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Y. Li et al.
4.1.1 Carbon Carrier Materials
Carbon referent carrier materials [6–9] due to their high specific surface area, good
electrical conductivity, electrochemical stability, low cost, easy processing, and other
characteristics.
4.1.1.1 Carbon Black
Carbon black is currently the most commonly used carrier material for fuel cell
catalysts [10–14], including acetylene black, VulcanXC-72, Bleak Pearl 2000, etc.
All these carbon materials have good conductivity. Acetylene black has a small
specific surface area, but because there are no micropores, it will not hinder mass
transfer of reactants. Although Bleak Pearl 2000 has a high specific surface area, there
are too many micropores, resulting in uneven distribution of active substances and
ineffective utilization of active sites on the inner surface of the catalyst. VulcanXC-72
produced by Cabot Company is a carbon black material graphitized by amorphous
activated carbon, with a specific surface area of about 250m
2 g
−1 , good electrical
conductivity, and good pore structure (mesopore area accounts for about 53% of the
specific surface area). Therefore, it is currently the most used catalyst carrier in fuel
cell electrocatalysts [15].
4.1.1.2 Carbon Nanotube
Carbon nanotubes (CNTs), also known as bucky tubes, are seamless and hollow
tube structures composed of honeycomb-shaped hexagonal carbon. According to
the thickness of the tube wall, CNTs can be divided into two types: one is singlewalled carbon nanotubes (SWCNTs); the other is multi-walled carbon nanotubes
(MWCNTs). Compared with Vulcan XC-72, firstly, CNTs have a unique hollow
structure, good electrical conductivity and thermal stability, stable chemical properties, large specific surface area, a and special interaction between delocalized π
electrons and catalyst metal d electrons, so as to enable electrocatalyst to have higher
catalytic activity [2, 16]. Secondly, CNTs are purer and contain less impurities, while
Vulcan XC-72 contains a certain amount of organic sulfur impurities, which will
have a certain toxic effect on Pt catalyst, thus affecting its electrocatalytic activity.
Thirdly, CNTs have a complete planar structure and few cracks, which makes it easy
to form a three-phase interface in the catalytic process of metal particles deposited
on its surface, thus facilitating the catalysis of metal catalysts. Therefore, when
CNTs are used as the carrier material for oxygen reduction catalysis, if the metal
catalyst deposited on the surface of CNTs can form an orderly catalytic layer, it is
conducive to electron conduction and mass transfer, thus achieving a higher catalytic
performance [1, 17]. However, due to the high curvature and chemical inertness of
CNTs, its surface is not easily loaded with metal catalytic particles. Even if loaded,
Y. Li et al.
4.1.1 Carbon Carrier Materials
Carbon referent carrier materials [6–9] due to their high specific surface area, good
electrical conductivity, electrochemical stability, low cost, easy processing, and other
characteristics.
4.1.1.1 Carbon Black
Carbon black is currently the most commonly used carrier material for fuel cell
catalysts [10–14], including acetylene black, VulcanXC-72, Bleak Pearl 2000, etc.
All these carbon materials have good conductivity. Acetylene black has a small
specific surface area, but because there are no micropores, it will not hinder mass
transfer of reactants. Although Bleak Pearl 2000 has a high specific surface area, there
are too many micropores, resulting in uneven distribution of active substances and
ineffective utilization of active sites on the inner surface of the catalyst. VulcanXC-72
produced by Cabot Company is a carbon black material graphitized by amorphous
activated carbon, with a specific surface area of about 250m
2 g
−1 , good electrical
conductivity, and good pore structure (mesopore area accounts for about 53% of the
specific surface area). Therefore, it is currently the most used catalyst carrier in fuel
cell electrocatalysts [15].
4.1.1.2 Carbon Nanotube
Carbon nanotubes (CNTs), also known as bucky tubes, are seamless and hollow
tube structures composed of honeycomb-shaped hexagonal carbon. According to
the thickness of the tube wall, CNTs can be divided into two types: one is singlewalled carbon nanotubes (SWCNTs); the other is multi-walled carbon nanotubes
(MWCNTs). Compared with Vulcan XC-72, firstly, CNTs have a unique hollow
structure, good electrical conductivity and thermal stability, stable chemical properties, large specific surface area, a and special interaction between delocalized π
electrons and catalyst metal d electrons, so as to enable electrocatalyst to have higher
catalytic activity [2, 16]. Secondly, CNTs are purer and contain less impurities, while
Vulcan XC-72 contains a certain amount of organic sulfur impurities, which will
have a certain toxic effect on Pt catalyst, thus affecting its electrocatalytic activity.
Thirdly, CNTs have a complete planar structure and few cracks, which makes it easy
to form a three-phase interface in the catalytic process of metal particles deposited
on its surface, thus facilitating the catalysis of metal catalysts. Therefore, when
CNTs are used as the carrier material for oxygen reduction catalysis, if the metal
catalyst deposited on the surface of CNTs can form an orderly catalytic layer, it is
conducive to electron conduction and mass transfer, thus achieving a higher catalytic
performance [1, 17]. However, due to the high curvature and chemical inertness of
CNTs, its surface is not easily loaded with metal catalytic particles. Even if loaded,