27595
Formation Mechanism of TiO 2 Nanotubes and Their Applications in Photoelectrochemical Water Splitting and Supercapacitors .
 Chemical: TiO 2
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: TiO 2 
Answer:
 Chemical: TiO 2