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 g_cat⁻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.