The Controllable Synthesis Of Hollow Graphene Balls As Highly Efficient Electrocatalyst For Theoxygen Reduction Reaction

The wide use of fossil fuels has brought serious environmental problelms such as global warming, energy shortage. Fuel cell as a kind of clear, efficient energy, has gained widespread attention owing to its high energy conversion and excellent security. However, platinum for catalyzing the cathodic oxygen reduction reaction has seriously hampered the process of their commercialization because of its exorbitant price and scarce resource. Thus to develop novel nonprecious metal catalyst for oxygen reduction reaction is always the focus of academia. Graphene-based carbon materials because of their high specific surface area and high conductivity have been widely concerned for catalysing oxygen reduction reaction.The silica nanoparticles of different diameters were synthesized with ethyl orthosilicate, and the self-assembly silica was obtained via gravitational sedimentation.The 3D interconnected graphene networks with a hollow structure was synthesized with silica as the template, methane as the carbon source by chemical vapor deposition method. The experimental results had demonstrated that the obtained 3D-hollow graphene balls exhibited comparable catalytic activity, longer-term stability and higher methanol tolerance than a commercial Pt/C catalyst. Such excellent performances may be attributed to the fast reactant transport and high electron transfer rate provided by 3D continuous networks. In addition, hollow urchin-like graphene balls were obtained with silica etching by NaOH as the template, methane as the carbon source by chemical vapor deposition method. The electrocatalytic performances show that hollow urchin-like graphene balls exhibits an excellent methonal tolerence and long-term stability, indicating a promissing application for oxygen reduction reaction.