1D porous C3N4/rGO composites with enhanced photocatalytic nitrogen fixation performance

Abstract

A modified thermal polycondensation method is developed to fabricate 1D porous C3N4/rGO (P-CN/rGO) composites using melamine and graphene oxide (GO) as raw materials. The resultant P-CN/rGO with specific surface area of 87.533 m2 g−1 shows an excellent photocatalytic nitrogen fixation performance. The NH3 yield rate of P-CN/rGO reaches to 9.8 mg L−1 h−1 gcat−1 under visible-light irradiation, which is 11.8 times greater in comparison with bulk C3N4 used alone. Such superior photocatalytic activity should be ascribed to the unique features of P-CN and the introduction of rGO. The 1D porous rod-like structure of P-CN provides a large number of active sites to activate N2 molecules and facilitate rapid charge transfer. The coupled rGO serves as co-catalyst to expand the light-harvest region of the composite from the ultraviolet to the visible-light region. Besides, it is disclosed that the high conductivity of rGO can facilitate the migration of photogenerated electrons from the photocatalyst to N2, thus preventing the electron–hole recombination and significantly ameliorating the photocatalytic nitrogen fixation performance. A reasonable photocatalytic mechanism is also proposed.