为了提高Sn基材料表面CO_(2)电化学还原为甲酸盐的法拉第效率,利用一步溶剂热法合成了具有丰富硫空位的Cu掺杂SnS_(2)纳米花(Cu-SnS_(2-x))催化剂,在较宽的电位窗口实现了CO_(2)电化学还原制备甲酸盐。结果表明,通过调控催化剂制备过程...为了提高Sn基材料表面CO_(2)电化学还原为甲酸盐的法拉第效率,利用一步溶剂热法合成了具有丰富硫空位的Cu掺杂SnS_(2)纳米花(Cu-SnS_(2-x))催化剂,在较宽的电位窗口实现了CO_(2)电化学还原制备甲酸盐。结果表明,通过调控催化剂制备过程中Cu和Sn的摩尔比,在-1.1 V vs.RHE电位条件下得到了72.64%的FE_(formate),电流密度J_(formate)达到-14.38 mA/cm^(2)。二维纳米片阵列增加了催化活性位点,Cu掺杂所产生的硫空位能够协同提高催化活性、促进电子转移,从而提高甲酸盐的选择性。展开更多
A series of multi-hydroxyl bis-(quaternary ammonium)ionic liquids(Ils1‒7)was prepared as bifunctional catalysts for the chemical fixation of CO_(2).All these ionic liquid compounds were efficient for the catalytic syn...A series of multi-hydroxyl bis-(quaternary ammonium)ionic liquids(Ils1‒7)was prepared as bifunctional catalysts for the chemical fixation of CO_(2).All these ionic liquid compounds were efficient for the catalytic synthesis of cyclic carbonates and oxazolidinones via the cycloaddition reactions between CO_(2) and epoxides or aziridines with excellent yield and high selectivity in the absence of co-catalyst,metal and solvent.Due to the synergistic effects of hydroxyl groups and halogen anion,the cycloaddition reactions proceeded smoothly either at atmospheric pressure or room temperature.The selectivity for substituted oxazolidinones at 5-and 4-positions can be tuned via changing the reaction conditions.Finally,possible mechanisms including the activation of both CO_(2) and epoxide or aziridines were proposed based on the literatures and experimental results.展开更多
Hydrate-based CO_(2) sequestration is an effective method for reducing the greenhouse effect,and the presence of porous media and NaCl can impact the formation characteristics of hydrates.This study uses the constant ...Hydrate-based CO_(2) sequestration is an effective method for reducing the greenhouse effect,and the presence of porous media and NaCl can impact the formation characteristics of hydrates.This study uses the constant volume temperature search method to investigate the effects of quartz sand particle size(0.006‒0.03 mm),water saturation(30%–90%),and NaCl concentration(1%‒9%)on the phase equilibrium and kinetics of CO_(2) hydrates within a temperature range of 273‒285 K and pressure range of 1.0‒3.5 MPa.The results indicate that a decrease in quartz sand particle size or an increase in NaCl concentration shifts the hydrate phase equilibrium curve towards lower temperatures and higher pressures,making hydrate generation conditions more demanding.In different particle size systems,there are no significant changes in the rate of CO_(2) hydrate formation or conversion rate.The highest hydrate conversion rate of 71.1%is observed in a 0.015 mm particle size system.With increasing water saturation,both the generation rate and conversion rate of CO_(2) hydrates show a trend of first increasing and then decreasing.Meanwhile,low concentrations of NaCl(1%–3%)are found to enhance the formation and conversion rates of CO_(2) hydrates.However,as NaCl concentration increases,the rate of CO_(2) hydrate formation and conversion rate decrease.展开更多
Since hydrate resources play a part of the stratigraphic framework structure in sediments,establishing a safe and economic method for hydrates exploitation remains the primary challenge to this day.Among the proposed ...Since hydrate resources play a part of the stratigraphic framework structure in sediments,establishing a safe and economic method for hydrates exploitation remains the primary challenge to this day.Among the proposed methods,the spontaneous displacement of CH_(4) from hydrate cages by CO_(2) seems to be a perfect mechanism to address gas production and CO_(2) storage,especially in today's strong demand for carbon reduction and replacing clean energy.After extensive lab researches,in the past decade,injecting a mixture of CO_(2) and small molecule gas has become a key means to enhance displacement efficiency and has great potential for application.However,there is a lack of in-depth research on gas flow in the reservoir,while the injected gas always passes through low-saturated hydrate areas with high permeability and then occurs gas channel in a short term,finally resulting in the decreases in gas production efficiency and produced gas quality.Therefore,we explored a new injection-production mode of alternate injection of N2 and CO_(2) in order to fully coordinate the advantages of N_(2) in enhanced hydrate decomposition and CO_(2) in solid storage and heat compensation.These alternate"taking"and"storing"processes perfectly repair the problem of the gas channel,achieving self-regulation effect of CH_(4) recovery and CO_(2) storage.The 3-D experimental results show that compared to the mixed gas injection,CH_(4) recovery is increased by>50%and CO_(2) storage is increased by>70%.Additionally,this alternate injection mode presented a better performance in CH_(4) concentration of produced gas and showed outstanding N_(2) utilization efficiency.Further,we analyzed its self-adaptive gas flow mechanism and proposed an application model of"one injection and multiple production".We look forward to this study accelerating the application of CO_(2)-CH_(4) replacement technology.展开更多
Carbon emission reduction and clean energy development are urgent demands for mankind in the coming decades.Exploring an efficient CO_(2) storage method can significantly reduce CO_(2) emissions in the short term.In t...Carbon emission reduction and clean energy development are urgent demands for mankind in the coming decades.Exploring an efficient CO_(2) storage method can significantly reduce CO_(2) emissions in the short term.In this study,we attempted to construct sediment samples with different residual CH_(4) hydrate amounts and reservoir conditions,and then investigate the potentials of both CO_(2) storage and enhanced CH_(4) recovery in depleted gas hydrate deposits in the permafrost and ocean zones,respectively.The results demonstrate that CO_(2) hydrate formation rate can be significantly improved due to the presence of residual hydrate seeds;However,excessive residual hydrates in turn lead to the decrease in CO_(2) storage efficiency.Affected by the T-P conditions of the reservoir,the storage amount of liquid CO_(2) can reach 8 times that of gaseous CO_(2),and CO_(2) stored in hydrate form reaches 2-4 times.Additionally,we noticed two other advantages of this method.One is that CO_(2) injection can enhance CH_(4) recovery rate and increases CH_(4) recovery by 10%-20%.The second is that hydrate saturation in the reservoir can be restored to 20%-40%,which means that the solid volume of the reservoir avoids serious shrinkage.Obviously,this is crucial for protecting the goaf stability.In summary,this approach is greatly promising for high-efficient CO_(2) storage and safe exploitation of gas hydrate.展开更多
文摘为了提高Sn基材料表面CO_(2)电化学还原为甲酸盐的法拉第效率,利用一步溶剂热法合成了具有丰富硫空位的Cu掺杂SnS_(2)纳米花(Cu-SnS_(2-x))催化剂,在较宽的电位窗口实现了CO_(2)电化学还原制备甲酸盐。结果表明,通过调控催化剂制备过程中Cu和Sn的摩尔比,在-1.1 V vs.RHE电位条件下得到了72.64%的FE_(formate),电流密度J_(formate)达到-14.38 mA/cm^(2)。二维纳米片阵列增加了催化活性位点,Cu掺杂所产生的硫空位能够协同提高催化活性、促进电子转移,从而提高甲酸盐的选择性。
文摘A series of multi-hydroxyl bis-(quaternary ammonium)ionic liquids(Ils1‒7)was prepared as bifunctional catalysts for the chemical fixation of CO_(2).All these ionic liquid compounds were efficient for the catalytic synthesis of cyclic carbonates and oxazolidinones via the cycloaddition reactions between CO_(2) and epoxides or aziridines with excellent yield and high selectivity in the absence of co-catalyst,metal and solvent.Due to the synergistic effects of hydroxyl groups and halogen anion,the cycloaddition reactions proceeded smoothly either at atmospheric pressure or room temperature.The selectivity for substituted oxazolidinones at 5-and 4-positions can be tuned via changing the reaction conditions.Finally,possible mechanisms including the activation of both CO_(2) and epoxide or aziridines were proposed based on the literatures and experimental results.
基金the National Natural Science Foundation of China(NSFC 21676145)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,China).
文摘Hydrate-based CO_(2) sequestration is an effective method for reducing the greenhouse effect,and the presence of porous media and NaCl can impact the formation characteristics of hydrates.This study uses the constant volume temperature search method to investigate the effects of quartz sand particle size(0.006‒0.03 mm),water saturation(30%–90%),and NaCl concentration(1%‒9%)on the phase equilibrium and kinetics of CO_(2) hydrates within a temperature range of 273‒285 K and pressure range of 1.0‒3.5 MPa.The results indicate that a decrease in quartz sand particle size or an increase in NaCl concentration shifts the hydrate phase equilibrium curve towards lower temperatures and higher pressures,making hydrate generation conditions more demanding.In different particle size systems,there are no significant changes in the rate of CO_(2) hydrate formation or conversion rate.The highest hydrate conversion rate of 71.1%is observed in a 0.015 mm particle size system.With increasing water saturation,both the generation rate and conversion rate of CO_(2) hydrates show a trend of first increasing and then decreasing.Meanwhile,low concentrations of NaCl(1%–3%)are found to enhance the formation and conversion rates of CO_(2) hydrates.However,as NaCl concentration increases,the rate of CO_(2) hydrate formation and conversion rate decrease.
基金financially supported by the National Natural Science Foundation of ChinaChina(Nos.22378424,22127812,U20B6005,52004136)+1 种基金the Science Foundation of China University of Petroleum,Beijing(No.2462023BJRC017)Hunan Provincial Department of Education Scientific Research Project(No.22B0310)。
文摘Since hydrate resources play a part of the stratigraphic framework structure in sediments,establishing a safe and economic method for hydrates exploitation remains the primary challenge to this day.Among the proposed methods,the spontaneous displacement of CH_(4) from hydrate cages by CO_(2) seems to be a perfect mechanism to address gas production and CO_(2) storage,especially in today's strong demand for carbon reduction and replacing clean energy.After extensive lab researches,in the past decade,injecting a mixture of CO_(2) and small molecule gas has become a key means to enhance displacement efficiency and has great potential for application.However,there is a lack of in-depth research on gas flow in the reservoir,while the injected gas always passes through low-saturated hydrate areas with high permeability and then occurs gas channel in a short term,finally resulting in the decreases in gas production efficiency and produced gas quality.Therefore,we explored a new injection-production mode of alternate injection of N2 and CO_(2) in order to fully coordinate the advantages of N_(2) in enhanced hydrate decomposition and CO_(2) in solid storage and heat compensation.These alternate"taking"and"storing"processes perfectly repair the problem of the gas channel,achieving self-regulation effect of CH_(4) recovery and CO_(2) storage.The 3-D experimental results show that compared to the mixed gas injection,CH_(4) recovery is increased by>50%and CO_(2) storage is increased by>70%.Additionally,this alternate injection mode presented a better performance in CH_(4) concentration of produced gas and showed outstanding N_(2) utilization efficiency.Further,we analyzed its self-adaptive gas flow mechanism and proposed an application model of"one injection and multiple production".We look forward to this study accelerating the application of CO_(2)-CH_(4) replacement technology.
基金financially supported by the National Natural Science Foundation of China,China(22378424,52004136,22127812,U20B6005)the Science Foundation of China University of Petroleum Beijing(2462023BJRC017)Hunan Provincial Department of Education Scientific Research Project(22B0310).
文摘Carbon emission reduction and clean energy development are urgent demands for mankind in the coming decades.Exploring an efficient CO_(2) storage method can significantly reduce CO_(2) emissions in the short term.In this study,we attempted to construct sediment samples with different residual CH_(4) hydrate amounts and reservoir conditions,and then investigate the potentials of both CO_(2) storage and enhanced CH_(4) recovery in depleted gas hydrate deposits in the permafrost and ocean zones,respectively.The results demonstrate that CO_(2) hydrate formation rate can be significantly improved due to the presence of residual hydrate seeds;However,excessive residual hydrates in turn lead to the decrease in CO_(2) storage efficiency.Affected by the T-P conditions of the reservoir,the storage amount of liquid CO_(2) can reach 8 times that of gaseous CO_(2),and CO_(2) stored in hydrate form reaches 2-4 times.Additionally,we noticed two other advantages of this method.One is that CO_(2) injection can enhance CH_(4) recovery rate and increases CH_(4) recovery by 10%-20%.The second is that hydrate saturation in the reservoir can be restored to 20%-40%,which means that the solid volume of the reservoir avoids serious shrinkage.Obviously,this is crucial for protecting the goaf stability.In summary,this approach is greatly promising for high-efficient CO_(2) storage and safe exploitation of gas hydrate.
