A challenging task of modern and sustainable catalysis is to rethink key processes at the heart of renewable energy technology in light of metal-free catalytic architectures designed and fabricated from cheap and easily accessible building blocks. This contribution describes the synthesis of highly N doped, carbon nanotube (CNT)-netting composites from cheap raw materials. With physical mixtures of CNTs and food-grade components as the starting materials, their thermal treatment generates foamy, N-doped carbon-based architectures. The mesoporous nature of the N-doped carbon phase grown around intertwined carbon nanotube networks and the easy control of the final material 3D shape make the protocol highly versatile for its full exploitation in the production of materials for catalysis. In addition to offering unique advantages with respect to the classical N-doped CNT powders, the 3D metal-free composites are highly versatile systems for a number of liquid-phase and gas-phase catalytic processes, under a wide operative temperature range. In this paper we demonstrate their excellent and to some extent unique catalytic performance in two fundamental and catalyst-demanding processes: (i) the electrochemical oxygen reduction reaction (ORR) and (ii) the direct, steam-free dehydrogenation of ethylbenzene (EB) to styrene (ST).

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Graphene oxide mediated exfoliation of expanded graphite in aqueous solution and incorporated nanodiamonds as metal-free catalysts.

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The macroscopic shaping of carbon nanostructure materials with tunable porosity, morphologies, and functions, such as carbon nanotubes (CNT) or carbon nanofibers (CNF), into integrated structures is of great interest, as it allows the development of novel nanosystems with high performances in filter applications and catalysis. In the present work, we report on a low temperature chemical fusion (LTCF) method to synthesize a self-macronized carbon nanotubes foam (CNT-foam) with controlled size and shape by using CNT as a skeleton, dextrose as a carbon source, and citric acid as a carboxyl group donor reacting with the hydroxyl group present in dextrose. The obtained composite has a 3D pore structure with a high accessible surface area (>350 m 2 g À1 ) and tunable meso-and macro-porosity formed by the addition of a variable amount of ammonium carbonate into the starting mixture followed by a direct thermal decomposition. The as-synthesized CNT-foam also exhibits a relatively high mechanical strength which facilitates its handling and transport, while the nanoscopic morphology of the CNT significantly reduces the problem of diffusion and contributes to an improvement of the effective surface area for subsequent applications. These CNT-foams are successfully employed as selective and recyclable organic absorbers with high efficiency in the field of waste water treatment.