Ni2P/Cu(OH)2催化剂的制备及其全解水性能研究

通过化学处理法在泡沫铜基底表面生成Cu(OH)₂纳米线,大大增加了基底材料的表面积和导电性.采用水热法在Cu(OH)₂纳米线表面制备片状Ni-CH/Cu(OH)₂前驱体,对Ni-CH/Cu(OH)₂前驱体进行低温磷化得到多级结构Ni₂P/Cu(OH)₂催化剂.通过扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)和X射线衍射仪(XRD)对催化剂的物质结构和表面形貌进行了表征.采用线性伏安法、恒电位等技术对催化剂的电化学性能进行测试.在1.0 mol·L^-1 KOH碱性溶液中,当电流密度为10 mA·cm^-2时,Ni₂P/Cu(OH)₂的析氢反应(HER)和析氧反应(OER)过电位分别为133和333 mV,且均具有较好的稳定性.将这种多级结构Ni₂P/Cu(OH)₂催化剂分别用作阳极和阴极进行全解水电解,电流密度达到10 ...     

阻燃超疏水棉纤维的制备及性能

将氢氧化镁(Mg(OH)₂)凝胶沉积到棉纤维上,以提高棉纤维表面粗糙度和阻燃性能,随后将含有Mg(OH)₂的棉纤维浸渍到聚二甲基硅氧烷(PDMS)溶液,获得阻燃超疏水棉织物。 并对棉纤维进行了傅里叶变换红外光谱仪(FTIR)、扫描电子显微镜(SEM)、疏水性、热稳定性、阻燃性能和耐久性测试。 结果表明,Mg(OH)₂负载到织物上,使得织物表面具有一定的微/纳米结构,形成了粗糙涂层。 当Mg(OH)₂浓度为1.0 mol/L时,Mg(OH)₂/PDMS改性的织物接触角(CA)可达158°,极限氧指数(LOI)提升至24.5%,导热系数为0.0525 W/(m·K), 具有超疏水和阻燃性能。 整理后织物经过20次洗涤,100次磨擦,极端条件处理后,CA仍大于150°,LOI值高于23%,显示了较好的耐久性。     

分子自组装法制备具有可控浸润性的铜表面

通过简单浸泡的方法在铜基底上制备出了具有微纳米复合结构的氧化铜, 再利用混合硫醇溶液[含HS(CH₂)₉CH₃和 HS(CH₂)₁₁OH]对浸泡后的表面进行修饰, 通过控制溶液中HS(CH₂)₁₁OH的浓度, 制备出一系列具有不同浸润性的铜表面, 实现表面从超疏水到超亲水的有效调控. 研究发现, 表面浸润的可控性源于表面复合结构与不同化学组成的协同作用, 微纳米复合结构的存在为表面浸润性的调节提供了必要的条件.     

氧化锌有序结构在Au(111)和Cu(111)上的生长

利用NO₂或O₂作为氧化剂,研究了氧化锌在Au(111)和Cu(111)上的生长和结构。NO₂表现了更好的氧化性能,有利于有序氧化锌纳米结构或薄膜的生长。在Au(111)和Cu(111)这两个表面上,化学计量比氧化锌都形成非极性的平面化ZnO(0001)的表面结构。在Au(111)上,NO₂气氛下室温沉积锌倾向于形成双层氧化锌纳米结构;而在更高的沉积温度下,在NO₂气氛中沉积锌则可同时观测到单层和双层氧化锌纳米结构。O₂作为氧化剂时可导致形成亚化学计量比的ZnO_x结构。由于铜和锌之间的强相互作用会促进锌的体相扩散,并且铜表面可以被氧化形成表面氧化物,整层氧化锌在Cu(111)上的生长相当困难。我们通过使用NO₂作为氧化剂解决了这个问题,生长出了覆盖Cu(111)表面的满层有序氧化锌薄膜。这些有序氧化锌薄膜表面显示出莫尔条纹,表明存在一个ZnO和Cu(111)之间的莫尔超晶格。实验上观察到的超晶格结构与最近理论计算提出的Cu(111)上的氧化锌薄膜结构相符,具有最小应力。我们的研究表明,氧化锌薄膜的表界面结构可能会随氧化程度或氧化剂的不同而变化,而Cu(111)的表面氧化也可能影响氧化锌的生长。当Cu(111)表面被预氧化成铜表面氧化物时,ZnO_x的生长模式会发生变化,锌原子会受到铜氧化物晶格的限域形成单位点锌。我们的研究表明了氧化锌的生长需要抑制锌向金属基底的扩散,并阻止亚化学计量比ZnO_x的形成。因此,使用原子氧源有利于在Au(111)和Cu(111)表面上生长有序氧化锌薄膜。     

介孔TiO2担载Cu（OH）2及其催化炔烃氧化偶联反应

在有序介孔TiO₂中原位担载了高分散的Cu（OH）₂,并将其应用于炔烃的氧化偶联（Glaser）多相催化反应,该催化剂表现出很高的催化活性.Cu（OH）₂为催化剂的主要活性组分,TiO₂的有序介孔和较大的比表面积有利于Cu（OH）₂的分散以及反应物和产物的扩散,具有重要的应用前景.     

超薄Ni(OH)2纳米片修饰Zn0.5Cd0.5S纳米颗粒作为二维/零维异质结构光催化剂可见光下光催化制氢

设计与制备高效的光解水催化剂是解决能源问题和环境问题的策略之一.硫化镉因其可在可见光引发下分解水制氢而受到广泛关注,然而光腐蚀严重,过电势高,载流子复合快速以及表面反应动力学缓慢等缺点极大地限制了其在光解水反应中的实际应用.本文采用简单液相法将均匀的Zn_0.5Cd_0.5S纳米颗粒锚定在超薄Ni(OH)₂纳米薄片上,构建紧密的二维/零维异质结构.通过调控Ni(OH)₂纳米片的含量,制备出不同Ni(OH)₂质量比(3%,5%,7%,9%,11%)的二维/零维Ni(OH)₂/Zn_0.5Cd_0.5S复合材料,并考察其可见光激发的光催化分解水制氢性能.在可见光照射下,Ni(OH)₂/Zn_0.5Cd_0.5S复合材料的光催化性能要大幅度地优于未修饰的Zn_0.5Cd_0.5S纳米颗粒,甚至远高于贵金属Pt修饰的Zn_0.5Cd_0.5S.在不同Ni(OH)₂含量的纳米复合材料中,7%Ni(OH)₂/Zn_0.5Cd_0.5S具有最高效的产氢性能,产氢速率可达6.87 mmol·h^–1·g^–1,且在波长为420 nm的表观量子产率为16.8%.在同等条件下,二维/零维7%Ni(OH)₂/Zn_0.5Cd_0.5S复合光催化剂的光催化分解水产氢速率分别约为纯Zn_0.5Cd_0.5S纳米颗粒和Pt/Zn_0.5Cd_0.5S光催化剂的43倍和8倍,甚至要高于零维/零维7%Ni(OH)₂/Zn_0.5Cd_0.5S纳米复合材料.7%Ni(OH)₂/Zn_0.5Cd_0.5S复合光催化剂具有优异的光催化产氢循环性能,通过循环反应后样品的X射线衍射,X射线光电子能谱和透射电子显微镜等表征,结果表明Ni(OH)₂/Zn_0.5Cd_0.5S在经过20 h的使用后,其晶体结构、表面化学成分和形貌结构未发生明显改变.通过研究样品的时间分辨荧光光谱,线性扫描伏安响应,光电流性能及电化学交流阻抗等,发现二维Ni(OH)₂纳米片的修饰能一定程度降低Zn_0.5Cd_0.5S的过电势,还能有效促进Zn_0.5Cd_0.5S的光生电子-空穴的分离和光生电子的转移.本文认为二维/零维Ni(OH)₂/Zn_0.5Cd_0.5S光催化活性的大幅提升主要由于Zn_0.5Cd_0.5S与Ni(OH)₂之间独特且牢固的纳米结构,在该过程中超薄Ni(OH)₂纳米片不仅能为Zn_0.5Cd_0.5S纳米颗粒的负载提供平台,而且作为一种高效的助催化剂,促进光生电子的转移以及为制氢反应提供更多的活性位点.本文可为多功能,高效及低成本的二维-零维异质结构光催化剂的制备及在太阳能转化方面的应用提供一定借鉴.     

孔隙结构可调的Cu2O球状纳米结构及其NO2气体传感性质

报道在聚乙烯吡咯烷酮(PVP)的协助作用下,通过简单调节OH^-离子的浓度及Cu²⁺的释放速度,将Cu₂O调节为具有不同空腔特征(介孔、空心及实心)结构的纳米球.研究表明, OH^-根离子的扩散动力学是决定产物结构的关键因素.当[OH^-] > 0.05 mol·L^-1时,高的化学势使其迅速扩散到PVP胶团内部,与吸附在PVP链上的Cu²⁺反应形成Cu(OH)₂,在抗坏血酸(Vc)的还原作用下经过重结晶得到Cu₂O实心球纳米结构;当[OH^-] < 0.025 mol·L^-1时,其扩散速度下降,首先与吸附在PVP胶团外部的Cu²⁺反应形成Cu(OH)₂, Cu(OH)₂的形成阻碍了OH^-离子的向内扩散,形成具有较大空腔(~220 nm)的空心球;当0.025 mol·L^-1 < [OH^-] < 0.05 mol·L^-1时,形成较小空腔(30-60 nm)的空心球.以NH₃水为OH^-缓释源时,虽然OH^-浓度较低,但同时Cu²⁺的浓度也低,胶团外部形成的Cu(OH)₂不足以阻碍OH^-离子的向内扩散,反应过程中NH₃的释放及较低的OH^-浓度阻碍了重结晶的发生,从而形成Cu₂O介孔纳米球.对三种典型结构特征的产物进行了NO₂气体传感性质研究,结果表明, Cu₂O介孔纳米球相比空心结构和实心结构具有更为优异的响应性.结合比表面积数据,我们认为介孔纳米球疏散的结构有利于NO₂气体的扩散和O₂的吸附,从而表现出了更灵敏的气体传感性.     

铜在碱性溶液中阳极过程的研究

用慢电势扫描和恒电流法研究铜在浓碱中的阳极过程,并用角分辨X射线光电子能谱测试了铜表面二次钝化膜。结果表明,该膜由内层Cu₂O和外层CuO-Cu(OH)₂组成,越靠近膜的表面,CuO/Cu(OH)₂含量比越小,吸附水越多。据此提出成膜的电化学氧化-表面转化历程。     

固体催化剂用于二元醇分子内环化制内酯的研究

将钌改性的固体催化剂Ru-Co(OH)₂-CeO₂用于以分子氧作为氧化剂的二元醇的催化氧化内酯化反应中, 发现该催化剂具有很好的催化反应性能. 该催化剂可优先氧化伯碳上的羟基. 对反应机理的研究表明, 活性中心钌首先与反应物形成醇化物, 经β-氧化消除反应使得其中一羟基氧化, 经异构环化、氧化进一步脱氢形成内酯.     

前驱体物相转变对浆态床合成甲醇催化剂活性的影响

采用并流共沉淀法, 通过考察老化温度, 研究CuO/ZnO/Al₂O₃催化剂前驱体晶相及组成的变化对浆态床催化合成甲醇的反应活性的影响. 结果表明, 前驱体的物相转变对浆态床合成甲醇活性影响显著, 单斜晶系锌孔雀石(Cu,Zn)₂CO₃(OH)2和斜方晶系绿铜锌矿(Cu,Zn)₅(CO₃)₂(OH)₆晶体是产生高活性催化剂的主要物相. 随着Cu²⁺/Zn²⁺进入Zn₅(CO₃)₂(OH)₆/Cu₂CO₃(OH)₂晶格, 离子同晶取代量增加, 催化剂前驱体中形成了固定铜锌比的锌孔雀石和绿铜锌矿物相. 焙烧后催化剂比表面积增大, CuO-ZnO固溶体协同作用加强, 浆态床催化合成甲醇的活性提高.     

Factors affecting the spontaneous motion of condensate drops on superhydrophobic copper surfaces

The coalescence-induced condensate drop motion on some superhydrophobic surfaces (SHSs) has attracted increasing attention because of its potential applications in sustained dropwise condensation, water collection, anti-icing, and anticorrosion. However, an investigation of the mechanism of such self-propelled motion including the factors for designing such SHSs is still limited. In this article, we fabricated a series of superhydrophobic copper surfaces with nanoribbon structures using wet chemical oxidation followed by fluorization treatment. We then systematically studied the influence of surface roughness and the chemical properties of as-prepared surfaces on the spontaneous motion of condensate drops. We quantified the "frequency" of the condensate drop motion based on microscopic sequential images and showed that the trend of this frequency varied with the nanoribbon structure and extent of fluorination. More obvious spontaneous condensate drop motion was observed on surfaces with a higher extent of fluorization and nanostructures possessing sufficiently narrow spacing and higher perpendicularity. We attribute this enhanced drop mobility to the stable Cassie state of condensate drops in the dynamic dropwise condensation process that is determined by the nanoscale morphology and local surface energy.     

Bulk Nanostructuring of Janus-Type Metal Electrodes

The stable deposition of reactive nanostructures on metal electrodes is a key process for modern technologies including energy conversion/ storage, electrocatalysis or sensing. Here a facile, scalable route is reported, which allows the bulk nanostructuring of copper foam electrodes with metal, metal oxide or metal hydroxide nanostructures. A concentration-gradient driven synthetic approach enables the fabrication of Janus-type electrodes where one face features Cu(OH)₂ nanowires, while the other face features CuO nanoflowers. Thermal or chemical conversion of the nanostructured surfaces into copper oxide or copper metal is possible whilst retaining the respective nanostructure morphologies. As proof of concept, the functionalized electrodes are promising in electrocatalytic water oxidation and water reduction reactions.     

超疏水低粘着铜表面制备及其防覆冰性能

用喷砂处理在铜片表面形成微米级丘陵状凹坑,再用表面氧化处理在铜片表面制备菊花花瓣状CuO纳米片.通过喷砂-表面氧化处理在铜片表面成功构建了微米-纳米复合结构,这种表面氟化后与水滴的接触角高达161°,滚动角低至1°,显示出优异的超疏水性和很低的粘着性.低温下,这种表面与水滴间的热量交换较小,水滴不易凝结,有效地提高了抗结霜性.抗结霜性良好的超疏水铜有望在热交换器或低温运行设备等领域获得应用,这种简便的超疏水铜表面的制备方法也给其它工程材料超疏水表面的工业化制备提供了一个思路.     

Copper hydroxide nanoneedle and nanotube arrays fabricated by anodization of copper

Cu(OH)2 nanoneedle and nanotube arrays were electrochemically synthesized by anodization of a copper foil in an aqueous solution of KOH. The nanoneedles and nanotubes were constructed from nanosheets of Cu(OH)2. Controlling the electrochemical conditions can qualitatively modulate the lengths, amounts, and shapes of Cu(OH)2 nanostructures. The composition of as-prepared Cu(OH)2 nanostructures has been confirmed by X-ray diffraction and select-area electron diffraction. The influences of the KOH concentration of the aqueous electrolyte, the reaction temperature, and current density on the morphology of Cu(OH)2 nanostructures were investigated, and the formation mechanism of the nanostructures is discussed. Furthermore, Cu(OH)2 nanoneedles can be successfully transformed to CuO nanoneedles with little morphology change by heating. This work developed a simple, clean, and effective route for fabrication of large area Cu(OH)2 or CuO nanostructured films.     

Controlled reactions on a copper surface: synthesis and characterization of nanostructured copper compound films

We report the synthesis of nanostructured copper compound films on a copper surface under mild conditions. A series of low-dimensional structures including Cu(OH)(2) fibers and scrolls, CuO sheets and whiskers, and Cu(2)(OH)(2)CO(3) rods have been successfully grown on the copper surfaces at ambient temperature and pressure. Most of the structures are phase-pure single crystallites. The films were formed by the direct oxidation of copper in aqueous solutions of NaOH with an oxidant (NH(4))(2)S(2)O(8). The evolution of the ultrafine structures as a function of the reaction conditions has been revealed, from fibers of Cu(OH)(2) to scrolls of Cu(OH)(2) to sheets or whiskers of CuO. By replacing NaOH with NaHCO(3) in the synthesis, square/rectangular rod arrays of Cu(2)(OH)(2)CO(3) were obtained. The controlled reactions allow the large-scale, template-free, cost-effective synthesis of copper compound films with ordered, uniform, stable, ultrafine structures.     

Superhydrophobic silicon surfaces with micro-nano hierarchical structures via deep reactive ion etching and galvanic etching

An effective fabrication method combining deep reactive ion etching and galvanic etching for silicon micro-nano hierarchical structures is presented in this paper. The method can partially control the morphology of the nanostructures and enables us to investigate the effects of geometry changes on the properties of the surfaces. The forming mechanism of silicon nanostructures based on silver nanoparticle galvanic etching was illustrated and the effects of process parameters on the surface morphology were thoroughly discussed. It is found that process parameters have more impact on the height of silicon nanostructure than its diameter. Contact angle measurement and tilting/dropping test results show that as-prepared silicon surfaces with hierarchical structures were superhydrophobic. What's more, two-scale model composed of micropillar arrays and nanopillar arrays was proposed to study the wettability of the surface with hierarchical structures. Wettability analysis results indicate that the superhydrophobic surface may demonstrate a hybrid state at which water sits on nanoscale pillars and immerses into microscale grooves partially.     

仿生超疏水表面的抗冷凝失效研究进展

在存在一定过冷度或蒸汽过饱和度的条件下,水蒸汽可在固体表面凝结成核.随着过冷度增大,液滴成核半径将随之减小,冷凝液滴的生长融合将无法避免地发生在超疏水表面不可或缺的微/纳米结构内.若液滴不能及时排出,则会滞留在表面结构内并挤出空气,形成局部浸润,导致材料表面的超疏水性能下降或失效,甚至引起泛洪.本文首先总结了表面因冷凝...     

微波热解法制备Cu/Cu2O纳米材料

在二乙二醇溶剂体系中利用微波介电加热分解醋酸铜前体,进一步还原得到Cu2O和Cu纳米粒子以及Cu/Cu2O核壳结构。 采用X射线衍射、透射电子显微镜、扫描电子显微镜和紫外吸收光谱测试技术对产物的形貌、结构和组成进行了研究,结果表明,得到的Cu/Cu2O核壳结构直径为500 nm左右。 对比实验研究了不同聚合度乙二醇系列溶剂、反应时间以及表面活性剂或配位剂对产物形貌、组成的影响,表明低聚合度乙二醇和长的反应时间有利于醋酸铜还原形成铜。     

Production and characterization of stable superhydrophobic surfaces based on copper hydroxide nanoneedles mimicking the legs of water striders

The present work reports a simple and economic route for production and characterization of stable superhydrophobic surfaces from thin copper layers coated on arbitrary solid substrates. The thin copper layer was anodized in a 2 M aqueous solution of potassium hydroxide to form a thin film of copper hydroxide nanoneedles; then the film was reacted with n-dodecanethiol to form a thermally stable Cu(SC12H25)2 superhydrophobic coating. The contact angle of the modified nanoneedle surface was higher than 150 degrees , and its tilt angle was smaller than 2 degrees . Furthermore, the surface fabricated on copper foil kept its superhydrophobic property after heating at 160 degrees C in air for over 42 h. This technique has also been applied for fabrication of copper wire with superhydrophobic submicrofiber coating to mimic water strider legs. The maximal supporting force of the superhydrophobic copper column has also been investigated in comparison to real water striders.     

特殊浸润性表面的液滴凝结

以铝片为基底, 经电化学腐蚀和沸水处理制备了多级微纳米结构; 通过气相沉积和涂油分别制备了超疏水表面、 疏水超润滑(slippery)表面和亲水slippery表面; 探究了表面不同的特殊浸润性(超亲水、 超疏水、 疏水slippery和亲水slippery)对液滴凝结的影响. 结果表明, 超亲水表面的液滴凝结属于膜状冷凝, 超疏水表面和slippery表面的液滴凝结均属于滴状冷凝. 超疏水表面液滴合并时, 合并的液滴会不定向弹离表面. 疏水slippery表面和亲水slippery表面由于表面浸润性的不同导致液滴成核密度和液滴合并的差异, 亲水slippery表面凝结液滴的最大体积远大于疏水slippery表面凝结液滴的最大体积. 4种表面的雾气收集效率由大到小依次为亲水slippery表面>疏水slippery表面>超亲水表面>超疏水表面.