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The as - formed Pt NPs have a cluster - like structure and are mainly composed of 3 . 5 nm primary Pt particles with ( 100 ) surface atoms .
 Chemical: Pt; Chemical: Pt
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: Pt; Chemical: Pt