18142
Cd , Zn , Sn , and Co produce the most photoactive M - Cu oxides , all showing a 200 - 300 % improvement in photocurrent over CuO .
 Chemical: Cd; Chemical: Zn; Chemical: Sn; Chemical: Co; Chemical: Cu; Chemical: oxides; Chemical: CuO
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: Cd; Chemical: Zn; Chemical: Sn; Chemical: Co; Chemical: Cu; Chemical: oxides; Chemical: CuO