Visible light induced photodegradation of organic pollutants on nitrogen and fluorine co-doped TiO_2 photocatalyst

The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the absorption edge of TiO 2 to shift to a lower energy region. The photocatalytic activity of co doped TiO 2 with anatase phases was found to be 2 4 times higher than that of the commercial TiO 2 photocatalyst Degussa P25 for phenol decomposition under visible light irradiation. The co doped TiO 2 powders only contain anatase phases even at 1000℃. Apparently, ammonium fluoride added retarded phase transformation of the TiO 2 powders from anatase to rutile. The substitutional fluorine and interstitial nitrogen atoms in co doped TiO 2 polycrystalline powder were responsible for the vis light response and caused the absorption edge of TiO 2 to shift to a lower energy region.

Preparation of nitrogen and sulfur co-doped ultrathin graphitic carbon via annealing bagasse lignin as potential electrocatalyst towards oxygen reduction reaction in alkaline and acid media

Renewable lignin used for synthesizing materials has been proven to be highly potential in specific electrochemistry.Here,we report a simple method to synthesize nitrogen and sulfur co-doped carbon nanosheets by using bagasse lignin,denoted as lignin-derived carbon(LC).By adjusting the ratio of nitrogen source and annealing temperature,we obtained the ultrathin graphitic lignin carbon(LC-4-1000)with abundant wrinkles with high surface area of 1208 m2g_1 and large pore volume of 1.40 cm3g_1.In alkaline medium,LC-4-1000 has more positive half-wave potential and nearly current density compared to commercial Pt/C for oxygen reduction reaction(ORR).More importantly,LC-4-1000 also exhibits comparable activity and superior stability for ORR in acid medium due to its high graphitic N ratio and a direct four electron pathway for ORR.This study develops a cost-effective and highly efficient method to prepare biocarbon catalyst for ORR in fuel cells.

Nitrogen and Sulfur Co-doped Porous Carbon Derived from ZIF-8 as Oxygen Reduction Reaction Catalyst for Microbial Fuel Cells

Nitrogen and sulfur co-doped porous nanocarbon (ZIF-C-N-S) catalyst was successfully synthesized derived from ZIF-8 and thiourea precursors.The electrochemical measurements indicate that the as-obtained ZIF-C-N-S catalyst exhibits higher electrocatalytic activity for oxygen reduction reaction (ORR) in alkaline electrolyte and superior durability-longer than commercial Pt/C catalyst.The enhancment of electrocatalytic activity mainly be come from the open pore structure,large specific surface area as well as the synergistic effect resulted from the co-doping of N and S atoms.In addition,the ZIF-C-N-S catalyst is also used as the air cathode catalyst in the microbial fuel cell (MFC) device.The maximum power density and stable output voltage of ZIF-C-N-S based MFC are 1315 mW/m2 and 0.48 V,respectively,which is better than that of Pt/C based MFC.

Controllable active sites and facile synthesis of cobalt nanoparticle embedded in nitrogen and sulfur co-doped carbon nanotubes as efficient bifunctional electrocatalysts for oxygen reduction and evolution reactions

Development of efficient and promising bifunctional electrocatalysts for oxygen reduction and evolutionreactions is desirable. Herein, cobalt nanoparticles embedded in nitrogen and sulfur co-doped carbonnanotubes(Co@NSCNT) were prepared by a facile pyrolytic treatment. The cobalt nanoparticles and co-doping of nitrogen and sulfur can improve the electron donor-acceptor characteristics of the carbon nan-otubes and provide more active sites for catalytic oxygen reduction and evolution reactions. The preparedCo@NSCNT, annealed at 900℃, showed excellent electrocatalytic performance and better durability thancommercial platinum catalysts. Additionally, Co@NSCNT-900 catalysts exhibited comparable onset poten-tials and Tafel slopes to ruthenium oxide. Overall, Co@NSCNT showed high activity and improved dura-bility for both oxygen evolution and reduction reactions.

Influence of nitrogen doping on thermal stability of fluorinated amorphous carbon thin films

Nitrogen doping fluorinated amorphous carbon (a-C∶F) films were deposited using radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) and annealed in Ar environment in order to investigate their thermal stability. Surface morphology and the thickness of the films before and after annealing were characterized by AFM and ellipsometer. Raman spectra and FTIR were used to analyze the chemical structure of the films. The results show that the surface of the films becomes more homogeneous either by the addition of N2 or after annealing. Deposition rate of the films increases a little at first and then decreases sharply with the increase of N2 source gas flux. It is also found that the fraction of aromatic rings structure increases and the thermal stability of the films is strengthened with the increase of N2 flux. Nitrogen doping is a feasible approach to improve the thermal stability of a-C∶F films.

Photocatalytic Destruction of Nitrogen Monoxide over La^(3+) and N Co-doped SrTiO_3 Powders under Visible Light Irradiation

Lanthanum and nitrogen co-doped SrTiO_3 was prepared by a mechanochemical reaction using SrTiO_3, urea and La_2O_3 as the raw materials. The samples were characterized by X-ray diffraction, X-ray photoelectron spectrometer, transmission electron microscopy, and nitrogen adsorption-desorption isotherm measurements. Lanthanum doping could increase the doping content of nitrogen in the sample. The sample prepared with 0.2 mol% La_2O_3, 22 mol% urea and 77.8 mol% SrTiO_3 by mechanochemical reaction, which has nearly the same nitrogen and lanthanum doping fractions, exhibited high photocatalytic activities. Under the irradiation of light with wavelength larger than 400, and 290 nm, the photocatalytic activity of nitrogen and lanthanum co-doped SrTiO_3 were 2.6 and 2 times greater than that of pure SrTiO_3.

Effects of nitrogen content on structure and electrical properties of nitrogen-doped fluorinated diamond-like carbon films

Nitrogen-doped fluorinated diamond-like carbon(FN-DLC)films were prepared on single crystal silicon substrate by radio frequency plasma enhanced chemical vapor deposition(RF-PECVD)under different deposited conditions with CF4,CH4 and nitrogen as source gases.The influence of nitrogen content on the structure and electrical properties of the films was studied.The films were investigated in terms of surface morphology,microstructure,chemical composition and electrical properties.Atomic force microscopy(AFM)results revealed that the surface morphology of the films became smooth due to doping nitrogen.Fourier transform infrared absorption spectrometry(FTIR)results showed that amouts of C=N and C≡N bonds increased gradually with increasing nitrogen partial pressure r(r=p(N2)/p(N2+CF4+CH4)).Gaussian fit results of C 1s and N 1s in X-ray photoelectron spectra (XPS)showed that the incorporation of nitrogen presented mainly in the forms ofβ-C3N4 and a-CNx(x=1,2,3)in the films.The current-voltage(I-V)measurement results showed that the electrical conductivity of the films increased with increasing nitrogen content.

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.

多孔氮氟共掺杂碳气凝胶的制备及其在锂硫电池中的应用

锂硫电池以其超高的理论能量密度,已成为最具发展潜力的新一代电化学储能技术,但硫正极存在电导率低、体积膨胀、多硫化物穿梭效应等技术瓶颈问题,制约了其实际应用。通过甲醛和3-氨丙基三乙氧基硅烷的醛胺缩合和溶胶-凝胶化反应合成了席夫碱二氧化硅凝胶,经与聚四氟乙烯乳液冷冻干燥、热处理同步刻蚀二氧化硅以及碳化制备了多孔氮氟共掺杂碳气凝胶(NF-CA)。以NF-CA为载体制备的NF-CA/S正极材料表现出优异的循环性能和倍率性能,0.2 C循环初始放电比容量高达1322 mA∙h/g,1 C循环200圈可逆比容量可保持564 mA∙h/g,2C倍率下可逆比容量高达598mA∙h/g。

Convenient room-temperature synthesis of sulfur and nitrogen co-doped NiCo-LDH coupled with CNTs on NiCo foam as battery-type electrode for high performance hybrid supercapacitor

The convenient synthesis of the composite electrode with high supercapacitance performance plays an important role in practical application but is challenging.Herein,the carbon nanotubes(CNTs)coupled with lowcrystalline sulfur and nitrogen co-doped Ni Co-LDH(denoted as SN-Ni Co-LDH)nanosheets array are grown on Ni Co foam(NCF)substrate by two convenient steps of metal induced self-assembly and corrosion engineering,which present the advantages of operating at roomtemperature and low preparation costs.Benefiting from the S–N co-doping and low-crystallinity of Ni Co-LDH,the prepared SN-Ni Co-LDH@CNTs@NCF electrode presents a topping charge capacity of 2470 C·g^(-1)(4.94 C·cm^(-2))at 5 m A·cm^(-2).Furthermore,the fabricated asymmetry supercapacitor(ASC)achieves an extraordinary energy density of 77 Wh·kg^(-1)(0.617 m Wh·cm^(-2))at a power density of 438 W·kg^(-1)(3.5 m W·cm^(-2))and outstanding stability(91%capacity retention after 5000 cycles at20 m A·cm^(-2)).Impressively,the structure evolution of Ni Co-LDH during the charge/discharge processes has been thoroughly elucidated by in-situ Raman spectra.Therefore,this work verifies a powerful strategy and practical value for preparing composite electrodes with high supercapacitance performance,and also provides guidance for the rational design of the smart electrodes.

Enhanced photocatalytic hydrogen production from Co-MOF/CN by nitrogen and sulfur co-doped coal-based carbon quantum dots

A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nanoparticles on the surface of sheet cobalt-based metal-organic framework(Co-MOF)and graphitic carbon nitride(g-C_(3)N_(4),CN).The structure and properties of the obtained catalysts were systematically analyzed.NSCQDs effectively broaden the absorption of Co-MOF and CN in the visible region.The new composite photocatalyst has high hydrogen production activity and the hydrogen production rate reaches 6254μmol/(g·h)at pH=9.At the same time,NSCQDs synergy Co-MOF/CN composites have good stability.After four cycles of hydrogen production,the performance remains relatively stable.The tran sient photocurrent response and Nyquist plot experimental results further demonstrate the improvement of carrier separation efficiency in composite catalysts.The semiconductor type(n-type semico nductor)of the single-phase catalyst was determined by the Mott-Schottky test,and the band structure was analyzed.The conductive and valence bands of CN are-0.99 and 1.72 eV,respectively,and the conduction and valence bands of Co-MOF are-1.85 and 1.33 eV,respectively.Th e mechanism of the photocatalytic reaction can be inferred,that is,Z-type heterojunction is formed between CN an d Co-MOF,and NSCQDs was used as cocatalyst.

氟、氮共掺杂绿色荧光碳点用于替加环素检测的机理研究

通过溶剂热法制备了氟、氮共掺杂的绿色荧光碳点(F,N-CDs)。对所制备的F,N-CDs进行了全面表征和稳定性评估。本文目的是分析TIGE对F,N-CDs的猝灭机制,并构建高效、简便、高灵敏度和高准确性的荧光传感平台。此平台的成功构建为替加环素的检测提供了理论支撑,并为相关领域的研究和应用提供了支持。

Promotion of activation ability of N vacancies to N2 molecules on sulfur-doped graphitic carbon nitride with outstanding photocatalytic nitrogen fixation ability

Nitrogen vacancies and sulfur co-doped g-C3N4 with outstanding N2 photofixation ability was synthesized via dielectric barrier discharge plasma treatment. X-ray diffraction, ultraviolet–visible spectroscopy, N2 adsorption, scanning electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectroscopy, and temperature-programmed desorption were used to characterize the as-prepared catalyst. The results showed that plasma treatment cannot change the morphology of the as-prepared catalyst but introduces nitrogen vacancies and sulfur into g-C3N4 lattice simultaneously. The as-prepared co-doped g-C3N4 displays an ammonium ion production rate as high as 6.2 mg·L^-1·h^-1·gcat^-1, which is 2.3 and 25.8 times higher than that of individual N-vacancy-doped g-C3N4 and neat g-C3N4, respectively, as well as showing good catalytic stability. Experimental and density functional theory calculation results indicate that, compared with individual N vacancy doping, the introduction of sulfur can promote the activation ability of N vacancies to N2 molecules, leading to promoted N2 photofixation performance.

离子改性的CON材料用于吸附分离NF_(3)

从半导体刻蚀废气中吸附分离NF_(3)具有重要的工业应用价值。通过在多孔有机分子笼(cage-like organic network,CON)中引入碘离子,制得了高NF_(3)吸附选择性的离子型吸附剂(I-CON)。DFT理论计算表明,碘离子的引入在吸附剂孔道表面形成了离子化的电场环境,使被吸附的NF_(3)分子发生诱导极化,因此增强了材料对NF_(3)的吸附能力。单组分气体吸附测试结果表明,相较于CON,I-CON对NF_(3)的吸附容量从30.49mL/g提高到45.13mL/g,理想吸附溶液理论选择性从10.59~15.49提高到15.01~19.47;在穿透曲线测试中,I-CON也比CON表现出更强的NF_(3)动态吸附能力。以上结果证实了离子改性能够增强材料对NF_(3)的吸附分离性能,为分离与回收NF_(3)提供了技术参考。

水环境敏感地区大型微电子园区废水处理工程实例

位于太湖流域的江苏某大型微电子产业园区排放的废水主要含有胺类、有机溶剂、氟化物、重金属等特征污染物。针对这些污染物,采用了高密度沉淀、生物滤池辅以碳源投加强化脱氮、臭氧-生物活性炭联用及膜处理的组合工艺流程。污水处理厂投产运营后,通过对聚合氯化铝(PAC)和碳源投加的良好控制,高密度沉淀池除磷(去除率84.4%)、除氟(去除率57.6%)以及硝化反硝化滤池脱氮(氨氮去除率96.4%、总氮去除率88.8%)均取得了理想的效果。根据当地水环境容量要求,出水主要污染物CODCr、BOD5、NH3-N、F-执行《地表水环境质量标准》(GB 3838—2002)中Ⅲ类水限值要求并稳定达标,TN及TP排放标准按TN≤5mg/L,TP≤0.15mg/L执行并稳定达标。工程总投资45600万元,每日运维成本约1.22元/t,其中电费约0.30元/t,药剂费约0.87元/t,污泥外运处置费约0.05元/t。

补连塔煤矿矿井水综合利用研究及其具体成效

简要分析了我国煤矿矿井水排放及综合利用现状,阐述了补连塔煤矿矿井水综合利用项目研究的必要性以及该项目采用的矿井水处理工艺。该项目的应用取得以下显著成效:矿井水100%达标回用加快了沉陷区生态环境综合治理项目的实施;从根本上消除了采空区积水隐患保障了煤矿安全生产;免除了矿井水入河排污费、减少了矿井水新水用量;采用“三级三用二循环”矿井水治理保护模式,让矿井水转变为绿色水源,有效缓解了矿区用水矛盾。

水体氟污染对微藻氮营养吸收的影响研究

选取环境中广泛存在且易于人工培养的蛋白核小球藻和莱茵衣藻作为受试生物,通过测定藻液中硝态氮和铵态氮浓度的变化,研究F~-浓度和处理时间对微藻氮营养吸收的影响.结果表明,高浓度F~-(≥50 mmol/L)明显抑制两种藻的氮营养吸收,且浓度越大,抑制作用越强.在处理条件相同的情况下,蛋白核小球藻对F~-的耐受性更强,而莱茵衣藻对F~-更敏感.

N,P co-doped 3D porous carbon with self-assembled morphological control via template-free method for potassiumion battery anodes

The larger ionic radius of potassium ions than that of lithium ions significantly limits the accomplishment of rapid diffusion kinetics in graphite electrodes for potassium-ion batteries(PIBs),resulting in comparatively poor rate performance and cycle stability.Herein,we report a high-rate performance and cycling stability amorphous carbon electrode achieved through nitrogen and phosphorous co-doping.The as-prepared N,P co-doped carbon electrodes have distinct 3D structures with large surface areas,hierarchical pore architectures,and increased interlayer spaces resulting from the direct pyrolysis of supramolecular self-assembled aggregates without templates.The obtained electrode N3P1 exhibits a reversible specific capacity of 258 m Ah·g^(-1)at a current density of 0.1A·g^(-1)and a good long-term cycle performance(96.1%capacity retention after 800 cycles at 0.5 A·g^(-1)).Kinetic investigations show that the N3P1 electrode with the welldeveloped porous structure and large number of surface defects exhibits capacitive-driven behavior at all scan rates,which may be attributed by N and P co-doping.Ex-situ transmission electron microscopy analyses in the fully discharged and charged states demonstrate structural stability and reversibility owing to the expanded interlayer space.The suggested synthesis approach is simple and effective for producing heteroatom-doped carbon materials for PIBs and other advanced electrochemical energy storage materials.

The radiation hardness of the nitrogen-fluorine implanted buried oxide layer in silicon-on-insulator materials against higher total dose irradiation

Nitrogen(N) and fluorine(F) ions were sequentially implanted into the buried oxide(BOX) to improve the total dose radiation hardness of the BOX layer in silicon-oninsulator(SOI) materials. The radiation response of the BOX layers modified by the ion implantation was characterized by flat-band voltage shifts and trapped charge changes in the BOX, based on the capacitance-voltage(C-V) measurements on the polysilicon-BOX-semiconductor(PBS) structures fabricated on the SOI materials, before and after irradiation using Co-60 γ rays with various doses range from 0.7 to 1.7Mrad(Si). The experimental results show that a considerably enhanced hardness for the BOX layer can be achieved by this co-implantation of nitrogen and fluorine on proper process conditions, and the radiation responses of the BOX layers are directly associated with the anneal times after nitrogen implantation.In particular, the rebound and fluctuation phenomena of the BOX radiation response were observed with increasing dose, according to the changes in the flat-band voltages, which cannot be explained in terms of the increase in radiation induced interface state density, and the related mechanisms were analyzed and discussed.

非金属掺杂改性TiO_2光催化剂的机理

为了扩展TiO2光催化剂对可见光的利用,以非金属元素对其进行掺杂和改性是近年来很活跃的研究内容,文献报道主要有氮、碳、硫、氟等非金属元素的改性结果。各种不同的改性方法如高温气氛还原、脉冲激光沉积、离子溅射、机械化学、溶液湿法等都可以得到非金属元素改性。本文重点探讨了氮改性TiO2光催化剂的结果,氮改性TiO2的方法和改性机理,讨论了氮改性TiO2的结构及其对可见光的利用机理等,对碳、硫、氟等元素掺杂改性也作了简要介绍。