Enhanced thermoelectric efficiency of Cu2−xSe–Cu2S composite by incorporating Cu2S nanoparticles

The study of thermoelectric transport properties in Cu_2−xSe and Cu₂S has gained an importance in the thermoelectric research during last few years due to their superionic behavior and low cost. Here, we reported a facile method to enhance the thermoelectric efficiency of Cu_2−xSe by introducing Cu₂S nanoparticles (NPs) in the matrix of Cu_2−xSe. The observed efficiency is a direct result of simultaneous improvement of Seebeck coefficient (S) because of the external strain induced by Cu₂S nanoinclusions in Cu_2−xSe and decline in the total thermal conductivity by suppressing both electronic and lattice thermal contributions. Such higher S and lower thermal conductivity is realized for a composite structure with 10 wt% nanoinclusions of Cu₂S which effectively contributed to higher ZT value of 0.90 at moderate temperature of 773 K. Thus, it is believed that the proposed hybrid structure is a promising p-type thermoelectric material for mid-temperature range energy harvesting applications.     

Cu粉粒径对PEEK/Cu导热复合材料性能的影响

以铜(Cu)粉为导热填料,采用模压法制备了聚醚醚酮(PEEK)/Cu导热复合材料,并研究了铜粉粒径对PEEK/Cu导热复合材料导热性能、力学性能及结晶性能的影响。结果表明:随着Cu粉粒径的增大,PEEK/Cu导热复合材料的力学性能逐渐下降;当Cu粉粒用量为30%、粒径为10μm时导热复合材料的导热系数达到最佳值0.396 W/(m·K),相比于纯PEEK提高了67.80%;熔融焓与结晶度随着Cu粉粒径的增大而逐渐减小,因而PEEK/Cu导热复合材料的结晶性能降低。     

Ag/Cu耦合催化剂的Cu晶面调控用于电催化二氧化碳还原

电催化二氧化碳还原是降低大气中二氧化碳浓度和缓解温室效应的有效方法。然而，将CO₂电还原为具有高附加值和高能量密度的碳氢化合物或燃料(C₂₊产物)仍然具有十足的挑战性。为了降低大气中二氧化碳浓度和将其转换为有价值的工业品，本文通过优化Ag/Cu耦合催化剂中Cu的晶面，有效地促进了其还原CO₂至C₂H₄和C₂H₅OH等C₂₊产物。利用暴露Cu₂O(100)晶面的Ag/Cu₂O-(100)，暴露Cu₂O(111)晶面的Ag/Cu₂O-(111)以及具有Cu₂O(100)和(111)晶面的Ag/Cu₂O-(100/111)还原制备得到了三种具有不同Cu晶面的Ag/Cu耦合催化剂。控制Cu/Ag比均为30∶1，采用H型电解槽，在CO₂饱和的0.1mol/L KHCO     

Cu/金刚石复合材料研究进展

近年来,随着5G通信的发展,其核心器件的导热散热问题受到重视。在5G条件下,频率显著提高,从而导致产生的热量显著提高,影响核心器件的稳定,传统的导热散热材料无法满足需求,因此开发具有更高导热性能的材料成为当前研究热点。金刚石的导热系数是铜的5倍,而密度则为铜的近三分之一,且膨胀系数更小。将金刚石和铜进行复合,可以发挥各自优势,有效提升热导率,从而成为最有前途的新型散热材料之一。文章介绍了Cu/金刚石复合材料的研究状况,对制备方法、性能指标、影响因素等方面进行了分析,并对未来需要解决的问题进行了梳理。     

Cu2O/CuO/Cu电极光电催化还原CO2

利用表面氧化法在铜基底上制备CuO纳米带(CuO NRs),通过电化学法将Cu_2O沉积到CuO NRs上,得到复合电极Cu_2O/CuO/Cu。借助X射线衍射(XRD)、透射电子显微镜(TEM)对Cu_2O/CuO/Cu复合电极的结构进行了表征。通过线性扫描伏安法(LSV)、光电流-时间测试、电化学阻抗测试对Cu_2O/CuO/Cu复合电极光电催化CO_2性能进行了考察。借助变色酸分光光度法来测定CO_2光电还原产物。结果表明:氧化铜在铜基底上呈纳米带生长;复合电极Cu_2O/CuO/Cu对CO_2有较强的光响应性,表现出优异的光电催化性能;Cu_2O/CuO/Cu复合电极光电催化还原CO_2的主要产物是甲醇,在0.1 mol/L NaHCO_3溶液中光电催化6 h后,甲醇质量浓度为32.2mg/L。     

Cu2O光催化剂综述

介绍Cu_2O光催化降解机理,禁带宽度,光生载流子利用率和溶液pH影响Cu_2O光催化降解活性,通过掺杂,负载贵金属,碳材料修饰和半导体复合可提高Cu_2O光催化性能。     

乙腈溶液中 Cu(Ⅱ)、Cu(Ⅰ)的测定

铈量法间接测定溶液中铜(Ⅰ):在酸性溶液中,铁(Ⅲ)氧化铜(Ⅰ),产生等当量的铁(Ⅱ)、用铈(Ⅳ)滴定铁(Ⅱ),间接测定铜(Ⅰ)。铜(Ⅱ)80毫克不干扰测定,方法重现性和准确性均好。     

Effects of Cu–Zn phases on electronic properties in ZnO:Cu films

Theory predicts Cu-doped ZnO (ZnO:Cu) has p-conductivity; however, this has only been demonstrated in a small number of experimental and mechanistic studies. In this paper, ZnO:Cu films were grown in situ with varying Cu content, prepared using radiofrequency atomic source–assisted molecular-beam vapor deposition. The results indicate that ZnO:Cu films with dopant of Cu²⁺ only had n-type behavior. As the Cu content increased, Cu⁺ was the major dopant and the ZnO:Cu films had p-type behavior. However, excess Cu dopant resulted in the formation of second phases of Cu₂O and Cu–Zn. The formation of a Cu–Zn phase increased the content of Zn vacancy, thus increasing hole concentration. Stronger alloy scattering decreased carrier mobility. Therefore, Cu⁺ dopant and Zn vacancy give ZnO:Cu films p-conductivity properties.     

Cu/Ti-MCM-41,Cu/Ti-HMS的制备表征与脱硫性能

以水热合成法成功合成了Cu/Ti-MCM-41、Cu/Ti-HMS介孔分子筛,采用XRD、SEM、TEM、FT-IR、BET等手段对分子筛进行了表征。结果表明,合成的分子筛具有良好的晶体结构,Ti已进入分子筛骨架,Cu元素以氧化物Cu O形式存在于分子筛表面并使得分子筛孔道直径分布更集中。用H2O2为氧化剂,合成的Cu/Ti-MCM-41、Cu/Ti-HMS分子筛为催化剂,用于氧化脱硫反应,实验结果表明,Cu O的π键复合配位吸附作用可有效提高Cu/Ti-MCM-41、Cu/Ti-HMS的脱硫性能,脱硫率达到92.8%、88.5%;再生后,分子筛的脱硫率有所下降,表面Cu O的流失和分子筛结构的坍塌是导致Cu/Ti-MCM-41、Cu/Ti-HMS脱硫性能下降的原因。     

Interaction of carbon monoxide with Cu–Pd and Cu–Ni bimetallic clusters

Interaction of CO with Cu–Pd and Cu–Ni bimetallic clusters deposited on a ZnO substrate has been investigated by core-level spectroscopy. The surface reactivity of both these alloy clusters increases with the decrease in cluster size, giving rise to dissociative adsorption at small cluster size. The surface reactivity also increases with the increase in Pd or Ni content and the reactivity of the alloy clusters is unlike that of either component metal. Thus, dissociative adsorption occurs on small Cu–Pd clusters unlike on either Cu or Pd clusters of comparable size. The reactivity of the Cu–Ni clusters, on the other hand, falls somewhere between those of Cu and Ni clusters. This revised version was published online in August 2006 with corrections to the Cover Date.     

Oxygen-enhanced water gas shift on ceria-supported Pd–Cu and Pt–Cu bimetallic catalysts

Aiming at enhancing H₂ production in water gas shift (WGS) for fuel cell application, a small amount of oxygen was added to WGS reaction toward oxygen-enhanced water gas shift (OWGS) on ceria-supported bimetallic Pd–Cu and Pt–Cu catalysts. Both CO conversion and H₂ yield were found to increase by the oxygen addition. The remarkable enhancement of H₂ production by O₂ addition in short contact time was attributed to the enhanced shift reaction, rather than the oxidation of CO on catalyst surface. The strong dependence of H₂ production rate on CO concentration in OWGS kinetic study suggested O₂ lowers the CO surface coverage. It was proposed that O₂ breaks down the domain structure of chemisorbed CO into smaller domains to increase the chance for coreactant (H₂O) to participate in the reaction and the heat of exothermic surface reaction helping to enhance WGS kinetics. Pt–Cu and Pd–Cu bimetallic catalysts were found to be superior to monometallic catalysts for both CO conversion and H₂ production for OWGS at 300 °C or lower, while the superiority of bimetallic catalysts was not as pronounced in WGS. These catalytic properties were correlated with the structure of the bimetallic catalysts. EXAFS spectra indicated that Cu forms alloys with Pt and with Pd. TPR demonstrated the strong interaction between the two metals causing the reduction temperature of Cu to decrease upon Pd or Pt addition. The transient pulse desorption rate of CO₂ from Pd–Cu supported on CeO₂ is faster than that of Pd, suggesting the presence of Cu in Pd–Cu facilitate CO₂ desorption from Pd catalyst. The oxygen storage capacity (OSC) of CeO₂ in the bimetallic catalysts indicates that Cu is much less pyrophoric in the bimetallic catalysts due to lower O₂ uptake compared to monometallic Cu. These significant changes in structure and electronic properties of the bimetallic catalysts are the result of highly dispersed Pt or Pd in the Cu nanoparticles.     

Water-gas shift reaction over Cu–Zn,Cu–Fe,and Cu–Zn–Fe composite-oxide catalysts prepared by urea-nitrate combustion

Water-gas shift reaction was investigated over Cu–Zn, Cu–Fe and Cu–Zn–Fe composite-oxide catalysts at atmospheric pressure from 200 to 375 °C in terms of reducing the CO content with maximal H₂ yield. The Cu_0.15ZnFe₂ spinel catalyst expressed a higher CO conversion level and H₂ yield at a lower temperature compared to the Cu_0.15Zn and Cu_0.15Fe catalysts. Adding H₂O to the feed up to 30% (v/v), but not above, increased the CO reduction level, presumably by increasing the hydroxyl species to react with the adsorbed CO. Increasing the W/F ratio to 0.24 g s cm^?3 increased the CO conversion level to 0.76 at 275 °C with the Cu_0.15ZnFe₂ catalyst, and could be further increased to 0.86 at 350 °C by increasing the Cu molar ratio to 0.30 (Cu_0.30ZnFe₂). Nevertheless, increasing the Cu molar content to 0.50 reduced the CO conversion level. No requirement for adding O₂ when using the Cu_0.30ZnFe₂ catalyst at >260 °C was observed. Increasing the CO content in the reactant decreased its conversion level. The performance of the Cu_0.30ZnFe₂ catalyst was stable over a test period in a CO-rich condition. No undesired product was detected, suggesting a higher selectivity for hydrogen production with a low CO content.     

Cu(Ⅱ)-固绿FCF-CPB体系瑞利光散射测定饮料中的Cu

在p H为3.87的Tris-盐酸介质中,Cu(Ⅱ)与固绿FCF在溴代十六烷基吡啶(TPB)存在下结合生成离子缔合物,使体系的瑞利光散射(RLS)信号显著增强并产生新的瑞利散射光谱,最大瑞利散射峰位于366 nm波长处,Cu(Ⅱ)的质量浓度在0.01~0.22 mg/L范围内与体系的瑞利散射增强程度(ΔIRLS)呈线性关系,检出限为0.009 5 mg/L,定量限为0.013 mg/L。由此建立了高灵敏、快速准确测定Cu(Ⅱ)的瑞利散射新方法,还研究了体系的瑞利散射光谱特征及适宜反应条件。该方法的加标回收率为98.0%~101%,相对标准偏差RSD(n=5)为1.8%~2.4%,适于市售饮料中Cu的测定。     

13X—Cu分子筛投产

13X—Cu分子筛,成品为球状(φ4～6mm)或条状,溶于强酸或强碱,不溶于水,系轻质油品用脱硫醇催化剂。该产品已由湘潭市第二化工厂试验成功并投产。经茂名石油公司、石油七厂考察评定,脱硫醇效果好,催化剂强度     

焦磷酸盐电镀Cu—Sn合金

焦磷酸盐电镀Cu-Sn合金镀液组成如下:1)铜离子源:最好是焦磷酸铜,也可以选用硫酸铜、硝酸铜、磷酸铜、甲烷磺酸铜、氨基磺酸铜及氯化铜等。镀液中铜离子的最佳质量浓度为0.1~5 g/L。2)锡离子源:最好是焦磷酸亚锡,也可以用氯化亚锡、硫酸亚锡、醋酸亚锡、氨基磺酸亚锡、葡萄糖酸     

Pd—Cu系合金电镀

概述了Ｐｄ－Ｃｕ系合金等电镀工艺，可以获得不含Ｎｉ，Ｃｏ等引起皮肤过敏的金属的镀层，适用于接触皮肤的装饰品电镀。     

脉冲电镀Cu—Sn合金

一引言“脉冲电镀”是一般术语,指用一个脉冲电源与一个电镀槽相连接而构成一个电镀体系。它与普通电镀的区别在于使用脉冲电源。故采用方波、锯齿波以及交直流选加等均可进行脉冲电镀。脉冲电镀的特点是:峰值电流密度高,能增大阴极极化,得到纯净致密的镀层;特别是带有负向脉冲电流的脉冲电镀,它能除去毛刺,增加整平性,消除氢脆等;脉冲电镀还能降低浓差极化,提高电流密度。总之,脉冲电镀与直流电镀比较,在减少镀层的孔隙率,增加结合力,节省原材料以及对镀层的物理化学性能……等方面都有明显的影响。     

Cu2O光催化降解苯酚

以Cu2 O粒子为光催化剂 ,钨丝灯为光源 ,研究了Cu2 O粒子对苯酚有机污染物的光催化降解过程。并考察了光照时间 ,催化剂用量 ,催化剂种类 ,不同光源 ,苯酚的初始浓度和溶液的酸度对苯酚光催化降解过程的影响。结果表明 ,Cu2 O粒子在钨丝灯光照射下 ,能较好地降解苯酚。