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

Abstract 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 m 2  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 m 2  g −1 ). These materials were characterized by optical microscopy, scanning and transmission electron microscopy, N 2 sorption isotherms, infrared absorption spectroscopy and elemental analysis. The influence of pyrolysis temperature (300, 400 and 500 °C) was studied.