Long-Term Performance of Pt-Decorated Carbon Nanotube Cathodes in Phosphoric Acid Fuel Cells

Abstract

We report the electrochemical properties and performance of Pt-decorated carbon nanotube (Pt-CNT) catalysts for long-term operation in phosphoric acid fuel cells (PAFCs). Electrochemical measurements of Pt-CNT catalysts including cyclic voltammetry, rotating ring disk electrode voltammetry, and electrochemical impedance spectroscopy were conducted to evaluate the catalyzed oxygen reduction reaction (ORR). Furthermore, we tested the long-term performance of the Pt-CNT catalysts in 2 00 Â 2 00 PAFC cathodes operating at 190°C in 85% H 3 PO 4 for extended periods (up to 240 days). Lifetime studies show that electrodes containing the Pt-CNT catalysts were approximately 20 times more stable than conventional Pt-C catalyst materials, even with a substantially thinner catalyst layer. This finding of the enhanced Pt-CNT catalyst stability bodes well for possible personal electronics or automotive applications, where catalyst longevity is an essential requirement.

Effect of praseodymium oxide and cerium–praseodymium mixed oxide in the Pt electrocatalyst performance for the oxygen reduction reaction in PAFCs

“…Figure 5 shows the performance of Pt/C, PtPrO x /C and PtCe 0.9 Pr 0.1 O y /C catalysts during the long term CA tests in hot H 3 PO 4 (110°C) at 0.88 V (versus DHE). Quasiexponential current decays can be observed, which may be attributed to the diffusion limitation of O 2 in phosphoric acid as well as degradation and dissolution of some catalyst components [11,29,30]. A driving force for dissolution of Pr or Ce oxides may be the concentration difference of the metal cations between the electrode surface and the bulk solution.…”

HIGH-PERFORMANCE Pt/CNTs CATALYSTS VIA HYDROGEN PLASMA FOR METHANOL ELECTROOXIDATION

“…25. During the synthesis of CNTs, the total reaction pressure in the chamber was kept at 4 kPa and the°o w rates of CH 4 and H 2 were 3.3 sccm and 55 sccm, respectively. The input power of microwave plasma was 500 W with a growth time of 1 h.…”

“…Numerous studies have been devoted to the preparation of Pt catalysts. [3][4][5][6][7][8][9][10][11] It is well known that the speci¯c activity of catalysts is strongly related to their size, distribution and the support, wherein highly distributed catalyst nanoparticles with small size and narrow size distribution are ideal for high electrocatalyst activity owing to their large surface-to-volume ratio. To achieve high dispersion, Pt catalysts are usually supported on high-surface-area carbon supports, such as carbon nanotubes (CNTs), which are of great interest as catalyst supports for application in fuel cells due to their outstanding electrical and structural properties.…”

“…[12][13][14][15] Multiwalled carbon nanotubes (MWCNTs) have been extensively used as the supports of the anode catalysts and showed improved performance in DMFCs, because of the higher nanoparticle dispersion than that of the catalysts supported on carbon black. [3][4][5][6][7][8][9][10][11] Among the preparation methods reported in the literature for carbon nanotubes-supported Pt catalysts (Pt/CNTs), colloidal chemistry methods are the most adopted routes. [16][17][18][19] Although highly dispersed Pt catalysts can be attained, these methods are relatively high in costand low in e±ciency.…”

Activation of gold decorated carbon nanotube hybrids for targeted gas adsorption and enhanced catalytic oxidation

“…Highly selective gas adsorbing materials have attracted wide interest as carbon capture and fuel cells, and thus stand as promising solutions to 40 achieve sustainable development. While the major breakthroughs achieved in the past decades followed routes targeting selective gas sieving via adsorption within nano-structured activated combinatorial materials, [1][2][3][4][5][6][7][8][9][10] processing large amounts of well organized materials such as metal nanoparticles (NPs) 11 , Metal Organic Frameworks (MOFs) or 45 zeolites remains a challenge.…”