Retention of the high optical absorptance in thermally aged black chrome on variably sensitized Cu

The chemical composition, morphology, selective absorber characteristics, and degradation of selective absorber characteristics at high temperatures of black chrome solar selective coating are influenced by various substrate pre-treatments like mechanical polishing, chemical etching, and electropolishing prior to film deposition. The major oxide content in the deposit is formed as Cu₂(OH)₂CrO₄ (JCPDS 38-0230), which on high temperature annealing decomposes to CuCrO₄ (JCPDS 34-0507), CuO (JCPDS 41-0254), and Cu₂O (JCPDS 5-0667). Formation of the oxides of Cu at high temperatures retains the high optical absorption characteristics of the coating even after high temperature degradation.     

纳米CuO的制备及其在微孔装药中的应用

采用常温固相反应法在聚乙二醇2000作为分散剂条件下制备了纳米Cu O,用超声共混法制备了纳米Al/Cu O。借助X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等方法对所制备样品的性能进行表征和分析。结果表明:制备的纳米Cu O结构形貌统一,类似八面体结构,一次粒径在30nm左右,和球形的纳米Al粉混合均匀,形成纳米Al/Cu O,团聚后在100~200nm之间,差热分析(DTA)其放热量为2 798J·g-1。将纳米Al/Cu O配制成含能油墨,用喷墨打印装置实现了药室直径为0.7mm、厚度为1mm的10×10阵列装药,并研究了纳米Al/Cu O在微孔装药中的应用。结果表明,纳米Al/Cu O在微孔中能稳定燃烧,燃烧时间在微秒级,火焰长度约为2~4cm,燃速约为0.142 9m/s。     

系列催化剂同时脱硫脱硝性能

FCC烟气中的SO₂和NO是主要的大气污染物,选择性催化还原是一种很好的脱除方法。采用浸渍法制备了CuO不同负载量的CuO/γ-Al₂O₃系列催化剂,通过XRD和H₂-TPR对催化剂进行表征,使用常压固定床流动法微型催化反应装置考察催化剂在以CO为还原气时,同时脱硫脱硝的催化活性。结果表明,CuO作为活性组分很好地分散在γ-Al₂O₃载体上,不破坏其结构;不同CuO负载量的CuO/γ-Al₂O₃催化剂具有良好的脱硫脱硝活性,脱硝率超过95.00%,脱硫率最低也能达到80.00%,CuO负载质量分数为10%的CuO/γ-Al₂O₃催化剂有最佳的脱硫脱硝活性;以CO作还原剂,CuO/γ-Al₂O₃系列催化剂的活性温度较高,脱硝率在700 ℃达到最大,为97.90%,脱硫率在760 ℃达到最大,为93.34%。CuO负载质量分数为10%的CuO/γ-Al₂O₃催化剂可作为一种较好的高温脱硫脱硝催化剂。     

Fabrication and NO2 gas sensing performance of TeO2-core/CuO-shell heterostructure nanorod sensors

TeO₂-nanostructured sensors are seldom reported compared to other metal oxide semiconductor materials such as ZnO, In₂O₃, TiO₂, Ga₂O₃, etc. TeO₂/CuO core-shell nanorods were fabricated by thermal evaporation of Te powder followed by sputter deposition of CuO. Scanning electron microscopy and X-ray diffraction showed that each nanorod consisted of a single crystal TeO₂ core and a polycrystalline CuO shell with a thickness of approximately 7 nm. The TeO₂/CuO core-shell one-dimensional (1D) nanostructures exhibited a bamboo leaf-like morphology. The core-shell nanorods were 100 to 300 nm in diameter and up to 30 μm in length. The multiple networked TeO₂/CuO core-shell nanorod sensor showed responses of 142% to 425% to 0.5- to 10-ppm NO₂ at 150°C. These responses were stronger than or comparable to those of many other metal oxide nanostructures, suggesting that TeO₂ is also a promising sensor material. The responses of the core-shell nanorods were 1.2 to 2.1 times higher than those of pristine TeO₂ nanorods over the same NO₂ concentration range. The underlying mechanism for the enhanced NO₂ sensing properties of the core-shell nanorod sensor can be explained by the potential barrier-controlled carrier transport mechanism.

PACS

61.46. + w; 07.07.Df; 73.22.-f     

易于微孔道填充的纳米CuO的制备

分别采用直接沉淀法和快速沉淀法成功地制备了易于微孔道填充的纳米Cu O粉末。直接沉淀法的铜源是无水Cu SO4,沉淀剂是Na2CO3;快速沉淀法的铜源是Cu(CH3COO)2·H2O,沉淀剂是Na OH。通过XRD、SEM、TEM和SAED等分析手段表征产物的晶体结构、微观形貌及晶粒尺寸。结果表明,直接沉淀法的陈化时间对制备样品形貌和结构有影响。当前躯体陈化时间为3 h时,直接沉淀法制备的Cu O纳米颗粒平均粒径约为25 nm;快速沉淀法制备的Cu O纳米颗粒平均粒径约为6 nm。与直接沉淀法相比,快速沉淀法制备的纳米Cu O粒径更小、颗粒分散更均匀。     

含能油墨配方设计及其在微孔装药中的应用

为优化微装药方法及设计合适的含能油墨配方,将喷墨打印装药和湿法压装两种装药方法结合起来,发现装药密度得到明显提高,装药均一性较好。采用激光点火方式,结合高速摄影和X射线衍射(XRD)等对微孔燃烧过程及其燃烧产物进行分析,获得了含能油墨中载体种类、纳米Al/Cu O含量和Φ值对微孔燃烧的影响规律。发现硝化棉(NC)不但有很好的油墨性能、装药性能,而且点火燃烧性能良好。得到以下结论:载体为NC且质量分数为7.5%,Al/Cu O的Φ值为1.6,初步测得最优配方下平均冲量约为145μN·s。     

Direct synthesis and characterization of spongy CuO with nanosheets from Cu3(btc)2 microporous metal-organic framework

Spongy CuO was successfully synthesized via direct pyrolysis of Cu₃(btc)₂ (btc = benzene-1,3,5-tricarboxylate) microporous metal-organic framework (MOF) in a horizontal tube furnace in the air, in which the Cu₃(btc)₂ was used as the Cu source and complexing molecule precursor. The as-prepared products were characterized by a series of techniques including XRD, SEM, EDX, TEM, and SAED. Results from SEM showed that the as-prepared spongy CuO with average diameter altering from 10 to 20 μm consists of nanosheets with average edge length in the range of 80-200 nm and thickness of about 30 nm, which was also confirmed by TEM analysis. The XRD and SAED results showed that a purity phase of CuO was obtained after pyrolysis. It was also found that the reaction temperature played a key role in the formation of spongy CuO microstructures. The spongy material could be found potential application in various fields such as catalysis, absorption, and gas sensing.