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Herein , we develop a novel three - dimensional ( 3D ) sulfur - nitrogen co - doped carbon foams ( S - N - CF ) with hierarchical pore structures , using a convenient , economical , and scalable method .
 Chemical: sulfur - nitrogen co - doped carbon; Chemical: S; Chemical: N
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: sulfur - nitrogen co - doped carbon; Chemical: S; Chemical: N