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1.
多数被发掘的古代青铜文物表面都附着有某些钢锈,其中以粉状锈(Cu_2(OH)_3Cl)对铜器的腐蚀最为严重.迄今已有一些文献介绍粉状锈的生成机理,但对其反应过程的动力学研究尚未见报导。作为青铜合金中含量最丰的元素铜,被氧化腐蚀是分步进行的.本工作主要用X-光衍射及分光光度法对一价铜锈CuCl在潮湿环境中进行氧化反应的速度常数及表观活化能进行测定核算;对反应的中间产物及伴随现象进行分析探讨。  相似文献   

2.
采用浆液浸渍法制备了小同载体负载的Cu2(OH)3Cl催化剂,考察了催化剂对甲醇氧化羰基化合成碳酸二甲酯(DMC)反应的催化性能.结果表明,各载体负载的Cu2(OH)3Cl催化剂活性均高于传统的负载CuCl2催化剂;以比表面积较大的活性炭(AC)为载体的催化剂活性最高.以Cu2(OH)3Cl/AC(w(Cu)=18.71%)为催化剂时,甲醇转化率、DMC选择性和DMC时宅收率可分别达到6.93%,67.3%和139.1mg/(g·h);其催化性能比较稳定,反应60h后其催化活性略有下降.通过CO程序升温脱附、X射线衍射、X射线光电子能谱和扫描电镜等技术对催化剂进行了表征.结果表明,在反应过程中催化剂的活性物种Cu2(OH)3Cl的晶粒逐渐团聚、长大,并且转化为CuCl2和CuO;同时,新鲜催化剂中唯一的CuⅡ物种部分转化为CuⅠ物种.  相似文献   

3.
红外反射及红外—光声光谱法对青铜生锈过程的研究   总被引:2,自引:0,他引:2  
在自制Cu-Sn-Pb合金表面上进行盐酸腐蚀,用红外反射及红外-光声光谱方法监测粉状锈(Cu_2(OH)_3Cl)的生长过程。结果发现,在酸性环境中Cu_2(OH)_3Cl生长迅速;二价铜锈的生成需通过一价铜锈(CuCl)这一中间产物;粉状锈有传染性,可通过空气由锈蚀样品传至无锈样品,锈体颗粒对光线的散射作用强,结合热力学计算对青铜生锈机理进行了探索。  相似文献   

4.
"Powdery corrosion" is called "cancer" of cultural relics of bronze. For many years theexperts concerned at home and abroad cannot make distinct progress in the control or cure ofpowdery corrosion. This paper introduces in detail analyses of XRD, SEM. TEM and XRFA on afragment of serials bells with serious powdery corrosion from the Cai Hou Tomb, pointingout that the components of powdery corrosion are mainly atacamite (Cu_2(OH)_3Cl), cuprite(Cu_2O) and cassiterite (SnO_2) in the worse crystalline state. In the bell's matrix, there arecorrosion gullies which has the same phase components as the powdery corrosion. Obviously,this discovery has very important significance for studying the formation mechanism ofpowdery corrosion.  相似文献   

5.
《结构化学》2021,40(8)
Two novel copper carboxyly-phosphonates, namely, Cu_(2.5)(5-pnc)(SO_4)_(0.5)(OH)(H_2O)_(0.5)(1) and Cu_(0.5)(5-pncH_2)(H_2O)_(1.5)(2)(5-pncH_3 = 5-phosphono-1-naphthalenecarboxylic acid), have been synthesized and characterized by X-ray diffraction, infrared spectroscopy, elemental analysis, and thermogravimetric analysis. In compound 1, each {PO_3C} tetrahedron is corner-shared with two {Cu(1)O_4}, two {Cu(2)O_5} and one {Cu(3)O_5},thus forming a one-dimensional inorganic chain along the c axis containing 8-membered rings of [Cu_3O_4S] and 19-membered cages of [Cu_5O_(10)P_4]. The inorganic chains are further connected by a 5-pnc~(3-) ligand to generate a three-dimensional framework. Compound 2 exhibits a one-dimensional structure, in which the inorganic chains of [Cu-O-Cu]_n are connected by the organic ligands through hydrogen bonding interactions, forming an infinite two-dimensional layer. Magnetic measurements of 1 indicate that dominant antiferromagnetic interactions are mediated between the Cu~(2+) centers.  相似文献   

6.
报道了通过分散聚合反应在碱式碳酸铜微球表面锚接聚苯乙烯纳米粒子, 以调节其亲水/亲油性的方法. 结果表明, 锚接的聚苯乙烯纳米粒子尺寸愈大, 所得的改性碱式碳酸铜微球疏水性愈强. 用对油和水润湿性适中的改性碱式碳酸铜微球为乳化剂, 能够制备出稳定的油包水型Pickering乳液. 改性碱式碳酸铜微球组装在Pickering乳液的分散相液滴表面, 形成一个固体壳层. 将Pickering 乳液的分散相水核凝胶化, 合成出分级结构琼脂糖凝胶微球.  相似文献   

7.
This paper presents the results of in situ non‐destructive X‐ray fluorescence determination of the chemical analysis of a collection of ten bronze statues that are on display at the Egyptian museum of Cairo. The statues are from the late period of the ancient Egyptian history. In addition, destructive technique X‐ray diffraction analysis was applied on 11 damaged archaeological objects to determine the corrosion products and the alloy compositions. Specimens of the latter objects were subjected to metallographic examinations to determine the microstructure of the alloy. Surprisingly, the results indicated that all ten statues and 10 of the 11 damaged objects were made of lead – bronze alloy; the percentage of the lead varied from 3.43 to 18.04, the tin varied from 2.53 to 10.67. The chemical composition of the patina on eight damaged objects is essentially composed of (Cu2O) cuprite for all objects in addition to other compounds such as (SnO2) cassiterite in two objects, (PbCO3) cerussite in three other objects and (Cu2(OH)3Cl) atacamite or (Cu(OH)3Cl) paratacamite in two other objects. The formation of chlorides and carbonate resulted from the interaction between surrounding environment and the alloy. The results of the metallographic examinations indicated a non‐homogenous structure and the increase of the lead content increases the globular lead particles. In spite of this condition, the galvanic corrosion tendency when the alloy is exposed to moist air or soil is not possible as lead compounds are electrically insulating. Another advantage for using leaded bronze in making statues is being heavy and thus leads to stability. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

8.
采用扫描电镜、电子探针微区分析、微区X射线衍射及X光荧光光谱等仪器分析手段,对一块被粉状锈(主要成分为Cu2(OH)3Cl)严重腐蚀的东汉青铜镜残片进行元素和结构的分区分析。剖面分析表明,青铜合金在浇铸过程中的偏析作用是造成其电化学腐蚀的内在因素;铜锈的生成是分步进行的;氯元素对合金的侵蚀由表面直至基体深部;生锈过程中铜元素从合金内部向表面外扩散。运用相平衡理论、电化学腐蚀原理及化学热力学对青铜器  相似文献   

9.
Two comparable discrete complexes [CuⅡ(CH3CN)2L2]·2(ClO4) 1 and [CuI2I2L2]·(DMF)2 2 were successfully synthesized by the reaction of CuⅡ and CuⅠ salts with a novel dinucleating ligand 2,5-bis(3-pyridinylmethylthio)-1,3,4-thiadiazole)(L),respectively.Complex 1 presents a single nuclear structure while 2 has a dimeric structure where two CuI ions are doubly bridged by halide ions in a μ2-fashion.Both discrete molecules were outspreaded into a one-dimensional supramolecular chain via aromatic interactions such as C-H…π and π…π interactions.  相似文献   

10.
加料方式对CuO/ZnO/Al2O3系催化剂前驱体性质的影响   总被引:5,自引:4,他引:5  
用XRD、TG-DTG、TPR技术研究了不同加料方式对CuO/ZnO/Al2O3系催化剂前驱体物相组成及其结晶情况的影响,用加压微反装置考察了催化剂合成甲醇反应活性。结果表明, 加料方式对Cu2+形成的中间化合物的物相组成及结晶度影响显著,对Zn2+及Al3+的沉淀物相的影响很小。不同加料方式对催化剂前驱体物相组成及催化剂性能的影响主要是形成的初始前驱体中Cu的物相及结晶度不同。正加法主要形成Cu2(OH)3NO3,并流法主要形成无定形Cu2CO3(OH)2,后者与Zn5(CO3)2(OH)6相互作用转化为(Cu,Zn)2CO3(OH)2和(Cu,Zn)5(CO3)2(OH)6,由它们分解形成的CuO-ZnO固溶体是合成甲醇反应的活性相。并流法能最大程度的形成CuO-ZnO固溶体,有利于CuO粒子的细化,其催化活性较好。  相似文献   

11.
A new three-dimensional coordination polymer composed of Cu~(2+) centres and semiquinoid linkers(dhbq~(2-)) was synthesized which was composed by two independent,enantiomeric,interpenetrated[Cu_2(dhbq)_3]~(2-) networks with(10,3)-a topology.The compound has good water stability and typical behaviors of semiconductor,whose conductivity increases along with raising temperature.The chemiresistive humidity sensor made from this material shows good properties including linear sensitivity,high response,fast response and recovery,and particularly narrow hysteresis during humidity adsorption and desorption  相似文献   

12.
在铜氧基超导体中,超导电性与接近充满的Cu3d-O2p价带空穴浓度有关.若干研究表明,添加空穴进入CuO_2面σ(P_(x,y))轨道,但另外一些工作认为,空穴态存在于Cu-O面π(p_(x,y))或π(p_z)轨道,还有其它一些作者建议,空穴集居于BaO面上σ(p_z)轨道.通过理论计算来区分未占O2p态的特征具有重要意义.因此,本文对模型簇Cu_3O_(12)~(17-)进行了Fenske-Hall MO计算,探讨了添加空穴态的对称性和添加对Cu-O键强度的影响.  相似文献   

13.
14.
在水和乙醇溶剂中,通过Cu(Ⅱ),Fe(Ⅲ)和Fe(Ⅱ)与2,2'-联咪唑协同作用,构筑了四种新的超分子配合物[Cu(H2biim)(gly)(H2O)]Cl·H2O(1),[Cu(H2biim)(C3H2O4)(H2O)]·1.5H2O(2),[Fe2(μ-O)(H2biim)4(H2O)2](NO3)4·C2H5OH(3)和[Fe(H2biim)3]SO4(4)(H2biim=2,2'-联咪唑;gly-=甘氨酸根;C3H2O24-=丙二酸根).并通过元素分析,红外光谱和X射线单晶衍射对其组成、结构和谱学性质进行研究.H2biim配体,丙二酸根和甘氨酸根三种配体都采用了双齿螯合方式与金属离子配位.配合物1~4中,通过H2biim配体的N-H键与阴离子、水分子和溶剂分子形成多种氢键,如R12(7),R22(9)和R12(4)等,以及H2biim配体之间的π-π堆积,阳离子不对称单元构筑了多维结构的超分子配合物.  相似文献   

15.
The synthesis of dimethyl carbonate by oxidative carbonylation of methanol over CuCl/SiO2-TiO2 catalysts has been investigated in a slurry reaction system. The γ-Cu2(OH)3Cl crystals were detected by X-ray diffraction on the catalysts after reaction. It was revealed that γ-Cu2(OH)3Cl was formed by CuCl reacting with O2 and by-product water. The catalytic tests showed that γ-Cu2(OH)3Cl was largely inactive for this reaction, may be attributed to its high stability that resisted the Cu+/Cu2+ redox cycle.  相似文献   

16.
With regard to the reaction of higheralcohol synthesis(HAS),the optimizations of activity and selectivity towards C_(2+) alcohol are restricted by the improper equilibrium in two different CO activation pathways and chain growth capacity.Herein,we find that delibrately controlling the compositions of catalysts is an effective strategy to achieve the equilibrium of CO activation pathways and promote the chain growth.As a result,the optimized Cu_(0.25)Co_(0.75) alloy catalyst can achieve a large proportion of higher alcohol in alcohol products(C_(2+)OH/MeOH=4.40),together with high CO conversion of 71.27% and space-time-yield of 147.65 g kg~(-1) h~(-1).The mechanistic studies suggest that the good performance of Cu_(0.25)Co_(0.75) catalyst is attributed to the synergistic effect between alloyed Cu and Co.  相似文献   

17.
用循环伏安法研究了2,2’-联喹啉推动Cu~(2+)在水/硝基苯界面的转移,提出了配合转移机理,并研究了配合反应过程的动力学,测定了Cu~(2+)和2,2’-联喹啉形成的1:2配合物的界面热力学参数和配合物的形成速率常数k.  相似文献   

18.
在β-环糊精(β-CD)水溶液的安全吸收剂量范围内,利用β-CD来调控Cu2+的辐射还原.随着β-CD的加入,硝酸铜的辐射还原产物从Cu2O逐渐转变为Cu.当β-CD浓度增大至8.0mmol·L-1时,辐射还原产物主要为Cu纳米粒子.在辐照过程中,Cu2+的还原没有经历Cu2O的中间过程.这是由于β-CD对·OH的清除减少了·OH与水化电子(ea-q)的反应,增大了ea-q的产额,从而有利于Cu的生成.另外,β-CD通过羟基在Cu纳米粒子表面的吸附可增强Cu纳米粒子在水溶液中的稳定性.用紫外-可见(UV-Vis)吸收光谱、粉末X射线衍射(XRD)和选区电子衍射(SAED)对Cu2+辐射还原产物进行了表征.  相似文献   

19.
用醇羰基化催化剂的合成,表征及溶解性研究   总被引:6,自引:2,他引:4  
用CuCl,甲醇和空气为原料,合成了甲醇氧化羰基化反应催化剂甲氧基氯化铜,最佳的合成条件是:55度,8h,CuCl与璃的比为1:40(重量比),甲氧基氯化铜的产率为94.5%,对甲氧基氧化铜的溶解进行了讨论;18度时,甲氧基氯化铜在5.3%的氯化氢甲醇溶液中的溶解度为12.3%,用IR,TGA和XRD对所合成的甲氧基氯化铜进行了表征,在IR图谱中发现了官能团-OCH3,CH3的特征吸收峰,证明所合成的产物为甲厮氯化铜,XRD谱显示三个强峰,分别 位于2θ=11.9度,28.6度,47.5度处,根据TGA知该化合物高于180度时会分解,其失重率为17.5%,与理论值17.7%相当。  相似文献   

20.
六氰合铁酸铜钴薄膜修饰铂电极的电化学、XRD及XPS研究   总被引:4,自引:0,他引:4  
采用循环伏安法在铂电极上电聚合了六氰合铁酸铜钴薄膜,并用电化学、XRD 和XPS对该薄膜进行了表征。研究表明此薄膜属于取代型的多核六氰合铁酸盐,由 Cu~(2+),Co~(2+)和Fe~(2+)共同占据晶格格点。通过改变Cu~(2+),Co~(2+)和 Fe~(3+)在沉积液中的比例可以改变聚合膜的性质。随沉积液中Cu~(2+)含量的增加 ,聚合膜中铜的含量相应增加而晶格常数则逐渐减小,但保持着面心立方的晶格对 称性。当沉积液中Cu~(2+):Co~(2+):Fe~(3+) = 1:1:2时,得到的聚合膜具有比较 典型的性质,该薄膜修饰的铂电极在pH 4~10之间均能保持着稳定的电化学响应。 其对一价阳离子的选择性顺序为K~+ > Li~+ > Na~+ > NH_4~+,与单组分的六氰铁 酸酮和六氰合铁酸钴都存在着较大的差别。XPS实验表明氧化态薄膜中铁元素以Fe (III)存在,并且在X射线的照射下很快转化为Fe(II)。  相似文献   

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