温度对乙醇电催化氧化的影响

升高温度可以提高反应速率和增加物质的输运，因此通过不同温度下反应机理的研究可以深入理解电催化过程，对催化剂的设计具有指导意义。本工作初步建立了变温原位红外测定方法。采用温控电极，用电势测温法进行温度的校准，实验得出控温仪器加热温度Th与电极表面温度TS的关系为TS = 0.57Th + 7.71 (30 ℃ < Th ≤ 50 ℃)；TS = 0.62Th + 5.12 (50 ℃ < Th ≤ 80 ℃)，误差分析最大温差为1 ℃。利用该方法我们研究了商业Pt/C催化剂在不同温度下乙醇的电氧化过程。从循环伏安图可以明显看到随着温度的升高整体氧化电流增大，起始电位、峰电位均负移，说明热活化使得氧化反应更容易进行；第一个峰电流与第二个峰电流的比值用于定性评估CO2的选择性，对比25 ℃，商业Pt/C催化剂在65 ℃下第一峰提高30%，说明高温有利于C―C键的断裂。对比25 ℃ 的原位红外谱图，我们发现35 ℃及50 ℃下商业Pt/C催化剂上CO2产物的起始电位负移200 mV，说明高温下，Pt/C催化剂能在更低的电位提供含氧物种；而CH3CHO、CH3COOH起始电位不随温度变化。用CO2与CH3COOH的积分面积比来评估CO2选择性，发现高温低电位其选择性最高，说明高温低电位有利于乙醇完全氧化生成CO2，而高温高电位下表面吸附含氧物种占据了活性位，阻碍C―C键断裂。国家自然科学基金(21773198, U1705253, 21621091)国家重点研发计划(2017YFA0206500)资助项

Pt纳米微粒电极上CO吸附的电化学循环伏安和原位FTIR反射光谱

用化学还原法制备铂金属纳米微粒.经TEM表征纳米Pt微粒的平均直径为2.5nm.应用电化学循环伏安法研究了该纳米微粒电极的电化学性质,与本体Pt相比,吸附在Pt纳米微粒表面CO的氧化电流峰较宽.原位傅里叶变换红外反射光谱检测到Pt纳米微粒电极表面的孪生吸附态CO,以及随电极电位变化线型吸附和孪生吸附态CO向桥式吸附态CO的转化过程.还发现了Pt纳米微粒上吸附态CO的增强红外吸收等一系列特殊性能.国家自然科学基金资助项目(批准号:29833060,20021002)

Effect of pH and Au Nanoparticles on Cytochrome c Investigated by Electrochemistry and UV-Vis Absorption Spectroscopy

Corresponding author. Email: [email protected]; Tel: +86-592-2180181制备了粒径均匀、平均粒子尺度为(4.7±0.6)nm,表面修饰3-巯基丙酸(MPA)的金纳米粒子(AuNPs).利用电化学和紫外-可见(UV-Vis)吸收光谱研究了pH和AuNPs对细胞色素c(Cytc)结构的影响.UV-Vis吸收光谱结果表明,pH为7.5-3.0时,Cytc和Cytc-AuNPs复合物的结构没有发生明显变化.当pH=2.0时,Cytc和Cytc-AuNPs复合物的Soret谱峰位置均发生明显移动,说明pH诱导其构象发生变化.循环伏安(CV)结果表明,表面修饰了MPA的AuNPs能促进Cytc和电极之间的电子传输,与修饰了柠檬酸根的AuNPs相比,其生物兼容性更好.pH的变化会引起CV中Cytc峰电流的改变和峰电位的移动.随着pH值的降低,Cytc电活性的量逐渐减小,并且pH诱导Cytc发生不可逆变性.AuNPs的引入使自由态的Cytc耐酸性增强,而使得吸附态的Cytc耐酸能力减弱.国家自然科学基金(20833005,20873116,60936003,21021002)资助项

电化学联用技术研究微生物的胞外电子传递机制

胞外电子传递(EET)是指氧化还原反应所产生的电子在微生物细胞内和细胞外的电子受体/电子供体之间互相转移的过程,这一过程伴随着能量和物质的转化。阐明EET机制是提高微生物能量和物质转化效率的基础,为元素的生物地球化学循环、金属防腐以及生物电化学系统的应用等提供理论支撑。电化学技术作为研究电极/溶液界面电子转移的简便、有效方法,在研究微生物的直接电子传递和间接电子传递机制中发挥了重要的作用,也促进了EET机制的研究从宏观层面到微观层面不断深入。本文综述了研究微生物EET机制所涉及的电化学联用技术(包括微电极、扫描电化学显微镜、电化学联用光学显微镜和光谱电化学等);详细介绍了这些电化学联用技术的功能和优势;重点阐述了这些电化学联用技术如何推动着EET机制的研究,从宏观的生物膜层面到微观的单个微生物细胞、蛋白和分子层面不断深入;展望了新的电化学联用技术在EET研究领域的应用前景。国家重点研发计划项目项目(No.2017YFA0206500);;国家自然科学基金项目(No.21777155,21773198,U1705253,21621091)资助~

Progresses on the research of the interfacial compatibility between lithium electrode and polymer electrolyte

对聚合物电解质(PE)的研究主要包括两个方面:第一,在保持聚合物电解质机械强度的前提下提高其室温离子迁移性(包括离子电导率和锂离子迁移数);第二,改善聚合物电解质与电极,特别是与锂电极的界面相容性,即在降低锂电极/聚合物电解质(Li/PE)初始界面阻抗的同时增强其界面稳定性。改善Li/PE界面相容性对于锂聚合物蓄电池的商业化具有重要意义。综述了Li/PE界面研究特点及Li/PE界面研究的最新进展。It mainly includes two aspects for the research of polymer electrolyte (PE): First is the enhancement of self-performance, i.e., improving the ability of ion transfer (including ionic conductivity and Li+ transference number) at room temperature in the case of good mechanical strength; Second is the improvement of the interfacial compatibility with electrodes, especially with lithium electrode, i.e., enhancing the interfacial stability between lithium electrode and polymer electrolyte (Li / PE) on the condition of reducing initial interfacial resistance. It is of significance for the commercialization of lithium polymer secondary batteries to improve the interfacial compatibility between Li / PE. In this paper, the general features on the research of Li / PE interface were introduced, and the progresses on the research of the interfacial compatibility between Li/PE were reviewed.国家“973”项目(2002CB211804);; 国家自然科学基金(90206039)资

CO adsorption on electrode of Pt nanoparticles investigated by cyclic voltammetry and in situ FTIR spectroscopy

Pt nanoparticles were prepared by the chemical reduction method. The average diameter of Pt nanoparticles was determined to be 2.5 nm by TEM. The electrochemical properties of Pt nanoparticles were studied by cyclic voltammetry. In comparison with massive Pt, the oxidation current peak of CO adsorbed on Pt nanoparticles is broader. Twin adsorbates of CO on Pt nanoparticles were determined by in situ FTIRS for the first time. It has revealed that the linear and twin-bonded CO can be converted into bridge-bonded CO with the variation of electrode potential. A series of special properties of Pt nanoparticles, such as enhanced IR absorption of CO adsorbates, were also observed

钯纳米粒子及其团聚体特殊红外性能的CO分子探针红外光谱

以聚乙烯吡咯烷酮(PVP)为稳定剂, 用乙醇还原氯钯酸制备分散的钯纳米粒子(Pdn). 从分散于电极表面的Pdn出发, 以50 mV·s-1的扫描速度, 在 0.25～1.25 V间循环扫描30 min可以制备团聚体 Pdnag. 固/气和固/液界面透射和反射CO分子探针红外光谱研究结果指出, 吸附在Pdn上非对称和对称桥位上的桥式吸附态CO(COB)在1964 和 1905 cm-1给出两个红外吸收谱峰, 但CO吸附在Pdnag上仅在1963 cm-1给出一个方向倒反的异常红外谱峰. 此外, CO谱峰的半峰宽由Pdn上的14 cm-1变为Pdnag上的24 cm-1. Pdn形成团聚体Pdnag后, Pd纳米粒子间相互作用增强, Pdn和Pdnag红外光学性质的显著差别初步归因于纳米粒子之间的相互作用

Room Temperature Synthesis of Thorn-Like Pd Nanoparticles and Their Enhanced Electrocatalytic Property for Ethanol Oxidation

Corresponding authors. Email: [email protected],[email protected], Tel:+86-592-2180181.[中文文摘]室温下以氯化胆碱为稳定剂,用化学还原法合成了刺状Pd纳米粒子(Pdtnh0o0r0n).透射电子显微镜和电化学循环伏安研究结果表明Pdtnh0o0r0n具有较高密度的台阶位,与商业Pd黑催化剂相比较,Pdtnh0o0r0n对乙醇氧化的电催化活性显著提高,氧化电流密度是商业Pd黑催化剂的1.2倍(-0.40--0.30V)-1.5倍(-0.65--0.40V),起始氧化电位和峰电位均负移50mV.相同电流密度下,Pdtnh0o0r0n催化剂对乙醇的氧化电位均更低.[英文文摘]Thorn-like Pd nanoparticles (Pdtnh0o0r0n ) were synthesized at room temperature by a reduction of PdCl2 with L-ascorbic acid and with choline chloride as a stabilizer. Characterization of Pdtnh0o0r0n by transmission electron microscopy and cyclic voltammetry indicated that the synthesized Pd tnh0o0r0n has a relatively high density of surface step sites. By comparison with the commercially available Pd black catalyst, Pdtnh0o0r0n exhibits better catalytic activity towards ethanol oxidation. The oxidation current density on Pdthorn n000 was 1.2 times (-0.40 - -0.30 V) - 1.5 times (-0.65 - -0.40 V) as that on Pd black, and the onset potential and the peak potential of ethanol oxidation both shifted 50 mV in the negative direction. The oxidation potential of ethanol on Pdthorn n000 is lower at the same current density.国家自然科学基金(20833005,20873116,60936003); 超分子结构和材料国家重点实验室(SKLSSM200910)资助项

Application of IR spectroscopy in Li-ion batteries studies

综述了傅立叶变换红外光谱在锂离子电池基础研究中应用的进展,主要包括负极表面SEI膜的组成和结构、电解液稳定性、电极材料的结构表征以及聚合物电解质的表征等。Progress in applications of FTIRS in studies of Li-ion batteries was reviewed. It included composition and structure of SEI film on anode, stability of electrolyte, structure characterization of electrode materials and characterization of polymer electrolyte.国家"973"项目(2002CB211804);; 国家自然科学基金项目(20173045