基于泡沫铜的多孔碳均匀负载Cu3P纳米颗粒的制备及其光催化降解染料性能北大核心CSCD

为了开发活性高、易回收的光催化剂,采用多步热解法制备了基于泡沫铜的多孔碳均匀负载Cu_(3)P纳米颗粒。在泡沫铜(FC)基底原位生长铜基金属-有机框架晶态材料(Cu-MOF),通过热解处理使得泡沫铜表面覆盖了均匀负载于碳材料的Cu_(2)O/Cu纳米颗粒(Cu_(2)O/Cu@NPC@FC-400)。对该材料进行磷化处理得到目标光催化剂Cu_(3)P@NPC@FC-400。利用X射线粉末衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫散射光谱(UV-Vis DRS)、X射线光电子能谱(XPS)和扫描电子显微镜(SEM)等表征材料的组成和形貌。以罗丹明B(Rh B)溶液作为模拟废水,探究其光催化性能及机理。结果发现,Cu_(3)P@NPC@FC-400材料对罗丹明B染料具有良好的光催化性能,在3 h内染料去除率可达94%。该材料便于回收,循环利用10次后,光催化活性保持不变。此外,该材料对于含有7种染料的复杂体系也具有优异的光降解性能。该催化剂具有稳定性高、回收简便的优势,可用于处理含有多种染料的废水。     

基于Keggin型杂多酸的无机-有机杂化物的合成和光催化活性

采用水热合成方法制备了2个基于Keggin型杂多酸的无机-有机杂化物, 化学式分别为{[Cu₂(4,4′- bipy)₄(H₂O)₄](SiMo₁₂O₄₀)·18H₂O}_n(1)和{[Cu₂(4,4′-bipy)₄(H₂O)₄](PMo₆W₆O₄₀)·18H₂O}_n(2)(bipy=bipyridine). 结构分析 表明2个化合物同构, Cu²⁺是六配位, 分别与4个4,4′-bipy上的N原子和2个水分子上的O原子结合, 形成 [Cu(4,4′-bipy)₂(H₂O)₂]_n²ⁿ⁺二维层状结构. 杂多阴离子通过静电与配位阳离子[Cu(4,4′-bipy)₂(H₂O)₂]_n²ⁿ⁺作用交叉排列在层间. 通过红外光谱、 粉末X射线衍射和固体紫外-可见漫反射光谱等对化合物的性质进行了表征. 研究了所合成化合物对水溶性染料亚甲基蓝的降解活性, 发现2种化合物对于亚甲基蓝均表现出显著的光降解活性, 并对它们的催化机理进行了讨论.     

Ag,Zn,Pd掺杂对铜基催化剂草酸二甲酯选择性加氢反应的影响

采用密度泛函理论方法, 构建了Ag, Zn, Pd原子掺杂的Cu(111)和Cu₂O(111)活性晶面, 探讨了不同金属掺杂对Cu(111)和Cu₂O(111)催化剂的草酸二甲酯(DMO)加氢反应活性和选择性的影响. 研究结果显示, 掺杂Zn可有效阻止乙醇酸甲酯(MG)进一步加氢, 提高MG的选择性, Ag助剂可以有效提高加氢活性; 而Pd助剂的添加使MG的生成能垒增高, 降低了MG的选择性. Ag-Cu(111)表面具有适宜的d带中心, 生成CH₃OOCCH₂OH的活性最高. 在Ag, Zn, Pd原子掺杂的Cu₂O(111)表面, Ag-Cu₂O(111)能带带隙小、 价带强度高, 在DMO加氢反应中具有最佳的催化活性. 基于上述结果, 提出铜基催化剂结构调变和性能调控的理论方法, 为高效催化剂的设计提供可靠的理论指导.     

Hydrothermal Syntheses of CuO,CuO/Cu2O,Cu2O,Cu2O/Cu and Cu Microcrystals Using Ionic Liquids

In this paper, CuO, CuO/Cu₂O, Cu₂O, Cu₂O/Cu and Cu microcrystals were synthesized via a hydrothermal method by mixing Cu(NO₃)₂·3H₂O and NaOH together in the presence of an ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate([BMIM]BF₄) or 1-butyl-3-methylimidazolium chloride([BMIM]Cl). The structures and the morphologies of the obtained products were characterized by means of X-ray diffractometer(XRD), field-emission scanning electron microscopy/energy-dispersive spectroscopy(FESEM/EDS), transmission electron microscopy/selected area electron diffraction(TEM/SAED) and Raman spectroscopy. The result of XRD indicates that Cu₂O and Cu microcrystals are cubic phase and the Raman spectra confirm the presence of carbon. The results of FESEM and TEM images show Cu₂O microcrystals as rule cubes of 2 μm in length and Cu particles of 5 μm in diameter. According to the difference between crystal structures, bi-component and single component products were synthesized by adjusting the reaction conditions. A possible formation mechanism of Cu₂O and Cu was proposed in[BMIM]BF₄.     

Cr掺杂Cu2O的光催化性质的第一性原理研究

采用第一性原理计算的方法,研究了不同浓度及不同位置Cr掺杂Cu₂O体系的缺陷形成能、电子结构和可见光区域的光催化性质及产生机理。结果表明,本征Cu₂O显示半导体特性,在可见光区域吸收很弱;不同浓度、不同位置的Cr掺杂体系均是稳定的,显示金属特性。与本征Cu₂O相比,随着Cr掺杂浓度的增大,体系在可见光范围内的吸收峰均有不同程度的增强,并且两个Cr原子近邻掺杂时可见光区域的吸收系数最大,光催化效率最强。态密度分析发现,Cr掺杂体系在可见光范围的吸收主要由Cr 3d态电子的带内跃迁产生;不同掺杂浓度和结构构型主要影响材料在长波长段的物理性质,而对短波长段的性质影响很小。因此,通过增大Cr掺杂浓度及调控掺杂位置可以提高Cu₂O在可见光区域的光催化效率,推动Cu₂O在光催化方面的发展。     

Highly Efficiency p-Type Dye Sensitized Solar Cells Based on Polygonal Star-morphology Cu2O Material of Photocathodes

Cuprous oxide（Cu2O）,as an important p-type semiconductor,has been widely investigated due to its high electron transmission and facile preparation.However,the electrode made of only Cu2O has been rarely investigated.In order to demonstrate the possibility that material Cu2O can be applied to the electrode of p-type dye sensitized solar cells（DSSCs）,the photo-electrodes made of prepared Cu2O powder and commercial Cu2O particles have been fabricated.The results show that the electrode based on as-prepared Cu2O（Cu2O-2） powder exhibits higher performance than that based on commercial Cu2O（Cu2O-1） particle.The device based on Cu2O-2 electrode reaches into an open-circuit voltage of 0.71 V,a short-circuit current density of 1.3 mA/cm^2,a fill factor（FF） of 46%,and a conversion efficiency of 0.42% measured under AM 1.5G（100 mW/cm^2） illumination.The enhancement performance of Cu2O-2 is attributed to the high dye adsorption of Cu2O-2 compared with that of Cu2O-1.To the best of our knowledge,this is the highest conversion efficiency value reported for solar cells based on Cu2O-DSSC.This work provides that Cu2O is also a candidate for constructing the electrode of p-type dye sensitized solar cells.     

Isoelectric point-controlled preferential photodeposition of platinum on Cu2O-TiO2 composite surfaces

Isoelectric point-controlled preferential adsorption of[PtCl₆]^2- on Cu₂O/TiO₂ composite surfaces is revealed to play a key role in the photodeposition process.     

1-辛基-3-甲基咪唑功能化石墨片负载氧化亚铜催化二氧化碳电还原制乙烯

电催化还原二氧化碳制备乙烯是备受关注的热点问题,高效催化剂的制备是决定乙烯产率的关键因素。本文在1-辛基-3-甲基咪唑氯的水溶液(OmimCl : H₂O = 1 : 5,体积比)中通过电剥离石墨棒制备了1-辛基-3-甲基咪唑功能化石墨片(ILGS),在水溶液中负载氧化亚铜后得到氧化亚铜/1-辛基-3-甲基咪唑功能化石墨片复合材料(Cu₂O/ILGS),通过透射电镜、X射线光电子能谱、拉曼光谱和X射线衍射对其组成和结构进行了系统研究,发现ILGS由多层石墨烯组成,表面富含缺陷。这些缺陷被1-辛基-3-甲基咪唑通过共价键修饰,形成类似鸟巢状的微结构,平均直径5 nm的Cu₂O纳米颗粒在石墨片表面均匀分散。在0.1 mol∙L⁻¹碳酸氢钾水溶液中,研究了Cu₂O/ILGS在不同电压下催化CO₂电还原的性能。结果表明,Cu₂O是主要活性中心并在CO₂还原过程中被逐渐还原成铜,导致产物的法拉第效率随着反应时间而变,在−1.3 V (vs RHE)电压下,乙烯的法拉第效率最高达到14.8%,其性能归因于Cu₂O/ILGS复合材料中的鸟巢状微结构对Cu₂O纳米颗粒的稳定作用。     

Template Effect of Hydrophobically Associating Polymers on theConstruction of Cuprous Oxide Micro Structure

To determine the template effect of hydrophobically associating copolymers(HACPs) on the morphology of nano/micro structures, six HACPs were synthesized and used as templates to biomimetically synthesize cuprous oxide(Cu₂O), an important semiconductor. This experiment showed a clear relationship between the associating state of the HACP molecules and the morphology of the Cu₂O particles. Cu₂O hollow spheres were preferentially prepared when the HACP molecules were in an intramolecular associating state. Furthermore, a Cu₂O hexapod was easily obtained when the HACP molecules were in an intermolecular associating state. The morphologies of the Cu₂O crystals prepared in the presence of the HACPs also confirmed this result.     

基于氨基化煤基碳点的复合光催化剂的制备及对CO2还原的催化性能

采用过氧化氢氧化法剥离出煤炭结构中的晶体碳[煤基碳点(CDs)], 并通过亚硫酰氯氯化及乙二胺钝化等步骤对其进行氨基化修饰, 制得N, S共掺杂的氨基化煤基碳点(NH₂-CDs), 再利用其表面的氨基和含氧基等官能团的配位及分散作用, 将由氯化铜原位还原得到的氧化亚铜(Cu₂O)纳米粒子包覆于其中, 制备了复合催化剂Cu₂O/NH₂-CDs, 表征了其结构和形貌, 并考察了其可见光催化还原CO₂/H₂O的性能. 结果发现, NH₂-CDs的存在使复合催化剂不仅具备了较强的CO₂吸附性能, 而且还具有了高效的电子-空穴对分离和电子转移能力, 从而表现出优异的光催化还原CO₂制备HCOOH的性能. 反应6 h时, 产物HCOOH的量为2582.4 μmol/g cat, 约为同条件下纯Cu₂O作为光催化剂时产物HCOOH产率的7.3倍.     

氧化/还原预处理对Cu2O/AC催化甲醇氧化羰基化的影响

将醋酸铜热解制备的Cu₂O/AC(活性炭)催化剂,在氧化(O₂/N₂)和还原(H₂/N₂、CO/N₂)气氛下进行预处理。350 ℃下预处理4 h,氧化气氛中Cu₂O完全被氧化为CuO,还原气氛中Cu₂O被还原为单质铜。经CO/N₂预处理的催化剂表面Cu⁰分散性好,催化活性显著升高。在常压固定床微型反应装置上测试,在140 ℃的反应温度下,碳酸二甲酯的时空收率和选择性分别达到了261.9 mg/(g·h)和74.7%。反应后,还原气氛(H₂/N₂、CO/N₂)预处理的催化剂与Cu₂O/AC催化剂中铜物种价态组成趋于一致,催化活性亦趋于一致。关联反应前后催化剂表面铜物种的变化和催化活性的差异,可以认为Cu⁰具有较高的初始催化活性,Cu₂O活性和价态均较为稳定,CuO活性较低。     

氮杂碳原位包覆Cu2O/Co3O4@C异质结构复合材料的设计构筑及高效储锂性能

通过液相法合成了Cu₂O纳米立方体, 并在其基础上利用金属有机框架化合物(MOFs)的自组装形貌调控, 进一步构建了层级多孔Co₃O₄和氮杂碳双壳层的Cu₂O/Co₃O₄@C异质结构复合材料. 利用X射线衍射(XRD)、 扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 热重分析(TGA)、 BET比表面积及孔径分析、 拉曼光谱和X射线光电子能谱(XPS)等表征手段证实了Cu₂O/Co₃O₄@C异质结构复合材料的成功构筑. 双壳层结构设计和丰富的层级孔道结构有效抑制了材料在充放电循环过程中的体积膨胀, 材料在循环100次后仍保持了原有的形貌和构造. 表面多孔结构对电解液的充分浸润、 异质结构的界面内建电场以及缺陷氮杂碳的表面包覆有效提升了材料的电子和离子导电能力. 异质结构设计、 形貌调控、 多孔特性和氮杂碳的协同作用, 使得Cu₂O/Co₃O₄@C复合材料呈现出优异的电化学性能, 在0.1 A/g电流密度下的首次放电比容量达到2065 mA·h/g, 在 2 A/g电流密度下的可逆放电比容量高于360 mA·h/g, 在1 A/g电流密度下循环350次后仍有530 mA·h/g的高可逆放电比容量.     

偏压控制Cu2O和Cu在TiO2表面的生长及其光电化学性质

基于TiO2/Ti电极在含Cu2+溶液中的循环伏安图,调节电沉积的沉积电压,我们在TiO2平整表面制备出Cu2O和/或Cu颗粒.通过扫描电镜(SEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)表征,发现Cu2O和Cu有不同的生长机制:Cu2O颗粒在TiO2表面分散结晶,而Cu颗粒是在已生长的颗粒上成核,从而形成堆积颗粒结构.这是由于在Cu2O/TiO2界面和Cu/TiO2界面形成不同的能带结构,使得电子的转移方式不同.与纯TiO2光阳极比较,可以观察到Cu2O/TiO2和Cu/TiO2异质结构的光电流均有显著增强.特别地,存在一个电压区间使得Cu2O和Cu同时生长在TiO2表面,此时对应的光电流比较稳定并且能达到最大.紫外-可见(UV-Vis)漫反射光谱、电化学阻抗谱(EIS)和光电流-电压特性曲线均显示,Cu2O和Cu明显有助于光的可见光吸收,同时Cu/TiO2在光电转换过程中显示更宽波段的可见光利用率.此外,开路电压的增加、有效的电荷分离和电极/电解质界面上载流子的快速迁移也增强了材料的光电化学性质.     

Cuprous Oxide/Nitrogen-doped Graphene Nanocomposites as Electrochemical Sensors for Ofloxacin Determination

Cu₂O/nitrogen-doped grapheme(NG) nanocomposite material was prepared via a facile one step chemical reduction and characterized by means of X-ray diffraction(XRD) and scanning electron microscopy(SEM). A new electrochemical sensor was then fabricated by coating Cu₂O/nitrogen-doped graphene nanocomposite with Nafion on glassy carbon electrode(Cu₂O/NG/Nafion/GCE). The electrochemical response of this modified electrode toward ofloxacin was examined by cyclic voltammetry. The results indicate that Cu₂O/NG/Nafion composite-modified electrode exhibits higher catalytic activity in the electrochemical oxidation of ofloxacin compared with glassy carbon electrode(GCE), Cu₂O/Nafion modified electrode(Cu₂O/Nafion/GCE), and N-doped graphene/Nafion modified electrode(NG/Nafion/GCE). Under optimal conditions, the peak current was found to be linearly proportional to the concentration of ofloxacin in the 0.5-27.5 μmol/L and 27.5-280 μmol/L ranges with a lower detection limit of 0.34 μmol/L, higher sensitivity of 39.32 μA·L·mmol^-1 and a shorter reaction time of less than 2 s. In addition, Nafion can enhance the stability of the modified electrode and prevent some negative species. Thus the modified electrode exhibits good selectivity and a long working life. The Cu₂O/NG/Nafion composite modified electrode shows promising application in electrochemical sensors, biosensors, and other related fields because of its excellent properties.     

放射性碘分子在Cu2O表面的吸附:第一性原理密度泛函研究

采用第一性原理密度泛函计算方法和周期性平板模型系统研究了放射性碘分子在Cu₂O三个低指数表面的吸附行为。通过计算若干平衡吸附构型的结构参数和吸附能评估了不同特征吸附位的作用。构型优化计算表明所选晶面存在适度的结构弛豫。计算结果表明,与Cu₂O（110）表面相比,Cu₂O（100）和（111）晶面表现出更高的碘分子吸附反应活性。其中,表面氧原子位（O_S）和配位未饱和铜原子位（Cu_CUS）分别为Cu₂O（100）和（111）晶面的能量最优吸附位点。此外,针对几种典型吸附结构计算分析了其电子结构信息,以进一步阐明吸附体系之间的相互作用机理。     

脉冲沉积制备Cu_2O/TiO_2纳米管异质结的可见光光催化性能

在用阳极氧化法制备有序排列TiO2纳米管阵列薄膜的基础上,引入脉冲沉积工艺,成功实现了均匀、弥散分布的Cu2O纳米颗粒修饰改性TiO2纳米管阵列,形成Cu2O/TiO2纳米管异质结复合材料.利用场发射扫描电镜(FESEM)、场发射透射电镜(FETEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和紫外-可见漫反射光谱(UV-Vis DRS)对样品进行表征,重点研究了Cu2O/TiO2纳米管异质结的光电化学特性和对甲基橙(MO)的可见光催化降解性能.结果表明,Cu2O纳米颗粒均匀附着在TiO2纳米管阵列的管口和中部位置,所制备的Cu2O/TiO2纳米管异质结具有高效的可见光光催化性能;在浓度为0.01 mol?L-1的CuSO4溶液中制得的Cu2O/TiO2纳米管异质结表现出最好的电化学特性和光催化性能;另外,对Cu2O纳米颗粒影响光催化活性的机理进行了讨论.     

N_2O在钾改性Cu-Co尖晶石型复合氧化物上的催化分解(英文)

制备了几个不同组成的Cu-Co尖晶石型复合氧化物,用于N2O分解反应,在活性较高的Cu0.8Co0.2Co2O4表面浸渍碱金属盐溶液,制备改性催化剂,考察了碱金属助剂类型、钾前驱物和钾负载量等对改性催化剂活性的影响。用BET、XRD、SEM、XPS等方法表征了催化剂结构。结果表明,几种碱金属碳酸盐改性Cu0.8Co0.2Co2O4的催化活性发生了显著变化,其中,K改性催化剂的活性有明显提高,而Cs的表面改性反而降低了催化剂活性;钾前驱物对K/Cu-Co的催化活性也有较大影响,其中,加入碳酸钾明显提高了催化剂的活性,而加入硝酸钾和醋酸钾反而降低了催化剂活性;有氧无水、有氧有水气氛中,400!C下N2O在碳酸钾改性催化剂0.05K/Cu0.8Co0.2Co2O4上的转化率分别达到了100%和87.6%;该催化剂在400!C下的恒温反应活性和稳定性均高于未改性催化剂。     

铜修饰多孔镍自支撑电极的构建及其葡萄糖氧化性能

采用水热合成法制备了正八面体Cu₂O/Cu修饰的多孔Ni(NF)自支撑电极(Cu₂O/Cu-NF),并对其进行了形貌和结构表征。 在三电极体系下,在碱性介质中以循环伏安法和恒电位安培法测试其对葡萄糖催化氧化性能。 结果表明,150 ℃水热法制备的自支撑电极对葡萄糖的电催化氧化活性最强。 响应电流与葡萄糖浓度在3.7×10^-3~1.1 mmol/L和1.4~5.0 mmol/L范围内呈线性相关,响应灵敏度分别是6929和706.1 μA/(mmol·L^-1·cm²),且具有良好的选择性和稳定性,对无酶葡萄糖传感器的发展有重要意义。     

ZrO2修饰Cu催化剂还原以及反应过程中表面组成的变化

通过热分解法制备Cu模型催化剂,然后经浸渍制备ZrO₂/Cu催化剂,采用SEM、XPS考察了催化剂表面形态和组成,并采用in-situ Raman考察了催化剂在还原和吸附CO和水的过程中随时间的变化。结果表明,还原前Cu催化剂表面主要存在CuO物种,而在ZrO₂/Cu表面,除了CuO物种,还存在着大量的表面羟基物种。ZrO₂/Cu相对Cu更加容易还原为Cu⁰,同时,ZrO₂在催化剂表面聚集形成絮状态,而Cu催化剂还原后主要形成Cu₂O物种。Cu催化剂表面吸附CO后,除了形成Cu-CO外,Cu₂O物种均会迅速消失形成CO₂。Cu催化剂对水的作用比较弱,但是ZrO₂/Cu催化剂和水作用较强,并且通过Cu-OH中间物形成Cu₂O物种。     

Spherical Cu2O Assembled by Small Nanoparticles and Its High Efficiency in Photodegradations of Methylene Blue Under Different Light Sources

Well-dispersed mesoporous spherical Cu₂O assembled by small nanoparticles was synthesized by a green and rapid solution route at room temperature under assistance of ultrasonic, using eco-friendly ascorbic acid(AA) as the main reducing agent and glucose as a weak reducing agent and soft template. The Cu₂O spheres were characterized by XRD, SEM, HRTEM, XPS and N₂ adsorption-desorption isotherm. Its optical property was studied by UV-Vis diffuse reflectance absorption spectrum and the photocatalytic activities were evaluted by photodegradations of me-thylene blue(MB) under different light sources. The results show that each spherical Cu₂O(ca. 200 nm in diameter) was accumulated by numerous small nanoparticles of 8-10 nm and mesopores exist between the nanoparticles, which result in a high BET surface area. The spherical Cu₂O exhibits good light-harvesting ability in both UV and visible light region and excellent photodegradation activities to high concentrations of MB solutions under both UV-visible light and visible light.