Photocatalytic Activities of Graphitic Carbon Nitride Powder for Water Reduction and Oxidation under Visible Light

Graphitic carbon nitride (g-C3N4) with a band gap of 2.7 eV is studied as a nonmetallic photocatalyst for H2 or O2 evolution from water under ultraviolet (UV) and visible light. The g-C3N4 catalyst exhibits activities for water reduction into H2 or water oxidation into O2 in the presence of a proper sacrificial electron donor or acceptor, respectively, even without the need for precious metal cocatalysts. When bis(1,5-cyclooctadiene)platinum complex [Pt(cod)2] (a nonionic complex) is used as a precursor of Pt cocatalyst instead of H2PtCl6 (an ionic complex), enhanced H2 evolution activity is acquired. This difference in activity is primarily due to the better dispersion of Pt nanoparticles on g-C3N4, which is…