▎ 摘　　要

Three dimensional cauliflower-fungus-like graphene (3D CFG), which possesses high conductivity and excellent catalytic activity, was directly synthesized from CO2. Furthermore, it was demonstrated that the dye-sensitized solar cell (DSSC) with 3D CFG as a counter electrode exhibited a high energy conversion efficiency of 8.1%, which is 10 times higher than that (0.7%) of a DSSC with a counter electrode based on the regular graphene synthesized via chemical exfoliation of graphite. The efficiency is even better than that (7.5%) of the DSSCs with an expensive Pt counter electrode. This would provide a novel approach not only to synthesize free-standing 3D graphene for solar cells, but also to control CO2 emission.