Inorganic Graphenes

Inorganic Graphenes List

Nanomaterials refer to materials with the nanometer scale size, which can be divided into one-dimension nanomaterials, two-dimension nanomaterials and three-dimension nanomaterials. Nanomaterials are characterized by surface effect, interfacial effect, small size effect, quantum size effect and macroscopic quantum tunneling effect. Nanomaterials exhibit special properties under certain conditions and can be used as absorbing materials, superconducting materials, luminescent materials, catalytic materials, semiconductor materials and other functional materials. Inorganic graphenes are a class of two-dimensional nanomaterials, which has the advantages of high flexibility and transparency. Inorganic graphenes have broad application prospects in many fields, such as wearable smart devices and flexible energy storage devices. Besides, the structure and composition of inorganic graphenes can be adjusted and diverse performances can be obtained.

Applications:

• Electronic devices field: Some of the inorganic graphenes have high charge carrier mobility and adjustable band gaps, which is suitable for electronic devices designing. For example, the field effect transistor based on inorganic graphenes has high switching ratio and high charge carrier mobility. In addition, as an important kind of inorganic graphenes, black phosphorus is flexible and suitable for flexible electronic devices.

Figure 1. A field effect transistor based on inorganic graphenes.

• Catalysis field: Inorganic graphenes play important roles in the field of catalysis, mainly including electrocatalysis and photocatalysis. Inorganic graphenes have excellent electronic properties and high specific surface area, and they can be used as electrocatalysts. Moreover, with high specific surface area and abundant surface-active sites, inorganic graphenes can collect and transfer light. They can significantly reduce the distance of charge migration and improve the effect of charge separation, which is quite suitable for photocatalysis.

Figure 2. An example of inorganic graphenes applied in catalysis field.

• The others: Inorganic graphenes can also be used in many other fields, such as batteries, supercapacitors, solar cells, sensors and the others.

Classification:

According to the composition, inorganic graphenes are divided into elemental materials, nonmetallic compounds, metallic compounds and salt compounds.

• Elemental materials: Elemental materials that can be considered as inorganic graphenesmainly include graphene, black phosphorus, pure metals and the others.Graphene is made of carbon atoms with hexagonal honeycomb structure, and it can be made of graphite by van der Waals forces. Black phosphorus is the allotrope of phosphorus.Similar to graphite, black phosphorus blocks are also composed of lamellae of black phosphorus that are connected by van der Waals forces.In addition, pure metal materials have gradually become a recent research focus. For example, two-dimensional gold, silver, copper, platinum, iridium, palladium, and aluminum all have hexagonal honeycomb structures that resemble graphene.
• Nonmetallic compounds: Nonmetallic compounds that can be considered as inorganic graphenesmainly include hexagonal boron nitride, graphene oxide and the others.The structure of hexagonal boron nitride is formed by proportional covalent connection of carbon and nitrogen atom with graphene-like hexagonal structures.Graphene oxide is a graphene derivative. The surface and edges of graphene oxide are modified with oxygen-containing functional groups, which basically retain the lamellar structure of graphene.
• Metallic compounds: This type inorganic graphenes include quite a few types, such as metal oxides, metal halides, transition metal oxides and the others.
• Salt compounds: This type inorganic graphenesmainly include inorganic perovskite compounds, clay minerals, and the others. Among them, clay minerals are water-bearing layered aluminosilicates.

References

1. Tao L, Cinquanta E, Chiappe D, et al. Silicene field-effect transistors operating at room temperature[J]. Nature Nanotechnology, 2015, 10(3):227-31.
2. Gao M R, Chan M K Y, Sun Y. Edge-terminated molybdenum disulfide with a 9.4- interlayer spacing for electrochemical hydrogen production[J]. Nature Communications, 2015, 6:7493.