21 results found
Taublaender MJ, Mezzavilla S, Thiele S, et al., 2020, Hydrothermale synthese von konjugierten polymeren am beispiel von pyrronpolymeren und polybenzimidazolen, Angewandte Chemie, Vol: 132, Pages: 15160-15171, ISSN: 0044-8249
Various polyimides and polyamides have recently been prepared by hydrothermal synthesis in nothing but H 2 O under high pressure and high temperature conditions. However, none of these polymers have a conjugated polymer backbone. We hereby report an extension of the synthetic scope of this simple and naturally environmentally friendly polymerisation technique to the production of conjugated polymers. Selected representatives of two different polymer classes, pyrron polymers and polybenzimidazoles, were synthesized hydrothermally. In addition to a mechanistic discussion of polymer formation, an electrochemical characterization of the most promising product is presented.
Taublaender MJ, Mezzavilla S, Thiele S, et al., 2020, Hydrothermal generation of conjugated polymers using the example of pyrrone polymers and polybenzimidazoles, Angewandte Chemie International Edition, Vol: 59, Pages: 15050-15060, ISSN: 1433-7851
Various polyimides and polyamides have recently been prepared via hydrothermal synthesis in nothing but H2 O under high-pressure and high-temperature conditions. However, none of the prepared polymers feature a truly conjugated polymer backbone. Here, we report on an expansion of the synthetic scope of this straightforward and inherently environmentally friendly polymerization technique to the generation of conjugated polymers. Selected representatives of two different polymer classes, pyrrone polymers and polybenzimidazoles, were generated hydrothermally. We present a mechanistic discussion of the polymer formation process as well as an electrochemical characterization of the most promising product.
Taublaender MJ, Mezzavilla S, Thiele S, et al., 2020, Back Cover: Hydrothermal Generation of Conjugated Polymers Using the Example of Pyrrone Polymers and Polybenzimidazoles (Angew. Chem. Int. Ed. 35/2020), Angewandte Chemie International Edition, Vol: 59, Pages: 15268-15268, ISSN: 1433-7851
Taublaender MJ, Mezzavilla S, Thiele S, et al., 2020, Hydrothermal Generation of Conjugated Polymers Using the Example of Pyrrone Polymers and Polybenzimidazoles, Angewandte Chemie, ISSN: 0044-8249
Andersen SZ, Colic V, Yang S, et al., 2019, A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements (vol 570, pg 504, 2019), NATURE, Vol: 574, Pages: E5-E5, ISSN: 0028-0836
Mezzavilla S, Katayama Y, Rao R, et al., 2019, Activity-or Lack Thereof-of RuO2-Based Electrodes in the Electrocatalytic Reduction of CO2, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 123, Pages: 17765-17773, ISSN: 1932-7447
Sebastian-Pascual P, Mezzavilla S, Stephens IEL, et al., 2019, Structure-sensitivity and Electrolyte Effects in CO2 Electroreduction: From Model Studies to Applications, CHEMCATCHEM, Vol: 11, Pages: 3624-3643, ISSN: 1867-3880
Andersen SZ, Colic V, Yang S, et al., 2019, A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements, Nature, Vol: 570, Pages: 504-508, ISSN: 0028-0836
The electrochemical synthesis of ammonia from nitrogen under mild conditions using renewable electricity is an attractive alternative to the energy-intensive Haber–Bosch process, which dominates industrial ammonia production. However, there are considerable scientific and technical challenges facing the electrochemical alternative, and most experimental studies reported so far have achieved only low selectivities and conversions. The amount of ammonia produced is usually so small that it cannot be firmly attributed to electrochemical nitrogen fixation rather than contamination from ammonia that is either present in air, human breath or ion-conducting membranes, or generated from labile nitrogen-containing compounds (for example, nitrates, amines, nitrites and nitrogen oxides) that are typically present in the nitrogen gas stream, in the atmosphere or even in the catalyst itself. Although these sources of experimental artefacts are beginning to be recognized and managed concerted efforts to develop effective electrochemical nitrogen reduction processes would benefit from benchmarking protocols for the reaction and from a standardized set of control experiments designed to identify and then eliminate or quantify the sources of contamination. Here we propose a rigorous procedure using 15N2 that enables us to reliably detect and quantify the electrochemical reduction of nitrogen to ammonia. We demonstrate experimentally the importance of various sources of contamination, and show how to remove labile nitrogen-containing compounds from the nitrogen gas as well as how to perform quantitative isotope measurements with cycling of 15N2 gas to reduce both contamination and the cost of isotope measurements. Following this protocol, we find that no ammonia is produced when using the most promising pure-metal catalysts for this reaction in aqueous media, and we successfully confirm and quantify ammonia synthesis using lithium electrodeposition in tetrahydrofuran13. The use
Stephens I, Andersen S, Colic V, et al., 2019, Quantitative protocol for the electroreduction of N2 to NH3 under ambient conditions, National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Mezzavilla S, Horch S, Stephens IEL, et al., 2019, Structure Sensitivity in the Electrocatalytic Reduction of CO2 with Gold Catalysts., Angew Chem Int Ed Engl
An understanding of the influence of structural surface features on electrocatalytic reactions is vital for the development of efficient nanostructured catalysts. Gold is the most active and selective known electrocatalyst for the reduction of CO2 to CO in aqueous electrolytes. Numerous strategies have been proposed to improve its intrinsic activity. Nonetheless, the atomistic knowledge of the nature of the active sites remains elusive. We systematically investigated the structure sensitivity of Au single crystals for electrocatalytic CO2 reduction. Reaction kinetics for the formation of CO are strongly dependent on the surface structure. Under-coordinated sites, such as those present in Au(110) and at the steps of Au(211), show at least 20-fold higher activity than more coordinated configurations (for example, Au(100)). By selectively poisoning under-coordinated sites with Pb, we have confirmed that these are the active sites for CO2 reduction.
Mezzavilla S, Horch S, Stephens IEL, et al., 2019, Structure Sensitivity in the Electrocatalytic Reduction of CO2with Gold Catalysts, Angewandte Chemie, Vol: 131, Pages: 3814-3818, ISSN: 0044-8249
Pizzutilo E, Knossalla J, Geiger S, et al., 2017, The Space Confinement Approach Using Hollow Graphitic Spheres to Unveil Activity and Stability of Pt-Co Nanocatalysts for PEMFC, ADVANCED ENERGY MATERIALS, Vol: 7, ISSN: 1614-6832
Mezzavilla S, Baldizzonev C, Swertz A-C, et al., 2016, Structure-Activity-Stability Relationships for Space-Confined PtxNiy Nanoparticles in the Oxygen Reduction Reaction, ACS CATALYSIS, Vol: 6, Pages: 8058-8068, ISSN: 2155-5435
Mezzavilla S, Cherevko S, Baldizzone C, et al., 2016, Experimental Methodologies to Understand Degradation of Nanostructured Electrocatalysts for PEM Fuel Cells: Advances and Opportunities, CHEMELECTROCHEM, Vol: 3, Pages: 1524-1536, ISSN: 2196-0216
Polymeros G, Baldizzone C, Geiger S, et al., 2016, High temperature stability study of carbon supported high surface area catalysts-Expanding the boundaries of ex-situ diagnostics, ELECTROCHIMICA ACTA, Vol: 211, Pages: 744-753, ISSN: 0013-4686
Knossalla J, Mezzavilla S, Schuth F, 2016, Continuous synthesis of nanostructured silica based materials in a gas-liquid segmented flow tubular reactor, NEW JOURNAL OF CHEMISTRY, Vol: 40, Pages: 4361-4366, ISSN: 1144-0546
Mezzavilla S, Baldizzone C, Mayrhofer KJJ, et al., 2015, General Method for the Synthesis of Hollow Mesoporous Carbon Spheres with Tunable Textural Properties, ACS APPLIED MATERIALS & INTERFACES, Vol: 7, Pages: 12914-12922, ISSN: 1944-8244
Baldizzone C, Mezzavilla S, Hodnik N, et al., 2015, Activation of carbon-supported catalysts by ozonized acidic solutions for the direct implementation in (electro-)chemical reactors, CHEMICAL COMMUNICATIONS, Vol: 51, Pages: 1226-1229, ISSN: 1359-7345
Baldizzone C, Mezzavilla S, Carvalho HWP, et al., 2014, Confined-space alloying of nanoparticles for the synthesis of efficient PtNi fuel-cell catalysts, Angewandte Chemie International Edition, Vol: 53, Pages: 14250-14254, ISSN: 1433-7851
The efficiency of polymer electrolyte membrane fuel cells is strongly depending on the electrocatalyst performance, that is, its activity and stability. We have designed a catalyst material that combines both, the high activity for the decisive cathodic oxygen reduction reaction associated with nanoscale Pt alloys, and the excellent durability of an advanced nanostructured support. Owing to the high specific activity and large active surface area, the catalyst shows extraordinary mass activity values of 1.0 A mgPt−1. Moreover, the material retains its initial active surface area and intrinsic activity during an extended accelerated aging test within the typical operation range. This excellent performance is achieved by confined‐space alloying of the nanoparticles in a controlled manner in the pores of the support.
Meier JC, Galeano C, Katsounaros I, et al., 2014, Design criteria for stable Pt/C fuel cell catalysts, BEILSTEIN JOURNAL OF NANOTECHNOLOGY, Vol: 5, Pages: 44-67, ISSN: 2190-4286
Mezzavilla S, Zanella C, Aravind PR, et al., 2012, Carbon xerogels as electrodes for supercapacitors. The influence of the catalyst concentration on the microstructure and on the electrochemical properties, JOURNAL OF MATERIALS SCIENCE, Vol: 47, Pages: 7175-7180, ISSN: 0022-2461
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