Effect of Different Support Morphologies and Pt Particle Sizes in Electrocatalysts for Fuel Cell Applications

Abstract

The performance of a low temperature fuel cell is strongly correlated with parameters like the platinum particle size, platinum dispersion on the carbon support, and electronic and protonic conductivity in the catalyst layer as well as its porosity. These parameters can be controlled by a rational choice of the appropriate catalyst synthesis and carbon support. Only recently, particular attention has been given to the support morphology, as it plays an important role for the formation of the electrode structure. Due to their significantly different structure, mesoporous carbon microbeads (MCMBs) and multiwalled carbon nanotubes (MWCNTs) were used as supports and compared. Pt nanoparticles were decorated on these supports using the polyol method. Their size was varied by different heating times during the synthesis, and XRD, TEM, SEM, CV, and single cell tests used in their detailed characterization. A membrane-electrode assembly prepared with the MCMB did not show any activity in the fuel cell test, although the catalyst's electrochemical activity was almost similar to the MWCNT. This is assumed to be due to the very dense electrode structure formed by this support material, which does not allow for sufficient mass transport.

Development of multiwalled carbon nanotubes platinum nanocomposite as efficient PEM fuel cell catalyst

“…It is important to note that the catalyst performance in a Fuel cell depends on a no. of parameters like the metal (e.g., Pt) used [51][52][53][54], metal loading [54][55][56], type and purity of substrate [5,[57][58][59][60][61][62][63] etc. Apart from the above another important factor which determines the catalyst performance is the interaction/bond between the metal and substrate.…”

Oxygen Reduction Reaction

“…CNTs are attractive support materials in fuel cell applications and are by far the most-explored carbon nanostructures as catalyst supports in fuel cells due to their excellent mechanical strength, a high surface area and a high electric conductivity and because they have reported to show an improved catalytic activity [22,32,78] compared to CB. The carbon surface is functionalised to provide oxygen-binding groups for the growth of metal catalyst ions [79]. CNTs can be single-walled (SWCNT) or multi-walled (MWCNT), depending on the structure.…”

Highly purified CNTs: an exceedingly efficient catalyst support for PEM fuel cell

“…This is in contrast to most of the previously reported studies, in which CNTs were usually treated with acid, to introduce some functional groups and provide nuclei sites for Pt loading. 13,21,22,29,30,[32][33][34] However, the walls of CNTs are quite inert structures and functionalization only takes place at the ends/ edges. 64 Thus, in the case of functionalized CNTs, the desired covalent linkages with Pt can only be formed at the tube ends.…”

“…10 Also, a support with high surface area should be conducting, resistant to corrosion, and hydrophobic, to avoid any mass transport problem while enhancing the activity of catalyst. Particularly varied examples in the literature have indicated that tailored morphologies and surface modica-tions of the support material, especially carbon-based materials such as carbon black, [11][12][13][14][15][16][17][18][19][20][21] mesocarbon micro beads (MCMB), [22][23][24][25] carbon bers, vapor grown carbon bers (VGCF), [26][27][28] carbon nanotubes (CNTs), 21,27,[29][30][31][32][33][34][35][36][37][38] graphene [39][40][41][42][43] and others, [44][45][46] greatly inuences the catalytic properties. A brief account of these is given in Table 1 along with the fuel cell power density achieved for a given catalyst loading (on the cathode side).…”