Preparation of High‐Platinum‐Utilization Gas Diffusion Electrodes for Proton‐Exchange‐Membrane Fuel Cells

Abstract

We evaluated an electrochemical catalyzation technique for producing gas-diffusion electrodes for proton-exchange-membrane fuel cells (PEMFC). The electrochemical technique deposits platinum catalyst particles in regions of the electrode that are in ionic contact with the proton-exchange membrane and in electronic contact with the carbon support. Since ionic and electronic contact are necessary components of catalyst utilization in gas-diffusion electrodes, the electrochemical catalyzation technique reduces the amount of platinum required for PEMFC. We present data for oxygen reduction and hydrogen oxidation with gas-diffusion electrodes containing 0.05 mg Pt/cm 2.

Effect of direct liquid water injection and interdigitated flow field on the performance of proton exchange membrane fuel cells

“…Efforts of sputtering the catalyst onto the surface of the electrode that is later hot pressed onto the membrane and mixing the catalystsubstrate with the membrane ionomer into an ink and applying it directly onto the membrane have resulted in significant improvements in the fuel cell performance and major reduction in the catalyst loading, from as high as 5 mg Pt/cm 2 to 0.2 mg Pt/cm 2 , [1][2][3][4][5][6] . Note that the voltage loss caused by gas crossover can be minimized by using a thicker membrane and keeping the membrane well hydrated.…”

Elektrodenarchitektur in galvanischen und elektrolytischen Energiezellen

“…So wurde elektrochemische Abscheidung als Wegz ur selektiven Herstellung von Katalysatoren an der Dreiphasengrenze vorgeschlagen (Abbildung 5). [58,62] Dazu wird eine Gasdiffusionselektrode in eine wässrige Lç-sung von Pt-Salz und Nafion-Ionomer getaucht und ein gepulstes elektrisches Potential wird angelegt, um die Pt-Ionen zu kleinen Pt-Nanopartikeln zu reduzieren, die zusammen mit Nafion-Aggregaten (ionenleitende Zweige) auf dem hydrophilen Kohlenstoffträger abgeschieden werden. Durch die Minimierung der nichtgenutzten Pt-Oberfläche über selektive Abscheidung von Pt an der ionisch/elektrischen Grenzschicht kçnnte dieses Verfahren die notwendige Katalysatormenge auf ein Sechstel des aktuellen Werts verringern und dabei eine etwas hçhere Aktivität als herkçmmlich hergestellte Pt/C-Elektroden liefern.…”

Carbon Nanotubes Supported Metal Nanoparticles for the Applications in Proton Exchange Membrane Fuel Cells (PEMFCs)

“…In this process, functionalized CNTs are first mixed with the metal precursors in aqueous solution to produce a homogeneous solution. A pulse current, such as direct current or CV, is then added for the reduction of metal ions promoting the deposition of metal NPs on CNTs, which usually produces metal NPs/CNTs with high efficiency in PEMFCs as compared to those prepared by the conventional deposition techniques (Choi et al, 1998;Taylor et al, 1992;Thompson et al, 2001). An approach for the electrochemical deposition of Pt particles with a narrow size distribution on CNTs was reported by Tsai et al , who successfully electrodeposited Pt and PtRu NPs on the dense CNTs directly grown on carbon cloths in EG containing H 2 SO 4 aqueous solutions.…”