A gas delivery device includes a nitric oxide generating system. The system has a medium including i) a source of nitrite ions, or ii) a source of nitrite ions and a Cu(II)-ligand complex. A working electrode is in contact with the medium, wherein i) when the medium includes the source of nitrite ions, the working electrode is a copper containing conductive material or a base material coated with a copper containing conductive material, or ii) when the medium includes the source of nitrite ions and the Cu(II)-ligand complex, the working electrode is platinum, gold, carbon, a carbon coated material, and/or mercury. A reference/counter electrode is in contact with the medium and electrically isolated from the working electrode. An inlet conduit is to deliver oxygen gas to the medium, and an outlet conduit is to transport a stream of oxygen gas and nitric oxide from the medium.