26960
The change in the Tafel slope for the ORR with increasing overpotential meant that the exchange current density for the ORR varied from 0 . 007 nA cm ( - 2 ) to 10 nA cm ( - 2 ) , depending on the applied potential .
 None
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:  
Answer:
 None