A Pt@three-dimensional graphene (Pt@3DG) composite hydrogel with a unique porous nanostructure was prepared and used as an efficient, recyclable and robust catalyst for the reduction of 4-nitrophenol to 4-aminophenol under mild conditions. The influence of graphene architecture on catalytic activities was comparatively investigated by loading the same amount of Pt on reduced graphene oxide. Pt@3DG exhibits a very high catalytic activity owing to the three-dimensional macroporous framework with high specific surface area, numerous activation sites and efficient transport pathways. Moreover, catalyst separation can be easily achieved by simple filtration, and the catalyst can be reused for at least five runs, maintaining its high catalytic activity.

The relationship was established between tunable and uniform GOSs and the structures and catalytic properties of 3D rGO sponge.

Three-dimensional graphene (3DG) sponge has attracted increasing attention because it 10 combines the unique properties of cellular materials and the excellent performance of graphene. 11The preparation of 3DG sponge depends mainly on the self-assembly of graphene oxide sheets. 12Here, we demonstrate facile fabrication of 3DG sponge with a large-scale and ordered porous 13 structure, exploiting the liquid crystals of large graphene oxide (LGO) and ultralarge graphene 14 oxide (ULGO) sheets. The resulting materials exhibit a low density, high porosity and elasticity. Our 15 work explores a new strategy for organizing the ordered alignment of controlled large GO sheets 16 and exploring the relationship between the microstructures and mechanical properties of 3DG 17 sponge. 18