AC/Ni-Co复合电极材料的制备及其催化析氢性能

采用复合电沉积法制备了AC(活性炭) / Ni-Co 复合电极。XRD 和SEM 测试结果表明, AC 微粒的复合未改变Ni-Co 合金电极的物相结构, 但使镀层的表面粗糙度和真实表面积增大。通过稳态阴极极化曲线和电化学交流阻抗技术考察了不同电极在1 mol·L-1 NaOH 溶液中的催化析氢性能, 结果表明, 镀液中AC 含量为3 g·L-1时所制备的AC/ Ni-Co 复合电极较Ni 电极和Ni-Co 合金电极具有更高的催化析氢活性, 电流密度为30 mA·cm-2时, 析氢反应极化电位分别比Ni 电极和Ni-Co 合金电极正移230 mV 和140 mV , 表观交换电流密度分别是Ni 电极和Ni-Co 合金电极的42 倍和9 倍, 复合电极催化析氢性能的提高主要归因于电极真实表面积的增大。      

纳米TiO2修饰 Ni-W-P电极的制备及其光电催化析氢性能

在Cu基体上电沉积Ni-W-P合金后，通过溶胶-凝胶法制备了纳米TiO2修饰Ni-W-P合金电极．利用扫描电子显微镜（SEM）、X射线衍射（XRD）、阴极极化曲线测试了TiO2／Ni-W-P电极的表面形貌、结构及催化析氢性能，考察了烧结温度、TiO2膜层厚度对电极结构和性能的影响．实验结果表明：550℃下烧结1h、拉膜15次制备的TiO2／Ni-W-P电极光电催化析氢性能最佳，500W碘钨灯照射下析氢过电位减小约140mV；此时TiO2为锐态矿型和金红石型混晶结构，平均晶粒尺寸约7nm．     

Ni/TiO2复合镀层光催化抗菌性能的研究

为了研究TiO2在镀层中的光催化抗菌活性,以不锈钢为基体,制备了Ni/TiO2光催化抗菌功能性复合镀层,测定了镀层中TiO2微粒的复合量,考察了Ni/TiO2电极的光催化析氢性能,利用ESEM观察了镀层的表面形貌,并探讨了半导体TiO2光催化杀灭细菌的机理.研究表明:当镀层中TiO2复合量达到21.98%时,Ni/TiO2复合镀层对大肠杆菌、绿脓杆菌、粪链球菌和金黄色葡萄球菌的抗菌率均大于95%;在光照射下,Ni/TiO2电极阴极析氢反应的起始电位正移了约200mV.     

脱合金化制备纳米多孔Ni、NiO阳极材料及其电催化析氧性能

采用快速凝固与脱合金化相结合的方法制备纳米多孔Ni,经热处理氧化获得纳米多孔NiO,运用XRD、SEM、TEM、BET等对纳米多孔Ni、NiO的物相、形貌结构、孔径分布进行表征,并通过循环伏安、稳态极化、电化学阻抗法研究了其作为电极的电催化析氧性能。结果表明,Ni_(15)Al_(85)和Ni_5Al_(95)脱合金化后均获得了纳米多孔Ni,Al含量的增加使得Ni的孔径尺寸与骨架强度减小,Ni_5Al_(95)形成的纳米多孔Ni在10 mA·cm~(-2)电流密度下的析氧过电位比Ni_(15)Al_(85)形成的纳米多孔Ni低95 mV,但随着反应的进行,纳米多孔Ni表面的孔洞开始坍塌和脱落,导致其析氧稳定性降低。NiO继承了Ni的纳米多孔结构,比表面积和骨架强度进一步增大,Ni_5Al_(95)合金获得的纳米多孔NiO在10 mA·cm~(-2)电流密度下的析氧过电位仅为357 mV,相比Ni电极降低了14. 3 mV,室温下析氧反应的表观交换电流密度是Ni电极的1. 2倍,表观活化自由能降低了8. 59 k J·mol~(-1),经1 000圈循环伏安后过电位降低了12 mV(J=100 mA·cm~(-2)),具有优良的电催化析氧性能和良好的稳定性。     

Ni-S-Co涂层电极的制备及其电化学性能的研究

采用电沉积的方法以泡沫镍为基体制备出非晶Ni-S-Co合金电极.用电化学测试方法分析涂层的电化学行为.结果表明,较好的制备涂层电极条件为: CoSO4·7H2O掺杂浓度为10g/L,电流密度为50mA/cm2,温度为50℃,电沉积时间为40min,pH值为4.当电解电流密度为1200A/m2时,非晶Ni-S-Co合金电极的极化电位较非晶Ni-S合金电极低95mV,较Ni金属电极低405mV;根据Tafel曲线计算出Ni、非晶Ni-S以及非晶Ni-S-Co电极的表面活化能分别为49.5、40.3和38.6kJ/mol.Ni-S-Co电极具有更高的交换电流密度和更低的析氢活化能,因此具有更高的析氢催化活性.     

稀土铈对镍-钴合金电极的析氢催化性能的影响

采用电沉积方法制备了Ni—Co和Ni—Co(RE)合金电权。通过电化学方法研究了其在7mol/L KOH溶波中的析氢电催化活性。实验发现，与Fe电权相比，Ni—Co和Ni—Co(RE)合金电权的析氢电位正移，其中Ni—Co(RE)合金电权的析氢电位正移250mV。通过扫描电镜和合金镀层成分分析，探讨了稀土饰对Ni—Co合金电权析氢电催化性能的影响。结果表明，稀土饰的加入提高了合金电权在7mol/L KOH溶液中的析氢电催化活性和电化学稳定性。有利于降低槽压，减少能耗。     

Ni-W-TiO2复合镀工艺及其镀层性能研究

为了进一步提高Ni-W合金镀层的析氢电催化活性,用电沉积方法制备了Ni-W-TiO2复合镀层,通过阴极极化曲线和交流阻抗等电化学技术研究了其在碱性溶液中的析氢电催化活性,并用扫描电镜观察了电极的表面形貌.结果表明,在Ni-W合金中掺入TiO2微粒可增大电极的比表面积,并改变Ni-W合金在碱性介质中的析氢反应机理.Ni-W-TiO2复合镀层有较高的析氢电催化活性,可用作电解水反应的活性电极.     

非晶态Fe-Mo合金在碱性溶液中的电催化析氢活性

研究了电沉积制备的非晶态Fe-Mo合金(组成分别为Fe82Mo18、Fe74Mo26和Fe71Mo29)电极在30％KOH溶液中，303～343K的温度范围内的析氢催化性能。三种非晶态合金都显示出较好的催化析氢活性。温度为343K，析H2电流密度为300nA／cm^2时的析H2过电位为150～157mV。非晶态Fe82Mol8、Fe74Mo26和Fe71Mo29合金上析H2反应的表观活化能分别为57．18，47．33，102．28kJ／mol。     

多孔Ni-WC复合电极的制备及其在酸性溶液中的电催化析氢性能

目前,关于多孔Ni-WC电极的电催化析氢(HER)性能的报道较少。以多孔海绵镍为基体,采用复合电沉积制备多孔Ni-(WC)x复合电极。运用扫描电镜(SEM)和X射仪线衍射仪(XRD)表征电极的表面形貌和微观结构,通过阴极极化、电化学阻抗(EIS)、循环伏安、计时电流法研究多孔Ni-(WC)x电极在0.5 mol/L H2SO4溶液中的电催化析氢性能。结果表明:与多孔基体Ni电极相比,多孔Ni-(WC)x电极具有较低的析氢过电位、较低的电化学反应阻抗、较小的表观活化能以及较大的交换电流密度;随着镀液中WC浓度的升高,所制备的多孔Ni-(WC)x电极的电催化析氢活性增强,其中Ni-(WC)40电极的表观交换电流密度是多孔Ni基体电极的966.7倍,其表观活化能为5.95 kJ/mol,并具有较好的耐蚀性和析氢稳定性。     

深共晶溶剂中电沉积制备Co-Fe-Gd/NF电极及其析氢性能研究

为了制备出在碱性环境中具备高效能的廉价析氢电极催化剂,选择不同的沉积电位在氯化胆碱-尿素(ChCl-urea)中电沉积制备出五种Co-Fe-Gd/NF电极催化剂。通过扫描电镜(SEM)和光谱仪(EDX)对电极表面形貌、元素含量及分布情况进行表征,X射线光电子能谱(XPS)对电极表面化学性质进行表征。结合线性扫描伏安法(LSV)、电化学阻抗技术(EIS)和循环伏安法(CV)电化学测试结果,表明-1.24 V沉积电位下制备的Co-Fe-Gd/NF-3电极具备优异的析氢催化性能,在10 mA·cm^-2时的过电位仅为71 mV,最小的塔菲尔斜率(45 mV·dec^-1)与电荷转移电阻(0.28503Ω·cm^-2)表明其具备更快的析氢反应动力学过程,电化学活性表面积(ECSA)最大为390.5,为析氢过程提供更多的反应活性位点。对电极进行循环伏安耐久性测试与计时电流法(I-t)测试,结果表明Co-Fe-Gd/NF-3电极催化剂在碱性环境中稳定性良好。     

复合电沉积法制备Sn-TiO2纳米薄膜

采用复合电沉积法制备了TiO2质量分数为20.86%的Sn-TiO2纳米薄膜,研究了阴极电流密度、镀液温度、TiO2微粒的悬浮量等因素对薄膜中TiO2含量的影响,采用扫描电子显微镜(SEM)、X射线衍射(XRD)对热处理后的SnO2-TiO2复合薄膜进行了表征,以甲基橙为模型化合物对薄膜的光催化性能进行了测定.结果表明,在最佳工艺下所得复合纳米薄膜具有优异的光催化活性.     

Nanocrystallized SrHA/SrHA-SrTiO(3)/SrTiO(3)-TiO(2) multilayer coatings formed by micro-arc oxidation for photocatalytic application

Novel photocatalytic coatings containing strontium hydroxyapatite (SrHA), strontium titanate (SrTiO(3)), and TiO(2) were formed by micro-arc oxidation (MAO) in an aqueous electrolyte containing strontium acetate and β-glycerophosphate disodium at 530?V for 0.1-5?min. The structure evolution of the coatings was investigated as a function of processing time, and the photocatalytic activity of the coatings was evaluated by measuring the decomposition rate of methyl orange under ultraviolet irradiation. During the MAO processing of the coatings, it was observed that some granules appeared in the electrolyte adjacent to the anode and they increased in amount as the processing time was prolonged. The obtained results show that the granules are amorphous and poorly crystallized SrHA with negative charges. The coating prepared for 5?min presents a microporous structure of SrHA/SrHA-SrTiO(3)/SrTiO(3)-TiO(2) multilayers, in which the SrHA outermost layer and the SrHA-SrTiO(3) intermediate layer are nanocrystallized. It is suggested that formation of the granules, electro-migration of the granules onto the pre-formed layer, and crystallization of the adhered granules are possible mechanisms for the formation of a SrHA/SrHA-SrTiO(3)/SrTiO(3)-TiO(2) multilayer coating. This coating shows much higher photocatalytic decomposition efficiency relative to the MAO-formed TiO(2) coating, and is expected to have an important photocatalytic application.     

Effect of filler types and calcination temperature on the microstructure and the nitric oxide photocatalytic activity of composite titanium dioxide films

The composite titanium dioxide (TiO(2)) films coating on the woven glass fabric were prepared by a modified sol-gel process, using pre-calcinated TiO(2) nanoparticle or silica gel as filler. The characterized physicochemical properties of the prepared catalyst films showed that the specific surface area, the microstructure and the crystal structure of the catalysts were greatly affected by the fillers and the calcination temperature. The physicochemical properties of composite films and the photocatalytic activity of nitric oxide (NO) show that the pre-calcinated TiO(2) nanoparticle is more favorable than silica gel as filler. The pre-calcinated TiO(2) nanoparticle filler can increase the photocatalytic activities of the catalysts by increasing the specific surface area, introducing a bimodal mesoporous structure, and creating a polymorphous crystal structure. And the TiO(2)-TiO(2) film calcinated at 400 degrees C exhibits the highest photocatalytic activity for NO oxidation and is more active than Degussa P25.     

Effect of surface fluorination of TiO2 particles on photocatalitytic activity of a hybrid multilayer coating obtained by sol-gel method

A multilayer photoactive coating containing surface fluorinated TiO(2) nanoparticles and hybrid matrices by sol gel approach based on renewable chitosan was applied on poly(lactic acid) (PLA) film by a step wise spin-coating method. The upper photoactive layer contains nano-sized functionalized TiO(2) particles dispersed in a siloxane based matrix. For the purpose of improving TiO(2) dispersion at the air interface coating surface, TiO(2) nanoparticles were modified by silane coupling agent 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FTS) with fluoro-organic side chains. An additional hybrid material consisting of chitosan (CS) cross-linked with 3-glycidyloxypropyl trimethoxy silane (GOTMS) was applied as interlayer between the PLA substrate and the upper photoactive coating to increase the adhesion and reciprocal affinity. The multilayer TiO(2)/CS-GOTMS coatings on PLA films showed a thickness of ~4-6 μm and resulted highly transparent. Their structure was exhaustively characterized by SEM, optical microscope, UV-vis spectroscopy and contact angle measurements. The photocatalytic activity of the multilayer coatings were investigated using methyl orange (MeO) as a target pollutant; the results showed that PLA films coated with surface fluorinated particles exhibit higher activity than films with neat particles, because of a better dispersion of TiO(2) particles. The mechanical properties of PLA and films coated with fluorinated particles, irradiated by UV light were also investigated; the results showed that the degradation of PLA substrate was markedly suppressed because of the UV adsorptive action of the multilayer coating.     

等离子喷涂Al_2O_3-TiO_2-ZrO_2涂层及其耐磨损性能

采用液相喷雾造粒法将准微米Al_2O_3,TiO_2,纳米ZrO2颗粒团聚成微米粉体,并用等离子喷涂技术制备了含纳米颗粒的Al_2O_3-TiO_2-ZrO_2陶瓷涂层.在MM200型环块磨损试验机上进行了常温干摩擦试验,比较了含有纳米颗粒的Al_2O_3-TiO_2-ZrO_2涂层和传统Al_2O_3-TiO_2陶瓷涂层的耐磨损性能,并用扫描电镜观察磨损后的磨痕形貌.结果表明,含有纳米颗粒的涂层耐磨损性能明显优于传统的陶瓷涂层.     

Ion-assisted codeposition of CaF2-rich CaF2-TiO2 composites as infrared-transmitting films

The influence of the TiO(2) concentration (相似文献   

(Bi, C and N) codoped TiO2 nanoparticles

Bi, C and N codoped TiO2 photocatalysts were prepared by doping TiO2 with BiCl3 and KSCN in a sol-gel process (denoted as (Bi,SCN)-TiO2). The catalyst samples were then characterized by XRD, TEM, diffuse reflectance spectra (DRS), XPS, FT-IR and N2 sorption. Bi, C and N elements were detected both by XPS and elemental analysis, while S element was not found, suggesting that SCN- group may have decomposed during the sol-gel process. The effects of the doping on the properties and photocatalytic activity of the TiO2 were investigated. It was found that the cation and the anion affected the properties of TiO2 differently. The optical absorption onset of TiO2 red shifted in the presence of Bi3+, while long tail occurred in the presence of SCN-. The order of photoreactivity for TiO2 samples was as follow: (Bi,SCN)-TiO2>Bi-TiO2>undoped TiO2>p25 TiO2, whatever under UV or visible light illumination. The high photoreactivity of the doped TiO2 was also discussed.     

激光原位合成Al_2O_3-TiO_2复合陶瓷涂层组织结构与性能

先利用火焰喷涂技术在中国低活化马氏体钢表面制备了CrFeAlTi涂层,然后通过激光原位反应技术在火焰喷涂涂层表面原位合成了Al_2O_3-TiO_2复合陶瓷涂层。分别采用体视显微镜、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)、显微硬度计、立式万能摩擦磨损试验机以及静态铅铋腐蚀实验装置等分析测试手段对涂层的形貌、微观组织结构、物相组成、显微硬度、干滑动摩擦磨损性能以及耐液态铅铋合金腐蚀性能等进行了研究。实验结果表明:激光原位合成的Al_2O_3-TiO_2复合陶瓷涂层表面整体平整、光滑、致密,基本没有凹坑、裂纹和孔隙等缺陷,与基体之间形成了良好的冶金结合。涂层内部存在完全结晶区和非结晶区,且界面明显。涂层表面主要物相为Al_2O_3,TiO_2,(Al.948Cr.052)_2O_3,Fe_2TiO_5和FeCr等。涂层截面平均显微硬度约为1864.2HV0.2,比基体CLAM钢提高了约3倍,且沿横截面方向呈平稳过渡的阶梯状分布。与基体CLAM钢相比,涂层具有良好的耐磨性能,其磨损量仅为基体的1/6,并且涂层在液态铅铋中表现出良好的耐腐蚀性能。     

复合电沉积制备SnO2/TiO2薄膜及其光电催化性能

为了寻求廉价、高效和稳定的光催化剂,用复合电沉积技术在紫铜片上制备了Sn/TiO2薄膜,经300℃热氧化使之形成SnO2/TiO2复合电极.利用SEM,XRD对薄膜进行了表征,以甲基橙为模型化合物,对复合电极的光催化和光电催化性能进行了测定.研究表明:该薄膜由0.3~1μm的颗粒构成,每个颗粒又由纳米晶粒形成;电极具有多孔结构,膜中的SnO2以两种不同的晶体结构存在;在薄膜质量相等的情况下,SnO2/TiO2薄膜的光催化活性是纯TiO2粒子膜的2.87倍;外加一定偏压下,其催化性能大幅度提高.     

The effect of erbium on the adsorption and photodegradation of orange I in aqueous Er3+-TiO2 suspension

Pure TiO(2) and erbium ion-doped TiO(2) (Er(3+)-TiO(2)) catalysts prepared by the sol-gel method were characterized by means of XRD and diffusive reflectance spectra (DRS). The XRD results showed that erbium ion doping could enhance the thermal stability of TiO(2) and inhibit the increase of the crystallite size, and the DRS results showed that the optical absorption edge slightly shifted to red direction owing to erbium ion doping and the Er(3+)-TiO(2) catalysts had three typical absorption peaks located at 490, 523 and 654 nm owing to the transition of 4f electron from (4)I(15/2) to (4)F(7/2), (2)H(11/2) and (4)F(9/2). With a purpose of azo dyes degradation, orange I was used as a model chemical. And the adsorption isotherm, degradation and mineralization of orange I were investigated in aqueous suspension of pure TiO(2) or Er(3+)-TiO(2) catalysts. The results showed that Er(3+)-TiO(2) catalysts had higher adsorption equilibrium constants and better adsorption capacity than pure TiO(2). The adsorption equilibrium constants (K(a)) of Er(3+)-TiO(2) catalysts were about twice of that of pure TiO(2). The maximum adsorption capacity (Q(max)) of 2.0% Er(3+)-TiO(2) catalyst was 13.08x10(-5)mol/g, which was much higher than that of pure TiO(2) with 9.03x10(-5)mol/g. Among Er(3+)-TiO(2) catalysts, 2.0% Er(3+)-TiO(2) catalyst achieved the highest Q(max) and K(a) values. The kinetics of the orange I degradation using different Er(3+)-TiO(2) catalysts were also studied. The results demonstrated that the degradation and mineralization of orange I under both UV radiation and visible light were more efficient with Er(3+)-TiO(2) catalyst than with pure TiO(2), and an optimal dosage of erbium ion at 1.5% achieved the highest degradation rate. The higher photoactivity under visible light might be attributable to the transitions of 4f electrons of Er(3+) and red shifts of the optical absorption edge of TiO(2) by erbium ion doping.