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We developed a one-step method to obtain a high dispersion of Pt-based alloy nanoparticles on graphene by using both the carrier function and the reducibility of carbon without the addition of any other reducing agents. This method opens up a general and feasible route for the synthesis of different metals, binary and ternary alloys (such as Pt, Pt-Cu, Pt-Ni, Pt-Ni-Cu, Pt-Co-Cu, Pt-Au-Cu, and so on) on graphene sheets, which would bring potential applications in many fields. Particular in this study, the obtained PtCu/G composites exhibit superior electrochemical activities and high poison tolerance toward methanol oxidation compared to Pt/graphene and commercial Pt/graphene composites, demonstrating that the PtCu/graphene can be used as promising catalysts for direct methanol fuel cells.-2 -

Three-dimensional (3D) honeycomb-like birnessite networks composed of ultrathin two-dimensional (2D) nanosheets were firstly synthesized through a facile and low-cost synthetic route. By using carbon microspheres as a template instead of graphene, hierarchical birnessite structures assembled by ultrathin nanosheets including york-shell and hollow structures were obtained besides the ultrathin birnessite nanosheets with a thickness of about 0.7 nm. By assembling carbon spheres into an ordered 3D array, novel 3D honeycomb-like birnessite structures assembled by ultrathin nanosheets were firstly prepared. When evaluated as an anode material for Li-ion batteries, the 3D honeycomb-like networks show enhanced electrochemical performances with high capacities, excellent cycling stability and good rate capability, which can be ascribed to the novel 3D honeycomb-like macroporous structure with a 3D inverse opal structure, well-ordered macropores, interconnected walls and a regular periodicity.

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In this work, we report a facile approach to synthesize uniform Co3O4 hollow spheres with tunable shell numbers via controllably annealing cobalt(ii) complex precursors at different heating rates.