Photocatalytic production of hydrogen peroxide by two-electron reduction of dioxygen with carbon-neutral oxalate using a 2-phenyl-4-(1-naphthyl)quinolinium ion as a robust photocatalyst.

Efficient photocatalytic production of hydrogen peroxide (H(2)O(2)) from O(2) and oxalate has been made possible by using a 2-phenyl-4-(1-naphthyl)quinolinium ion as a robust photocatalyst in an oxygen-saturated mixed solution of a buffer and acetonitrile with a high quantum yield of 14% (maximum 50% for the two-electron process) at λ = 334 nm and a high H(2)O(2) yield of 93% at λ > 340 nm.