6641
Novel Three - Dimensional Nanoporous Alumina as a Template for Hierarchical TiO2 Nanotube Arrays .
 Chemical: Alumina; Chemical: TiO2
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: Alumina; Chemical: TiO2