China has recently implemented a dual-carbon strategy to combat climate change and other environmental issues and is committed to modernizing it sustainably.This paper supports these goals and explores how the digital...China has recently implemented a dual-carbon strategy to combat climate change and other environmental issues and is committed to modernizing it sustainably.This paper supports these goals and explores how the digital economy and green finance intersect and impact carbon emissions.Using panel data from 30 Chinese provinces over the period 2011-2021,this paper finds that the digital economy and green finance can together reduce carbon emissions,and conducts several robustness tests supporting this conclusion.A heterogeneity analysis shows that these synergistic effects are more important in regions with low levels of social consumption Meanwhile,in the spatial dimension,the synergistic effect of the local digital economy and green finance adversely impacts the level of carbon emissions in surrounding areas.The findings of this paper provide insights for policymakers in guiding capital flow and implementing carbon-reduction policies while fostering the growth of China’s digital economy and environmental sustainability.展开更多
Climate change is an important societal issue. Large effort in society is spent on addressing it. For adequate measures, it is important that the phenomenon of climate change is well understood, especially the effect ...Climate change is an important societal issue. Large effort in society is spent on addressing it. For adequate measures, it is important that the phenomenon of climate change is well understood, especially the effect of adding carbon dioxide to the atmosphere. In this work, a theoretical fully analytical study is presented of the so-called greenhouse effect of carbon dioxide. The effect of this gas in the atmosphere itself was already determined as being of little importance based on empirical analysis. In the current work, the effect is studied both phenomenologically and analytically. In a first attempt of energy transfer by radiation only, it is solved by ideal-gas-law equations and the atmosphere is divided into an infinite number of layers each absorbing and reemitting infrared radiation (surpassing the classical Beer-Lambert analysis of absorption). The result is that the exact structure of the atmosphere is irrelevant for the analysis;we might as well keep the two-box model for any analytical approach. However, the results are unsatisfactory in that they cannot explain the profile of the atmosphere. In a new approach, the atmosphere is solved by taking both radiative as well as thermodynamic processes into account. The model fully fits the empirical data and an analytical equation is given for the atmospheric behavior. Upper limits are found for the greenhouse effect ranging from zero to a couple of mK per ppm CO2. It is shown that it cannot explain the observed correlation of carbon dioxide and surface temperature. This correlation, however, is readily explained by Henry’s Law (outgassing of oceans), with other phenomena insignificant. Finally, while the greenhouse effect can thus, in a rudimentary way, explain the behavior of the atmosphere of Earth, it fails describing other atmospheres such as that of Mars. Moreover, looking at three cities in Spain, it is found that radiation balances only cannot explain the temperature of these cities. Finally, three data sets with different time scales (60 years, 600 thousand years, and 650 million years) show markedly different behavior, something that is inexplicable in the framework of the greenhouse theory.展开更多
In ground tests of hypersonic scramjet, the highenthalpy airstream produced by burning hydrocarbon fuels often contains contaminants of water vapor and carbon dioxide. The contaminants may change the ignition characte...In ground tests of hypersonic scramjet, the highenthalpy airstream produced by burning hydrocarbon fuels often contains contaminants of water vapor and carbon dioxide. The contaminants may change the ignition characteristics of fuels between ground tests and real flights. In order to properly assess the influence of the contaminants on ignition characteristics of hydrocarbon fuels, the effect of water vapor and carbon dioxide on the ignition delay times of China RP-3 kerosene was studied behind reflected shock waves in a preheated shock tube. Experiments were conducted over a wider temperature range of 800-1 500 K, at a pressure of 0.3 MPa, equivalence ratios of 0.5 and 1, and oxygen concentration of 20%. Ignition delay times were determined from the onset of the excited radical OH emission together with the pressure profile. Ignition delay times were measured for four cases: (1) clean gas, (2) gas vitiated with 10% and 20% water vapor in mole, (3) gas vitiated with 10% carbon dioxide in mole, and (4) gas vitiated with 10% water vapor and 10% carbon dioxide, 20% water vapor and 10% carbon dioxide in mole. The results show that carbon dioxide produces an inhibiting effect at temperatures below 1 300 K when Ф = 0.5, whereas water vapor appears to accelerate the ignition process below a critical temperature of about 1 000 K when Ф = 0.5. When both water vapor and carbon dioxide exist together, a minor inhibiting effect is observed at Ф = 0.5, while no effect is found at Ф = 1.0. The results are also discussed preliminary by considering both the combustion reaction mechanism and the thermophysics properties of the fuel mixtures. The current measurements demonstrate vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of China RP-3 kerosene at air-like O2 concentration. It is important to account for such effects when data are extrapolated from ground testing to real flight conditions.展开更多
Styrene was polymerized in supercritical (sc) CO2 with benzoyl peroxide (BPO) as initiator. It was found that the polymerization was accelerated by the external magnetic field.
The effects of various factors on the electrocarboxylation of organic compounds with carbon dioxide catalyzed by metalloporphyrin are studied.The optimal potential of electrocar- boxylation is -1.6 V(vs.SCE).A weak pr...The effects of various factors on the electrocarboxylation of organic compounds with carbon dioxide catalyzed by metalloporphyrin are studied.The optimal potential of electrocar- boxylation is -1.6 V(vs.SCE).A weak protic solvent methanol can enhance catalytic activity. Tetrabutylammonium iodide is the best one of five electrolytes.The yields and current efficiencies of electrocarboxylation are increased slowly as the concentration of catalyst increases.展开更多
The effects of peptides,amino acids and organic bases as an axial ligand on reaction ac- tivities in the electrocarboxylation of benzyl chloride with CO_2 catalyzed by CoTPP are reported. The imidazole organic base,pe...The effects of peptides,amino acids and organic bases as an axial ligand on reaction ac- tivities in the electrocarboxylation of benzyl chloride with CO_2 catalyzed by CoTPP are reported. The imidazole organic base,peptide containing —SH and amino acid containing imidazolyl en- hance the catalytic activity.The effect of imidazole amounts on the catalytic activity of CoTPP is studied.展开更多
The utilization of a green financial system,particularly through the implementation of green credit,plays a pivotal role in fostering environmentally sustainable,low-carbon economic growth and facilitating the transit...The utilization of a green financial system,particularly through the implementation of green credit,plays a pivotal role in fostering environmentally sustainable,low-carbon economic growth and facilitating the transition toward a more ecologically responsible economy.This paper employs a two-way fixed-effects model,utilizing provincial panel data spanning from 2012 to 2020,to investigate the influence of green credit on regional carbon emissions within different regions of China.The results reveal a significant reduction in carbon emissions as a consequence of the green credit program’s implementation.The analysis of the pathway indicates that green credit is instrumental in mitigating carbon emissions by instigating shifts in the energy mix,with evidence suggesting a partial mediating effect.Furthermore,a heterogeneity analysis discovered that the suppressive impact of green credit on carbon emissions is more pronounced in the eastern and western regions of China,while it is less significant in the central and northeastern areas.The implications of this study provide robust evidence in support of the role of green credit in reducing carbon emissions and can serve as a valuable resource for policymakers aiming to promote the expansion of green credit programs and,in turn,contribute to substantial reductions in carbon emissions.展开更多
The increase of atmospheric carbon dioxide and the global warming due to its greenhouse effect resulted in worldwide concerns. On the other hand, carbon dioxide might be considered as a valuable and renewable carbon s...The increase of atmospheric carbon dioxide and the global warming due to its greenhouse effect resulted in worldwide concerns. On the other hand, carbon dioxide might be considered as a valuable and renewable carbon source. One approach to reduce carbon dioxide emissions could be its capture and recycle via transformation into chemicals using the technologies in C1 chemistry. Despite its great interest, there are difficulties in CO2 separation on the one hand, and thermodynamic stability of carbon dioxide molecule rendering its chemical activity low on the other hand. Carbon dioxide has been already used in petrochemical industries for production of limited chemicals such as urea. The utilization of carbon dioxide does not necessarily involve development of new processes, and in certain processes such as methanol synthesis and methane steam reforming, addition of CO2 into the feed results in its utilization and increases carbon efficiency. In other cases, modifications in catalyst and/or processes, or even new catalysts and processes, are necessary. In either case, catalysis plays a crucial role in carbon dioxide conversion and effective catalysts are required for commercial realization of the related processes. Technologies for CO2 utilization are emerging after many years of research and development efforts.展开更多
Through our newly-developed "chemical vapor deposition integrated process (ISVD-IP)'" using carbon OlOXlae (t..u2) as me raw matenal and only carbon source introduced, CO2 could be catalytically activated and c...Through our newly-developed "chemical vapor deposition integrated process (ISVD-IP)'" using carbon OlOXlae (t..u2) as me raw matenal and only carbon source introduced, CO2 could be catalytically activated and converted to a new solid-form product, i.e., carbon nanotubes (CO2-derived) at a quite high yield (the single-pass carbon yield in the solid-form carbon-product produced from CO2 catalytic capture and conversion was more than 30% at a single-pass carbon-base). For comparison, when only pure carbon dioxide was introduced using the conventional CVD method without integrated process, no solid-form carbon-material product could be formed. In the addition of saturated steam at room temperature in the feed for CVD, there were much more end-opening carbon nano-tubes produced, at a slightly higher carbon yield. These inspiring works opened a remarkable and alternative new approach for carbon dioxide catalytic capture to solid-form product, comparing with that of CO2 sequestration (CCS) or CO2 mineralization (solidification), etc. As a result, there was much less body volume and almost no greenhouse effect for this solid-form carbon-material than those of primitive carbon dioxide.展开更多
The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 red...The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 reduction.In this work,we synthesize a series of porous bimetallic Cu–Sb alloys with different compositions for the catalytic reduction of CO2 to C2H4.It is demonstrated that the alloy catalysts are much more efficient than the pure Cu catalyst.The performance of the alloy catalysts depended strongly on the composition.Further,the alloy with a Cu:Sb ratio of 10:1 yielded the best results;it exhibited a high C2H4 Faradaic efficiency of 49.7%and a high current density of 28.5 mA cm?2 at?1.19 V vs.a reversible hydrogen electrode(RHE)in 0.1 M KCl solution.To the best of our knowledge,the electrocatalytic reduction of CO2 to C2H4 using Cu–Sb alloys as catalysts has not been reported.The excellent performance of the porous alloy catalyst is attributed to its favorable electronic configuration,large surface area,high CO2 adsorption rate,and fast charge transfer rate.展开更多
The chemical transformation of CO2under mild conditions remains a great challenge because of itsexceptional kinetic and thermodynamic stability.Two important reactions in the transformation ofCO2are the N‐formylation...The chemical transformation of CO2under mild conditions remains a great challenge because of itsexceptional kinetic and thermodynamic stability.Two important reactions in the transformation ofCO2are the N‐formylation reaction of amines using hydrosilanes and CO2,and the cycloaddition ofCO2to epoxides.Here,we report the high efficiency of bifunctional metallosalen complexes bearingquaternary phosphonium salts in catalyzing both of these reactions under solvent‐free,mild conditionswithout the need for co‐catalysts.The catalysts’bifunctionality is attributed to an intramolecularcooperative process between the metal center and the halogen anion.Depending on the reaction,this activates CO2by permitting either the synergistic activation of Si–H bond via metal–hydrogen coordinative bond(M–H)or the dual activation of epoxide via metal–oxygen coordinativebond(M–O).The one‐component catalysts are also shown to be easily recovered and reusedfive times without significant loss of activity or selectivity.The current results are combined withprevious work in the area to propose the relevant reaction mechanisms.展开更多
The combination of a zinc phthalocyanine(ZnPc)catalyst and a stoichiometric amount of dimethyl formamide(DMF)provided a simple route to formamide derivatives from amines,CO2,and hydrosilanes under mild conditions.We d...The combination of a zinc phthalocyanine(ZnPc)catalyst and a stoichiometric amount of dimethyl formamide(DMF)provided a simple route to formamide derivatives from amines,CO2,and hydrosilanes under mild conditions.We deduced that formation of an active zinc‐hydrogen(Zn‐H)species promoted hydride transfer from the hydrosilane to CO2.The cooperative activation of the Lewis acidic ZnPc by strongly polar DMF,led to formation of activated amines and hydrosilanes,which promoted the chemical reduction of CO2.Consequently,the binary ZnPc/DMF catalytic system showed excellent yields and superior chemoselectivity,representing a simple and sustainable pathway for the reductive transformation of CO2into valuable chemicals as an alternative to conventional halogen‐containing process.展开更多
Complexation combined with supercritical fluid extraction was used to extract Cu2+ in this study. The effects of pressure, temperature, volume of CO2 on the efficiency of extraction were systematically investigated. A...Complexation combined with supercritical fluid extraction was used to extract Cu2+ in this study. The effects of pressure, temperature, volume of CO2 on the efficiency of extraction were systematically investigated. At the optimum condition a 57.32% recovery was achieved. Addition of suitable amount of methanol (v/v = 5%) to the supercritical CO2 can increase in the extraction of Cu2+ (72.69%, RSD = 2.12%, n = 3). And the recovery can further increase in the presence of non-ionic surfactant Triton X-100 because of its function of solubilization. Surfactant was first used in the extraction of metal ions in the present study, and the results are satisfied (90.52%, RSD = 2.20%, n = 3).展开更多
Molecular dynamics method was used to establish composite wall/inorganic nanopores of three pore sizes, three shale oil systems, five CO_(2)-cosolvent systems, and pure CO_(2) system. The process of CO_(2)-cosolvent d...Molecular dynamics method was used to establish composite wall/inorganic nanopores of three pore sizes, three shale oil systems, five CO_(2)-cosolvent systems, and pure CO_(2) system. The process of CO_(2)-cosolvent displacement of crude oil in shale nanopores and carbon storage was simulated and the influencing factors of displacement and storage were analyzed. It is shown that the attraction of the quartz wall to shale oil increases with the degree of hydroxylation. The higher the degree of quartz hydroxylation, the more difficult it is to extract the polar components of shale oil. Nanopore size also has a great impact on shale oil displacement efficiency. The larger the pore size, the higher the shale oil displacement efficiency. The closer the cosolvent molecules are to the polarity of the shale oil, the higher the mutual solubility of CO_(2) and shale oil. The more the non-polar components of shale oil, the lower the mutual solubility of CO_(2) and shale oil with highly polar cosolvent. Ethyl acetate is more effective in stripping relatively high polar shale oil, while dimethyl ether is more effective in stripping relatively low polar shale oil. Kerogen is highly adsorptive, especially to CO_(2). The CO_(2) inside the kerogen is not easy to diffuse and leak, thus allowing for a stable carbon storage. The highest CO_(2) storage rate is observed when dimethyl ether is used as a cosolvent, and the best storage stability is observed when ethyl acetate is used as a cosolvent.展开更多
The influence of different factors on the plasma chemical reactions is widely studied today. However, insufficient consideration is given to the research of paramagnetic phenomena which takes place in plasma systems. ...The influence of different factors on the plasma chemical reactions is widely studied today. However, insufficient consideration is given to the research of paramagnetic phenomena which takes place in plasma systems. The results of modeling the process of redistribution carbon isotopes between different phases while oxidizing it in high-frequency low-temperature plasma in an external magnetic field are shown in the article. The equilibrium concentrations of components involved in the oxidation process in a plasma system are defined. A principle possibility of isotope-selective plasma chemical reactions in a magnetic field was experimentally determined. The increase of concentration of 13C in the gas phase up to 1.3 times relative to natural abundance was obtained. It was found that the content of the carbon heavy isotope in the gas phase depends on the magnetic field action area. The best results were achieved with the combination of magnetic field impact area and the priority area of the appearance of plasma chemical reactions products.展开更多
Interactions between elevated [CO2] and soil water availability have the potential impact on crops and future food security of the world. The study was conducted to investigate vegetative growth response of soybeans u...Interactions between elevated [CO2] and soil water availability have the potential impact on crops and future food security of the world. The study was conducted to investigate vegetative growth response of soybeans under two [CO2] (380 and 800 μmol mol-1) with three soil moisture levels in controlled environment. Slow growth rate and altered crop phenology of soybeans were observed under elevated [CO2] at early stage (V-3/V-4), but showed positive physiologically response at later stage (R3) indicating adoptive mechanism of plants to high [CO2]. Elevated [CO2] decreases the number of leaves by 23% and 14% and reduces in leaf areas by 11.7% and 9.7% compared with ambient [CO2] at 29 and 44 days after planting (DAP), respectively. Adaptive mechanism of plants to high [CO2] produced 39% and 83.7% greater leaf number and leaf areas, respectively at later stage (R3) of the crop growth (59 DAP). There was a reduction in a specific leaf area (SLA) at 29 DAP (22.2%) but an increase at 44 DAP (1.4%) and 58 DAP (8.5%) under elevated [CO2]. Dry matter production of plants was increased significantly for elevated [CO2]. Increase in leaf C (<1%) and reduction in N concentration (6.0% - 9.5%) increased the C:N ratio of soybean leaves (4.4% - 12.98%) under elevated [CO2]. Elevated [CO2] with normal soil moisture condition produced a maximum number of pods (54.8% - 122.4%) and an increase in dry weight of pods (29.8% - 56.6%). Plants under elevated [CO2] produced significantly greater numbers of root nodules per plant by 114% compared with plants under ambient [CO2] at 44 DAP. These results show a direct and interactive effect of elevated [CO2] and soil moisture on plant growth that will affect not only the global food security but also nutritional security.展开更多
The global warming issues associated with fossil fuels have forced the world to shift towards environment-friendly alternatives. The studies on the capture and storage of CO<sub>2</sub> have gained signifi...The global warming issues associated with fossil fuels have forced the world to shift towards environment-friendly alternatives. The studies on the capture and storage of CO<sub>2</sub> have gained significant research attention, and to attract the world towards CO<sub>2</sub> capturing and storing, it is necessary to find suitable applications for this captured CO<sub>2</sub>. Methanol is one of the products which can be produced by utilizing the captured CO<sub>2</sub> and hydrogen that can be produced by water splitting. Keeping in view both these green fuel production processes, this study proposes a combined application of both these technologies for the production of methanol, which is an important chemical used in manufacturing industries. This review paper presents a brief study of both carbon capture and hydrogen production technologies. It also provides research trends, economic aspects, and methods of incorporating both these technologies to produce methanol. Additionally, the prospects of the approach in Oman have also been presented.展开更多
Although single-atom catalysts(SACs)have attracted enormous attention for their applications in the electrochemical reduction of CO_(2)(CO_(2)RR)due to their extraordinary catalytic activity and well-defined active ce...Although single-atom catalysts(SACs)have attracted enormous attention for their applications in the electrochemical reduction of CO_(2)(CO_(2)RR)due to their extraordinary catalytic activity and well-defined active centers,neighboring effects and their influence on the electrochemical performance of SACs have not been well investigated.In this review,we present a summary of the neighboring effects on SACs for the CO_(2)RR process,where the surrounding atoms not only induce electronic modulation of the metal atom but also participate in the CO_(2)RR.Both theoretical and experimental studies have pointed out that the neighboring sites of the anchored metal center can provide second active/adsorption locations during the catalytic process,enhancing CO_(2)RR performance tremendously.This review supplies advanced insights into the significant roles and impacts of neighboring effects on the catalytic process,which also benefit the development of advanced SACs to achieve efficient electrocatalysis.展开更多
A reaction-coupling strategy is often employed for CO_(2)hydrogenation to produce fuels and chemicals using oxide/zeolite bifunctional catalysts.Because the oxide components are responsible for CO_(2)activation,unders...A reaction-coupling strategy is often employed for CO_(2)hydrogenation to produce fuels and chemicals using oxide/zeolite bifunctional catalysts.Because the oxide components are responsible for CO_(2)activation,understanding the structural effects of these oxides is crucial,however,these effects still remain unclear.In this study,we combined In_(2)O_(3),with varying particle sizes,and SAPO‐34 as bifunctional catalysts for CO_(2)hydrogenation.The CO_(2)conversion and selectivity of the lower olefins increased as the average In_(2)O_(3)crystallite size decreased from 29 to 19 nm;this trend mainly due to the increasing number of oxygen vacancies responsible for CO_(2) and H_(2) activation.However,In_(2)O_(3)particles smaller than 19 nm are more prone to sintering than those with other sizes.The results suggest that 19 nm is the optimal size of In_(2)O_(3)for CO_(2)hydrogenation to lower olefins and that the oxide particle size is crucial for designing catalysts with high activity,high selectivity,and high stability.展开更多
文摘China has recently implemented a dual-carbon strategy to combat climate change and other environmental issues and is committed to modernizing it sustainably.This paper supports these goals and explores how the digital economy and green finance intersect and impact carbon emissions.Using panel data from 30 Chinese provinces over the period 2011-2021,this paper finds that the digital economy and green finance can together reduce carbon emissions,and conducts several robustness tests supporting this conclusion.A heterogeneity analysis shows that these synergistic effects are more important in regions with low levels of social consumption Meanwhile,in the spatial dimension,the synergistic effect of the local digital economy and green finance adversely impacts the level of carbon emissions in surrounding areas.The findings of this paper provide insights for policymakers in guiding capital flow and implementing carbon-reduction policies while fostering the growth of China’s digital economy and environmental sustainability.
文摘Climate change is an important societal issue. Large effort in society is spent on addressing it. For adequate measures, it is important that the phenomenon of climate change is well understood, especially the effect of adding carbon dioxide to the atmosphere. In this work, a theoretical fully analytical study is presented of the so-called greenhouse effect of carbon dioxide. The effect of this gas in the atmosphere itself was already determined as being of little importance based on empirical analysis. In the current work, the effect is studied both phenomenologically and analytically. In a first attempt of energy transfer by radiation only, it is solved by ideal-gas-law equations and the atmosphere is divided into an infinite number of layers each absorbing and reemitting infrared radiation (surpassing the classical Beer-Lambert analysis of absorption). The result is that the exact structure of the atmosphere is irrelevant for the analysis;we might as well keep the two-box model for any analytical approach. However, the results are unsatisfactory in that they cannot explain the profile of the atmosphere. In a new approach, the atmosphere is solved by taking both radiative as well as thermodynamic processes into account. The model fully fits the empirical data and an analytical equation is given for the atmospheric behavior. Upper limits are found for the greenhouse effect ranging from zero to a couple of mK per ppm CO2. It is shown that it cannot explain the observed correlation of carbon dioxide and surface temperature. This correlation, however, is readily explained by Henry’s Law (outgassing of oceans), with other phenomena insignificant. Finally, while the greenhouse effect can thus, in a rudimentary way, explain the behavior of the atmosphere of Earth, it fails describing other atmospheres such as that of Mars. Moreover, looking at three cities in Spain, it is found that radiation balances only cannot explain the temperature of these cities. Finally, three data sets with different time scales (60 years, 600 thousand years, and 650 million years) show markedly different behavior, something that is inexplicable in the framework of the greenhouse theory.
基金supported by the National Natural Science Foundation of China(90916017)
文摘In ground tests of hypersonic scramjet, the highenthalpy airstream produced by burning hydrocarbon fuels often contains contaminants of water vapor and carbon dioxide. The contaminants may change the ignition characteristics of fuels between ground tests and real flights. In order to properly assess the influence of the contaminants on ignition characteristics of hydrocarbon fuels, the effect of water vapor and carbon dioxide on the ignition delay times of China RP-3 kerosene was studied behind reflected shock waves in a preheated shock tube. Experiments were conducted over a wider temperature range of 800-1 500 K, at a pressure of 0.3 MPa, equivalence ratios of 0.5 and 1, and oxygen concentration of 20%. Ignition delay times were determined from the onset of the excited radical OH emission together with the pressure profile. Ignition delay times were measured for four cases: (1) clean gas, (2) gas vitiated with 10% and 20% water vapor in mole, (3) gas vitiated with 10% carbon dioxide in mole, and (4) gas vitiated with 10% water vapor and 10% carbon dioxide, 20% water vapor and 10% carbon dioxide in mole. The results show that carbon dioxide produces an inhibiting effect at temperatures below 1 300 K when Ф = 0.5, whereas water vapor appears to accelerate the ignition process below a critical temperature of about 1 000 K when Ф = 0.5. When both water vapor and carbon dioxide exist together, a minor inhibiting effect is observed at Ф = 0.5, while no effect is found at Ф = 1.0. The results are also discussed preliminary by considering both the combustion reaction mechanism and the thermophysics properties of the fuel mixtures. The current measurements demonstrate vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of China RP-3 kerosene at air-like O2 concentration. It is important to account for such effects when data are extrapolated from ground testing to real flight conditions.
基金This work is financially supported by National Key Basic Research Project(G2000048010)the National Natural Science Foundation of China for financial support(29725308).
文摘Styrene was polymerized in supercritical (sc) CO2 with benzoyl peroxide (BPO) as initiator. It was found that the polymerization was accelerated by the external magnetic field.
文摘The effects of various factors on the electrocarboxylation of organic compounds with carbon dioxide catalyzed by metalloporphyrin are studied.The optimal potential of electrocar- boxylation is -1.6 V(vs.SCE).A weak protic solvent methanol can enhance catalytic activity. Tetrabutylammonium iodide is the best one of five electrolytes.The yields and current efficiencies of electrocarboxylation are increased slowly as the concentration of catalyst increases.
文摘The effects of peptides,amino acids and organic bases as an axial ligand on reaction ac- tivities in the electrocarboxylation of benzyl chloride with CO_2 catalyzed by CoTPP are reported. The imidazole organic base,peptide containing —SH and amino acid containing imidazolyl en- hance the catalytic activity.The effect of imidazole amounts on the catalytic activity of CoTPP is studied.
文摘The utilization of a green financial system,particularly through the implementation of green credit,plays a pivotal role in fostering environmentally sustainable,low-carbon economic growth and facilitating the transition toward a more ecologically responsible economy.This paper employs a two-way fixed-effects model,utilizing provincial panel data spanning from 2012 to 2020,to investigate the influence of green credit on regional carbon emissions within different regions of China.The results reveal a significant reduction in carbon emissions as a consequence of the green credit program’s implementation.The analysis of the pathway indicates that green credit is instrumental in mitigating carbon emissions by instigating shifts in the energy mix,with evidence suggesting a partial mediating effect.Furthermore,a heterogeneity analysis discovered that the suppressive impact of green credit on carbon emissions is more pronounced in the eastern and western regions of China,while it is less significant in the central and northeastern areas.The implications of this study provide robust evidence in support of the role of green credit in reducing carbon emissions and can serve as a valuable resource for policymakers aiming to promote the expansion of green credit programs and,in turn,contribute to substantial reductions in carbon emissions.
文摘The increase of atmospheric carbon dioxide and the global warming due to its greenhouse effect resulted in worldwide concerns. On the other hand, carbon dioxide might be considered as a valuable and renewable carbon source. One approach to reduce carbon dioxide emissions could be its capture and recycle via transformation into chemicals using the technologies in C1 chemistry. Despite its great interest, there are difficulties in CO2 separation on the one hand, and thermodynamic stability of carbon dioxide molecule rendering its chemical activity low on the other hand. Carbon dioxide has been already used in petrochemical industries for production of limited chemicals such as urea. The utilization of carbon dioxide does not necessarily involve development of new processes, and in certain processes such as methanol synthesis and methane steam reforming, addition of CO2 into the feed results in its utilization and increases carbon efficiency. In other cases, modifications in catalyst and/or processes, or even new catalysts and processes, are necessary. In either case, catalysis plays a crucial role in carbon dioxide conversion and effective catalysts are required for commercial realization of the related processes. Technologies for CO2 utilization are emerging after many years of research and development efforts.
基金the National 973 Program of Ministry of Sciences and Technologies of China(2011CB201202)the National Natural Science Foundation of China(20776089)
文摘Through our newly-developed "chemical vapor deposition integrated process (ISVD-IP)'" using carbon OlOXlae (t..u2) as me raw matenal and only carbon source introduced, CO2 could be catalytically activated and converted to a new solid-form product, i.e., carbon nanotubes (CO2-derived) at a quite high yield (the single-pass carbon yield in the solid-form carbon-product produced from CO2 catalytic capture and conversion was more than 30% at a single-pass carbon-base). For comparison, when only pure carbon dioxide was introduced using the conventional CVD method without integrated process, no solid-form carbon-material product could be formed. In the addition of saturated steam at room temperature in the feed for CVD, there were much more end-opening carbon nano-tubes produced, at a slightly higher carbon yield. These inspiring works opened a remarkable and alternative new approach for carbon dioxide catalytic capture to solid-form product, comparing with that of CO2 sequestration (CCS) or CO2 mineralization (solidification), etc. As a result, there was much less body volume and almost no greenhouse effect for this solid-form carbon-material than those of primitive carbon dioxide.
文摘The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 reduction.In this work,we synthesize a series of porous bimetallic Cu–Sb alloys with different compositions for the catalytic reduction of CO2 to C2H4.It is demonstrated that the alloy catalysts are much more efficient than the pure Cu catalyst.The performance of the alloy catalysts depended strongly on the composition.Further,the alloy with a Cu:Sb ratio of 10:1 yielded the best results;it exhibited a high C2H4 Faradaic efficiency of 49.7%and a high current density of 28.5 mA cm?2 at?1.19 V vs.a reversible hydrogen electrode(RHE)in 0.1 M KCl solution.To the best of our knowledge,the electrocatalytic reduction of CO2 to C2H4 using Cu–Sb alloys as catalysts has not been reported.The excellent performance of the porous alloy catalyst is attributed to its favorable electronic configuration,large surface area,high CO2 adsorption rate,and fast charge transfer rate.
基金supported by the National Natural Science Foundation of China (21676306,21425627)the National Key Research and Development Program of China (2016YFA0602900)the Natural Science Foundation of Guangdong Province (2016A030310211,2015A030313104)~~
文摘The chemical transformation of CO2under mild conditions remains a great challenge because of itsexceptional kinetic and thermodynamic stability.Two important reactions in the transformation ofCO2are the N‐formylation reaction of amines using hydrosilanes and CO2,and the cycloaddition ofCO2to epoxides.Here,we report the high efficiency of bifunctional metallosalen complexes bearingquaternary phosphonium salts in catalyzing both of these reactions under solvent‐free,mild conditionswithout the need for co‐catalysts.The catalysts’bifunctionality is attributed to an intramolecularcooperative process between the metal center and the halogen anion.Depending on the reaction,this activates CO2by permitting either the synergistic activation of Si–H bond via metal–hydrogen coordinative bond(M–H)or the dual activation of epoxide via metal–oxygen coordinativebond(M–O).The one‐component catalysts are also shown to be easily recovered and reusedfive times without significant loss of activity or selectivity.The current results are combined withprevious work in the area to propose the relevant reaction mechanisms.
基金supported by the National Natural Science Foundation of China (21676306,21425627)the National Key Research and Development Program of China (2016YFA0602900)+1 种基金the Natural Science Foundation of Guangdong Province (2016A030310211)the Characteristic Innovation Project (Natural Science) of Guangdong Colleges and Universities~~
文摘The combination of a zinc phthalocyanine(ZnPc)catalyst and a stoichiometric amount of dimethyl formamide(DMF)provided a simple route to formamide derivatives from amines,CO2,and hydrosilanes under mild conditions.We deduced that formation of an active zinc‐hydrogen(Zn‐H)species promoted hydride transfer from the hydrosilane to CO2.The cooperative activation of the Lewis acidic ZnPc by strongly polar DMF,led to formation of activated amines and hydrosilanes,which promoted the chemical reduction of CO2.Consequently,the binary ZnPc/DMF catalytic system showed excellent yields and superior chemoselectivity,representing a simple and sustainable pathway for the reductive transformation of CO2into valuable chemicals as an alternative to conventional halogen‐containing process.
文摘Complexation combined with supercritical fluid extraction was used to extract Cu2+ in this study. The effects of pressure, temperature, volume of CO2 on the efficiency of extraction were systematically investigated. At the optimum condition a 57.32% recovery was achieved. Addition of suitable amount of methanol (v/v = 5%) to the supercritical CO2 can increase in the extraction of Cu2+ (72.69%, RSD = 2.12%, n = 3). And the recovery can further increase in the presence of non-ionic surfactant Triton X-100 because of its function of solubilization. Surfactant was first used in the extraction of metal ions in the present study, and the results are satisfied (90.52%, RSD = 2.20%, n = 3).
基金Supported by National Natural Science Foundation of China(52304021,52204031)Natural Science Foundation of Sichuan Province(2022NSFSC0205)National Science and Technology Major Project of China(2017ZX05049006-010).
文摘Molecular dynamics method was used to establish composite wall/inorganic nanopores of three pore sizes, three shale oil systems, five CO_(2)-cosolvent systems, and pure CO_(2) system. The process of CO_(2)-cosolvent displacement of crude oil in shale nanopores and carbon storage was simulated and the influencing factors of displacement and storage were analyzed. It is shown that the attraction of the quartz wall to shale oil increases with the degree of hydroxylation. The higher the degree of quartz hydroxylation, the more difficult it is to extract the polar components of shale oil. Nanopore size also has a great impact on shale oil displacement efficiency. The larger the pore size, the higher the shale oil displacement efficiency. The closer the cosolvent molecules are to the polarity of the shale oil, the higher the mutual solubility of CO_(2) and shale oil. The more the non-polar components of shale oil, the lower the mutual solubility of CO_(2) and shale oil with highly polar cosolvent. Ethyl acetate is more effective in stripping relatively high polar shale oil, while dimethyl ether is more effective in stripping relatively low polar shale oil. Kerogen is highly adsorptive, especially to CO_(2). The CO_(2) inside the kerogen is not easy to diffuse and leak, thus allowing for a stable carbon storage. The highest CO_(2) storage rate is observed when dimethyl ether is used as a cosolvent, and the best storage stability is observed when ethyl acetate is used as a cosolvent.
文摘The influence of different factors on the plasma chemical reactions is widely studied today. However, insufficient consideration is given to the research of paramagnetic phenomena which takes place in plasma systems. The results of modeling the process of redistribution carbon isotopes between different phases while oxidizing it in high-frequency low-temperature plasma in an external magnetic field are shown in the article. The equilibrium concentrations of components involved in the oxidation process in a plasma system are defined. A principle possibility of isotope-selective plasma chemical reactions in a magnetic field was experimentally determined. The increase of concentration of 13C in the gas phase up to 1.3 times relative to natural abundance was obtained. It was found that the content of the carbon heavy isotope in the gas phase depends on the magnetic field action area. The best results were achieved with the combination of magnetic field impact area and the priority area of the appearance of plasma chemical reactions products.
文摘Interactions between elevated [CO2] and soil water availability have the potential impact on crops and future food security of the world. The study was conducted to investigate vegetative growth response of soybeans under two [CO2] (380 and 800 μmol mol-1) with three soil moisture levels in controlled environment. Slow growth rate and altered crop phenology of soybeans were observed under elevated [CO2] at early stage (V-3/V-4), but showed positive physiologically response at later stage (R3) indicating adoptive mechanism of plants to high [CO2]. Elevated [CO2] decreases the number of leaves by 23% and 14% and reduces in leaf areas by 11.7% and 9.7% compared with ambient [CO2] at 29 and 44 days after planting (DAP), respectively. Adaptive mechanism of plants to high [CO2] produced 39% and 83.7% greater leaf number and leaf areas, respectively at later stage (R3) of the crop growth (59 DAP). There was a reduction in a specific leaf area (SLA) at 29 DAP (22.2%) but an increase at 44 DAP (1.4%) and 58 DAP (8.5%) under elevated [CO2]. Dry matter production of plants was increased significantly for elevated [CO2]. Increase in leaf C (<1%) and reduction in N concentration (6.0% - 9.5%) increased the C:N ratio of soybean leaves (4.4% - 12.98%) under elevated [CO2]. Elevated [CO2] with normal soil moisture condition produced a maximum number of pods (54.8% - 122.4%) and an increase in dry weight of pods (29.8% - 56.6%). Plants under elevated [CO2] produced significantly greater numbers of root nodules per plant by 114% compared with plants under ambient [CO2] at 44 DAP. These results show a direct and interactive effect of elevated [CO2] and soil moisture on plant growth that will affect not only the global food security but also nutritional security.
文摘The global warming issues associated with fossil fuels have forced the world to shift towards environment-friendly alternatives. The studies on the capture and storage of CO<sub>2</sub> have gained significant research attention, and to attract the world towards CO<sub>2</sub> capturing and storing, it is necessary to find suitable applications for this captured CO<sub>2</sub>. Methanol is one of the products which can be produced by utilizing the captured CO<sub>2</sub> and hydrogen that can be produced by water splitting. Keeping in view both these green fuel production processes, this study proposes a combined application of both these technologies for the production of methanol, which is an important chemical used in manufacturing industries. This review paper presents a brief study of both carbon capture and hydrogen production technologies. It also provides research trends, economic aspects, and methods of incorporating both these technologies to produce methanol. Additionally, the prospects of the approach in Oman have also been presented.
基金the support from the National Natural Science Foundation of China Grant Council of Hong Kong Joint Research Scheme(N_PolyU502/21)the funding for Projects of Strategic Importance of The Hong Kong Polytechnic University(Project Code:1-ZE2V)+2 种基金Shenzhen Fundamental Research Scheme-General Program(JCYJ20220531090807017)the Natural Science Foundation of Guangdong Province(2023A1515012219)Departmental General Research Fund(Project Code:ZVUL)from Department of Applied Biology and Chemical Technology of Hong Kong Polytechnic University.
文摘Although single-atom catalysts(SACs)have attracted enormous attention for their applications in the electrochemical reduction of CO_(2)(CO_(2)RR)due to their extraordinary catalytic activity and well-defined active centers,neighboring effects and their influence on the electrochemical performance of SACs have not been well investigated.In this review,we present a summary of the neighboring effects on SACs for the CO_(2)RR process,where the surrounding atoms not only induce electronic modulation of the metal atom but also participate in the CO_(2)RR.Both theoretical and experimental studies have pointed out that the neighboring sites of the anchored metal center can provide second active/adsorption locations during the catalytic process,enhancing CO_(2)RR performance tremendously.This review supplies advanced insights into the significant roles and impacts of neighboring effects on the catalytic process,which also benefit the development of advanced SACs to achieve efficient electrocatalysis.
文摘A reaction-coupling strategy is often employed for CO_(2)hydrogenation to produce fuels and chemicals using oxide/zeolite bifunctional catalysts.Because the oxide components are responsible for CO_(2)activation,understanding the structural effects of these oxides is crucial,however,these effects still remain unclear.In this study,we combined In_(2)O_(3),with varying particle sizes,and SAPO‐34 as bifunctional catalysts for CO_(2)hydrogenation.The CO_(2)conversion and selectivity of the lower olefins increased as the average In_(2)O_(3)crystallite size decreased from 29 to 19 nm;this trend mainly due to the increasing number of oxygen vacancies responsible for CO_(2) and H_(2) activation.However,In_(2)O_(3)particles smaller than 19 nm are more prone to sintering than those with other sizes.The results suggest that 19 nm is the optimal size of In_(2)O_(3)for CO_(2)hydrogenation to lower olefins and that the oxide particle size is crucial for designing catalysts with high activity,high selectivity,and high stability.