【目的】CO_(2)捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)因其可直接降低碳排放而备受关注,CO_(2)管道作为CCUS的重要环节,其建设呈现出快速发展趋势。为了保证CO_(2)管道系统建设与运行的整体安全,深入剖析管道...【目的】CO_(2)捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)因其可直接降低碳排放而备受关注,CO_(2)管道作为CCUS的重要环节,其建设呈现出快速发展趋势。为了保证CO_(2)管道系统建设与运行的整体安全,深入剖析管道设计规范的相关规定尤为重要。【方法】深入调研了国内外CO_(2)管道主要标准的发展历史及现状,重点分析了CO_(2)管道设计中管道材料选择、CO_(2)脱水、阀室设置、管道放空、管道干燥封存等方面的要点及其需要注意的问题。【结果】基于CO_(2)自身的特殊性质,管道材料的选择应与CO_(2)的输送相态相适应,且能够承受管道减压过程中可能发生的低温影响;CO_(2)管道阀室间距、位置的设置应与管道路由、泄压放空设施的位置等相结合,对各环节进行统筹考虑;密相/超临界CO_(2)泄压及放空会带来低温、地势低洼处聚集等问题,为防止对人员健康及环境造成威胁,CO_(2)管道路由选择应避免通过人口密集区的高地势侧;内腐蚀是CO_(2)管道主要失效形式之一,其主要控制手段为对CO_(2)气源进行充分脱水;由于CO_(2)溶于水的弱酸性质及易形成水合物的特点,对干燥过程中控制管内水气的要求较严格;如果管道不能立即投产,建议对管道注入干燥氮气,并采取0.05~0.07 MPa(表压)的微正压封存。【结论】中国CO_(2)管道标准的制定正处于起步阶段,应借鉴国外众多成熟标准的规定,尤其亟需开展CO_(2)管道泄漏试验研究,以获得更多数据支撑,为中国CO_(2)管道的设计、建设及规范制订提供借鉴。(图3,表4,参22)展开更多
Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high...Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high-quality interfacial contact.Herein,we develop a novel strategy to in-situ grow ultrathin/V-doped graphene(NG)layer on TiO_(2) hollow spheres(HS) with large area and intimate interfacial contact via a chemical vapor deposition(CVD).The optimized TiO^(2)/NG HS nanocomposite achieves total CO_(2)conversion rates(the sum yield of CO,CH_(3)OH and CH_(4))of 18.11μmol·g^(-1)h^(-1),which is about 4.6 times higher than blank T1O_(2)HS.Experimental results demonstrate that intimate interfacial contact and abundant pyridinic N sites can effectively facilitate photogenerated charge carrier separation and transport,realizing enhanced photocatalytic CO_(2)reduction performance.In addition,this work provides an effective strategy for in-situ construction of graphene-based photocatalysts for highly efficient photocatalytic CO_(2)conversion.展开更多
Photosynthesis in nature has been deemed as the most significant biochemical reaction,which maintains a relatively stable content of O_(2) and CO_(2) in the atmosphere.Herein,for a deeper comprehension of natural phot...Photosynthesis in nature has been deemed as the most significant biochemical reaction,which maintains a relatively stable content of O_(2) and CO_(2) in the atmosphere.Herein,for a deeper comprehension of natural photosynthesis,an artificial photosynthesis model reaction of photochemical CO_(2) to CO conversion(CO_(2)+2 H^(+)+2e^(-)→CO+H_(2)O)catalyzed by a homogeneous hexanuclear ring cobalt complex{K_(2)[CoO_(3)PCH_(2)N(CH_(2)CO_(2))_(2)]}_(6)(Co6 complex)is developed.Using the[Ru(bpy)_(3)]^(2+)as a photosensitizer and TEOA as a sacrificial electron donor,an optimal turnover frequency of 503.3 h^(‒1) and an apparent quantum efficiency of 0.81%are obtained.The good photocatalytic CO_(2) reduction performance is attributed to the efficient electron transfer between Co6 complex and[Ru(bpy)_(3)]^(2+),which boosts the photogenerated carriers separation of the photosensitizer.It is confirmed by the j‐V curves,light‐assisted UV‐vis curves,steady‐state photoluminescence spectra and real‐time laser flash photolysis experiments.In addition,the proposed catalytic mechanism for CO_(2) reduction reaction catalyzed by the Co6 complex is explored by the potassium thiocyanate poison experiment,Pourbaix diagram and density functional theory calculations.展开更多
文摘【目的】CO_(2)捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)因其可直接降低碳排放而备受关注,CO_(2)管道作为CCUS的重要环节,其建设呈现出快速发展趋势。为了保证CO_(2)管道系统建设与运行的整体安全,深入剖析管道设计规范的相关规定尤为重要。【方法】深入调研了国内外CO_(2)管道主要标准的发展历史及现状,重点分析了CO_(2)管道设计中管道材料选择、CO_(2)脱水、阀室设置、管道放空、管道干燥封存等方面的要点及其需要注意的问题。【结果】基于CO_(2)自身的特殊性质,管道材料的选择应与CO_(2)的输送相态相适应,且能够承受管道减压过程中可能发生的低温影响;CO_(2)管道阀室间距、位置的设置应与管道路由、泄压放空设施的位置等相结合,对各环节进行统筹考虑;密相/超临界CO_(2)泄压及放空会带来低温、地势低洼处聚集等问题,为防止对人员健康及环境造成威胁,CO_(2)管道路由选择应避免通过人口密集区的高地势侧;内腐蚀是CO_(2)管道主要失效形式之一,其主要控制手段为对CO_(2)气源进行充分脱水;由于CO_(2)溶于水的弱酸性质及易形成水合物的特点,对干燥过程中控制管内水气的要求较严格;如果管道不能立即投产,建议对管道注入干燥氮气,并采取0.05~0.07 MPa(表压)的微正压封存。【结论】中国CO_(2)管道标准的制定正处于起步阶段,应借鉴国外众多成熟标准的规定,尤其亟需开展CO_(2)管道泄漏试验研究,以获得更多数据支撑,为中国CO_(2)管道的设计、建设及规范制订提供借鉴。(图3,表4,参22)
文摘Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high-quality interfacial contact.Herein,we develop a novel strategy to in-situ grow ultrathin/V-doped graphene(NG)layer on TiO_(2) hollow spheres(HS) with large area and intimate interfacial contact via a chemical vapor deposition(CVD).The optimized TiO^(2)/NG HS nanocomposite achieves total CO_(2)conversion rates(the sum yield of CO,CH_(3)OH and CH_(4))of 18.11μmol·g^(-1)h^(-1),which is about 4.6 times higher than blank T1O_(2)HS.Experimental results demonstrate that intimate interfacial contact and abundant pyridinic N sites can effectively facilitate photogenerated charge carrier separation and transport,realizing enhanced photocatalytic CO_(2)reduction performance.In addition,this work provides an effective strategy for in-situ construction of graphene-based photocatalysts for highly efficient photocatalytic CO_(2)conversion.
文摘Photosynthesis in nature has been deemed as the most significant biochemical reaction,which maintains a relatively stable content of O_(2) and CO_(2) in the atmosphere.Herein,for a deeper comprehension of natural photosynthesis,an artificial photosynthesis model reaction of photochemical CO_(2) to CO conversion(CO_(2)+2 H^(+)+2e^(-)→CO+H_(2)O)catalyzed by a homogeneous hexanuclear ring cobalt complex{K_(2)[CoO_(3)PCH_(2)N(CH_(2)CO_(2))_(2)]}_(6)(Co6 complex)is developed.Using the[Ru(bpy)_(3)]^(2+)as a photosensitizer and TEOA as a sacrificial electron donor,an optimal turnover frequency of 503.3 h^(‒1) and an apparent quantum efficiency of 0.81%are obtained.The good photocatalytic CO_(2) reduction performance is attributed to the efficient electron transfer between Co6 complex and[Ru(bpy)_(3)]^(2+),which boosts the photogenerated carriers separation of the photosensitizer.It is confirmed by the j‐V curves,light‐assisted UV‐vis curves,steady‐state photoluminescence spectra and real‐time laser flash photolysis experiments.In addition,the proposed catalytic mechanism for CO_(2) reduction reaction catalyzed by the Co6 complex is explored by the potassium thiocyanate poison experiment,Pourbaix diagram and density functional theory calculations.
