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| 1 | High resolution, binder-free investigation of the intrinsic activity of immobilized NiFe LDH nanoparticles on etched carbon nanoelectrodes显示文摘The determination of the intrinsic properties of nanomaterials is essentialfor their optimization as electrocatalysts, however it poses great challengesfrom the standpoint of analytical tools and methods. Herein, we report anovel methodology that allows for a binder-free investigation of electrocatalystnanoparficles. The potential-assisted immobilization of a non-noble metalcatalyst, i.e., nickel-iron layered double hydroxide (NiFe LDH) nanoparticles, wasemployed to directly attach small nanoparticle ensembles from a suspensionto the surface of etched carbon nanoelectrodes. The dimensions of this type ofelectrodes allowed for the immobilization of the catalyst material below thepicogram scale and resulted in a high resolution towards the faradaic currentresponse. In addition the effect of the electrochemical aging on the intrinsic activityof the catalyst was investigated in alkaline media by means of continuous cyclicvoltammetry. A change in the material properties could be observed, which wasaccompanied by a substantial decrease in its intrinsic activity. | Patrick Wilde Stefan Barwe Corina Andronescu Wolfgang Schuhmann Edgar Ventosa | 2018 | Nano Research2018，11，11： | 3 |
| 2 | 甘油氧化的光谱电化学傅里叶变换衰减全反射谱红外光谱薄膜流动池中硼酸镍层厚度的优化显示文摘在碱性甘油电氧化反应中,利用电化学傅里叶变换衰减全反射谱红外光谱法,研究了薄膜流动池中滴注硼酸镍催化剂负载量对玻碳电极性能的影响.连续操作的径向流动池包括一个位于内反射元件上方50μm的钻孔电极,可实现红外光谱分析.这是在确定条件下对电催化剂进行简便和可重复筛选的一个适合的方法,同时还提供了对复杂反应(如甘油氧化)产物选择性的检测.通过对泵送电解液进行更耗时的定量高效液相色谱分析,结果表明,衰减全反射红外光谱法可快速鉴定产物.在层流条件下,水中使用0.1 M甘油和1 M KOH,流速为5μL min^(-1)时,甘油转化率较高.转化率和选择性取决于催化剂的负载量,负载量又决定了催化剂层的厚度和粗糙度.由于在更粗糙的膜中停留时间更长有利于再吸附和C-C键断裂,因此当负载量最高达210μg cm^(-2)时,甘油转化率为73%且甲酸选择性接近80%.当最低负载量为13μg cm^(-2)时,甘油转化率达到63%,甲酸选择性降至60%,相应地,C_(2)物种(如乙醇酸盐)选择性较高,为8%.因此,只有催化剂负载量较低时才能形成几微米厚度范围内的薄膜,此时才适合进行优质催化剂的筛选. | Steffen Cychy Sebastian Lechler Zijian Huang Michael Braun Ann Cathrin Brix Peter Blümler Corina Andronescu Friederike Schmid Wolfgang Schuhmann Martin Muhler | 2021 | Chinese Journal of Catalysis2021，42，12： | 2 |
| 3 | Searching novel complex solid solution electrocatalysts in unconventional element combinations显示文摘Despite outstanding accomplishments in catalyst discovery,finding new,more efficient,environmentally neutral,and noble metalfree catalysts remains challenging and unsolved.Recently,complex solid solutions consisting of at least five different elements and often named as high-entropy alloys have emerged as a new class of electrocatalysts for a variety of reactions.The multicomponent combinations of elements facilitate tuning of active sites and catalytic properties.Predicting optimal catalyst composition remains difficult,making testing of a very high number of them indispensable.We present the high-throughput screening of the electrochemical activity of thin film material libraries prepared by combinatorial co-sputtering of metals which are commonly used in catalysis(Pd,Cu,Ni)combined with metals which are not commonly used in catalysis(Ti,Hf,Zr).Introducing unusual elements in the search space allows discovery of catalytic activity for hitherto unknown compositions.Material libraries with very similar composition spreads can show different activities vs.composition trends for different reactions.In order to address the inherent challenge of the huge combinatorial material space and the inability to predict active electrocatalyst compositions,we developed a high-throughput process based on co-sputtered material libraries,and performed high-throughput characterization using energy dispersive X-ray spectroscopy(EDS),scanning transmission electron microscopy(SEM),X-ray diffraction(XRD)and conductivity measurements followed by electrochemical screening by means of a scanning droplet cell.The results show surprising material compositions with increased activity for the oxygen reduction reaction and the hydrogen evolution reaction.Such data are important input data for future data-driven materials prediction. | Olga A.Krysiak Simon Schumacher Alan Savan Wolfgang Schuhmann Alfred Ludwig Corina Andronescu | 2022 | Nano Research2022，15，6： | 0 |
| 4 | Calibrating SECCM measurements by means of a nanoelectrode ruler.The intrinsic oxygen reduction activity of PtNi catalyst nanoparticles显示文摘Scanning electrochemical cell microscopy(SECCM)is increasingly applied to determine the intrinsic catalytic activity of single electrocatalyst particle.This is especially feasible if the catalyst nanoparticles are large enough that they can be found and counted in post-SECCM scanning electron microscopy images.Evidently,this becomes impossible for very small nanoparticles and hence,a catalytic current measured in one landing zone of the SECCM droplet cannot be correlated to the exact number of catalyst particles.We show,that by introducing a ruler method employing a carbon nanoelectrode decorated with a countable number of the same catalyst particles from which the catalytic activity can be determined,the activity determined using SECCM from many spots can be converted in the intrinsic catalytic activity of a certain number of catalyst nanoparticles. | Emmanuel Batsa Tetteh Tobias Loffler Tsvetan Tarnev Thomas Quast Patrick Wilde Harshitha Barike Aiyappa Simon Schumacher Corina Andronescu Richard D.Tilley Xingxing Chen Wolfgang Schuhmann | 2022 | Nano Research2022，15，2： | 0 |
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