Three-Dimensional Graphene-Based Nanomaterials as Electrocatalysts for Oxygen Reduction Reaction

Figure 4

Fabrication process for the 3D Fe₃O₄/N-GAs catalyst. (a) Stable suspension of GO, iron ions, and PPy dispersed in a vial. (b) Fe- and PPy-supporting graphene hybrid hydrogel prepared by hydrothermal self-assembly and floating on water in a vial and its ideal assembled model. (c) Monolithic Fe₃O₄/N-GAs hybrid aerogel obtained after freeze-drying and thermal treatment (reprinted from [46]; copyright 2012 American Chemical Society).