N-Doped Food-Grade-Derived 3D Mesoporous Foams as Metal-Free Systems for Catalysis

Abstract

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).

Three‐Dimensional Interconnected Porous Nitrogen‐Doped Carbon Hybrid Foam for Notably Promoted Direct Dehydrogenation of Ethylbenzene to Styrene

“…Upon heating, glucose carbonization happens at 250°C, [30] gases release from NH 4 Cl to blow the carbon skeleton and corrode the skeleton into porous morphology at 350°C. The foam framework is formed by the gas template role of NH 4 Cl under the protection of the as-formed carbon on the matrix. The foam framework is formed by the gas template role of NH 4 Cl under the protection of the as-formed carbon on the matrix.…”

“…[1] Various strategies have been adopted to prepare 3D carbon materials, such as self-assemble method, [2] direct-templated chemical vapor deposition (CVD) [3] and carbonization of 3D organic templates [4] , and the fruitful 3D structured carbon matrix has been fabricated (e. g., 3D graphene aerogel, [5] carbon foam [6] and 3D CNTs foam [7] ). [1] Various strategies have been adopted to prepare 3D carbon materials, such as self-assemble method, [2] direct-templated chemical vapor deposition (CVD) [3] and carbonization of 3D organic templates [4] , and the fruitful 3D structured carbon matrix has been fabricated (e. g., 3D graphene aerogel, [5] carbon foam [6] and 3D CNTs foam [7] ).…”

“…3D hierarchical carbon materials provide a versatile platform for various applications such as catalysis, adsorption, supercapacitor and separation. [1] Various strategies have been adopted to prepare 3D carbon materials, such as self-assemble method, [2] direct-templated chemical vapor deposition (CVD) [3] and carbonization of 3D organic templates [4] , and the fruitful 3D structured carbon matrix has been fabricated (e. g., 3D graphene aerogel, [5] carbon foam [6] and 3D CNTs foam [7] ). Despite the recent achievements in 3D carbon nanomaterials fabrication, there are still many challenges to overcome: Firstly, unstable pristine graphene network results in poor mechanical stability.…”

“…Glucose has been widely utilized as a precursor for the preparation of carbon materials featured with abundant oxygenated functional groups which play an important role in constructing supercapacitor with excellent charge-discharge property. [30] NH 4 Cl was employed as soft template for porous structure. Meanwhile, the released NH 3 as nitrogen resource for nitrogen doping and the released HCl can etch carbon nitride layer.…”

Gaseous Nitric Acid Activated Graphite Felts as Hierarchical Metal-Free Catalyst for Selective Oxidation of H2S

“…The most studied form of these metal-free catalysts consisted of carbon nanotubes doped with nitrogen atoms, which has been extensively used in several catalytic processes [8][9][10][11][12][13]. Recently, work reported by Pham-Huu and Gambastiani [14,15] has shown that nitrogen-doped mesoporous carbon film, synthesized from food stuff raw materials, displays a high performance for different catalytic processes such as oxygen reduction reaction (ORR), direct dehydrogenation of ethylbenzene and selective oxidation of H 2 S. Such nitrogen-doped metal-free catalysts display an extremely high stability as a function of time on stream or cycling tests which could be directly attributed to the complete lack of sintering consecutively to the direct incorporation of the nitrogen atoms inside the carbon matrix.…”