Carbon Nanotube Film by Filtration as Cathode Catalyst Support for Proton-Exchange Membrane Fuel Cell

Abstract

A simple filtration method is developed to prepare a partially oriented superhydrophobic film of carbon nanotubes (CNTs) that have been catalyzed with uniform small Pt nanoparticles (2.8 nm) at high metal loading (30 wt %). A proton-exchange membrane fuel cell with the oriented CNT film as the cathode achieves higher single-cell performance than those with carbon black and a disordered CNT-film-based cathode probably because of the enhanced electrocatalytic activity of Pt/CNT and improved mass transport within the oriented film.

Modeling an ordered nanostructured cathode catalyst layer for proton exchange membrane fuel cells

“…Most of the parameters used in the model validation are obtained from Li et al [18], who reported the measured cell performance data having an ordered nanostructured CCL. Since the present model predicts an ordered nanostructured CCL performance, to compare with the measured cell performance, the membrane ohmic overpotential is accounted using an expression presented by Baschuk and Li [56]:…”

“…5 shows the comparison between the predicted and measured cell performance having an ordered nanostructured CCL. The lines represent the model predictions, while the symbol represents the measured cell performance data obtained from Li et al [18]. The solid line represents the predicted ordered nanostructured CCL performance at 343 K and 2 atm.…”

“…In order to overcome the issues associated with conventional CCL, such as carbon corrosion leading to loss of ECSA, low Pt utilization resulting in wastage of expensive Pt, and transport limitations resulting in overall performance loss, considerable efforts have 0378 [3,4,9,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. In an ordered nanostructured CCL, carbon nanotubes (CNTs) are being used as support material for Pt catalyst owing to their unique features, which include superior mechanical and electrical properties, high aspect ratio and enhanced mass transport capability [16,18,19,[33][34][35][36][37][38].On the surface of these CNTs, also referred to as electron conductors, Pt particles of approximately 2 nm are finely dispersed.…”

“…In an ordered nanostructured CCL, carbon nanotubes (CNTs) are being used as support material for Pt catalyst owing to their unique features, which include superior mechanical and electrical properties, high aspect ratio and enhanced mass transport capability [16,18,19,[33][34][35][36][37][38].On the surface of these CNTs, also referred to as electron conductors, Pt particles of approximately 2 nm are finely dispersed. A thin layer of Nafion is then deposited on the Pt-coated CNTs and aligned along the main transport direction (perpendicular to the membrane) of electron, proton and reactant gas to form an ordered or oriented nanostructured CCL.…”

“…Third, the electronic conductivity of CNTs is much higher along the tubes than across the tubes; as a result, there is negligible loss in potential when electrons transfer along the tubes [39,40]. Fourth, an oriented nanostructured CCL may exhibit superhydrophobicity, which can facilitate greater water removal within the CCL, thereby improving mass transport [18].…”