Recent advances in functionalized micro and mesoporous carbon materials: synthesis and applications.

Functionalized nanoporous carbon materials have attracted the colossal interest of the materials science fraternity owing to their intriguing physical and chemical properties including a well-ordered porous structure, exemplary high specific surface areas, electronic and ionic conductivity, excellent accessibility to active sites, and enhanced mass transport and diffusion. These properties make them a special and unique choice for various applications in divergent fields such as energy storage batteries, supercapacitors, energy conversion fuel cells, adsorption/separation of bulky molecules, heterogeneous catalysts, catalyst supports, photocatalysis, carbon capture, gas storage, biomolecule detection, vapour sensing and drug delivery. Because of the anisotropic and synergistic effects arising from the heteroatom doping at the nanoscale, these novel materials show high potential especially in electrochemical applications such as batteries, supercapacitors and electrocatalysts for fuel cell applications and water electrolysis. In order to gain the optimal benefit, it is necessary to implement tailor made functionalities in the porous carbon surfaces as well as in the carbon skeleton through the comprehensive experimentation. These most appealing nanoporous carbon materials can be synthesized through the carbonization of high carbon containing molecular precursors by using soft or hard templating or non-templating pathways. This review encompasses the approaches and the wide range of methodologies that have been employed over the last five years in the preparation and functionalisation of nanoporous carbon materials via incorporation of metals, non-metal heteroatoms, multiple heteroatoms, and various surface functional groups that mostly dictate their place in a wide range of practical applications.

Energy Efficient Synthesis of Ordered Mesoporous Carbon Nitrides with a High Nitrogen Content and Enhanced CO2 Capture Capacity.

Highly ordered mesoporous carbon nitrides (MCN) with 3D structure and a high nitrogen content are successfully prepared for the first time using "uncalcined" mesoporous silica template, KIT-6 and 3-amino-1,2,4-triazole as a single molecular carbon and nitrogen precursor. The prepared MCN with C and N stoichiometry of C3 N5 shows unique CN framework and exhibits the CO2 capture capacity of 5.63 mmol g-1 at 273 K and 30 bar, which is higher than that of MCN with 2D structure and C3 N4 stoichiometry.

Highly Ordered Nitrogen-Rich Mesoporous Carbon Nitrides and Their Superior Performance for Sensing and Photocatalytic Hydrogen Generation.

Mesoporous carbon nitrides (MCN) are fascinating materials with unique semiconducting and basic properties that are useful in many applications including photocatalysis and sensing. Most syntheses of MCN focus on creating theoretically predicted C3 N4 stoichiometry with a band gap of 2.7 eV using a nano-hard templating approach with triazine-based precursors. However, the performance of the MCN in semiconducting applications is limited to the MCN framework with a small band gap, which would be linked with the addition of more N in the CN framework, but this remains a huge challenge. Here, we report a precursor with high nitrogen content, 3-amino-1,2,4-triazole, that enables the formation of new and well-ordered 3D MCN with C3 N5 stoichiometry (MCN-8), which has not been predicted so far, and a low-band-gap energy (2.2 eV). This novel class of material without addition of any dopants shows not only a superior photocatalytic water-splitting performance with a total of 801 µmol of H2 under visible-light irradiation for 3 h but also excellent sensing properties for toxic acids.

Effect of Heat Treatment on the Nitrogen Content and Its Role on the Carbon Dioxide Adsorption Capacity of Highly Ordered Mesoporous Carbon Nitride.

Mesoporous carbon nitrides (MCNs) with rod-shaped morphology and tunable nitrogen contents have been synthesized through a calcination-free method by using ethanol-washed mesoporous SBA-15 as templates at different carbonization temperatures. Carbon tetrachloride and ethylenediamine were used as the sources of carbon and nitrogen, respectively. The resulting MCN materials were characterized with low- and high-angle powder XRD, nitrogen adsorption, high-resolution (HR) SEM, HR-TEM, elemental analysis, X-ray photoelectron spectroscopy, and X-ray absorption near-edge structure techniques. The carbonization temperature plays a critical role in controlling not only the crystallinity, but also the nitrogen content and textural parameters of the samples, including specific surface area and specific pore volume. The nitrogen content of MCN decreases with a concomitant increase in specific surface area and specific pore volume, as well as the crystallinity of the samples, as the carbonization temperature is increased. The results also reveal that the structural order of the materials is retained, even after heat treatment at temperatures up to 900 °C with a significant reduction of the nitrogen content, but the structure is partially damaged at 1000 °C. The carbon dioxide adsorption capacity of these materials is not only dependent on the textural parameters, but also on the nitrogen content. The MCN prepared at 900 °C, which has an optimum BET surface area and nitrogen content, registers a carbon dioxide adsorption capacity of 20.1 mmol g-1 at 273 K and 30 bar, which is much higher than that of mesoporous silica, MCN-1, activated carbon, and multiwalled carbon nanotubes.

Combinatorial synthesis and characterization of metal-open frameworks in mild and friendly conditions: application to CO2 adsorption.

Combinatorial screening using precipitation methods at room temperature can lead to a great diversity of carboxylate based Metal Organic Frameworks (MOFs) including already known or original porous solids. The investigation of the synthesis of MOFs in different solvent and solvent mixtures includes the use of solvents such as alcohols and tetrahydrofuran (THF) which would greatly facilitate large scale production. We also show the application of Principal Component Analysis (PCA) and clustering techniques on large libraries of XRD diffraction files in order to identify classes of similar phases and peculiar phases. The combinatorial screening of 105 samples in the La/btc system has led to the identification of two phases which are solvent depending. On the La(btc) compound, the CO2 adsorption measurements reveal a guest-host interactions as supported by XRD phase transformation upon thermal treatment. The mass transport can be assigned to a "single file diffusion" regime due to the one dimensional channel porous structure associated to small pore size.