This study introduces a simple method to produce ultralow loading catalyst-coated membrane electrodes, with an integrated carbon "nanoporous layer", for use in polymer electrolyte membrane fuel cells or other electrochemical devices. This approach allows fabrication of electrodes with loadings down to 5.2 μgPt cm–2 on the anode and cathode (total 10.4 μgPt cm–2, Pt3Zn/C catalyst) in a controlled, uniform, and reproducible manner. These layers achieve high utilization of the catalyst as measured through electrochemical surface area and mass specific activities. Electrodes composed of Pt/C, PtNi/C, Pt3Co/C, and Pt3Zn/C catalysts containing 5.2–7.1 μgPt cm–2 have been fabricated and tested. These electrodes showed an impressive performance of 111 ± 8 A mgPt–1 at 0.65 V on Pt3Co/C with a power density of 31 ± 2 kW gPt,total–1, about double that of the best previous literature electrodes under the same operating conditions. The performance appears apparently mass transport free and dominated by electrokinetics over a very wide potential range, and thus, these are ideal systems to study oxygen electrokinetics within the fuel cell environment. The improved performance is associated with reduced "contact resistance" and more specifically a reduction in the resistance to lateral current flow in the catalyst layer. Analytical expressions for the effect illuminate approaches to improve electrode design for electrochemical devices in which catalyst utilization is key.
With the European Space Agency (ESA) and NASA working to return humans to the moon and onwards to Mars, it has never been more important to study the impact of altered gravity conditions on biological organisms. These include astronauts but also useful micro-organisms they may bring with them to produce food, medicine, and other useful compounds by synthetic biology. Parabolic flights are one of the most accessible microgravity research platforms but present their own challenges: relatively short periods of altered gravity (~20s) and aircraft vibration. Live-imaging is necessary in these altered-gravity conditions to readout any real-time phenotypes. Here we present Flight-Scope, a new microscopy and microfluidics platform to study dynamic cellular processes during the short, altered gravity periods on parabolic flights. We demonstrated Flight-Scopes capability by performing live and dynamic imaging of fluorescent glucose uptake by yeast, S. cerevisiae, on board an ESA parabolic flight. Flight-Scope operated well in this challenging environment, opening the way for future microgravity experiments on biological organisms.
The data in this spreadsheet was used to produce the figures in the paper Authors: Colleen Jackson, Michalis Metaxas, Jack Dawson, Anthony Kucernak Title: Nanostructured Catalyst Layer Allowing Production of Ultralow Loading Electrodes for Polymer Electrolyte Membrane Fuel Cells with Superior Performance Journal: ACS Appl. Energy Mater. DOI: 10.1021/acsaem.3c01987 Please cite the above reference if you wish to use this data DOI of data: 10.5281/zenodo.10256698
Non-precious metal Fe–N/C heterogeneous catalysts efficiently catalyse epoxidation at 25 °C and atmospheric pressure using oxygen as oxidant. The reaction is studied using on-line oxygen consumption, electrochemistry, and UV-vis spectroscopy.
With the European Space Agency (ESA) and NASA working to return humans to the moon and onwards to Mars, it has never been more important to study the impact of altered gravity conditions on biological organisms. These include astronauts but also useful micro-organisms they may bring with them to produce food, medicine, and other useful compounds by synthetic biology. Parabolic flights are one of the most accessible microgravity research platforms but present their own challenges: relatively short periods of altered gravity (~20s) and aircraft vibration. Live-imaging is necessary in these altered-gravity conditions to readout any real-time phenotypes. Here we present Flight-Scope, a new microscopy and microfluidics platform to study dynamic cellular processes during the short, altered gravity periods on parabolic flights. We demonstrated Flight-Scope's capability by performing live and dynamic imaging of fluorescent glucose uptake by yeast, S. cerevisiae, on board an ESA parabolic flight. Flight-Scope operated well in this challenging environment, opening the way for future microgravity experiments on biological organisms.
The data in this spreadsheet was used to produce the figures in the paper Authors: Colleen Jackson, Michalis Metaxas, Jack Dawson, Anthony Kucernak Title: Nanostructured Catalyst Layer Allowing Production of Ultralow Loading Electrodes for Polymer Electrolyte Membrane Fuel Cells with Superior Performance Journal: ACS Appl. Energy Mater. DOI: 10.1021/acsaem.3c01987 Please cite the above reference if you wish to use this data DOI of data: 10.5281/zenodo.10256698
A simple, modified Metal-Organic Chemical Deposition (MOCD) method for Pt, PtRu and PtCo nanoparticle deposition onto a variety of support materials, including C, SiC, B4C, LaB6, TiB2, TiN and a ceramic/carbon nanofiber, is described. Pt deposition using Pt(acac)2 as a precursor is shown to occur via a mixed solid/liquid/vapour precursor phase which results in a high Pt yield of 90-92% on the support material. Pt and Pt alloy nanoparticles range 1.5-6.2 nm, and are well dispersed on all support materials, in a one-step method, with a total catalyst preparation time of ∼10 hours (2.4-4× quicker than conventional methods). The MOCD preparation method includes moderate temperatures of 350 °C in a tubular furnace with an inert gas supply at 2 bar, a high pressure (2-4 bar) compared to typical MOCVD methods (∼0.02-10 mbar). Pt/C catalysts with Pt loadings of 20, 40 and 60 wt% were synthesised, physically characterised, electrochemically characterised and compared to commercial Pt/C catalysts. TEM, XRD and ex situ EXAFS show similar Pt particle sizes and Pt particle shape identifiers, namely the ratio of the third to first Pt coordination numbers modelled from ex situ EXAFS, between the MOCD prepared catalysts and commercial catalysts. Moreover, electrochemical characterisation of the Pt/C MOCD catalysts obtained ORR mass activities with a maximum of 428 A gPt-1 at 0.9 V, which has similar mass activities to the commercial catalysts (80-160% compared to the commercial Pt/C catalysts).
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