Effects of oxygen/nitrogen co-incorporation on regulation of growth and properties of boron-doped diamond films

Regulation with nitrogen and oxygen co-doping on growth and properties of boron doped diamond films is studied by using laughing gas as dopant. As the concentration of laughing gas(N2O/C) increases from 0 to 10%, the growth rate of diamond film decreases gradually, and the nitrogen-vacancy(NV) center luminescence intensity increases first and then weakens. The results show that oxygen in laughing gas has a strong inhibitory effect on formation of NV centers, and the inhibitory effect would be stronger as the concentration of laughing gas increases. As a result, the film growth rate and nitrogen-related compensation donor decrease, beneficial to increase the acceptor concentration(~3.2×10^(19)cm^(-3)) in the film. Moreover, it is found that the optimal regulation with the quality and electrical properties of boron doped diamond films could be realized by adding appropriate laughing gas, especially the hole mobility(~700cm^(2)/V·s), which is beneficial to the realization of high-quality boron doped diamond films and high-level optoelectronic device applications in the future.

Hierarchically porous Fe/N/S/C nanospheres with high-content of Fe-Nx for enhanced ORR and Zn-air battery performance

Heteroatom-doped carbon-based transition-metal single-atom catalysts(SACs) are promising electrocatalysts for oxygen reduction reaction(ORR). Herein, with the aid of hierarchically porous silica as hard template, a facile and general melting perfusion and mesopore-confined pyrolysis method was reported to prepare single-atomic Fe/N–S-doped carbon catalyst(FeNx/NC-S) with hierarchically porous structure and well-defined morphology. The FeNx/NC-S exhibited excellent ORR activity with a half-wave potential(E_(1/2)) of 0.92 V, and a lower overpotential of 320 mV at a current density of 10 mA cm^(-2)for OER under alkaline condition. The remarkable electrocatalysis performance can be attributed to the hierarchically porous carbon nanospheres with S doping and high content of Fe-Nx sites(up to 3.7 wt% of Fe), resulting from the nano-confinement effect of the hierarchically porous silica spheres(NKM-5) during the pyrolysis process. The rechargeable Zn-air battery with FeNx/NC-S as a cathode catalyst demonstrated a superior power density of 194.5 mW cm-2charge–discharge stability. This work highlights a new avenue to design advanced SACs for efficient sustainable energy storage and conversion.

Role of doping and oxygen content in superconductivity of La_2 CuO_(4+δ)

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Morphology and crystal-plane effects of Zr-doped CeO2 nanocrystals on the epoxidation of styrene with tert-butylhydroperoxide as the oxidant

The morphology effect of Zr-doped CeOwas studied in terms of their activities in the selective oxidation of styrene to styrene oxide using tert-butyl hydroperoxide as the oxidant. In the present work, Zrdoped CeOnanorods exhibited the highest catalytic performance（yield of styrene oxide and TOF value）followed by nanoparticles and nanocubes. For the Zr-doped CeOnanorods, the apparent activation energy is 56.3 k J/mol, which is much lower than the values of catalysts supported on nanoparticles and nanocubes（73.3 and 93.4 k J/mol）. The high resolution transmission electron microscopy results indicated that（100） and（110） crystal planes are predominantly exposed for Zr-doped CeOnanorods while（100）and（111） for nanocubes,（111） for nanoparticles. The remarkably increased catalytic activity of the Zrdoped CeOnanorods is mainly attributed to the higher percentage of Cespecies and more oxygen vacancies, which are associated with their exposed（100） and（110） crystal planes. Furthermore, recycling studies proved that the heterogeneous Zr-doped CeOnanorods did not lose its initial high catalytic activity after five successive recycles.

Effect of oxygen on regulation of properties of moderately boron-doped diamond films

Regulation of oxygen on properties of moderately boron-doped diamond films is fully investigated.Results show that,with adding a small amount of oxygen(oxygen-to-carbon ratio<5.0%),the crystal quality of diamond is improved,and a suppression effect of residual nitrogen is observed.With increasing ratio of O/C from 2.5%to 20.0%,the hole concentration is firstly increased then reduced.This change of hole concentration is also explained.Moreover,the results of Hall effect measurement with temperatures from 300 K to 825 K show that,with adding a small amount of oxygen,boron and oxygen complex structures(especially B_(3)O and B_(4)O)are formed and exhibit as shallow donor in diamond,which results in increase of donor concentration.With further increase of ratio of O/C,the inhibitory behaviors of oxygen on boron leads to decrease of acceptor concentration(the optical emission spectroscopy has shown that it is decreased with ratio of O/C more than 10.0%).This work demonstrates that oxygen-doping induced increasement of the crystalline and surface quality could be restored by the co-doping with oxygen.The technique could achieve boron-doped diamond films with both high quality and acceptable hole concentration,which is applicable to electronic level of usage.

A review of nanocarbons in energy electrocatalysis: Multifunctional substrates and highly active sites

Nanocarbons are of progressively increasing importance in energy electrocatalysis, including oxygen reduction, oxygen evolution, hydrogen evolution, COreduction, etc. Precious-metal-free or metal-free nanocarbon-based electrocatalysts have been revealed to potentially have effective activity and remarkable durability, which is promising to replace precious metals in some important energy technologies,such as fuel cells, metal–air batteries, and water splitting. In this review, rather than overviewing recent progress completely, we aim to give an in-depth digestion of present achievements, focusing on the different roles of nanocarbons and material design principles. The multifunctionalities of nanocarbon substrates(accelerating the electron and mass transport, regulating the incorporation of active components,manipulating electron structures, generating confinement effects, assembly into 3 D free-standing electrodes) and the intrinsic activity of nanocarbon catalysts(multi-heteroatom doping, hierarchical structure,topological defects) are discussed systematically, with perspectives on the further research in this rising research field. This review is inspiring for more insights and methodical research in mechanism understanding, material design, and device optimization, leading to a targeted and high-efficiency development of energy electrocatalysis.

ELECTRICAL PROPERTIES OF LPCVD POLY-SILICON DOPED WITH OXYGEN ATOMS

The electrical conductivity of LPCVD polysilicon doped with oxygen atoms(acromymSIPOS)films has been measured to study the electrical properties of SIPOS.The results showthat the electrical properties of SIPOS depend on both oxygen contents and annealing processes.The electrical conductivity decreases while the oxygen content in SIPOS increases.The temper-.ature dependence of the electrical conductivity of SIPOS during annealing shows that there aretwo kinds of conduction mechanisms,that is,conductivities of SIPOS are concerned in the reac-tion of Si-O bonds and the recrystallization of SIPOS during low temperature500℃)and hightemperature900℃)annealing,respectively.In addition,the doping effect on the conductivityof SIPOS has been studied.It has been observed that doping made the increase of conductivityin SIPOS,but the oxygen contents apparently suppressed the increase of conductivity in doped-SIPOS.

Effects of Mg doping content and annealing temperature on the structural properties of Zn_(1-x)Mg_xO thin films prepared by radio-frequency magnetron sputtering

The doping content of Mg plays an important role in the crystalline structure and morphology properties of Zn_(1-x )Mg_xO thin films. Here,using radio-frequency magnetron sputtering method,we prepared Zn_(1-x )Mg_xO thin films on single crystalline Si(100) substrates with a series of x values. By means of X-ray diffraction(XRD) and scanning electron microscope(SEM),the crystalline structure and morphology of Zn_(1-x )Mg_xO thin films with different x values are investigated. The crystalline structure of Zn_(1-x )Mg_xO thin film is single phase with x<0.3,while there is phase separation phenomenon with x>0.3,and hexagonal and cubic structures will coexist in Zn_(1-x )Mg_xO thin films with higher x values. Especially with lower x values,a shoulder peak of 35.1° appearing in the XRD pattern indicates a double-crystalline structure of Zn_(1-x )Mg_xO thin film. The crystalline quality has been improved and the inner stress has been released,after the Zn_(1-x )Mg_xO thin films were annealed at 600 °C in vacuum condition.

氧等离子处理的二硫化钼场效应晶体管表面掺杂和湿度传感研究

二维半导体过渡金属二硫属化物(transition metal dichalcogenide,TMD)具有独特的电学、光学和力学性能,在数字电路、光伏器件和能量存储等多个领域中具有巨大的应用潜力。通过表面掺杂控制TMD的电学性能为实现灵敏传感提供了有效的方法。本文开展了氧等离子体对二硫化钼(MoS_(2))掺杂特性的研究。首先,测试了MoS_(2)场效应晶体管(field-effect transistor,FET)的输运特性,发现氧等离子体处理对FET具有p型掺杂作用。随后,通过拉曼光谱研究了掺杂机制的成因,并证实了沟道表面类MoO_(3)缺陷的形成。最后,研究了经等离子体处理的晶体管的湿度传感特性,由于氧等离子体处理使得沟道对水分子的吸收中心增加,在潮湿环境下晶体管具有十分灵敏的响应特性,源漏电流值变化了约54%。这项工作不仅提供了一种调控TMD电学性能的简单方法,也展示了低维材料化学传感器的发展潜力。

Rational design of efficient visible-light photocatalysts(1D@2D/0D)ZnO@Ni-doped BiOBr/Bi heterojunction:Considerations on hierarchical structures,doping and SPR effect

Simultaneously integrating heterogeneous interface,element doping,and metal decorating was a promising strategy to promote the visible-light-driven photocatalytic activity.Herein,we demonstrated a facile solvothermal route for Ni-doped BiOBr/Bi^(0) with ZnO 3D hierarchical heterojunction(denoted as Z@B/BiNi).The optimal photocatalysts of Z@B/Bi-Ni sample presented a remarkable catalytic performance of high concentrations of tetracycline solution(40 mg/L)than those of the Z@B/Bi,Z@B,BOB and ZnO photocatalysts toward the visible-light-driven degradation.The enhanced photocatalytic mechanism can be proposed as follows:(ⅰ)3D hierarchical heterojunction provided more active sites and accelerated the separation of charge carriers for photocatalytic TC;(ⅱ)formation of oxygen vacancies on the surface over Z@B/Bi-Ni by in-situ reduction of Bi^(0) and Ni doping could serve as the active sites for oxygen activation to adsorb free O_(2) and generate more superoxide radicals;(ⅲ)SPR effect of Bi metal were beneficial to carrier separation and also act as the active site to trap O_(2) molecules.This work clarified the role of unique morphologies,surface plasmonic resonance(SPR)effect of metal Bi,and Ni doping in Z@B/Bi-Ni,and its photocatalytic reaction mechanism was proposed by a series of experiments,characterization and DFT calculations,arousing a new perspective to design hierarchical heterojunction photocatalysts.

硼、磷共掺杂铁钴双金属材料的制备及其电催化析氧性能

采用一步水热法合成了硼、磷共掺杂铁钴材料(Fe-Co-B-P)。借助扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、傅里叶变换红外光谱(FT-IR)等技术对所合成材料的形貌、结构和组成进行表征。利用线性扫描伏安(LSV)、循环伏安(CV)、电化学阻抗谱(EIS)等技术研究材料电化学析氧反应(OER)性能。结果表明,Fe-Co-B-P表面疏松且粗糙,颗粒间有许多空隙。在电流密度为10和100 mA·cm^(-2)时,其过电势分别为278和309 mV,Tafel斜率为24 mV·dec-1,说明该材料具有较优的电催化析氧性能。其在连续进行10 h的计时电位测试过程中,电势基本保持在1.55 V(vs RHE),表明该催化剂具有较好的电化学稳定性。这是由于铁钴双金属与硼、磷非金属之间的协同作用促进了电子的传递。

O-NiCo_(2)S_(4)/CNT复合材料对多硫化锂催化转化性能研究

NiCo_(2)S_(4)由于具有丰富的催化位点和金属特性,能够催化锂硫电池中的多硫化锂的氧化还原转化。然而,其催化活性和化学吸附性不足以抑制多硫化锂在长循环中的穿梭效应。通过水热法结合空气煅烧制备了氧掺杂NiCo_(2)S_(4)/CNT复合材料(O-NiCo_(2)S_(4)/CNT),系统的实验证明氧掺杂后体相NiCo_(2)S_(4)的结晶度增强,表面NiCo_(2)S_(4)趋于无定形态,O-NiCo_(2)S_(4)/CNT的电导率升高。其次,O掺杂可以有效调节NiCo_(2)S_(4)中金属阳离子的电子结构,增强催化活性位点的化学吸附和催化转化能力,进而提升多硫化锂的转化动力学,抑制多硫化锂的穿梭效应。基于O-NiCo_(2)S_(4)/CNT功能化隔膜的锂硫电池在0.2 C下初始放电容量高达1362.7 mAh/g,循环150圈后的容量为923 mAh/g,每圈的容量衰减率仅为0.21%。在3 C下,容量可达到701.8 mAh/g。本工作表明,氧原子掺杂金属硫化物是开发高效催化剂的一种有效策略。

Fe掺杂NiSe@NiS复合材料电子调制和界面协同促进析氧性能研究

本研究采用溶剂热法,在泡沫镍(NF)基底上原位合成出Fe掺杂的硒化镍和硫化镍复合材料(Fe-NiSe@NiS/NF)。得益于Fe掺杂优化的电子结构、NiSe和NiS间的协同效应以及高效的电荷转移速率,Fe-NiSe@NiS/NF在1 mol/L KOH溶液中表现出优异的OER性能。在过电位为330 mV时可实现电流密度150 mA/cm^(2),且电压在稳定40 h后没有发生显著改变。

镍氮掺杂石墨炔用作高效氧还原电催化剂

氧还原反应是燃料电池中至关重要的一环。常规的氧还原反应催化剂是贵金属铂,但鉴于铂的高成本,研究者希望寻找一种低成本的替代催化剂,它更便宜并且具有相当于铂的催化效果。在前期研究中,已经对铁氮共掺杂石墨炔和钴氮共掺杂石墨炔进行了研究,它们均表现出了高效的氧还原反应活性,而与之具有相似电子结构的金属镍尚未研究。因此,此工作以氢取代石墨炔为基底,设计并合成了多种镍氮掺杂的石墨炔电催化剂,并进行了氧还原电化学测试,其中,镍质量分数2%并加入三聚氰胺进行烧制的镍氮掺杂石墨炔催化剂表现出最佳的氧还原电催化性能。对催化剂进行了一系列的物理表征:X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)和扫描电子显微镜(SEM),进一步分析了其结构和形貌。从物理表征及电化学测试结果可以看出,氮原子是构建催化活性位点的关键,而镍原子在提高催化剂性能方面起着至关重要的作用,氮和镍的协同作用使得镍氮掺杂石墨炔催化剂表现出优异的催化性能,这使其具有良好的应用前景。

过热度对无铅焊锡雾化粉末特性的影响

利用自行设计的超音速雾化制粉装置,研究了合金过热度对 SnAgCu 系无铅焊锡粉末有效雾化率、粒度分布、球形度及含氧量的影响。结果表明:随着合金过热度升高,粉末粒度有明显变细趋势,粉末氧含量随着过热度的升高而急剧增大;在其他条件不变,过热度为150℃时,雾化粉末的有效雾化率最高,且球形度较好。与 SnPb 雾化粉末相比,Sn_3Ag2.8Cu 无铅焊锡粉末具有较低的含氧量和较高的有效雾化率;Sn3Ag2.8CuCe 具有较高的氧含量,有效雾化率高于 SnPb,低于 Sn3Ag2.8Cu。

复合型助滤剂与煤表面氧的作用规律

依据XPS分析和热重-差热分析结果,采用多元线性回归的分析方法建立了煤表面氧与滤饼水分最低值之间的相关关系.在不使用助滤剂的情况下,影响滤饼水分最低值的主要因素是煤表面的总含氧量,特别是COO氧的含量,C—O—C,C—O—H氧对滤饼水分最低值的影响很小;加入复合型助滤剂以后,氧含量对滤饼水分的影响全部消失,复合型助滤剂屏蔽了煤表面氧对滤饼水分的影响,因而取得了良好的助滤效果.

MnO_x/CeO_2纳米棒催化剂在低温NH_3-SCR反应中的阳离子(Zr^(4+),Al^(3+),Si^(4+))掺杂效应（英文）

低温脱硝技术由于具有无需再加热烟气、方便燃煤电厂脱硝改造以及适用于一些烟气温度较低的非电力行业脱硝场合等优点,吸引了越来越多研究者的关注.低温脱硝催化剂是该技术中最关键的单元,因此其配方开发及相关工作已成为近年来的研究热点之一.商业化V_2O_5-WO_3/TiO_2催化剂在300–400°C的固定源烟气脱硝中表现出优异的性能,然而其低温脱硝性能却差强人意.并且,V_2O_5具有生物毒性,会造成二次污染.因此,低温脱硝催化剂的开发主要集中在环境友好的非钒基催化剂上.其中,MnO_x基催化剂由于具有优异的低温脱硝性能而成为重点研究对象.特别是MnO_x/CeO_2催化剂由于Ce O_2良好的氧化还原性能和较高的储释氧容量,引起了低温脱硝领域越来越多研究者的兴趣.然而,众所周知,CeO_2的比表面积和热稳定性并不令人满意.幸运的是,研究表明,阳离子掺杂可有效地克服CeO_2的上述缺点.此外,随着纳米材料制备科学与技术的发展,不同形貌的CeO_2已经能可控合成.研究表明,CeO_2纳米棒比其它形貌的CeO_2更适合用作载体,因为Ce O_2纳米棒主要暴露的{110}晶面易于形成氧空位以及与表面分散组分产生强相互作用.因此,在本工作中,我们在CeO_2纳米棒的晶格中掺入热稳定的Zr^(4+),Al^(3+),Si^(4+)等阳离子以提高其比表面积和热稳定性,并以该CeO_2纳米棒为载体负载MnO_x,考察了Zr^(4+),Al^(3+),Si^(4+)等阳离子掺杂对MnO_x/Ce O_2纳米棒催化剂低温脱硝性能的影响,筛选出最佳的掺杂离子.对制备的样品进行了透射电子显微镜、高分辨透射电子显微镜、X射线衍射、拉曼光谱、氮气物理吸附、氢气程序升温还原、氨气程序升温脱附、氨气吸附原位漫反射红外光谱和X射线光电子能谱等一系列表征分析,并利用氨气-选择性催化还原(NH_3-SCR)反应评价了其脱硝性能和抗水抗硫性能.结果表明,Si^(4+)掺杂的MnO_x/CeO_2纳米棒(MnO_x/CS-NR)催化剂具有最多的氧空位、表面酸性位和Mn^(4+)因而表现出最佳的脱硝活性.由于其氧化还原性能适当减弱,有效地抑制了氨气的非选择性催化氧化,从而表现出最低的N_2O生成量.此外,MnO_x/CS-NR催化剂还显示出最佳的抗水抗硫性能.综上所述,Si^(4+)是MnO_x/CeO_2纳米棒催化剂的最佳掺杂离子.

控氧对注水井管柱腐蚀行为的影响

目前,对L80钢溶解氧腐蚀的研究非常少,对交互作用控氧的研究几乎未见报道。利用高温高压腐蚀模拟试验,分别研究了L80钢在控氧前(1.00mg/L)、控氧后(0.05mg/L)以及控氧前后(1.00mg/L+0.05mg/L)交互作用下的腐蚀规律,主要研究了控制溶解氧含量对L80钢腐蚀行为的影响。利用扫描电镜(SEM)、X射线衍射仪(XRD)和激光共聚焦等技术,分析了腐蚀产物的形貌和成分。结果表明:控制溶解氧含量对L80钢有减缓腐蚀的作用;在控氧交互作用下,L80钢表面的腐蚀有缓解,但局部腐蚀的风险增大,控氧交互作用有促进腐蚀的作用。

Ce改性CuO/γ-Al_(2)O_(3)用于催化燃烧中Ce作用的探究

针对CuO(20%)/γ-Al_(2)O_(3)催化剂催化燃烧性能的欠缺,通过共沉淀捏合法制备了CuO(20%)/Ce_(x)Al_(100-x)O_(y)(x=1,3,5,7,10,12)系列催化剂,并通过XRD、BET、XPS、H2-TPR、TEM等系列表征方法对催化剂进行了表征,研究了Ce掺杂对催化燃烧效果的影响.表征结果表明,Ce掺杂可以促进催化剂表面CuO的分散,为反应提供更多活性位点,增强催化剂的低温还原性,并提供更多的表面吸附氧,这些都有利于催化燃烧活性的提高.同时,所有催化剂均在以典型的VOC甲苯作为底物的催化燃烧实验中进行了评估,其中CuO(20%)/Ce_(7)Al_(93)O_(y)表现出最高的催化燃烧活性,与CuO(20%)/γ-Al_(2)O_(3)相比,其T90降低了约30℃.比较其他结果,掺杂量低时,催化剂改性结果较差;而在掺杂量过多时,反而会严重损害催化剂性质,如催化剂中的γ-Al_(2)O_(3)骨架可能会坍塌,影响催化燃烧活性.这可以证明Ce掺杂可以有效提高催化剂的燃烧活性,而合适的Ce掺杂量对催化剂改性是很关键的.同时,还对所得的最优催化剂进行了稳定性和普适性的测试,并得出了较好的结果.综上,本研究集中于掺杂量对催化剂的影响,为后续研究提供了理论基础.

真空退火La_(0.7)Sr_(0.3)MnO_3薄膜的光诱导特性

用溶胶-凝胶(Sol-gel)法制备La_(0.7)Sr_(0.3)MnO_3(LSMO)靶材,用脉冲激光沉积(PLD)法在LaAlO_3(012)基片上沉积出厚度约为187 nm的LSMO薄膜,研究了真空退火对薄膜的输运和光诱导特性的影响.结果表明,薄膜的相变温度随着退火时间的增加而降低,薄膜的电阻率升高,在低温金属相光照使电阻率降低,在高温绝缘相光照则使电阻率升高.随着退火时间的增加,光电导(△p)先增大而后减小,在真空条件下退火40 min的薄膜光电导(△p)达到最大值为0.013Ωcm.根据双交换作用解释了薄膜光电导的变化规律.