18568
Coupling with atomic - resolution scanning transmission electron microscopy ( STEM ) and theoretical calculations , the outstanding activity is rationalized by the formation of Co overlayer structures on Pt NPs or Pt - Co alloy NPs .
 Chemical: Co; Chemical: Pt; Chemical: Pt - Co
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: Co; Chemical: Pt; Chemical: Pt - Co