19789
We report a new capping - agent - free strategy for the synthesis of substrate - supported porous icosahedral Au nanoparticles ( NPs ) with rough naked surfaces , based on the crystallization from substrate - supported thin solution layers followed by solid - phase thermolysis .
 Au
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Au