3055
The new Al / Pd Janus microspheres - prepared by depositing a Pd layer on one side of Al microparticles - are propelled efficiently by the thrust of hydrogen bubbles generated from different reactions of Al in strong acidic and alkaline environments , and by an oxygen bubble thrust produced at their partial Pd coating in hydrogen peroxide media .
 Chemical: Al; Chemical: Pd; Chemical: Pd; Chemical: Al; Chemical: hydrogen; Chemical: Al; Chemical: oxygen; Chemical: Pd; Chemical: hydrogen peroxide
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: Al; Chemical: Pd; Chemical: Pd; Chemical: Al; Chemical: hydrogen; Chemical: Al; Chemical: oxygen; Chemical: Pd; Chemical: hydrogen peroxide