27135
The quantum efficiency ( averaged over the solar spectrum ) for absorbed photons - to - hydrogen conversion was 7 . 4 % and solar - to - hydrogen energy efficiency of incident light was 0 . 9 % .
 Chemical: hydrogen; Chemical: hydrogen
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: hydrogen; Chemical: hydrogen