I first read about hydrogen sensing Titania nanotubules at slashdot. From Science Blog:
Titania nanotubes are 1500 times better than the next best material for sensing hydrogen and may be one of the first examples of materials properties changing dramatically when crossing the border between real world sizes and nanoscopic dimensions.(Titania is titanium oxide, just as alumina is aluminum oxide and zirconia is zirconium oxide .) The first thing springing to mind was the "O TITANIA" acrostic in Shakespeare:
Thou shalt remain here, whether thou wilt or no.
I am a spirit of no common rate,
The summer still doth tend upon my state;
ANd I do love thee. Therefore go with me.
I'll give thee fairies to attend on thee;
And they shall fetch thee jewels from the deep,