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Liu and co - workers , can cause the graphite layers to separate into graphene sheets via a high - temperature exfoliation , or even broken into small clusters / atoms , which then form graphene sheets by catalytic growth , demonstrating that two mechanisms exist in an arc discharge process simultaneously .
 Chemical: graphite; Chemical: graphene; Chemical: graphene
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: graphite; Chemical: graphene; Chemical: graphene