Synthesis of highly dispersed Pt nanoparticles into carbon supports by fluidized bed reactor atomic layer deposition to boost PEMFC performance

Abstract

The performance of proton exchange membrane fuel cells (PEMFCs) depends on the controlled size, dispersion and density of Pt nanoparticles (NPs) on carbon supports, which are strongly affected by the carbon characteristics and fabrication methods. Here, we demonstrated a high-performance Pt/carbon catalyst for PEMFCs using fluidized bed reactor atomic layer deposition (FBR-ALD) that was realized by an effective matching of the carbon supports for the FBR-ALD process and an optimization of the ionomer content during the preparation of the membrane electrode assembly (MEA). For this, the synthesis of Pt NPs was conducted on two porous supports (Vulcan XC-72R and functionalized carbon) by FBR-ALD. The functionalized carbon possessed a higher surface area with a large pore volume, abundant defects in a disordered structure and a large number of oxygen functional groups compared to those of the well-known Vulcan carbon. The favorable surface characteristics of the functionalized carbon for nucleation produced Pt particles with an increased uniformity and density and a narrow size range, which led to a higher electrochemical surface area (ECSA) than that of Pt/Vulcan carbon and commercial Pt/carbon. The PEMFC test of the respective Pt/carbon samples was investigated, and highly dense and uniform Pt/functionalized-carbon showed the highest performance through optimization of the higher ionomer content compared to that for the ALD Pt growth on Vulcan carbon and commercial Pt/carbon. In addition, the Pt catalyst using ALD demonstrated a significant long-term stability for the PEMFC. This finding demonstrates the remarkable advantages of FBR-ALD for the fabrication of Pt/carbon and the ability of functionalized carbon supports to achieve a high PEMFC efficiency and an enhanced durability.

The Synthesis of Low Pt loading Agcore- Pt atoms-exposedshell Structure by Ligand Exchange Method with High Electrocatalytic Performance for Hydrogen Evolution Reaction

“…Furthermore, the EDS elemental mapping observations in Figure 2(c-g) provide robust evidence that S element and Pt element only appear wherever Ag element shows up, which further strengthens this conclusion that Pt polysulfide precursor is adsorbed on the surface of Ag. As a control experiment, the two-step method was executed for pure Vulcan XC 72R carbon black substrate (C-Pt) to check whether the Pt polysulfide precursor could react with the substrate on the grounds that there are many oxygen-containing functional groups for the carbon substrate [21] , such as carboxyl group (-COOH) [22] , hydroxyl group (-OH) [22,23] , and carbonyl group(C=O) [22] , to adsorb hydrogen sulfide (H2S) through the formation of C-S or C-SH species. It is the same case with the Ag/C-nBA-Pt sample that the XRD peaks of Pt polysulfide precursor could not be found for the C-Pt sample (Figure 3(b)).…”

Calcined Co(II)-Triethylenetetramine, Co(II)- Polyaniline-Thiourea as the Cathode Catalyst of Proton Exchanged Membrane Fuel Cell

“…It is not necessary, in other words, to put an additional conducting medium like Vulcan-XC-72 into the preparation of the catalyst via calcination. The (002) plane peak represents the amorphous carbonaceous interlayer [ 25 , 26 ] and (100) was contributed by crystalline carbon [ 27 , 28 ]. Therefore, the intensity ratio of I 100 /I 002 can be used to illustrate the crystallinity of the co-catalysts.…”

Magnéli TiO2 as a High Durability Support for the Proton Exchange Membrane (PEM) Fuel Cell Catalysts

“…Unfortunately, the catalyst durability is a critical challenge that must be addressed for PEMFC's widespread commercialization since it directly reflects the life and cost of PEMFC's power-generation systems [5]. Carbon black has been the commonly used catalyst support material due to its low cost, high surface area, and availability [6][7][8]. Although catalyst degradation could result from many factors t, the primary contributors are believed to be (i) the dissolution and re-deposition (Ostwald ripening) of Pt, (ii) coalescence via crystal migration, and (iii) detachment of Pt particles from the catalyst support [9].…”