Single-atom cobalt-hydroxyl modification of polymeric carbon nitride for highly enhanced photocatalytic water oxidation: ball milling increased single atom loading.

Expediting the oxygen evolution reaction (OER) is the key to achieving efficient photocatalytic overall water splitting. Herein, single-atom Co-OH modified polymeric carbon nitride (Co-PCN) was synthesized with single-atom loading increased by ∼37 times with the assistance of ball milling that formed ultrathin nanosheets. The single-atom Co-NOH structure was confirmed experimentally and theoretically and was verified to enhance optical absorption and charge separation and work as the active site for the OER.