Preparation and Enhanced Visible-Light Photocatalytic H 2 -Production Activity of Graphene/C 3 N 4 Composites

Graphene and graphitic carbon nitride (g-C3N4) composite photocatalysts were prepared by a combined impregnation−chemical reduction strategy involving polymerization of melamine in the presence of graphene oxide (precursors) and hydrazine hydrate (reducing agent), followed by thermal treatment at 550 °C under flowing nitrogen. The resulting graphene/g-C3N4 composite photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, UV−visible spectrophotometry, nitrogen adsorption, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and photoluminescence spectroscopy. The transient photocurrent response was measured for several on−off cycles of…