We report the preparation of hexagonal mesoporous silica from single-source giant surfactants constructed via dihydroxyl-functionlized polyhedral oligomeric silsesquioxane (DPOSS) heads and a polystyrene (PS) tail. After thermal annealing, the obtained well-ordered hexagonal hybrid was pyrolyzed to afford well-ordered mesoporous silica. A high porosity (e.g., 581 m 2 /g) and a uniform and narrow pore size distribution (e.g., 3.3 nm) were achieved. Mesoporous silica in diverse shapes and morphologies were achieved by processing the precursor. When the PS tail length was increased, the pore size expanded accordingly. Moreover, such pyrolyzed, ordered mesoporous silica can help to increase both efficiency and stability of nanocatalysts.
N-doped carbon materials represent a type of metal-free catalyst for diverse organic synthetic reactions. However, single N-doped carbon materials perform insufficiently in the selective oxidation reaction of C−H bond compared with metal catalysts or multielement co-doped materials. There are a few reports on the application of three-dimensional (3D) carbon materials in such a reaction. Besides, the relationship between the well-developed porous structures, heteroatom doping, and their catalytic performance is unclear. In this study, 3D porous N-doped graphene aerogel catalysts with high activity and selectivity for the C−H bond oxidation under mild reaction conditions have been synthesized through a two-step method. Systematic studies on the dosage of N sources, pyrolysis temperature, and their influences on the catalytic performances have been evolved. Moreover, solid evidence of the synergistic effect of sp 2 C atoms adjacent to the N atoms and porous structure promoting the performance has been provided in this work.
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