MOF-derived carbonaceous materials enriched with nitrogen: Preparation and applications in adsorption and catalysis

Bhadra, Biswa Nath,Vinu, Ajayan,Serre, Christian,Jhung, Sung Hwa Elsevier 2019 Materials today Vol.25 No.-

<P><B>Abstract</B></P> <P>Porous carbons have been considered very important for a long time because of various possible applications. In this review, we summarize the current progress in the field of porous carbons, especially N-enriched carbons, obtained from the carbonization of MOFs with or without additional N-containing compounds. Moreover, metal- or metal oxide-loaded N-doped carbons are also dealt with. Not only the preparation but also the applications in adsorption and catalysis are summarized. More importantly, research ideas or trends will be suggested for further development of these fields. Finally, this study summarizes a number of methods for the preparation of N-enriched carbons (with or without metal or metal oxide) and their efficiencies in various potential applications, including adsorption (liquid-/gas-phase) and organo-/photo-/electro-catalyses, based on their physicochemical properties.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Anionic clay as the drug delivery vehicle: tumor targeting function of layered double hydroxide-methotrexate nanohybrid in C33A orthotopic cervical cancer model

Choi, Goeun,Piao, Huiyan,Alothman, Zeid A,Vinu, Ajayan,Yun, Chae-Ok,Choy, Jin-Ho DOVE MEDICAL PRESS 2016 INTERNATIONAL JOURNAL OF NANOMEDICINE Vol.11 No.-

<P>Methotrexate (MTX), an anticancer agent, was successfully intercalated into the anionic clay, layered double hydroxides to form a new nanohybrid drug. The coprecipitation and subsequent hydrothermal method were used to prepare chemically, structurally, and morphologically well-defined two-dimensional drug-clay nanohybrid. The resulting two-dimensional drug-clay nanohybrid showed excellent colloidal stability not only in deionized water but also in an electrolyte solution of Dulbecco’s Modified Eagle’s Medium with 10% fetal bovine serum, in which the average particle size in colloid and the polydispersity index were determined to be around 100 and 0.250 nm, respectively. The targeting property of the nanohybrid drug was confirmed by evaluating the tumor-to-blood and tumor-to-liver ratios of the MTX with anionic clay carrier, and these ratios were compared to those of free MTX in the C33A orthotopic cervical cancer model. The biodistribution studies indicated that the mice treated with the former showed 3.5-fold higher tumor-to-liver ratio and fivefold higher tumor-to-blood ratio of MTX than those treated with the latter at 30 minutes postinjection.</P>

Hierarchic Nanostructure for Auto-Modulation of Material Release: Mesoporous Nanocompartment Films

Ji, Qingmin,Acharya, Somobrata,Hill, Jonathan P.,Vinu, Ajayan,Yoon, Suk Bon,Yu, Jong-Sung,Sakamoto, Kazutami,Ariga, Katsuhiko WILEY-VCH Verlag 2009 Advanced Functional Materials Vol.19 No.11

<P>The preparation of mesoporous nanocompartment films composed of both hollow silica capsules and silica particles by using layer-by-layer (LbL) adsorption is described. The resultant nanocompartment films exhibit stepwise release of encapsulated water molecules without application of external stimuli. The hollow hierarchic pore structure of the silica capsules, including their internal void and mesoporous walls, is a key factor for the regulation and stepwise release of water, and is probably caused by the non-equilibrated concurrent evaporation of material from the mesopore and capillary penetration into the mesopores. The number of release steps and rate of release can be tuned by variation of several parameters including water content, ambient temperature, layer multiplicity, and co-adduct particle size. Application of the mesoporous nanocompartment films for the release of substances, including therapeutic agents and fragrances, indicates that the stepwise material release can be applied for a wide range of liquid substances. The films should lead to a novel material release system useful even for biomedical applications capable of controlled and sustained delivery of drug molecules.</P> <B>Graphic Abstract</B> <P>Hollow silica capsules are used to fabricate mesoporous compartment films capable of uptake and release of encapsulated molecules. Variable diffusion rates from interior to exterior result in an auto-modulated stepwise release behaviour without applying any external stimuli. <img src='wiley_img/1616301X-2009-19-11-ADFM200801762-content.gif' alt='wiley_img/1616301X-2009-19-11-ADFM200801762-content'> </P>

Superior adsorption capacity of mesoporous carbon nitride with basic CN framework for phenol

Haque, Enamul,Jun, Jong Won,Talapaneni, Siddulu Naidu,Vinu, Ajayan,Jhung, Sung Hwa The Royal Society of Chemistry 2010 Journal of materials chemistry Vol.20 No.48

<p>Highly basic 2D-mesoporous carbon nitride (MCN-1) shows the highest adsorption capacity and adsorption kinetic constant for phenol due to its well ordered porous structure with the in-built basic NH and NH<SUB>2</SUB> groups on the surface, high surface area and large pore volume, suggesting the potential application of MCN-1 for the purification of contaminated water.</p> <P>Graphic Abstract</P><P>The highest adsorption capacity and kinetic constant for phenol adsorption has been achieved over mesoporous carbon nitride due to the presence of in-built basic functional groups and excellent textural parameters. <img src='http://pubs.rsc.org/ej/JM/2010/c0jm02974b/c0jm02974b-ga.gif'> </P>

Highly Enhanced Photocatalytic Water-Splitting Activity of Gallium Zinc Oxynitride Derived from Flux-Assisted Zn/Ga Layered Double Hydroxides

Yang, Jae-Hun,Pei, Yi-Rong,Kim, Seung-Joo,Choi, Goeun,Vinu, Ajayan,Choy, Jin-Ho American Chemical Society 2018 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.57 No.48

<P>The Ga/Zn oxynitride solid solution [(GaN)<SUB>1-<I>x</I></SUB>(ZnO)<SUB><I>x</I></SUB>] is one of the promising visible light harvesting photocatalysts for overall water splitting. A series of (GaN)<SUB>1-<I>x</I></SUB>(ZnO)<SUB><I>x</I></SUB> (0.11 ≤ <I>x</I> ≤ 0.33) compounds are synthesized by calcining the carbonate-type Zn/Ga-LDH precursor with and without sodium carbonate flux at 850 °C for 8-14 h under a NH<SUB>3</SUB> gas flow. The solid solutions without flux are determined to be low in crystallinity, but platelike morphology with preferred orientation could be observed. On the other hand, those with flux turn out to be better in crystallinity, and eventually exhibit significantly higher photocatalytic activity for overall water splitting under visible light irradiation than those without flux. In addition, the band gap energies can also be engineered from 2.57 to 2.72 eV by changing a synthetic parameter such as nitridation time. It is, therefore, suggested that the present new approach can offer new opportunities for designing the next generation of photocatalytic systems.</P> [FIG OMISSION]</BR>

Molecular Orientation of Intercalants Stabilized in the Interlayer Space of Layered Ceramics: 1-D Electron Density Simulation

Yang, Jae-Hun,Pei, Yi-Rong,Piao, Huiyan,Vinu, Ajayan,Choy, Jin-Ho The Korean Ceramic Society 2016 한국세라믹학회지 Vol.53 No.4

In this review, an attempt is made to calculate one-dimensional (1-D) electron density profiles from experimentally determined (00l) XRD intensities and possible structural models as well in an effort to understand the collective intracrystalline structures of intercalant molecules of two-dimensional (2-D) nanohybrids with heterostructures. 2-D ceramics, including layered metal oxides and clays, have received much attention due to their potential applicability as catalysts, electrodes, stabilizing agents, and drug delivery systems. 2-D nanohybrids based on such layered ceramics with various heterostructures have been realized through intercalation reactions. In general, the physico-chemical properties of such 2-D nanohybrids are strongly correlated with their heterostructures, but it is not easy to solve the crystal structures due to their low crystallinity and high anisotropic nature. However, the powder X-ray diffraction (XRD) analysis method is thought to be the most powerful means of understanding the interlayer structures of intercalant molecules. If a proper number of well-developed (00l) XRD peaks are available for such 2-D nanohybrids, the 1-D electron density along the crystallographic c-axis can be calculated via a Fourier transform analysis to obtain structural information about the orientations and arrangements of guest species in the interlayer space.

Layer-by-Layer Films of Dual-Pore Carbon Capsules with Designable Selectivity of Gas Adsorption

Ji, Qingmin,Yoon, Suk Bon,Hill, Jonathan P.,Vinu, Ajayan,Yu, Jong-Sung,Ariga, Katsuhiko American Chemical Society 2009 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.131 No.12

<P>Stable, homogeneous ultrathin films of uniformly dimensioned dual-pore carbon capsules with mesoporous walls and macroscopic empty cores were fabricated using layer-by-layer methods based on electrostatic interaction between a polyelectrolyte and a surfactant coating of the carbon capsules. The resulting dual-porous carbon capsule films were investigated as a sensor substrate for vapors of different organic solvents. The carbon capsule films have much higher adsorption capacities than conventional electrolyte films and even than noncapsular mesoporous carbon films. The dual-pore carbon capsules have greater affinities for aromatic volatiles over their aliphatic counterparts, probably due to stronger pi-pi interactions. Additionally, the adsorption selectivity can be designed. Impregnation of additional recognition components into the carbon capsules permits further control over adsorption selectivity between aromatic and nonaromatic substances and between acids and bases in the prevailing atmosphere. Therefore, it is anticipated that the dual-pore carbon capsule films developed in this work will find application in sensing and separation applications because of their designable selectivity.</P>

Synthesis of a novel hierarchical mesoporous organic–inorganic nanohybrid using polyhedral oligomericsilsesquioxane bricks

Gandhi, Sakthivel,Kumar, Prem,Thandavan, Kavitha,Jang, Kiwan,Shin, Dong-Soo,Vinu, Ajayan The Royal Society of Chemistry 2014 NEW JOURNAL OF CHEMISTRY Vol.38 No.7

<P>A successful method has been demonstrated for the synthesis of a mesoporous organic–inorganic nanohybrid using amine functionalized polyhedral oligomericsilsesquioxane (POSS) and pluronic polymer as a silica precursor and structure directing agent, respectively. The results confirmed the presence of porous structure, along with the high surface area and uniform pore size distribution which can be utilized for various applications namely catalysis, drug-delivery, <I>etc.</I></P> <P>Graphic Abstract</P><P>A novel mesoporous silica with high surface area and ordered porosity has been developed using <I>N</I>-methylamino POSS and dichloromethylsilane. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4nj00292j'> </P>

Adsorption of Phenol on Mesoporous Carbon CMK-3: Effect of Textural Properties

Haque, Enamul,Khan, Nazmul Abedin,Talapaneni, Siddulu Naidu,Vinu, Ajayan,JeGal, Jong-Geon,Jhung, Sung-Hwa Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.6

Mesoporous carbon CMK-3s with different textural properties have been used for the adsorption of phenol to understand the necessary physicochemical properties of carbon for the efficient removal of phenol from contaminated water. The kinetic constants (both pseudo-second order and pseudo-first-order kinetics) increase with increasing pore size of carbons. The maximum adsorption capacities correlate well with micropore volume compared with surface area or total pore volume even though large pore (meso or macropore) may contribute partly to the adsorption. The pore occupancies also explain the importance of micropore for the phenol adsorption. For efficient removal of phenol, carbon adsorbents should have large micropore volume and wide pore size for high uptake and rapid adsorption, respectively.

Adsorption of Phenol on Mesoporous Carbon CMK-3: Effect of Textural Properties

Enamul Haque,Nazmul Abedin Khan,Siddulu Naidu Talapaneni,Ajayan Vinu,제갈종건,정성화 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.6

Mesoporous carbon CMK-3s with different textural properties have been used for the adsorption of phenol to understand the necessary physicochemical properties of carbon for the efficient removal of phenol from contaminated water. The kinetic constants (both pseudo-second order and pseudo-first-order kinetics) increase with increasing pore size of carbons. The maximum adsorption capacities correlate well with micropore volume compared with surface area or total pore volume even though large pore (meso or macropore) may contribute partly to the adsorption. The pore occupancies also explain the importance of micropore for the phenol adsorption. For efficient removal of phenol,carbon adsorbents should have large micropore volume and wide pore size for high uptake and rapid adsorption,respectively.