Facile synthesis of dual micro/macroporous carbonaceous foams by templating in highly concentrated water-in-oil emulsions

• A simple method for preparing micro/macroporous carbonaceous foams is reported.
• Highly concentrated emulsions are polymerized, and the organic foam is pyrolyzed.
• Macropores allow obtaining high pore volumes (3.6 mL g−1).
• The presence of micropores leads to large surface area (>700 m2 g−1).
• Macropore size increases during pyrolyzation, probably due to pore coalescence.

A simple method to synthesize carbonaceous porous foams is described, forming simultaneously micropores and macropores, by polymerizing in the external phase of highly concentrated water-in-oil (W/O) emulsions, and pyrolizing the resulting macroporous polymer foam. Highly concentrated W/O emulsions were prepared with 1,1-dichloroethene monomer in the external phase, which was polymerized at low temperature by a redox initiator. Monolithic low-density macroporous foams were obtained after polymerization and purification by soxhlet extraction. These foams were mainly macroporous, with low surface area (≈28 m2 g−1) and negligible microporosity and mesoporosity, as expected. The size (2–10 μm) and morphology of the macropores were consistent with the droplet size (2–10 μm) and shape (polyhedral) of the highly concentrated W/O emulsions. Pyrolization of the macroporous polymer foams allowed the formation of micropores while the macroporous texture was preserved, and consequently, dual micro/macroporous carbonaceous monoliths were obtained, with a large surface area (>800 m2 g−1). These materials were characterized by optical microscopy, scanning and transmission electron microscopy, N2 sorption isotherms, infrared absorption spectroscopy and elemental analysis. The influence of pyrolysis temperature (300, 400 and 500 °C) was studied.

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