hello! I want to know how oxygen pumps work. This photo displays one: http://www.ngk.co.jp/english/news/2008/image/0611_04.gif from: http://www.ngk.co.jp/english/news/2008/0611.html My question is, in order to pump the oxygen, does the oxygen have to go through the platinum electrode? or we can apply voltage to zirconia and have the oxygen pumped? thanks!