8719
By exploiting the quantized capacitance charging effect , the gold nanoparticles mediate the production of hydrogen without requiring an external power supply , while the MFC produces a stable power density .
 Chemical: hydrogen
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: hydrogen 
Answer:
 Chemical: hydrogen