Networked Graphitic Structures as Durable Catalyst Support for PEM Electrodes

Abstract

A PFSA‐stabilized Pt‐catalyst supported on a novel carbon material, carbon nano networks (CNNs), was synthesized. To benchmark its performance, it was compared to a commercial catalyst, supported on an amorphous carbon support, and to a PFSA stabilized Pt catalyst supported on commercial carbon nano tubes (CNTs). The PFSA‐Pt/CNNs exhibit improved performance compared to commercial catalysts in terms of ORR kinetic activity and durability. Even though PFSA‐Pt/CNTs should show comparable behavior to PFSA‐Pt/CNNs, our experimental results show a slightly superior performance. Optimization of the CNN synthesis route is expected to improve their properties as a carbon support. Since CNN mass production is expected to be cheaper than for CNTs because of the simplicity of the synthesis route, we conclude that CNNs are a promising material for the fuel cell market.

Electrocatalytic Activity and Durability of Pt-Decorated Non-Covalently Functionalized Graphitic Structures

“…Table 1 reports the temperature of oxidation, 700 °C, 630 °C and 610 °C for CNT20, CNN50 and CNN80, respectively. All the samples show higher oxidation resistance compared to for example carbon black or Vulcan, the most widely used catalyst supports [4,9,14]. The difference in oxidation resistance can be attributed to the presence of defects.…”

“…Previous studies reveal that CNN material is mainly meso-porous (2-50 nm), which is beneficial for catalysis as it assures an optimal mass transport [14]. For CNTs, the porosity largely depends on the packing parameter that can strongly vary if the carbon surface is functionalized [14]. Figure 1a reports the weight loss of the samples as a function of temperature from TGA analysis in air.…”

“…However, recent studies demonstrated that lowering Pt loading improves catalyst utilization and performance [29]. Previous studies reveal that CNN material is mainly meso-porous (2-50 nm), which is beneficial for catalysis as it assures an optimal mass transport [14]. For CNTs, the porosity largely depends on the packing parameter that can strongly vary if the carbon surface is functionalized [14].…”

“…Recent studies have proven that graphitic materials such as carbon nanotubes (CNTs), nanofibers, etc. are significantly more resistant to carbon corrosion than the widely used carbon black due to the higher stability of the sp 2 -hybridized carbon [3,[11][12][13][14][15][16][17][18]. Within the TU Delft group, we developed a novel carbon material that consists of networked carbon nanostructures (CNNs), currently produced by the TU Delft spin-off company CarbonX (formerly Minus9) [11,19].…”

“…The carbonization of the surfactant, being the primary carbon source, leads to the formation of networked, sponge-like, carbon graphitic structures (CNNs), which show promising properties for application as fuel cell supports, such as high electrical conductivity, great oxidation resistance, high specific surface area, micro-and meso-porosity, surface defects increasing the material ability to disperse in solution [11][12][13][14]19]. Previous studies showed that CNNs are more durable supports for platinum catalysts in the ORR compared to commercial carbon supports, while the simplicity and versatility of the synthesis route allows a cheaper production than CNTs [12][13][14].…”