4 Catalyst Materials for Oxygen Reduction Reaction
93
Fig. 4.4 Schematic diagram of preparation process of Fe 3 O 4 /n-Gas [83]
Graphene is a newly discovered nano material with many functions. It has a bright
application prospect. The application research of graphene in electrocatalysts still
needs continuous exploration.
4.1.1.6 Graphene with Stereoscopic Structure
Graphene has attracted much attention due to its unique physical and chemical properties, [37–39] especially the research on graphene-based devices [72, 73]. At present,
most researches mainly focus on the preparation and properties of two-dimensional
graphene materials. However, the size for two-dimensional materials is very small,
which greatly limits their processing and application. In addition, due to the strong
van der Waals force or dangling bond force between the two-dimensional graphene,
the prepared graphene is easy to agglomerate or stack, thus restricting the largescale production and actual use of graphene [74–77]. Three-dimensional graphene
is a structure which can effectively prevent agglomeration or stacking between twodimensional graphene [78, 79]. It not only maintains the intrinsic characteristics of
graphene, but also has unique self-supporting structure and porosity [80, 81]. In
addition, it can also provide large specific surface area, high mechanical strength
and fast electron and ion transport. Therefore, three-dimensional graphene is considered as an important direction for the development of graphene materials in the
future [80–82]. At present, there are mainly two methods for synthesizing threedimensional graphene [80]: one is a self-assembly method, which is a process of
reassembling precursors derived from graphene oxide or reducing graphene through
hydrothermal, vacuum filtration, templates and other technologies, including solution self-assembly, template self-assembly, solvothermal self-assembly, and organic
aerogel self-assembly. The other is a metal-catalyzed synthesis method, which is
mainly a process of removing a template or a catalyst by directly catalyzing a
93
Fig. 4.4 Schematic diagram of preparation process of Fe 3 O 4 /n-Gas [83]
Graphene is a newly discovered nano material with many functions. It has a bright
application prospect. The application research of graphene in electrocatalysts still
needs continuous exploration.
4.1.1.6 Graphene with Stereoscopic Structure
Graphene has attracted much attention due to its unique physical and chemical properties, [37–39] especially the research on graphene-based devices [72, 73]. At present,
most researches mainly focus on the preparation and properties of two-dimensional
graphene materials. However, the size for two-dimensional materials is very small,
which greatly limits their processing and application. In addition, due to the strong
van der Waals force or dangling bond force between the two-dimensional graphene,
the prepared graphene is easy to agglomerate or stack, thus restricting the largescale production and actual use of graphene [74–77]. Three-dimensional graphene
is a structure which can effectively prevent agglomeration or stacking between twodimensional graphene [78, 79]. It not only maintains the intrinsic characteristics of
graphene, but also has unique self-supporting structure and porosity [80, 81]. In
addition, it can also provide large specific surface area, high mechanical strength
and fast electron and ion transport. Therefore, three-dimensional graphene is considered as an important direction for the development of graphene materials in the
future [80–82]. At present, there are mainly two methods for synthesizing threedimensional graphene [80]: one is a self-assembly method, which is a process of
reassembling precursors derived from graphene oxide or reducing graphene through
hydrothermal, vacuum filtration, templates and other technologies, including solution self-assembly, template self-assembly, solvothermal self-assembly, and organic
aerogel self-assembly. The other is a metal-catalyzed synthesis method, which is
mainly a process of removing a template or a catalyst by directly catalyzing a