Electrocarboxylation of CO2 with Organic Substrates:Toward Cathodic Reaction

Electrocarboxylation of carbon dioxide(CO₂) using organic substrates has emerged as a promising method for the sustainable synthesis of value-added carboxylic acids due to its renewable energy source and mild reaction conditions.The reactivity and product selectivity of electrocarboxylation are highly dependent on the cathodic behavior,involving a sequence of electron transfers and chemical reactions.Hence,it is necessary to understand the cathodic reaction mechanisms for optimizing r...     

二氧化碳的自述

正我是CO_2,经常被人们提到,这是为什么呢?我的朋友说因为我是造成全球变暖的凶手之一。尽管我给人类带来很多危害和麻烦,但我不是故意的。除此之外,我还经常被人"谋杀",而且变得越来越严重。我只想给人们提供一些     

Integrated Photothermal Nanoreactors for Efficient Hydrogenation of CO2

To alleviate the energy crisis and global warming,photo thermal catalysis is an attractive way to efficiently convert CO₂ and renewable H₂ into value-added fuels and chemicals.However,the catalytic performance is usually restricted by the trade-off between the dispersity and light absorption property of metal catalysts.Here we demonstrate a simple SiO2-protected metalorganic framework pyrolysis strategy to fabricate a new type of integrated photothermal nanoreactor with a c...     

Sequential Growth of Cs3Bi2I9/BiVO4 Direct Z-Scheme Heterojunction for Visible-Light-Driven Photocatalytic CO2 Reduction

The high exciton binding energy and lack of a positive oxidation band potential restrict the photocatalytic CO₂ reduction efficiency of lead-free Bi-based halide perovskites Cs₃Bi₂X₉(X=Br,I).In this study,a sequential growth method is presented to prepare a visible-light-driven(λ> 420 nm) Z-scheme heterojunction photocatalyst composed of BiVO₄ nanocrystals decorated on a Cs₃Bi₂I₉ nanosheet for photocatalyt...     

Heterogeneous Catalysis for CO2 Conversion into Chemicals and Fuels

Catalytic conversion of CO₂ into chemicals and fuels is a viable method to reduce carbon emissions and achieve carbon neutrality.Through thermal catalysis,electrocatalysis,and photo(electro)catalysis,CO₂ can be converted into a wide range of valuable products,including CO,formic acid,methanol,methane,ethanol,acetic acid,propanol,light olefins,aromatics,and gasoline,as well as fine chemicals.In this mini-review,we summarize the recent progress in heterogeneous catalysis for ...     

MXene-Based Photocatalysts and Electrocatalysts for CO2 Conversion to Chemicals

The interest in CO₂ conversion to value-added chemicals and fuels has increased in recent years as part of strategic efforts to mitigate and use the excessive CO₂ concentration in the atmosphere.Much attention has been given to developing twodimensional catalytic materials with high-efficiency CO₂ adsorption capability and conversion yield.While several candidates are being investigated,MXenes stand out as one of the most promising catalysts and co-catalysts for ...     

Proximity Effect of Fe-Zn Bimetallic Catalysts on CO2 Hydrogenation Performance

The interaction between a promoter and an active metal crucially impacts catalytic performance.Nowadays,the influence of promoter contents and species has been intensively considered.In this study,we investigate the effect of the iron(Fe)-zinc(Zn) proximity of Fe-Zn bimetallic catalysts on CO₂ hydrogenation performance.To eliminate the size effect,Fe₂O₃and ZnO nanoparticles with uniform size are first prepared by the thermal decomposition method.By changing the l...     

Numerical controlled two optical paths CO2 laser die-cutting technology

A CO2 laser die-cutting system, which does not need die board any more, is a new technique for manufac-turing packing box. Two optical paths, the galvanometer scanning system and the flying optical system, are used to satisfy different processing needs. The scanning system is composed of galvanometer scanning mirrors and F-θ lens. And the flying optical system is driven by two servo motors. This paper presents the software and hardware design of the laser die-cutting system, the difference between the two optical paths, as well as the relationship among the cutting speed, thickness of wrapping paper and laser power. The cutting speed and thickness of wrapping paper are linearly increased by the incremental laser power, while the cutting speed is hyperbolically decreased by the incremental thickness of wrapping paper when the laser power is constant. The amount of incision is reduced by 20% and the processing time by 40% when tested by a low power RF CO2 laser die-cutting system using the optimized program. This tech- nique is also used for the reference of other rapid laser processing systems.     

工艺参数对CO2聚合物发泡宏观形态的影响

研究了超临界条件下CO2在PS中的发泡形态、溶解度与压力、温度和作用时间的关系.同时考虑发泡形态和溶解度的关系,对确定工艺参数具有积极意义.     

H2O/CO2污染对煤油燃料超声速燃烧影响数值研究

在纯净空气与H₂O/ CO₂污染空气来流对比试验结果基础上,采用数值计算方法和化学动力学方法,研究了H₂O和CO₂污染组分对煤油燃料超声速燃烧的影响,获得了试验手段难以得到的燃烧室流场参数和性能数据。完成了相应的煤油燃料超声速燃烧室二维数值计算,其中匹配了进口总温、总压、马赫数、氧气摩尔分数和工作当量油气比。将数值计算结果与相应试验测量值进行了对比分析,并结合燃烧室流场数据、性能参数分析了H₂O和CO₂污染的动力学影响、以及对燃烧室性能的影响。研究表明:(1)数值计算结果与实验测量值总体上吻合,两种手段均体现了纯净空气来流时不同煤油当量油气比的燃烧室性能,并反映了一致的“污染效应”影响趋势;(2) H₂O污染、H₂O+ CO₂污染的存在降低了煤油燃料超声速燃烧室性能,体现在燃烧诱导压升、燃烧效率、流向冲量增量的下降,而且随着污染组分含量的增加,燃烧室性能下降越加显著。      

Effects of PbO-B2O3-CuV2O6 glass on the microwave dielectric properties of （Pb0.5Ca0.5） （Fe0.5Nb0.5）O3 ceramics

The influences of the PbO-B2O3-CuV2O6 （PBC） additives on the microwave dielectric properties of （Pb0.5Ca0.5） （Fe0.5Nb0.5）O3 （PCFN） ceramics were investigated as a function of sintering temperature from 950 ℃ to 1 100 ℃. The sintering temperature of the specimens with the glass could be lowered from 1125 ℃ to 1 025℃ without the degradation of microwave dielectric properties. The microwave results showed that the dielectric constant cr was not significantly different while Qf values decreased with the increase of CuV206 content of PBC glass. For the specimens doped with PB-CV0.1 glass （81% PbO-9% B203-10% CuV2O6） and sintered at 1 025 ℃ for 3 h, the microwave dielectric properties of Qf=4 823 GHz, Cr=107.1 with TCF=＋15.03 ×10^-6/℃ were obtained.     

CuO/SnO2/TiO2纳米复合物的制备及光催化研究

采用溶胶-凝胶法,以硝酸铜、二氯化锡和钛酸四丁酯为原料,加入十六烷基三甲基溴化铵(CTAB)作软模板,制备CuO/SnO2/TiO2纳米复合物。分别用SEM、XRD、IR、UV-vis等对产物进行表征分析,CuO/SnO2/TiO2晶粒由锐钛矿相的TiO2、金红石相的SnO2和单斜晶系的CuO组成。以甲基橙为模拟污染物,研究其催化活性,结果表明CuO/SnO2/TiO2纳米复合物具有较好的光催化活性。     

Modulating the Selectivity of Photocatalytic CO2 Reduction in Barium Titanate by Introducing Oxygen Vacancies

Artificial photo synthetic reduction of CO₂ into valuable chemicals is one of the most promising approaches to solve the energy crisis and decreasing atmospheric CO₂ emissions.However,the poor selectivity accompanied by the low activity of photocatalysts limits the development of photocatalytic CO₂ reduction.Herein,inspired by the use of oxygen vacancy engineering to promote the adsorption and activation of CO₂ molecules,we introduced oxygen vacancies ...     

Effective and inexpensive gas chromatography method for detection of trace level SO2 in H2 fuel

Gas chromatography （GC） analysis of sulfer dioxide is challenging because SO2 is a highly mobile and chemically active molecule. For the conventional GC method with flame photometric detector （FPD） and direct-injection, it is often ineffective particularly when the SO2 level is as low as on the trace level. In this paper, a modified GC system integrated with an adsorption-desorption device was developed to detect the trace SO2 impurity in H2 fuel. Adsorbent GDX-502 is used in the adsorber to adsorb/collect SO2 from the sample gas and desorb/release it in a concentrated flow so that the conventional GC at downstream could detect it with an acceptable accuracy.     

可见光光催化剂Bi2WO6制备研究进展

综述了可见光光催化剂Bi2WO6制备研究进展,包括固相反应法、熔盐制备法、液相反应法、非晶态配合物法、水热法、微乳液-水热法、溶剂热法等。在这些制备方法中,水热法由于能够通过引入各种模板剂而方便地得到多种结构和形貌的Bi2WO6而被广泛采用,其它方法也各有其优点而有特定的使用场合。     

二氧化硅负载硅钨钼酸催化合成丁酮乙二醇缩酮

采用溶胶-凝胶法制备了二氧化硅负载硅钨钼酸催化剂.以其为催化剂,对以丁酮和乙二醇为原料合成丁酮乙二醇缩酮的反应条件进行了研究,较系统地研究了酮醇物质的量比、催化剂用量、带水剂环己烷,反应时间对收率的影响.实验表明,二氧化硅负载硅钨钼酸催化剂是合成丁酮乙二醇缩酮的良好催化剂,在n（丁酮）∶n（乙二醇）=1∶1.4,催化剂用量为原料总质量的0.6%,环己烷作带水剂10 mL,反应时间75min的优化条件下,丁酮乙二醇缩酮的收率可达96.77%.     

H3PW6Mo6O40/SiO2催化合成苯甲醛1,2-丙二醇缩醛

以二氧化硅负载磷钼钨酸H3PW6Mo6O40/SiO2为催化剂,苯甲醛和1,2-丙二醇为原料合成苯甲醛1,2-丙二醇缩醛.探讨H3PW6Mo6O40/SiO2对缩醛反应的催化活性,较系统地研究了醛醇物质的量比、催化剂用量、带水剂用量、反应时间等因素对产品收率的影响.实验表明:H3PW6Mo6O40/SiO2是合成苯甲醛1,2-丙二醇缩醛的良好催化剂,在n(苯甲醛)∶n(1,2丙二醇)=1∶1.5,催化剂用量为占总反应物质量的1.0%,带水剂环己烷用量10 mL,反应时间45 min的最佳条件下,苯甲醛1,2-丙二醇缩醛的收率可达83.3%.     

SiC-MoSi2-TiSi2涂层的设计及热力学分析

为了提高C/C复合材料的高温抗氧化性能,设计了网状的SiC填充高性能的MoSi2和微量的TiSi2涂层,对制备涂层的化学形成机理进行了热力学分析.结果表明,在选择的实验条件下,制备设计的涂层是完全可行的,实验制备的涂层在1773K有氧环境下具有良好的抗氧化性能.     

EF-H2O2-FeOX法深度处理畜牧业养殖废水技术研究

利用EF-H_2O_2-FeO_X法深度处理畜牧业养殖废水,结果表明,当pH值为3,电压为24 V,反应时间为45 min,电解质投加量为0.8 g/L,PAM投加量为2.5 mg/L时,对畜牧业养殖废水的深度处理效果最佳,COD的去除率可以达到99.1%。此方法具有成本低、设备简单、效果好等优点,在畜牧业养殖废水的深度处理领域具有广阔的应用前景。     

SiC-Al2O3-Y2O3体系陶瓷料浆的制备与性能研究

采用超声波分散法制备了SiC-Al2O3-Y2O3体系陶瓷料浆,利用Zeta电位分析仪、粘度计、pH测试仪等设备对料浆的物理性能进行了测试,讨论分析了Zeta电位、pH值、粘度、固含量、素坯强度、沉降速率对陶瓷料浆性能的影响规律,结果表明:pH值为9.5,固含量为58%,加入0.8%阿拉伯树胶作为分散剂时SiC-Al2O3-Y2O3体系陶瓷料浆流动性好、固含量高、不易沉降。