Thin versus Thick CO2 Market

The idea that trading is more costly the thinner the market is is common in most studies of market exchange with frictions. Surprisingly, this element is lacking from previous attempts to allow for frictions in pollution permit markets. This paper considers a CO₂ cap-and-trade model where trading costs develop endogenously as a function of the market size. The pre-trade allocation of permits determines whether the market size can be strongly influenced by expectations that have a role because of adjustment costs. The pre-trade allocation also sets preconditions for endogenously vanishing trading costs and thus has nonstandard effects on long-run trading levels and market allocations.     

Triazine-COF@Silicon nanowire mimicking plant leaf to enhance photoelectrocatalytic CO2 reduction to C2+ chemicals

Converting CO₂ and water into valuable chemicals like plant do is considered a promising approach to address both environmental and energy issues.Taking inspiration from the structures of natural leaves,we designed and synthesized a novel copper-coordinated covalent triazine framework （Cu CTF） supported by silicon nanowire arrays on wafer chip.This marks the first-ever application of such a hybrid material in the photoelectrocatalytic reduction of CO₂ under mild conditions.The Si@Cu CTF6 heterojunction has exhibited exceptional selectivity of 95.6%towards multicarbon products (C₂₊) and apparent quantum efficiency （AQE） of 0.89% for carbon-based products.The active sites of the catalysts are derived from the nitrogen atoms of unique triazine ring structure in the ordered porous framework and the abundant Cu–N coordination sites with bipyridine units.Furthermore,through DFT calculations and operando FTIR spectra analysis,we proposed a comprehensive mechanism for the photoelectrocatalytic CO₂ reduction,confirming the existence of key intermediate species such as *CO₂^-,*=C=O,*CHO and *CO–CHO etc.This work not only provides a new way to mimic photosynthesis of plant leaves but also gives a new opportunity to enter this research field in the future.     

Evaluating CO2 reduction strategies in the US

We constructed a model to simulate emissions of CO₂ from electricity generation in the US and, using the model, we developed 20-year projections of emissions under various regulatory scenarios.     

大气CO2、CH4、CO高精度观测混合标气配制方法

高精度、高准确度的大气CO2、CH4、CO浓度观测需使用以干洁大气为底气的标气.标气中水汽含量及CO2的δ13C对基于光学原理的观测系统有不可忽视的影响.本研究利用自组装的混合标气配制系统,以环境大气为底气,并通过添加高浓度气体或利用吸附剂吸附,调节目标物种浓度.CO2和CO吸附效率分别达99.7%和99.8%,标气水汽含量小于3.7×10-6(物质的量分数,下同),可配制不同浓度范围的CO2、CH4、CO混合标气.在青海瓦里关全球大气本底站配制环境大气浓度范围的标气,CO2、CH4、CO实际配制浓度同目标浓度的偏差小于10×10-6、30×10-9、30×10-9,CO2中δ13C同实际大气接近.本方法配制的标气已应用于我国本底站大气CO2、CH4、CO高精度观测,符合世界气象组织/全球大气观测(WMO/GAW)质量要求.     

CO2 mineralization by typical industrial solid wastes for preparing ultrafine CaCO3: A review

Mineral carbonation is a promising CO₂sequestration strategy that can utilize industrial wastes to convert CO₂into high-value CaCO₃.This review summarizes the advancements in CO₂mineralization using typical industrial wastes to prepare ultrafine CaCO₃.This work surveys the mechanisms of CO₂mineralization using these wastes and its capacities to synthesize CaCO₃,evaluates the effects of carbonation pathways and operating parameters on the preparation of CaCO₃,analyzes the current industrial application status and economics of this technology.Due to the large amount of impurities in solid wastes,the purity of CaCO₃prepared by indirect methods is greater than that prepared by direct methods Crystalline CaCO₃includes three polymorphs.The polymorph of CaCO₃synthesized by carbonation process is determined the combined effects of various factors.These parameters essentially impact the nucleation and growth of CaCO₃by altering the CO₂supersaturation in the reaction system and the surface energy of CaCO₃grains.Increasing the initial pH of the solution and the CO₂flow rate favors the formation of vaterite,but calcite is formed under excessively high pH.Vaterite formation is favored at lower temperatures and residence time.With increased temperature and prolonged residence time,it passes through aragonite metastable phase and eventually transforms into calcite.Moreover polymorph modifiers can decrease the surface energy of CaCO₃grains,facilitating the synthesis of vaterite.However,the large-scale application of this technology still faces many problems,including high costs,high energy consumption,low calcium leaching rate,low carbonation efficiency,and low product yield.Therefore,it is necessary to investigate ways to accelerate carbonation,optimize operating parameters,develop cost-effective agents,and understand the kinetics of CaCO₃nucleation and crystallization to obtain products with specific crystal forms Furthermore,more studies on life cycle assessment （LCA） should be conducted to fully confirm the feasibility of the developed technologies.     

包膜尿素对水田土壤排放NH3、NOx、CO2影响的研究

为了研究包膜尿素对水田土壤排放NH3、NOx和CO2的影响,采用水稻盆栽的方法,探讨了在水稻不同生育期内不同种类包膜尿素对水田土壤排放NH3、NOx和CO2的影响。结果表明,包膜尿素处理对水田土壤排放NH3、NOx和CO2均具有抑制作用,与普通尿素相比,包膜尿素LP40、LPSS、BB、SC60 NH3的挥发总量降低了5.4%~19.3%,NOx的挥发总量降低了8.1%~23.4%,CO2的挥发总量降低了1.6%~13.0%;施用包膜尿素能够抑制水田土壤NH3、NOx和CO2的排放。     

石油厌氧降解促进CO2的CH4转化

CO2是主要的温室气体,利用油藏进行CO2封存,并结合原油厌氧生物降解产生的H2对其进行CH4转化,将提高原油采收率,减少封存CO2长久潜在的危害.本研究以高矿化度的青海油田油井采出液为研究对象,添加碳酸氢盐进行厌氧培养,以研究其中CO2进行CH4转化的可能性.结果显示,厌氧培养体系中检测到CH4产生.且在培养过程中,碳酸氢盐添加体系内CO2相对含量降低,甲烷相对产量升高,沥青质和芳香烃组分的相对含量降低,表明青海油田油藏中存在产甲烷菌及与产甲烷过程相关的菌群,同时CO2封存利于增强原油的流动性、提高采收率.定量PCR分析表明,碳酸氢盐的添加抑制了部分微生物的生长但古菌在整个体系生命活动中的作用并未减弱,且产甲烷古菌占古菌的相对丰度明显升高.因此,在青海油田利用油藏微生物进行CO2封存并产生新甲烷能源,同时提高原油采收率具有可能性.     

Reduction of CO2 emission by optimally tracking a pre-defined target

The recent global financial crisis has highlighted the need for balanced and efficient investments in the reduction of the greenhouse effect caused by emissions of CO₂ on a global scale. In a previous paper, the authors proposed a mathematical model describing the dynamic relation of CO₂ emission with investment in reforestation and clean technology. An efficient allocation of resources to reduce the greenhouse effect has also been proposed. Here, this model is used to provide estimates of the investments needed in land reforestation and in the adoption of clean technologies for an optimum emission and abatement of CO₂, for the period of 1996–2014. The required investments are computed to minimize deviations with respect to the emission targets proposed in the Kyoto Protocol for European Countries. The emission target can be achieved by 2014 with investments in reforestation peaking in 2004, and a reduction of the expected GDP of 42%, relative to 2006. Investments in clean technology should increase between 2008 and 2010 with maximum transfer figures around 70 million American dollars. Total (cumulative) costs are, however, relatively high depending on the price of carbon abatement and the rate at which the expected CO₂ concentration in the atmosphere should be reduced. Results highlight the advantages for policy makers to be able to manage investments in climate policy more efficiently, controlling optimum transfers based on a portfolio of actions that tracks a pre-defined CO₂ concentration target.     

Boosting electrochemical reduction of CO2 to CO using molecule-regulated Ag nanoparticle in ionic liquids

Electrochemical reduction of CO₂ is a promising approach to convert CO₂ to high-valued chemicals and fuels. However, developing efficient electrocatalysts featuring desirable activity and selectivity is still a big challenge. In this work, a strategy of introducing functionalized molecules with desirable CO₂ affinity to regulate Ag catalyst for promoting electrochemical reduction of CO₂ was proposed. Specifically, 3-mercapto-1,2,4-triazole was introduced onto the Ag nanoparticle （Ag-m-Triz） for the first time to achieve selectively converting CO₂ to carbon monoxide（CO）. This Ag-m-Triz exhibits excellent performance for C_O2 reduction with a high CO Faradaic efficiency (FE_CO) of 99.2%and CO partial current density of 85.0 mA cm-2at-2.3 V vs. Ag/Ag+in H-cell when combined with the ionic liquid-based electrolyte, 30 wt%1-butyl-3-methylimidazolium hexafluorophosphate （[Bmim][PF₆]）-65 wt%acetonitrile （AcN）-5 wt%H₂O, which is 2.5-fold higher than the current density in Ag-powder under the same condition. Mechanism studies confirm that the significantly improved performance of Ag-m-Triz originates from （i） the stronger adsorption ability of C_O2 molecule and （ii） the weaker binding energy to form the COOH*intermediate on the surface of Ag-m-Triz compared with the Ag-powder catalyst, which boosts the conversion of CO₂ to CO. This research provides a facile way to regulate electrocatalysts for efficient CO₂ reduction by introducing functionalized molecules.     

珠江三角洲四种森林类型土壤CO2通量特征研究

采用开路式土壤CO2通量测量系统Li-8100&Li-8150对珠江三角洲地区尾叶桉(Eucalyptus urophylla)人工林、乡土树种恢复林、针阔叶混交林和常绿阔叶林4种林型的土壤CO2通量进行了观测。结果表明:4种森林类型年均土壤CO2通量为尾叶桉人工林(3.35μmol.m-2.s-1)>针阔叶混交林(2.66μmol.m-2.s-1)>乡土树种恢复林(2.09μmol.m-2.s-1)>常绿阔叶林(1.86μmol.m-2.s-1);旱季土壤CO2通量明显小于雨季。前3种森林类型凋落物呼吸处理表明,旱季对照组土壤CO2通量均小于相应的去除凋落物组、雨季则相反,全年的对比结果显示,3种森林类型的凋落物呼吸贡献分别达到1.3%、7.1%和10.8%。土壤CO2通量与10 cm土壤温度呈显著指数相关,且土壤CO2通量温度敏感指数表现为针阔叶混交林Q10最大(3.49),尾叶桉人工林Q10最小(1.95)。     

Rational engineering of triazine-benzene linked covalent-organic frameworks for efficient CO2 photoreduction

Three large π-conjugated and imine-based COFs, named TFP-TAB, TFP-TTA, and TTA-TTB, were synthesized via the ordered incorporation of benzene and triazine rings in the same host framework to study how the structural units affect the efficiency of CO₂ photoreduction.Results from both experiments and density-functional theory（DFT） calculations indicate the separation and transfer of the photoinduced charges is highly related to the triazine-N content and the conjugation degree in the skeletons of COFs. High-efficiency CO₂ photoreduction can be achieved by rationally adjusting the number and position of both benzene and triazine rings in the COFs. Specifically, TTA-TTB, with orderly interlaced triazine-benzene heterojunctions, can suppress the recombination probability of electrons and holes, which effectively immobilizes the key species（COOH） and lowers the free energy change of the potential-determining step, and thus exhibits a superior visible-light-induced photocatalytic activity that yields 121.7 μmol HCOOH g^-1h^-1. This research, therefore, helps to elucidate the effects of the different structural blocks in COFs on inherent heterogeneous photocatalysis for CO₂ reduction at a molecular level.     

CoTCPP integrates with BiOBr microspheres for improved solar-driven CO2 reduction performance

CO₂ photoreduction into carbon-based chemicals has been considered as an appropriate way to alleviate the energy issue and greenhouse effect. Herein, the 5, 10, 15, 20-tetra（4-carboxyphenyl） porphyrin cobalt（II）(CoTCPP) has been integrated with BiOBr microspheres and formed the CoTCPP/BiOBr composite. The as-prepared CoTCPP/BiOBr-2 composite shows optimized photocatalytic performance for CO₂ conversion into CO and CH₄ upon irradiation with 300 W Xe lamp, which is 2.03 and 2.58 times compared to that of BiOBr, respectively. The introduced CoTCPP significantly enhanced light absorption properties, promoted rapid separation of photogenerated carriers and boosted the chemisorption of CO₂ molecules. The metal Co²⁺ at the center of the porphyrin molecules also acts as adsorption center for CO₂ molecules,accelerating the CO₂ conversion into CO and CH₄. The possible mechanism of CO₂ photoreduction was explored by in-situ FT-IR spectra. This work offers a new possibility for the preparation of advanced photocatalysts.     

PIXGRO: A model for simulating the ecosystem CO2 exchange and growth of spring barley

A model, PIXGRO, developed by coupling a canopy flux sub-model (PROXEL_NEE; PROcess-based piXEL Net Ecosystem CO₂ Exchange) to a vegetation structure submodel (CGRO), for simulating both net ecosystem CO₂ exchange (NEE) and growth of spring barley is described. PIXGRO is an extension of the stand-level CO₂ and H₂O-flux model PROXEL_NEE, that simulates the NEE on a process basis, but goes further to include the dry matter production, partitioning, and crop development for spring barley. Dry matter partitioned to the leaf was converted to leaf area index (LAI) using relationships for the specific leaf area (SLA). The canopy flux component, PROXEL_NEE was calibrated using information from the literature on C3 plants and was tested using CO₂ flux data from an eddy-covariance (EC) method in Finland with long-term observations. The growth component (CGRO) was calibrated using data from the literature on spring barley as well as data from the Finland site. It was then validated against field data from two sites in Germany and partly via the use of MODIS remotely sensed LAI from the Finland site.Both the diurnal and the seasonal patterns of gross CO₂ uptake were very well simulated (R² = 0.92). A slight seasonal bias may be attributed to leaf ageing. Crop growth was also well simulated; simulated dry matter agreed with field observed data from Germany (R² = 0.90). For LAI, the agreement between the simulated and observed was good (R² = 0.80), giving an indication that functions describing the conversion of fixed CO₂ to dry matter and the subsequent partitioning leaf dry matter and LAI simulation were robust and provided reliable estimates.The MODIS LAI at a resolution of 1000 m agreed poorly (R² = 0.45) with the PIXGRO simulated LAI and the observed LAI at the Finland site in 2001. We attributed this to the coarse resolution of the image and/or the small size of the barley field (about 17 ha or 0.25 km²) at the Finland site. By deriving a regression relation between the observed LAI and NDVI from a higher resolution MODIS (500 m resolution), the MODIS-recalculated LAI agreed better with the PIXGRO-simulated LAI (R² = 0.86).PIXGRO provides a prototype model bridging the disciplines of plant physiology, crop modeling and remote sensing, for use in a spatial context in evaluating carbon balances and plant growth at stand level, landscape, regional, and with some care, continental scales. Since almost 50% of the European land surface is covered by crops, such a model is needed for the dynamic estimation of LAI and NEE of croplands.     

Facet effects on bimetallic ZnSn hydroxide microcrystals for selective electrochemical CO2 reduction

Employing crystal facets to regulate the catalytic properties in electrocatalytic carbon dioxide reduction reaction（eCO₂RR） has been well demonstrated on electrocatalysts containing single metals but rarely explored for bimetallic systems. Here, we synthesize Zn Sn（OH）₆（ZSO）microcrystals（MCs） with distinct facets and investigate the facet effects in eCO₂RR. Electrochemical studies and in situ Fourier Transform Infrared Spectroscopy（in situ-FTIR） reveal that ZSO MCs produce mainly C1 products of HCOOH and CO. The {111} facet of the ZSO MCS exhibits higher selectivity and faradaic efficiency（FE） than that of the {100} facet over a wide range of potentials（-0.9 V ～-1.3 V versus RHE）. Density Functional Theory（DFT） calculations elucidate that the {111} facet is favorable to the adsorption/activation of CO₂ molecules,the formation of intermediate in the rate-determining step, and the desorption of C1 products of CO and HCOOH molecules.     

Superhydrophobic ceramic membrane coupled with a biphasic solvent for efficient CO2 capture

An innovative strategy was proposed by integration of membrane contactor（MC） with biphasic solvent for efficient CO₂ capture from flue gas. The accessible fly ash-based ceramic membrane（CM） underwent hydrophobic modification through silane grafting, followed by fluoroalkylsilane decoration, to prepare the superhydrophobic membrane（CSCM）. The CSCM significantly improved resistance to wetting by the biphasic solvent, consisting of amine（DETA） and sulfolane（TMS）. Morphological characterizations and chemical analysis revealed the notable enhancements in pore structure and hydrophobic chemical groups for the modified membrane. Predictions of wetting/bubbling behavior based on static wetting theory referred the liquid entry pressure（LEP） of CSCM increased by 20 kPa compared to pristine CM. Compared with traditional amine solvents, the biphasic solvent presented the expected phase separation. Performance experiments demonstrated that the CO₂ capture efficiency of the biphasic solvent increased by 7%, and the electrical energy required for desorption decreased by 32%. The 60-h continuous testing and supplemental characterization of used membrane confirmed the excellent adaptability and durability of the CSCMs. This study provides a potential approach for accessing hydrophobic ceramic membranes and biphasic solvents for industrial CO₂ capture.     

桂林岩溶表层带土壤CO2体积分数时空变化规律及其意义

通过2010—2011年的监测建立了桂林盘龙洞坡地和洼地不同深度土壤CO2体积分数的季节性变化。监测土壤CO2体积分数空间上变化为:坡地80 cm>50 cm>30 cm;洼地80 cm>100 cm>50 cm>30 cm。监测土壤CO2体积分数时间上变化为2010年7月和2011年6月未CO2体积分数达到最高值,2010到2011年冬季为土壤CO2达到最低值。由于受到大气降水量急剧减少的影响2011年土壤CO2体积分数整体比2010年低。显示大气降水量也是影响土壤CO2体积分数的重要环境因素。为我国固碳减排科学的选择时间和空间提供有力的依据。     

Multiple sources of predictive uncertainty in modeled estimates of net ecosystem CO2 exchange

Net ecosystem CO₂ exchange (NEE) is typically measured directly by eddy covariance towers or is estimated by ecosystem process models, yet comparisons between the data obtained by these two methods can show poor correspondence. There are three potential explanations for this discrepancy. First, estimates of NEE as measured by the eddy-covariance technique are laden with uncertainty and can potentially provide a poor baseline for models to be tested against. Second, there could be fundamental problems in model structure that prevent an accurate simulation of NEE. Third, ecosystem process models are dependent on ecophysiological parameter sets derived from field measurements in which a single parameter for a given species can vary considerably. The latter problem suggests that with such broad variation among multiple inputs, any ecosystem modeling scheme must account for the possibility that many combinations of apparently feasible parameter values might not allow the model to emulate the observed NEE dynamics of a terrestrial ecosystem, as well as the possibility that there may be many parameter sets within a particular model structure that can successfully reproduce the observed data. We examined the extent to which these three issues influence estimates of NEE in a widely used ecosystem process model, Biome-BGC, by adapting the generalized likelihood uncertainty estimation (GLUE) methodology. This procedure involved 400,000 model runs, each with randomly generated parameter values from a uniform distribution based on published parameter ranges, resulting in estimates of NEE that were compared to daily NEE data from young and mature Ponderosa pine stands at Metolius, Oregon. Of the 400,000 simulations run with different parameter sets for each age class (800,000 total), over 99% of the simulations underestimated the magnitude of net ecosystem CO₂ exchange, with only 4.07% and 0.045% of all simulations providing satisfactory simulations of the field data for the young and mature stands, even when uncertainties in eddy-covariance measurements are accounted for. Results indicate fundamental shortcomings in the ability of this model to produce realistic carbon flux data over the course of forest development, and we suspect that much of the mismatch derives from an inability to realistically model ecosystem respiration. However, difficulties in estimating historic climate data are also a cause for model-data mismatch, particularly in a highly ecotonal region such as central Oregon. This latter difficulty may be less prevalent in other ecosystems, but it nonetheless highlights a challenge in trying to develop a dynamic representation of the terrestrial biosphere.     

大气CO2浓度和温度升高对岷江冷杉（Abies faxoniana）幼苗针叶化学特性的影响

以6年生岷江冷杉(Abies faxoniana)幼苗为研究对象,利用控制环境生长室进行了2个生长季的大气CO2浓度倍增和增温(+2.2℃)处理,旨在探讨岷江冷杉幼苗针叶化学特性对CO2浓度倍增和增温的响应.结果表明:大气CO2浓度倍增对岷江冷杉幼苗针叶的叶绿素含量无显著影响,但降低了针叶N、P和纤维素含量,并增加了针叶可溶性糖和淀粉含量.增温显著降低了1年生针叶的叶绿素b含量,同时降低了当年生和1年生针叶的N、P和纤维素含量;显著提高了针叶的可溶性糖和淀粉含量.CO2浓度倍增和增温同时作用显著增加了针叶叶绿素含量,但降低了针叶N、P和纤维素含量,而对针叶可溶性糖和淀粉含量无显著影响.大气CO2浓度倍增和增温对针叶的叶绿素、N和碳水化合物含量有显著的交互作用.在大气CO2浓度倍增和增温条件下,岷江冷杉针叶化学性质将发生改变,可能影响针叶的生物化学过程和凋落物分解.