27421
Bio - electrocatalytic reduction of oxygen starts from the T1 Cu potentials of SLAC , and is most efficient at the promoter - modified electrodes , thereby demonstrating good performance both in neutral and basic media and in solutions with a high NaCl content , such as sea water .
 Chemical: oxygen; Chemical: Cu; Chemical: NaCl
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: oxygen, Cu, NaCl 
Answer:
 Chemical: oxygen; Chemical: Cu; Chemical: NaCl