Three-Dimensional Porous Aerogel Constructed by g-C3N4 and Graphene Oxide Nanosheets with Excellent Visible-Light Photocatalytic Performance

It is curial to develop a high-efficient, low-cost visible-light responsive photocatalyst for the application in solar energy conversion and environment remediation. Here, a three-dimensional (3D) porous g-C3N4/graphene oxide aerogel (CNGA) has been prepared by the hydrothermal coassembly of two-dimensional g-C3N4 and graphene oxide (GO) nanosheets, in which g-C3N4 acts as an efficient photocatalyst, and GO supports the 3D framework and promotes the electron transfer simultaneously. In CNGA, the highly interconnected porous network renders numerous pathways for rapid mass transport, strong adsorption and multireflection of incident light; meanwhile, the large planar interface between g-C3N4 and GO nanosheets increases the active site and electron transfer rate. Consequently, the methyl orange removal ratio over the CNGA photocatalyst reaches up to 92% within 4 h, which is much higher than that of pure g-C3N4 (12%), 2D hybrid counterpart (30%) and most of representative g-C3N4-based photocatalysts. In addition, the dye is mostly decomposed into CO2 under natural sunlight irradiation, and the catalyst can also be easily recycled from solution. Significantly, when utilized for CO2 photoreduction, the optimized CNGA sample could reduce CO2 into CO with a high yield of 23 mmol g(-1) (within 6 h), exhibiting about 2.3-fold increment compared to pure g-C3N4. The photocatalyst exploited in this study may become an attractive material in many environmental and energy related applications.