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Figure 1. Preparation of porous graphene
Figure 2. Scanning electron microscope image of porous graphene (a side view; b top view)
Figure 3. Schematic of porous graphene etched by carbothermal reduction
Porous Graphene—Plates have nanopores, which are generally studied by theoretical calculations. The pores of graphene sheets help to improve the mass transfer and have potential applications in many fields. Heretofore, methods for the preparation of porous graphene, including bottom-up chemical processes by aryl-aryl coupling reactions and by high-energy technical processes, have generally been prepared on substrates with limited yields.
Researcher Han Baohang of the National Nanoscience Center has developed a method that can be scaled up and applied to a wide range of applications (see Figure 1). Graphene oxides and metal oxides or polyoxometalates are used to produce graphite at high temperatures. The olefins and the metal oxide nanoparticles are similar to the carbothermal reduction reaction in the coke blast furnace ironmaking process. The metal oxides are reduced to carbon or formed metal carbides on the graphene carbon, and participate in the carbothermal reduction. The reacted carbon atoms leave the graphene sheet in the form of carbon dioxide or carbon monoxide, thereby etching the nanoscale pores on the graphene sheet, ie, forming porous graphene (see FIG. 2 ).
This process can be observed in scanning electron microscopy by electron-beam heating assisted observation of the process of carbon thermal etching to form pores (see schematic in Figure 3) while pore size and/or nitrogen doping of porous graphene can be achieved by changing metal oxygen acids. The amount of salt or polyoxometallate used, or the use of metal oxides or polyoxometallates containing ammonium ions.
In this study, porous graphene was prepared using a variety of metal oxometalates or polyoxometalates, indicating that the method for the preparation of porous graphene by carbon thermal reduction etching has a wide range of applications, and the amount of preparation can be enlarged and not affected by the method. limit. The research work was completed by a team of graduate students Zhou Ding and others. The research results were published in the Nature Communications journal on September 2.
The above research work has been funded by the Ministry of Science and Technology's major scientific research program and the National Natural Science Foundation of China.
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