaust gas and chemical conversion via a sustainable CO2 recycling process into value ‐ added products using a green catalytic method. Details can be found in the full paper on pages 1251 – 1258 (Q. ‐ W. Song and L. ‐ N. He, Adv. Synth. Catal.­ 2016, 358, 1251 – 1258; DOI: 10.1002/adsc.201500639). [ABSTRACT FROM AUTHOR]

Supercritical carbon dioxide, an environmentally friendly medium, is promising as an alternative to traditional organic solvents. However, polar molecules and high molar mass compounds are often poorly soluble in supercritical carbon dioxide. The first host–guest complex obtained in such a solvent is discussed herein, together with an analysis of the driving forces for the formation of supramolecular structures and suggestions for possible applications to fix solubility issues. More information can be found in the Full Paper by F. Ingrosso, A. Marsura, M. F. Ruiz‐López et al. on page 2972 ff. [ABSTRACT FROM AUTHOR]

Carbon Dioxide Adsorbents An effective approach to functionalize water ‐ stable metal – organic frameworks (MOFs) by a combination of optimization and metalated ‐ ligand exchange (MLE) for enhanced CO2 separation performance is reported. The optimized UiO ‐ 66(Zr) shows a high BET surface area of 1730 m2 g−1 and a mesopore size of 3.9 nm. The approach described in the Full Paper by D. Zhao and colleagues on page 17246 ff. can enhance both CO2 working capacity and CO2/N2 selectivity simultaneously and thus is an alternative design to achieving water ‐ stable MOFs with high CO2 affinity for efficient CO2 separation. [ABSTRACT FROM AUTHOR]

The cover picture shows a copper(II) porous coordination polymer that can adsorb CO2 over CH4 at high selectivity under CO2/CH4 mixed gas conditions, and even in the coexistence of water. Flexibility and hydrophobicity of the coordination polymer are key factors to achieving high separation efficiency and high water tolerance. More details can be found in the Full Paper by Shin‐ichiro Noro, Takayoshi Nakamura, and co‐workers on page 1517 in Issue 10, 2015 (DOI: 10.1002/cplu.201500278). [ABSTRACT FROM AUTHOR]

Free Air CO2 Enrichment (FACE) systems are used to fumigate unconfined field plots with CO2. As these installationscan treat a sufficiently large area without interfering with naturalclimatic conditions, they are considered important tools for global change research worldwide. However, there is general consensus that elevated capital costs of existing FACE systems as well as high running costs may prevent their application at the required level of scale.A new and small FACE system that was designed to reduce both capitalcosts and CO2 use, is described in this paper. Due to itsintermediate size (8 m diameter) between the smaller Mini-FACE systems that were developed in Italy and the larger systems designed by the Brookhaven National Laboratory in the USA, it was named Mid-FACE. The Mid-FACE was at first developed as a prototype and then used to enrich field grown potato crops in a CO2 concentration gradient experimental design. Technical details of a Mid-FACE prototype and of the operational set-up are presented in this paper together withperformance data in terms of temporal and spatial control of CO2 concentrations within the experimental area. [ABSTRACT FROM AUTHOR]

Carboxylation Transition metal ‐ promoted carboxylation of various organic compounds has attracted much attention, and various types of reactions have been reported. In their Full Paper on page   1170   ff., which is featured on the Back Cover, Nozomi Saito, Zhongdong Sun, and Yoshihiro Sato report on the nickel(0) ‐ promoted carboxylation of aryl ynol ether that proceed in a highly regioselective manner to produce α ‐ substituted β ‐ aryloxyacrylic acid derivatives. Such derivatives could be transformed into the corresponding optically active β ‐ aryloxypropionic acid derivatives via rhodium ‐ catalyzed asymmetric hydrogenation. [ABSTRACT FROM AUTHOR]

The electrochemical reduction of CO2 The cover picture shows MoS2 and Ni‐doped MoS2 catalysts, and the reaction path of CO2 electrochemical reduction to CH4 on Ni‐doped MoS2. In their Full Paper on p. 1899 ff., J. K. Nørskov and co‐workers describe how their density functional theory calculations predict MoS2, MoSe2, and Ni‐doped MoS2 to have significantly improved activity for CO2 electrochemical reduction over the best transition metal catalysts. This activity arises from the binding of intermediates to different sites, which allows for deviations from the scaling relations between the intermediates on transition metals. Their results point to the broader application of the active edge sites of transition metal dichalcogenides in complex electrochemical processes. [ABSTRACT FROM AUTHOR]

Chemical activation of CO2is problematic due to its high thermodynamic and kinetic stability. Consequently, the use of CO2 for the efficient construction of CC bonds represents a significant challenge. An efficient domino ruthenium‐catalyzed reverse water‐gas‐shift (RWGS)–hydroformylation–reduction reaction of olefins with CO2 to alcohols is reported. For more details, see the Full Paper by I. Fleischer, M. Beller et al. on page 6888 ff. [ABSTRACT FROM AUTHOR]

SUMMARY This paper investigates the impact of an extensive introduction of electric vehicles ( EV) and plug-in hybrid vehicles ( PHEV) into the global energy system by 2050. The significant growth of automobile ownership in emerging countries is likely to increase world oil demand and the associated carbon dioxide emissions. In order to address these energy, security, and environmental concerns, the deployment of clean energy vehicles, such as EV and PHEV, is expected to play a crucial role due to their high fuel efficiency. Consequently, we develop both a global energy system model and a world vehicle penetration model, which can explicitly analyze the impact of EV introduction into the seasonal daily electric load curve, with consideration of the specific electricity charging profile through 2050. The simulation results confirm that EV deployment contributes to energy conservation, because oil demand reduction outstrips the growth in electricity demand and the associated fuel input into the power generation mix. Concerning carbon dioxide abatement, the magnitude of the impact relies on the carbon intensity of the power generation mix. If the intensity is low enough to guarantee a carbon mitigation effect due to EV fuel saving, emissions reduction is well assured. It should be noted, however, that in regions with high carbon intensity in the power generation mix, carbon emissions per mileage of EVs is almost equivalent to that of efficient gasoline vehicles such as hybrid vehicles, and the figure for PHEV is slightly higher than for hybrid vehicles. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(4): 20-36, 2014; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22373 [ABSTRACT FROM AUTHOR]

Microporous metal–organic frameworks (MMOFs) may find use in carbon dioxide capture and sequestration. In their Full paper on page 778   ff., featured on the Inside Cover, Heping Zeng, Jing Li et al. report that functionalization of two MOF structures by a methyl group leads to two opposing and competitive effects on CO2 adsorption: enhanced CO2 affinity and reduced porosity. When the positive effect is dominant in the competition, enhanced CO2 affinity overrides the loss induced by pore and surface ‐ area reduction, and thereby facilitates the CO2 uptake capacity of the framework. Furthermore, the authors show that the methyl ‐ functionalized compounds exhibit high separation capability for CO2 over other small gases including CH4, CO, N2, and O2. [ABSTRACT FROM AUTHOR]

A response by Sin et al. to a letter to the editor about their paper, which claims that ventilatory equivalents for carbon dioxide and oxygen are measures of ventilatory efficiency and not of pulmonary gas exchange efficiency, is presented.