View Anthony Wright’s profile on LinkedIn, the world’s largest professional community. Carolina Galeano, The presented synthesis method can be generalized for the deposition of many other metal/CNW hybrids by choosing the appropriate metal acetylacetonate. Um die Sprache auf, We have identified a more suitable language of this document. The degree of oxidation of only the Pt-NPs (mainly Pt(OH)2) of individual samples is shown in parentheses under the platinum loading. Deutschland | 562 followers on LinkedIn. electrocatalyst; fuel cells; hybrid nanomaterial; long-term stability; nanoparticle embedding; one-step synthesis; plasma-enhanced chemical vapor deposition (PE-CVD), http://www.xpsfitting.com/search/label/Platinum, Design criteria for stable Pt/C fuel cell catalysts, Anomalous current–voltage characteristics of SFIFS Josephson junctions with weak ferromagnetic interlayers. Auf LinkedIn können Sie sich das vollständige Profil ansehen und mehr über die Kontakte von Sebastian Tigges und Jobs bei ähnlichen Unternehmen erfahren. All spectra were fitted with the software CASA XPS according to a method described elsewhere [17], while atomic percentages were determined with the software Multipak. We have successfully used Al(acac)3 [17] and Pd(acac)2 as precursors, while others have demonstrated the use of Fe(acac)3 in a chemical vapor synthesis set-up [35]. Platinum acetylacetonate is dissociated by the pl... A typical CNW sheet of a sample processed at 8 Pa chamber pressure, 60 sccm argon carrier gas flow rate, and 350 °C substrate temperature is shown in a bright-field transmission electron microscope (TEM) micrograph in Figure 2a. When using GCEs as substrates for deposition and following characterization in CV, the deposited catalyst mass on these small substrates is in the range of 15–30 µg depending on Pt loading. Figure 6: A typical histogram of the Pt-NPs is shown in Figure 2c, displaying a narrow PSD with a geometric standard deviation [21] between 1.24 and 1.3. Ph.D. Thesis, Ruhr-Universität Bochum, Bochum, Germany, 2004. The wall density, as well as the growth rate, was found to increase with increasing gas flow rate, decreasing pressure and increasing substrate temperature, which agrees with a previous study [17]. Sie können die vorgenommenen Einstellungen jederzeit ändern, indem Sie in unserer Cookie-Richtlinie auf die Schaltfläche „Cookie-Einstellungen aktualisieren“ klicken. The calculated ECSA of all Pt/CNW samples is comparable to the ECSA of the standard commercial proton-exchange membrane fuel cell (PEMFC) catalyst, HiSPEC4000. in unserer Website integriert sind. Philippe Serp, Josef C. Meier, Sie ermöglichen Ihnen außerdem das Einloggen in personalisierte Bereiche sowie den Zugriff auf die Tools von Drittanbietern, die ggf. In these processes, long ultrasonication as well as reduction/heating procedures are required [6,10], both of which will impede industrial production. There are 70+ professionals named "Sebastian Wozniak", who use LinkedIn to exchange information, ideas, and … Figure 4: In the survey scan, no other signal besides those related to carbon, oxygen and platinum was detected. See the complete profile on LinkedIn and discover Raaj Shikhar’s connections and jobs at similar companies. Support by the Interdisciplinary Center for Analytics on the Nanoscale (ICAN) of the University of Duisburg-Essen, a DFG core facility (reference RI_00313), is gratefully acknowledged (user and service operation). Während seiner Ausbildung lag sein Schwerpunkt im Bereich Venture Capital. GWB-Novelle (GWB-Digitalisierungsgesetz) ist heute in Kraft getreten, Update BGH-Rechtsprechung zum Gesellschaftsrecht 12/2020, 2021 – The­men, die Sie be­we­gen wer­den, Mitteilungspflicht für grenzüberschreitende Steuergestaltungen, 2014 - 2016: Referendariat in Hamburg und Berlin, Stationen unter anderem beim Deutschen Bundestag und einer internationalen Wirtschaftskanzlei, Studium der Rechtswissenschaften in Düsseldorf, München und Heidelberg. b) A dark-field TEM micrograph of a porous CNW. The relative platinum loading and degree of oxidation were determined by X-ray photoelectron spectroscopy (XPS, see Experimental section). Er wird für Unternehmen in der Krise sowohl beratend mit einem Schwerpunkt auf gesellschaftsrechtliche Themen als auch in der Insolvenzverwaltung tätig. 5-7, 45141 Essen, Germany. At high gas velocities, more Pt can reach the substrate, as at lower gas velocities Pt is already deposited in the silica glass tube leading from the oven to the deposition chamber. Effect of substitutional defects on resonant tunneling diodes based on armchair graphene and boron nitride nanoribbons lateral heterojunctions [28] and Suzuki and coworkers [29]. Even though parts of the embedded Pt-NPs may not be in contact with the liquid electrolyte during CV, a sufficient ECSA and utilization were obtained. A Pt wire was used as the counter electrode, and Hg/HgSO4 (sat. View Sebastian Wendland’s profile on LinkedIn, the world's largest professional community. A similar issue limits surfactant-free chemical synthesis techniques, such as solvothermal and hydrothermal synthesis [9]. Wir setzen Cookies ein, um das Nutzungsverhalten auf unseren Websites auszuwerten und Ihnen personalisierte Inhalte präsentieren zu können. Ferdi Schüth and This increased long-term stability is surprising, as a significant percentage (at least >15% of the overall surface area at the highest mean particle diameter) of the PSD of our Pt/CNW catalyst layers are below or close to the threshold value for catalyst corrosion via Pt dissolution of 2 nm reported in the literature [16,34], which is not the case for HiSPEC4000 (mean particle diameter of 4.5 nm). Stefano Mezzavilla, [32]. The presented synthesis method is highly versatile, as a multitude of different metal acetylacetonates is commercially available, which facilitates the deposition of a variety of metal/CNW hybrids for optimization of performance and cost efficiency and use in applications other than electrocatalysis. Since the electrocatalytic performance of the Pt/CNW hybrid material is expected to depend on the amount, size, shape, distribution and oxidation of the embedded Pt-NPs [4], we carefully studied the influence of the four process parameters presented above on the physical and chemical properties of the resulting Pt-NPs. Figure 4: Tommy har angett 6 jobb i sin profil. High pressures and low carrier gas flow rates enable a morphology transition from CNWs to nanoflakes. Ve el perfil completo en LinkedIn y descubre los contactos y empleos de Ana M. en empresas similares. Anastasia V. Guravova, The morphology of the resulting samples was investigated using a scanning electron microscope (SEM; Inspect F and Helios 600 NanoLab DualBeam, FEI Deutschland GmbH). The electrochemical measurements were performed in a three-electrode electrochemical cell (glassy cell: double wall, temperature-controlled at 25 °C) filled with 0.1 M HClO4 electrolyte (AppliChem PanReac, 70%, for analysis, ACS, ISO). Some of the wiped off catalyst material was used for TEM measurements. Hence, these supports often require additional functionalization steps for avoiding metal particle agglomeration, which reduces the electrical conductivity and durability of the support. The plasma properties were monitored in situ by optical emission spectroscopy (see Supporting Information File 1). Weight percentages of Pt, C, and O of samples processed at different process pressures and a constant substrate temperature of 350 °C without the addition of hydrogen gas measured by XPS. Anthony has 1 job listed on their profile. Platinum acetylacetonate (98%, abcr GmbH) was placed inside an evaporator at the backside of the chamber, a silica glass tube was fitted to the exhaust of the evaporator that pointed towards the substrate holder, and the reactor chamber was evacuated to <5 × 10−6 mbar before the deposition process. Martin has 12 jobs listed on their profile. After 2000 accelerated stress test (AST) cycles, the most durable Pt/CNW layers still retain 50–70% of their maximum ECSA, while the commercial catalyst only has 30% left. ; Zhao, N.; Fang, B.; Li, H.; Bi, X. T.; Wang, H. Haxhiaj, I.; Tigges, S.; Firla, D.; Zhang, X.; Hagemann, U.; Kondo, T.; Nakamura, J.; Marzun, G.; Barcikowski, S. Shao-Horn, Y.; Sheng, W. C.; Chen, S.; Ferreira, P. J.; Holby, E. F.; Morgan, D. Kohsakowski, S.; Streubel, R.; Radev, I.; Peinecke, V.; Barcikowski, S.; Marzun, G.; Reichenberger, S. Yu, F.; Liu, M.; Ma, C.; Di, L.; Dai, B.; Zhang, L. Liu, Y.; Zhang, L.; Willis, B. G.; Mustain, W. E. Li, Y.; Gao, W.; Ci, L.; Wang, C.; Ajayan, P. M. Hiramatsu, M.; Kondo, H.; Hori, M. Graphene Nanowalls. It is possible that the absolute ECSA values and utilization of CV1, CV2, and CV3 might be somewhat overestimated, due to the limitations described in the Experimental section. This can be explained by the aforementioned removal of carbon at the Pt-NPs surface and slower degradation of the Pt/CNW catalysts as observed in Figure 8. Im Profil von Sebastian Tigges sind 2 Jobs angegeben. Wenn Sie diese Cookies nicht akzeptieren, stehen Ihnen die Funktionen der Website nur eingeschränkt zur Verfügung. View ibrahim ali’s profile on LinkedIn, the world's largest professional community. View Martin Schorsch’s profile on LinkedIn, the world’s largest professional community. Platinum acetylacetonate is dissociated by the plasma and the simultaneous deposition of Pt-NPs (black dots in the TEM image) and CNWs occurs. a) Bright-field TEM micrograph of a typical Pt/CNW sheet, showing homogeneously distributed Pt-NPs (black dots). doi:10.3762/bjnano.11.126. Se Mette Scheel Kristensens profil på LinkedIn – verdens største faglige netværk. See the complete profile on LinkedIn and discover peter’s connections and jobs at similar companies. A.; Baldizzone, C.; Mezzavilla, S.; Schüth, F.; Mayrhofer, K. J. J. Enz, T.; Winterer, M.; Stahl, B.; Bhattacharya, S.; Miehe, G.; Foster, K.; Fasel, C.; Hahn, H. Alaswad, A.; Baroutaji, A.; Achour, H.; Carton, J.; Al Makky, A.; Olabi, A. G. Rath, R.; Kumar, P.; Mohanty, S.; Nayak, S. K. Wang, Y.-J. View Raaj Shikhar Srivastava’s profile on LinkedIn, the world’s largest professional community. Informationen darüber, wie Sie Ihre Auswahl zu einem späteren Zeitpunkt ändern können, sowie weitere Informationen finden Sie in unserer, „Ver­ant­wort­li­cher″ wi­der Wil­len? XPS a) survey and elemental scans of b) the slightly oxidized sample P7 and c) the highly oxidized sample P6. In Figure 7, the calculated ECSA (see Experimental section) of three samples (CV1, CV2, and CV3) are compared to a commercially available catalyst powder (HiSPEC4000). Figure 3: Additionally, we have measured ORR mass activities of the Pt/CNW samples relative to those of the commercial catalyst with a rotating disk electrode at 1600 rpm. The RF power was kept constant at 500 W (load power) and the processing time was 50 min if not stated otherwise. As the precursor molecule provides much more carbon than platinum, the reduction in platinum loading likely results from a significant increase in the CNW growth and nucleation rate with substrate temperature (see Figure 4c) above the capability of the surrounding to provide sufficient Pt for embedding. Figure 5: However, these approaches typically require multiple-step procedures in which the support and catalytic nanoparticles (NPs) are first produced individually and then combined in a third step (i.e., NP sedimentation in liquid phase [13] or the supercritical CO2 method [14]) to form the required electrocatalyst [6]. for the Pt/CNW samples processed at different process parameters (CV1, CV2, and CV3) and a commercially available fuel cell catalyst (HiSPEC4000) measured by CV. профиль участника Alexey Lisikhin в LinkedIn, крупнейшем в мире сообществе специалистов. She is very focused and customers often named her personally at … Während seiner Ausbildung lag sein Schwerpunkt im Bereich Venture Capital. Mette har 9 job på sin profil. More remarkably, the density of the CNWs decreases drastically when increasing the hydrogen concentration in the plasma (Ar/H2 ≈118, Figure 4d, middle panel). Call for papers is still open for this thematic issue. The global fuel cell market reached a value of $4.5 billion USD in 2018 and is projected to reach a value of $9.5 billion USD by 2024, resulting in a compound annual growth rate of 13.2% during 2019–2024 [1]. An inductively coupled plasma-enhanced chemical vapor deposition process at a substrate temperature as low as 350 °C using platinum acetylacetonate as a single-source precursor was established for the deposition of a Pt/C electrocatalyst. Keywords: electrocatalyst; fuel cells; hybrid nanomaterial; long-term stability; nanoparticle embedding; one-step synthesis; plasma-enhanced chemical vapor deposition (PE-CVD). Figure 4 shows the influence of the carrier gas flow rate (a), pressure (b), and substrate temperature (c) on the CNW morphology. The platinum loading and degree of oxidation of the whole Pt/CNW catalyst layers are dependent on the carrier gas flow rate during synthesis. Raymond heeft een opleiding vermeld op zijn of haar profiel. The black dots in a) are identified as Pt-NPs. Please enable Javascript and Cookies to allow this site to work correctly! Figure 2: The proportion of carbon etchant (H and O) to CNW growth species (CH and C2) in the plasma, which is frequently regarded as one of the most critical parameters of crystalline CNW growth [19,24-27], is well-adjusted under the given deposition conditions and, as a result, promising electrocatalysts are obtained. Da­ten­schutz spielt ei­ne im­mer wich­ti­ge­re Rol­le. Remarkably, the degree of oxidation of the Pt-NPs can be controlled by varying the carrier gas flow rate at specific pressures without influencing the CNW morphology (as can be seen in Figure 4a). However, this does not affect the results for the significantly improved long-term stability of the Pt/CNW catalyst discussed in the following. [39] using standard data evaluation software (Origin). – Der In­sol­venz­ver­wal­ter als Da­ten­schüt­zer. The transparency register in AML directive, The private placement of equity securities. The porosity of the support can be observed in the dark-field TEM micrograph (Figure 2b) and has been reported to be beneficial in electrocatalysis, as it reduces mass transport limitations and increases the surface area [20]. M. Rosa Axet, Afterward, both GCEs were compared to each other via SEM, Raman spectroscopy, and XPS. Alaswad, A.; Baroutaji, A.; Achour, H.; Carton, J.; Al Makky, A.; Olabi, A. G. Rath, R.; Kumar, P.; Mohanty, S.; Nayak, S. K. Li, Y.; Sun, Y.; Qin, Y.; Zhang, W.; Wang, L.; Luo, M.; Yang, H.; Guo, S. Esmaeilifar, A.; Rowshanzamir, S.; Eikani, M. H.; Ghazanfari, E. Lopez-Sanchez, J. The dependence of mean particle diameter and geometric standard deviation on platinum loading of the catalyst layers for samples deposited at varying process parameters. Auf dieser Website setzen wir Cookies ein, um Ihnen das bestmögliche Nutzererlebnis bieten zu können. The calculations were performed by using where is the precursor gas flow rate, Δm is the mass of evaporated precursor, V is the molar volume of an ideal gas (22.4 mol/L), t is overall process time (including preheating), and M is the molar mass of the precursor (393.302 g/mol). Meier, J. C.; Galeano, C.; Katsounaros, I.; Witte, J.; Bongard, H. J.; Topalov, A. 1Faculty of Physics and CENIDE, University of Duisburg-Essen, Carl-Benz-Straße 199, 47057 Duisburg, Germany The degree of oxidation of only the Pt-NPs (mainly Pt(OH)2) of individual samples is shown in parentheses under the Pt weight loading. Wenn Sie damit einverstanden sind, klicken Sie bitte unten auf „Alle akzeptieren“. XPS a) survey and elemental scans of b) the slightly oxidized sample P7 and c) the highly oxidized ... Table 1 and Table 2 summarize weight percentages and degree of oxidation of the whole Pt/CNW layer (O content of Pt and C combined) and the degree of oxidation of only the Pt-NPs (Pt0/PtII-ratio) as determined by XPS of samples obtained with different process pressures (Table 1) and carrier gas flow rates (Table 2). ECSA maximum (columns) and ECSA initial values (red, dashed line, if the ECSAinitial < ECSAmax.) Benjamin a 3 postes sur son profil. See the complete profile on LinkedIn and discover Jeff’s connections and jobs at similar companies. В профиле участника Alexey указано 7 мест работы. Ong An accelerated stress test (AST) consists of 10,000 triangular potentiodynamic cycles between 0.4–1 V vs NHE with a scan rate of 1 V/s. Bekijk het volledige profiel op LinkedIn om de connecties van Raymond en vacatures bij vergelijkbare bedrijven te zien. Figure 6 shows the mean particle diameter (xc) and geometric standard deviation (σg) over the platinum loading of Pt/CNW layers deposited under different process conditions. Personalisierungscookies sammeln Informationen über Ihre Gewohnheiten bei der Nutzung unserer Website. A one-step, single-source approach for the deposition of Pt/CNW hybrid materials using plasma-enhanced chemical vapor deposition is presented. As a mother, it “feels weird” to share every intimate moment. Even though the influence of the physicochemical properties of Pt/C on its electrochemical characteristics has been extensively studied in the literature [16,23], the unique synthesis method presented here is expected to influence both the electrochemically active surface area (ECSA), oxygen reduction reaction (ORR) mass activites and stability of the catalytically active Pt-NP, due to the aforementioned embedding. The degree of oxidation of only the Pt-NPs (mainly Pt(OH)2) of individual samples is shown in parentheses under the Pt weight loading. Sebastian Tigges begann seine anwaltliche Laufbahn 2016 bei CMS. An increase in substrate temperature reduces the platinum loading in the resulting hybrid material (P10 vs P12 and P9 vs P11; Table 3). Sebastian Tigges ist Rechtsanwalt im Bereich Insolvenz und Restrukturierung. This extends the application of the synthesis process described here far beyond the Pt/CNW system. ORR mass activities were measured at 1600 rpm in oxygen-saturated 0.1M HClO4 at 25 °C and determined at 0.9 V vs NHE. Bo, Z.; Yang, Y.; Chen, J.; Yu, K.; Yan, J.; Cen, K. Santhosh, N. M.; Filipič, G.; Tatarova, E.; Baranov, O.; Kondo, H.; Sekine, M.; Hori, M.; Ostrikov, K.; Cvelbar, U. Tigges, S.; Wöhrl, N.; Hagemann, U.; Ney, M.; Lorke, A. Zhou, Z.; Li, X.; Li, Q.; Zhao, Y.; Pang, H. Esmaeilifar, A.; Rowshanzamir, S.; Eikani, M. H.; Ghazanfari, E. Lopez-Sanchez, J. Particle size distributions were measured by using the semi-automatic mode of the software pebbles [42], assuming a spherical particle shape. The utilization (calculated ECSA divided by theoretical ECSA of smooth, round particles) is approximately 33%, 59%, 18% and 65% for CV1, CV2, CV3 and HiSPEC4000, respectively. K2SO4) from Radiometer Analytical with an electrode potential of 680 mV vs NHE (measured by us) was used as the reference electrode. View Sebastian Lutz’s profile on LinkedIn, the world’s largest professional community. At moderate Pt loading (7.6 wt %), the substrate temperature does not have any influence on Pt loading (not shown here). In contrast, low carrier gas flow rates and moderate to high pressures (small absolute gas velocities) resulted in substantial oxidation of the Pt-NPs in the layer, as can be seen when comparing sample P6 to P2. Für eine optimale Darstellung laden Sie bitte die neuste Version herunter oder benutzen Sie einen anderen Browser. Consequently, embedding Pt-NP in the C-matrix not only results in narrow PSDs due to the suppression of particle growth by agglomeration but also in increased long-term stability as was observed for all Pt/CNW catalysts when compared to HiSPEC4000 (see Figure 8). View peter wendoh’s profile on LinkedIn, the world’s largest professional community. This is an Open Access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0). Higher platinum loadings result in higher mean particle diameters, while the geometric standard deviation does not vary significantly. Sebastian Tigges ist Rechtsanwalt im Bereich Insolvenz und Restrukturierung. Cost-efficiency, durability, and reliability of catalysts, as well as their operational lifetime, are the main challenges in chemical energy conversion. Yohann R. J. Thomas, For details on the experimental procedures, see the Experimental section. International Soccer Management Ba Phone: +49(0)172-8410604 E-Mail: info@ism-ba.com Web: www.ism-ba.com A table summarizing the process parameters for every sample shown in this work can be found in Supporting Information File 1, Table S1. Social-Media-Cookies sammeln Informationen darüber, wie Sie Inhalte von unserer Website über die sozialen Medien teilen, oder liefern Analysedaten zu Ihrem Nutzungsverhalten, wenn Sie zwischen Social-Media-Plattformen oder unseren Social-Media-Kampagnen und unseren eigenen Websites navigieren. A more detailed evaluation of the Raman data can be found in Supporting Information File 1. Ins­be­son­de­re für Ge­schäfts­füh­rer ei­ner Ge­sell­schaft ist ei­ne ver­läss­li­che Me­tho­de zur Be­stim­mung der Zah­lungs­un­fä­hig­keit un­ver­zicht­bar. Michael Niermann is a senior partner at the law firm and a special counsel for labour law, specialised in all questions ranging from the first job interview to the negotiation of termination solutions or litigation. EDS (Oxford Instruments), in combination with an aberration-corrected transmission electron microscope (TEM; JEOL 2200FS), was used to analyze the chemical composition and to record high-resolution micrographs at a sub-nanometer level. No peaks are found for the Pt-NPs in the investigated wavenumber region, which is supported by a study of Kimata et al. Sebastian has 1 job listed on their profile. Sebastian has 4 jobs listed on their profile. Here, we present a novel, one-step approach for the synthesis of Pt/C hybrid material by plasma-enhanced chemical vapor deposition (PE-CVD). This results from the etching effect of hydrogen on carbon structures, while Pt is not etched chemically. Bekijk het profiel van Raymond Tieman op LinkedIn, de grootste professionele community ter wereld. Compared to traditional synthesis methods, the simultaneous deposition of the Pt-NPs and the carbon matrix (CNWs) by using this novel approach yields Pt-NPs that are embedded in the C matrix and therefore show improved long-term stability compared to a commercial catalyst. However, in order to assess how performance-critical properties such as CNW morphology, Pt-loading, and PSD of the resulting Pt/CNW catalysts can be influenced by specific process parameters, these details were systematically studied. Figure 1: The addition of hydrogen into the plasma reduces the degree of oxidation of the whole Pt/CNW layer (P10 vs P9 vs P8; Table 3), most likely due to a depletion of atomic oxygen, as determined by OES (Supporting Information File 1, Figure S3), and subsequent formation of water. Pierre Lecante, View Marius Rosenberg’s profile on LinkedIn, the world’s largest professional community. Even though the exact position of the Pt-NPs is difficult to determine by projective imaging (such as TEM), ultrahigh resolution TEM images prove the formation of embedded Pt-NPs in the carbon matrix by resolving individual carbon layers, which are affected by the Pt-NP. In the right frame, the carbon layers split up as they pass around the Pt-NP (red arrow). 2020, 11, 1419–1431. Genauere Informationen zu den eingesetzten Tools finden Sie in unserer Datenschutzerklärung. The platinum loading and degree of oxidation of the whole Pt/CNW catalyst layers are dependent on the process pressure during synthesis. Therefore, the support surface is characterized by a low density of binding sites for anchoring Pt-NP, on which the Pt-NPs can then easily diffuse. Weight percentages of Pt, C, and O of samples processed at varying substrate temperature and hydrogen addition, and at constant pressure (10.5 Pa) and overall carrier gas flow rate (argon and hydrogen gas; 60 sccm) measured by XPS.

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