Studying the Link between the Potential of a Metal-Oxide Anode, the Current Efficiency for Chlorate, and the Current Losses for the Oxygen and Chlorine Evolution in a Wide Range of the Chlorate Electrolysis Conditions

Dependences of the current efficiency for chlorate and current losses for the oxygen evolution on the anode potential are studied. The study is performed in a cell without directed electrolyte circulation during the electrolysis of chloride–chlorate solutions of various compositions at the ORTA and ORTA-I1 anodes, at different current densities, temperatures, and solution pH. At identical temperatures, the dependences have extremums. The anode potentials corresponding to extremums coincide with critical potentials (found in a polarization study) for anodes covered with coatings containing ruthenium dioxide. The current efficiency for chlorate at ORTA-I1 is higher than that at ORTA, while the extremum region is less pronounced. The problem of how to substantially decrease the specific power consumption in the chlorate production by simultaneously increasing the anodic current density and the electrolysis temperature is considered.     

Electrochemical and Corrosion Behavior of Dimensionally Stable Anodes in Chlorate Electrolysis: Efficiency of the Sodium Chlorate Production at Elevated Temperatures

The electrochemical and corrosion behavior of dimensionally stable anodes in chlorate electrolysis is analyzed. The current efficiency (CE) for active chlorine and sodium chlorate is studied at 90°C as a function of the electrolysis duration, dichromate concentration, and solution pH. Effect of interruptions and decrease in the current on CE for the target product is examined. On average, the interruptions can diminish CE by 10–15%.     

SnO2表面卤化提高钙钛矿太阳能电池光伏性能

钙钛矿太阳能电池(PSCs)成为近几年来迅速发展的新型太阳能电池,其中将SnO₂纳米粒子层用作电子传输层(ETL)的钙钛矿太阳能电池器件得到了广泛的关注。SnO₂有着更低的制备温度,使其具备应用于柔性器件的潜力,但与钙钛矿层能级不匹配等问题限制着其发展。而在界面处加入钝化层,尤其是表面卤化的方法或可解决这一问题。本文综合研究了SnO₂表面卤化对钙钛矿太阳能电池光伏性能的影响,选用四丁基氯化铵(TBAC)、四丁基溴化铵(TBAB)和四丁基碘化铵(TBAI)三种钝化材料对SnO₂表面进行钝化处理,并对钝化材料溶液进行了浓度梯度研究。通过材料形貌、结构和光学性能表征以及电池器件性能测试分析等方法,证明了SnO₂表面卤化可提高钙钛矿层的质量和PSCs光伏性能,并从器件内部电荷传输动力学等角度解释了器件性能改善的原因。为进一步说明其性能改善的机理,采用基于密度泛函理论(DFT)的第一性原理计算方法对材料表面性质进行了深入研究,从能量、结构、电荷密度、态密度、功函数等角度解释了表面卤化提高SnO₂/钙钛矿界面处电子传输特性的原因。实验和理论计算均表明TBAC对于SnO₂具有较好的钝化效果,并随着溶液浓度的提升钝化作用越明显。SnO₂表面卤化作用的深入研究不仅对提高电池器件性能具有实际意义,还能够帮助理解太阳能电池界面现象,为界面改性提供新的研究思路。     

钛基金属氧化物电极制备及其氨氮废水降解性能

采用热分解方法制备了4种电极钛基金属氧化物：Ti/SnO₂+Sb₂O₃、Ti/SnO₂+Sb₂O₃/SnO₂+IrO₂、Ti/SnO₂+Sb₂O₃/SnO₂+RuO₂和Ti/SnO₂+Sb₂O₃/SnO₂+CeO₂. X-射线衍射分析表明Ti/SnO₂+Sb₂O₃/SnO₂+CeO₂电极的CeO₂晶体结构完好,连续工作较长时间电极表面没有明显析氧. 使用该电极电解氧化氨氮模拟废水（降解2 h）,氨氮模拟废水从高浓度（500 mg·L^-1）降解为较低浓度（180 mg·L^-1）,降解效率可达64%,电解活性最佳.     

Pr-PVP掺杂Ti/PbO2电极制备及其在有机物降解中的应用

在Ti基体上,采用电沉积法制备了镨和聚乙烯吡咯烷酮(PVP)掺杂的Ti/SnO₂-Sb₂O₃/Pr₂O₃-PVP-PbO₂ 电极. SEM显示Ti/SnO₂-Sb₂O₃/Pr₂O₃-PVP-PbO₂ 电极表面颗粒细化,镀层结构更加致密和均匀,XRD 测试表明掺杂使可以使电极的表面颗粒变小.循环伏安 (CV)分析表明共掺杂改性后的电极电催化活性明显提高.强化寿命测试显示Ti/SnO₂-Sb₂O₃/Pr₂O₃-PVP-PbO₂ 电极稳定性更好,使用寿命更长. 将所制备的电极应用于亚甲基蓝(MB)模拟染料废水的降解测试,与常规的Ti/PbO₂ 电极相比,Ti/SnO₂-Sb₂O₃/Pr₂O₃-PVP-PbO₂ 电极对亚甲基蓝具有更好的脱色率和 COD 除去率. 降解120min 后,对30 mg·L ^-1 亚甲基蓝的去除率分别可达到99%,对COD去除率为87.9%.     

电泳法制备的致密氧化锡薄膜及其在高稳定性钙钛矿太阳能电池中的应用

在平面型钙钛矿太阳能电池中常采用SnO₂作为电子传输层材料,相应的SnO₂薄膜常采用溶液旋涂法制备。但是由于前驱液中的纳米颗粒可能会发生部分团聚、基底和溶液难以完全避免灰尘等杂质颗粒混入,且最佳的SnO₂电子传输层的厚度通常仅有约20 nm,所以这种方法制备的电子传输层难以保证严格致密和无纳米针孔。在本工作中,我们报道了一种电泳沉积制备致密SnO₂薄膜的方法,并用其有效地提高了钙钛矿太阳能电池的光电转换效率和工况稳定性。通过电泳法,表面带负电荷的SnO₂纳米颗粒在电场的作用下沉积到氧化铟锡(ITO)阳极表面,这种方法得到的薄膜比旋涂法制备的更为致密。将其应用于n-i-p结构的钙钛矿太阳能电池中,能够使得暗电流降低并抑制载流子的非辐射复合,从而提高电池的短路电流和开路电压,进而实现更高的光电转换效率(从18.17%提高到19.52%),且能消除迟滞效应。更重要的是,长期工况稳定性测试表明基于电泳-旋涂法制备的器件在1个太阳的光照下、最大功率点处连续工作960 h后,仍然能够保持71%的初始效率;然而基于旋涂法制备的器件在工作100 h后即降低到初始效率的70%。本工作提供了一种全新的SnO₂电子传输层的制备方法,显著地提高了器件性能和工况稳定性,后续有望应用于制备大面积器件和电池模组。     

Ti/RuO2-IrO2-SnO2-Sb2O5阳极在农村饮用水消毒中的应用

采用热分解法制备了一种新型高效析氯阳极Ti/RuO₂-IrO₂-SnO₂-Sb₂O₅,将其应用于农村饮用水消毒频繁停开、低电解液浓度的特殊工况下,并与Ti/RuO₂-SnO₂-Sb₂O₅、Ti/RuO₂-TiO₂、Ti/RuO₂-TiO₂-IrO₂三种析氯阳极进行性能对比。通过SEM、EDS、XRD等方法表征测试阳极表面形貌、元素及组成,考察了氯化钠浓度、电流密度、停开频率对阳极析氯效果和寿命的影响。研究发现,Ti/RuO₂-IrO₂-SnO₂-Sb₂O₅阳极活性强、稳定性高;阳极涂层各组分高度融合为固溶体,结构致密,稳定性强;在15 g·L^-1 NaCl、400 A·m^-2电流密度、20℃条件下,Ti/RuO₂-IrO₂-SnO₂-Sb₂O₅阳极电解的电流效率达到91.55%;频繁停开、强化电解条件下寿命达到231 h,是Ti/RuO₂-TiO₂阳极的77倍,预估在400 A·m^-2电流密度下能够使用20年。     

Enhanced Electrochemical Performance of Na0.67Fe0.5Mn0.5O2Cathode with SnO2 Modification

P2-type layered oxide Na_0.67Fe_0.5Mn_0.5O₂ is recognized as a very promising cathode material for sodium-ion batteries due to the merits of high capacity, high voltage, low cost, and easy preparation. However, its unsatisfactory cycle and rate performances remain huge obstacles for practical applications. Here, we report a strategy of SnO₂ modification on P2-type Na_0.67Fe_0.5Mn_0.5O₂ to improve the cycle and rate performance. Scanning electron microscope(SEM) and transmission electron microscope(TEM) images indicate that an insular thin layer SnO₂ is coated on the surface of Na_0.67Fe_0.5Mn_0.5O₂ after medication. The coating layer of SnO₂ can protect Na_0.67Fe_0.5Mn_0.5O₂ from corrosion by electrolyte and the cycle performance is well enhanced. After 100 cycles at 1 C rate(1 C=200 mA/g), the capacity of SnO₂ modified Na_0.67Fe_0.5Mn_0.5O₂ retains 83 mA·h/g(64% to the initial capacity), while the capacity for the pristine Na_0.67Fe_0.5Mn_0.5O₂ is only 38 mA·h/g(33.5% to the initial capacity). X-Ray photoelectron spectroscopy reveals that the ratio of Mn⁴⁺ increases after SnO₂ modification, leading to less oxygen vacancy and expanded lattice. As a result, the capacity of Na_0.67Fe_0.5Mn_0.5O₂ increases from 178 mA·h/g to 197 mA·h/g after SnO₂ modification. Furthermore, the rate performance of Na_0.67Fe_0.5Mn_0.5O₂ is enhanced with SnO₂ coating, due to high electronic conductivity of SnO₂ and expanded lattice after SnO₂ coating. The capacity of SnO₂ modified Na_0.67Fe_0.5Mn_0.5O₂ at 5 C increases from 21 mA·h/g(pristine Na_0.67Fe_0.5Mn_0.5O₂) to 35 mA·h/g.     

Ionic conduction in Zn3(PO4)2.4H2O enables efficient discharge of the zinc anode in serum

Batteries contain corrosive or reactive components necessitating containment in a case, setting a limit to their miniaturization. Miniature, small-capacity batteries could power medical sensors in the body, for example sensing glucose for diabetes management. A miniature, case-less Zn-Ag/AgCl battery would consist merely of a zinc anode and a bioinert gel-coated Ag/AgCl cathode, if both operated efficiently in the interstitial fluid. Such a battery has not previously been built, primarily because of rapid corrosion of Zn. We show that the corrosion of zinc is significantly reduced by growth of Zn2+-ion-conducting, O2-impermeable, hopeite [Zn3(PO4)2.4H2O] lamellae on the Nafion-coated Zn anode. The hopeite lamellae allow discharge of the Zn anodes over three weeks at 86% current efficiency in physiological buffer and at 60% efficiency over two weeks in serum. The Zn|physiological buffer|Ag/AgCl cell operates at 1.00 V at 13 muA cm-2 and at 0.94 V at 0.2 mA cm-2 anodic current density.     

TiO2光电化学电池催化氧化甲基红

以钛基TiO₂薄膜为光阳极，研究了光电化学电池中阳极光催化降解偶氮染料甲基红的动力学. 结果表明，短接光电化学电池分隔了光催化过程的阴、阳极反应，有利于抑制光生载流子的复合，提高光催化氧化速率. 相同实验条件下短路光电流越大，则甲基红降解速率越高. 在基底和TiO₂薄膜之间夹层SnO₂得到组装电极Ti/SnO₂/TiO₂，进一步提高了光生载流子的分离效率；同时采用电化学阻抗谱（EIS）评价了电极的光催化性能.     

海水电解面临的挑战与机遇：含氯电化学中先进材料研究进展

氢气是一种清洁高效的能源载体,通过海水电解规模化制备氢气能够为应对全球能源挑战提供新的机遇。然而,缺乏高活性、高选择性和高稳定性的理想电极材料是在腐蚀性海水中连续电解过程的一个巨大挑战。为了缓解这一困境,需要从基础理论和实际应用两方面对材料进行深入研究。近年来,人们围绕电极材料的催化活性、选择性和耐腐蚀性进行了大量的探索。本文重点总结了高选择性和强耐腐蚀性材料的设计合成与作用机制。其中详细介绍了多种电极材料(如多金属氧化物、Ni/Fe/Co基复合材料、氧化锰包覆异质结构等)对氧气生成选择性的研究进展;系统论述了各种材料的抗腐蚀工程研究成果,主要讨论了本征抗腐蚀材料、外防护涂层和原位产生抗腐蚀物种三种情况。此外,提出了海水电解过程中存在的挑战和潜在的机遇。先进纳米材料的设计有望为解决海水电解中的氯化学问题提供新思路。     

基于配合物前驱体的CuO原位制备与电催化产氧活性研究

合成得到了含有N,N,N',N'-四羟乙基乙二胺(THEED)配体的Cu(Ⅱ)配合物[Cu(THEED)(H₂O)]SO₄,通过质谱、元素分析以及X-射线单晶衍射测定了它的组成和晶体结构,并用之作为电催化产氧催化剂的前驱体。在电解含有配合物的碱性NaOAc/NaOH溶液时可检测到氧气产生,并发现有黑色薄膜附着于阳极表面。利用扫描电子显微镜(SEM)、能量色散X射线(EDX)、X射线衍射(XRD)和X射线光电子能谱(XPS)确定该薄膜的主要成分是2 μm大小的无定形CuO颗粒。通过实验证明,CuO为真正的电催化水氧化催化剂,它具有较高活性和稳定性。在无Cu(Ⅱ)、0.10 mol/L NaOAc/NaOH溶液(pH=12.4)中,固定催化电压为1.35 V(相对于标准氢电极电压),催化电流密度可维持1.5 mA/cm²近6 h不变;7.5 h产生氧气97 μmol,法拉第效率95%。     

ZnO掺杂的SnO_2纳米纤维的制备、表征及气敏机理(英文)

以二水氯化亚锡(SnCl2·2H2O)为盐原料,采用静电纺丝的方法制备了SnO2纳米纤维.为了研究ZnO掺杂对SnO2形貌、结构及化学成分的影响,分别制备了不同含量ZnO掺杂的SnO2/ZnO复合材料.利用热重-差热分析(TG-DTA)、X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱仪、扫描电镜(SEM)及能量色散X射线(EDX)光谱对材料的结晶学特性及微结构进行了表征.制备的SnO2/ZnO复合材料是由纳米量级的小颗粒构成的分级结构材料.ZnO含量不同,对应的SnO2/ZnO复合材料结构不同.表征结果表明ZnO的掺杂量对SnO2材料的形貌及结构均起着重要作用.将制备的不同ZnO含量的SnO2/ZnO复合材料进行气敏测试,测试结果表明,Sn:Zn摩尔比为1:1制作的气敏元件对甲醇的灵敏度优于其它摩尔比的气敏元件.讨论了SnO2/ZnO复合材料气敏元件的敏感机理.同时针对Sn:Zn摩尔比为1:1时表现出最好的气敏响应,分析了其原因,包括Zn的替位式掺杂行为、ZnO的催化作用、过量ZnO对SnO2生长的抑制作用以及SnO2与ZnO晶粒界面处的异质结.     

电池结构对叶绿素电池光电性质的影响

叶绿素是绿色植物中吸收太阳能进行光合作用的主要色素,它在可见光范围内有很好的吸收特性^[1]。人们为了充分利用太阳能为人类造福开始了光合作用模拟,70年代后以叶绿素为光敏剂的研究成了科学家的热门课题。     

锰电解过程关键因素研究及技术经济性分析

从槽液Mn²⁺浓度、电解时间和过电位关键因素研究电解初期过程,在三电极体系采用计时电量法探讨和优化工艺参数. 研究表明,在不锈钢表面,锰的初期电解析氢显著. 随时间延长,锰逐渐覆盖于不锈钢表面,析氢更困难,其电流效率随之提升,在高过电位区出现极限电流,反应受扩散控制. 在含0.02 g·L^-1 SeO₂溶液体系中,在40 g·L^-1 Mn²⁺ + 120 g·L^-1 (NH₄)₂SO₄、过电位为0.151 V、槽液温度为40 ^oC、PH为6.6、时间为0.5 h的电解条件下,电流效率可达95.3%;在实用矿粉制液体系,效率也可达81.4%,较企业相同电解体系提高了15%.     

固定床电解槽变电流成对电解合成乙醛酸

对电解氧化乙二醛合成乙醛酸过程 ,固定床电解槽和变电流电解效果明显优于平板型电解槽和恒电流电解效果 .当阳极液中乙二醛和盐酸初始质量分数 (WCHOCHO 和WHCI)分别等于7.0 %和 8.0 %、阴极液为始终饱和的草酸溶液和微量的添加剂时 ,采用平均电流密度 (i)为 15 35A/m2 的变电流方式电解 ,阳极电流效率 (CEa)为 85 .3%、乙醛酸选择性 (RSa)为 93.9% ;阴极电流效率 (CEc)为 86 .7% ,乙醛酸选择性 (RSc)为 94 .0 % .阳极初产品中WCHOCOOH∶WCHOCHO≥ 4 0∶3,克服了阳极产品中乙二醛难以除去的困难     

Sub-100 nm hollow SnO2@C nanoparticles as anode material for lithium ion batteries and significantly enhanced cycle performances

Rational designing and controlling of nanostructures is a key factor in realizing appropriate properties required for the high-performance energy fields. In the present study, hollow SnO₂@C nanoparticles (NPs) with a mean size of 50 nm have been synthesized in large-scale via a facile hydrothermal approach. The morphology and composition of as-obtained products were studied by various characterized techniques. As an anode material for lithium ion batteries (LIBs), the as-prepared hollow SnO₂@C NPs exhibit significant improvement in cycle performances. The discharge capacity of lithium battery is as high as 370 mAh g^-1, and the current density is 3910 mA g^-1(5 C) after 573 cycles. Furthermore, the capacity recovers up to 1100 mAh g^-1 at the rate performances in which the current density is recovered to 156.4 mA g^-1(0.2 C). Undoubtedly, sub-100 nm SnO₂@C NPs provide significant improvement to the electrochemical performance of LIBs as superior-anode nanomaterials, and this carbon coating strategy can pave the way for developing high-performance LIBs.     

锂离子电池用三维氧化锡/石墨烯水凝胶负极材料

通过溶液水解反应在氧化石墨烯表面引入氧化锡(Sn O2)纳米颗粒,再经过自组装作用形成具有三维结构的氧化锡/石墨烯水凝胶(Sn O2-GH)负极材料。其中三维多孔的石墨烯水凝胶为碳质缓冲基体,Sn O2纳米颗粒为活性物质,其颗粒尺寸为2-3 nm,均匀分布在石墨烯层上,担载量可以达到54%(w,质量分数)。直接将该材料用作锂离子电池负极时,在5000 m A?g~(-1)的大电流密度下循环60次容量稳定在500 m Ah?g~(-1),电流减小到50 m A?g~(-1)循环80次后容量仍高达865 m Ah?g~(-1)。这些优异的循环稳定性和大电流充放电性能主要得益于三维石墨烯水凝胶的疏松、多孔结构和良好的导电性。石墨烯水凝胶能够提高电极比表面积,保证电解液对电极的浸润程度;内部空隙能够为锂离子的传输提供快速通道,缩短离子传输距离和时间。同时丰富的内部空间能够有效避免Sn O2纳米颗粒团聚,缓冲Sn O2巨大体积膨胀,维持电极结构的稳定性,是一种非常适于大电流充放电的锂离子电池负极材料。     

H型电解池中CO2电化学还原的阳极电解液问题

采用自制的H型电解池开展了KHCO₃溶液中电化学还原CO₂制甲酸的研究. 研究发现,在电解池中长时间电解时阴阳两极间的电压（槽电压）会持续升高,导致电解过程不可持续. 经过恒电位电解、恒电流电解、pH测试以及电解前后阳极室KHCO₃浓度分析等实验研究,作者发现,这是由以下过程引起的：阳极上的析氧反应产生的H⁺与电解液中的HCO₃^-反应生成水和CO₂,导致阳极室的HCO₃^-的消耗,之后阳极室的K⁺被迫扩散进入阴极室而导致阳极室电解质浓度下降. 因此,阳极室电解液导电性下降,进而引起阳极电位的升高. 研究发现,阳极电解液具有碱性时,都可能发生此种现象,因此,为了保证电解过程可持续且保持高的能量转换效率,阳极液的电解质不能是任何具有碱性的物质.     

Anodic oxidation of formic acid on PdAuIr /C-Sb_2O_5·SnO_2 electrocatalysts prepared by borohydride reduction

PdAuIr/C-Sb2O5·SnO2electrocatalysts with Pd∶Au∶Ir molar ratios of 90∶5∶5,70∶20∶10 and 50∶45∶5 were prepared by borohydride reduction method.These electrocatalysts were characterized by EDX,X-ray diffraction,transmission electron microscopy and the catalytic activity toward formic acid electro-oxidation in acid medium investigated by cyclic voltammetry(CV),chroamperometry(CA)and tests on direct formic acid fuel cell(DFAFC)at 100℃.X-ray diffractograms of PdAuIr/C-Sb2O5·SnO2electrocatalysts showed the presence of Pd fcc phase,Pd-Au fcc alloys,carbon and ATO phases,while Ir phases were not observed.TEM micrographs and histograms indicated that the nanoparticles were not well dispersed on the support and some agglomerates.The cyclic voltammetry and chroamperometry studies showed that PdAuIr/C-Sb2O5·SnO2(50∶45∶5)had superior performance toward formic acid electro-oxidation at 25℃compared to PdAuIr/C-Sb2O5·SnO2(70∶20∶10),PdAuIr/C-Sb2O5·SnO2(90∶5∶5)and Pd/C-Sb2O5·SnO2electrocatalysts.The experiments in a single DFAFC also showed that all PdAuIr/C-Sb2O5·SnO2electrocatalysts exhibited higher performance for formic acid oxidation in comparison with Pd/C-Sb2O5·SnO2electrocatalysts,however PdAuIr/C-Sb2O5·SnO2(90∶5∶5)had superior performance.These results indicated that the addition of Au and Ir to Pd favor the electro-oxidation of formic acid,which could be attributed to the bifunctional mechanism(the presence of ATO,Au and Ir oxides species)associated to the electronic effect(Pd-Au fcc alloys).