@article { ISI:000295843900024, title = {MgCl2 center dot 6PhCH(2)OH - a new molecular adduct as support material for ziegler-natta catalyst: synthesis, characterization and catalytic activity}, journal = {Dalton Transactions}, volume = {40}, number = {41}, year = {2011}, month = {SEP}, pages = {10936-10944}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Benzyl alcohol has been used to prepare a single phase MgCl2 center dot 6BzOH molecular adduct as a support for an ethylene polymerization catalyst (Ziegler catalyst). The structural, spectroscopic and morphological aspects of the MgCl2 center dot 6BzOH molecular adduct and the Ziegler catalyst have been thoroughly studied by various physicochemical characterization techniques. The presence of MgO6 octahedrons due to the interaction of Mg2+ with six -OH groups of the benzyl alcohol is confirmed from a Raman feature at 703 cm(-1), and structural studies. The supported catalyst activity has been evaluated for the ethylene polymerization reaction. The lower polymerization activity of the titanated Ziegler-Natta catalyst compared with a standard catalyst is attributed to the strong interaction of titanium chloride with the support and associated electronic factors.

}, issn = {1477-9226}, doi = {10.1039/c1dt10786k}, author = {Gnanakumar, Edwin S. and Thushara, K. S. and Bhange, Deu S. and Mathew, Renny and Ajithkumar, Thalasseril G. and Rajamohanan, P. R. and Bhaduri, Sumit and Gopinath, Chinnakonda S.} } @article { ISI:000286868600075, title = {Toward an understanding of the molecular level properties of ziegler-natta catalyst support with and without the internal electron donor}, journal = {Journal of Physical Chemistry C}, volume = {115}, number = {5}, year = {2011}, month = {FEB}, pages = {1952-1960}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Two Ziegler-Natta catalysts supported on molecular adducts, namely, MgCl2 center dot 6EtOH (ME) and MgCl2 center dot 5EtOH center dot EtOOCPh (Est-ME), have been prepared. A systematic effort has been made to unravel the molecular level structure property relationships of the catalysts and adducts. Ethylbenzoate is an internal electron donor, and its in situ formation through EtOH+PhCOCl coupling is successfully achieved. The above adduct has been treated with TiCl4, and the resultant catalyst (Ti/Est-ME) is evaluated for ethylene polymerization activity. Rand C-13 CP/MAS NMR of Est-ME (Ti/Est-ME) show carbonyl features at 1730 (1680) cm(-1) and 169 (170) delta, respectively, providing direct support for the presence of ester as an integral part. In spite of low surface area, Ti/Est-ME gives higher yield for ethylene polymerization than the one derived from ME. The results indicate that electronic environment is more important than surface area or any other single factor in determining the polymerization activity.

}, issn = {1932-7447}, doi = {10.1021/jp1078289}, author = {Thushara, K. S. and Gnanakumar, Edwin S. and Mathew, Renny and Jha, Ratnesh Kumar and Ajithkumar, Thalasseril G. and Rajamohanan, P. R. and Sarma, Krishna and Padmanabhan, Sudhakar and Bhaduri, Sumit and Gopinath, Chinnakonda S.} } @article { ISI:000305419900012, title = {Gamma-Al2-xMxO3 +/- y (M = Ti4+ through Ga3+): potential pseudo-3D mesoporous materials with tunable acidity and electronic structure}, journal = {Journal of Materials Chemistry}, volume = {22}, number = {27}, year = {2012}, month = {APR}, pages = {13484-13493}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A simple and highly efficient surfactant-free sol-gel process has been developed to obtain nanocrystalline mesoporous gamma-Al2O3 and metal ion incorporated mesoporous gamma-Al2O3 with general formula gamma-Al2-xMxO3 +/- y (where M = Ti4+ through Ga3+). Any one of the first row transition metal (TM) ions along with Ga3+ could be introduced into the gamma-Al2O3 framework in a direct one-pot synthesis process. The generality of the present synthesis recipe for metal ion incorporation in gamma-Al2O3 was demonstrated by preparation of an Al-Ga-M ternary oxide system with the metal ion composition of general formula Al9GaTM (TM = Ti4+ to Zn2+) and their characterization through various physicochemical and spectroscopic techniques. The mesoporous gamma-Al2-xMxO3 +/- y materials showed a BET surface area in the range of 200-400 m(2) g(-1) with a narrow pore size distribution. Wormhole mesoporosity makes the material pseudo-3D (p3D) with a small pore depth of few nm (\<10 nm). Metal ions in gamma-Al2O3 lead to changes in the acidity and electronic environment. XRD, TEM, and Al-27 MAS NMR studies demonstrate that the sol-gel process and the disordered mesoporous structure allow Ga and TM ions to be highly distributed and integrated in the gamma-Al2O3 framework. The efficacy of these materials in catalysis has been successfully evaluated for steam reforming of dimethylether: Ni, Cu and Zn containing Al9GaTM oxides showed high activity and stability. The smaller mesochannel depth (\<10 nm) and pseudo-3D characteristics that arise due to the wormhole-type disordered mesoporous framework of these alumina materials facilitate mass transport through them without any leaching of metal ions out of the lattice and pore blocking during the reaction, which makes them attractive in catalysis. This preparation method is versatile enough to be used for a reproducible synthesis of metal ion incorporated mesoporous gamma-Al2O3 by varying the metal content and their combinations, and it is expected that many other metal ions could be introduced into the lattice framework for a variety of applications by tuning acidity and electronic structure.

}, issn = {0959-9428}, doi = {10.1039/c2jm31184d}, author = {Mathew, Thomas and Sivaranjani, Kumarsrinivasan and Gnanakumar, Edwin S. and Yamada, Yusuke and Kobayashi, Tetsuhiko and Gopinath, Chinnakonda S.} } @article { ISI:000308361400011, title = {MgCl2 center dot 4((CH3)(2)CHCH2OH): a new molecular adduct for the preparation of TiClx/MgCl2 catalyst for olefin polymerization}, journal = {Dalton Transactions}, volume = {41}, number = {37}, year = {2012}, month = {JUL}, pages = {11311-11318}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A new molecular adduct of MgCl2 with isobutanol, namely MgCl2 center dot 4((CH3)(2)CHCH2OH) (MgiBOH), has been prepared as a precursor to the supporting material for an olefin polymerization catalyst. The MgiBOH adduct and final titanated Ziegler-Natta catalysts have been thoroughly characterized by powder XRD, thermal analysis, Raman spectroscopy and solid-state NMR for structural and spectroscopy aspects. A peak observed at 712 cm(-1) in the Raman spectra of MgiBOH indicates the characteristic Mg-O-6 breathing mode and the formation of the adduct. The diffraction feature at 2 theta = 7.8 degrees (d = 11.223 angstrom) in the XRD confirms the adduct formation and the layered structure. The aim of the present article is to study how the insertion of a bulky isobutanol moiety affects the structural and electronic properties of the MgCl2 isobutanol molecular adduct. Indeed, the focus of the present study is to explore how the presence of isobutanol, in the initial molecular adduct, influences the final Z-N catalyst properties and its activity.

}, issn = {1477-9226}, doi = {10.1039/c2dt31211e}, author = {Thushara, K. S. and Gnanakumar, Edwin S. and Mathew, Renny and Ajithkumar, Thalasseril G. and Rajamohanan, P. R. and Bhaduri, Sumit and Gopinath, Chinnakonda S.} } @article { ISI:000311190800033, title = {MgCl2 center dot 6C(6)H(11)OH: a high mileage porous support for ziegler-natta catalyst}, journal = {Journal of Physical Chemistry C}, volume = {116}, number = {45}, year = {2012}, month = {NOV}, pages = {24115-24122}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A new and single phase molecular adduct of MgCl2 with six cyclohexanol molecules MgCl2 center dot 6C(6)H(11)OH (MgCyOH) has been synthesized. Structural insight to this adduct was obtained by a variety of physicochemical methods. C-13 CPMAS spectrum and single pulse MAS spectra with high power proton decoupling recorded at different relaxation time showed the presence of two different sets of magnetically unequal cylcohexanol molecules present around Mg2+. A Raman feature of MgCyOH at 712 cm(-1) confirms that cylcohexanol molecules are present around Mg2+ in an octahedral environment. MgCyOH has been used as support material to prepare Ziegler-Natta (Z-N) active catalyst. Textural property of above Z-N catalyst exhibits high surface area (236 m(2)/g) with high porosity. Above active catalyst has been screened for ethylene polymerization. Depending on the cocatalyst employed (Me3Al, Et3Al, and iso-Bu3Al) and ethylene pressure, polyethylene yield varies an order of magnitude, from 378 to 3570 g/g catalyst, indicating a possible creation of different active sites and different interaction between cocatalyst and catalyst.

}, issn = {1932-7447}, doi = {10.1021/jp3074078}, author = {Gnanakumar, Edwin S. and Thushara, K. S. and Gowda, Ravikumar R. and Raman, Sumesh K. and Ajithkumar, Thalasseril G. and Rajamohanan, P. R. and Chakraborty, Debashis and Gopinath, Chinnakonda S.} } @article { ISI:000319027400029, title = {Functional and disordered meso-macroporous gamma-Al2-xMxO3 +/- y (M = Cu and/or Ce)}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {13}, number = {4, SI}, year = {2013}, month = {APR}, pages = {2682-2688}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {Disordered meso-macro porous Cu-Ce-Al2O3 nanocomposite (gamma-Al2-xMxO3 +/- y, M = Cu and or Ce) with different compositions has been synthesized. In situ templated sol-gel method has been adopted with simple EDTA ethylenediamine tetra aceticacid and ethylenediamine molecules to prepare gamma-Al2-xMxO3 +/- y, (M = Cu and or Ce). Above meso-macro porous materials were characterized by structural, spectroscopy, microscopy and textural techniques. Detailed characterization indicates that Cu2+ ions are introduced into the ceria and alumina lattice positions. Nano composite nature of the gamma-Al2-xMxO3 +/- y has been confirmed by detailed microscopy investigations. Catalytic activity of the above nanocomposite materials have been screened for environmentally important CO oxidation reaction. 30\% Ce-60\% Al and 10\% Cu containing material shows the best activity among other meso-nnacroporous material with (50\%) 100\% CO oxidation at (107 degrees C) 145 degrees C.}, keywords = {Alumina, CO oxidation, heterogeneous catalysis, Meso-Macroporous Material, Nanocomposite, Sol-gel synthesis}, issn = {1533-4880}, doi = {10.1166/jnn.2013.7384}, author = {Gnanakumar, Edwin S. and John, Jino C. and Raja, Thirumalaiswamy and Gopinath, Chinnakonda S.} } @article { ISI:000315707700003, title = {MgCl2 center dot 6CH(3)OH: a simple molecular adduct and its influence as a porous support for olefin polymerization}, journal = {ACS Catalysis}, volume = {3}, number = {3}, year = {2013}, month = {MAR}, pages = {303-311}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A single phase molecular adduct, MgCl2 center dot 6CH(3)OH has been synthesized using MgCl2 and the simplest alcohol, methanol. Structural, spectroscopic, and morphological studies have been carried out for a better understanding of the single phase MgCl2 center dot 6CH(3)OH adduct. C-13 CPMAS solid state NMR studies show all six methanol molecules are magnetically equivalent and present in a single environment around the Mg2+ center. Raman spectral analysis of the characteristic peak at 708 cm(-1) substantiates octahedral coordination of six CH3OH molecules around Mg2+. Solid state C-13 NMR measurements, made after heat treatment at different temperatures, have been utilized to understand the variations in CH3OH stoichiometry and coordination around Mg2+ with temperature. A titanated active catalyst, TiCl4 on MgCl2 center dot 6CH(3)OH, has also been synthesized and subjected to detailed characterizations. The active catalyst shows high surface area (102 m(2)/g) and mesoporosity. The titanated catalyst has been screened for ethylene polymerization reactions using different cocatalysts (R3Al; R= -CH3, -CH2CH3, and -CH2CH(CH3)(2)). A total of 7.25 kg of polyethylene per gram of catalyst has been obtained with Me3Al cocatalyst, which is six times higher in activity compared with commercial Me3Al/TiCl4/MgCl2 center dot 6EtOH-supported orted catalystAlthough porosity influences the catalytic activity, other factors also seem to contribute to the total catalytic activity.

}, keywords = {heterogeneous catalysis, MgCl2, Molecular adduct, olefin polymerization, Ziegler-Natta catalyst}, issn = {2155-5435}, doi = {10.1021/cs300730j}, author = {Gnanakumar, Edwin S. and Gowda, Ravikumar R. and Kunjir, Shrikant and Ajithkumar, Thalasseril G. and Rajamohanan, P. R. and Chakraborty, Debashis and Gopinath, Chinnakonda S.} } @article { ISI:000326946900004, title = {Rationally designed CuFe2O4-mesoporous Al2O3 composite towards stable performance of high temperature water-gas shift reaction}, journal = {Chemical Communications}, volume = {49}, number = {96}, year = {2013}, month = {JUL}, pages = {11257-11259}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

High temperature water-gas shift reaction was demonstrated for the first time on a CuFe2O4-mesoporous alumina nanocomposite between 350 and 550 degrees C with 70-80\% CO-conversion using simulated waste derived syngas under realistic conditions. Despite high Al-content, the catalyst exhibited stable activity, which was attributed to the nano-architectured robust porous nature of alumina integrated with surrounding CuFe2O4.

}, issn = {1359-7345}, doi = {10.1039/c3cc43699c}, author = {Subramanian, Vijayanand and Gnanakumar, Edwin S. and Jeong, Dae-Woon and Han, Won-Bi and Gopinath, Chinnakonda S. and Roh, Hyun-Seog} } @article { ISI:000336840900022, title = {9-Fluorenemethanol: an internal electron donor to fine tune olefin polymerization activity}, journal = {Dalton Transactions}, volume = {43}, number = {24}, year = {2014}, month = {MAR}, pages = {9143-9151}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A new MgCl2 based molecular adduct has been synthesized with 9-fluorenemethanol (9FM) as a novel internal electron donor (IED), along with ethanol (EtOH) (MgCl2 center dot n9FM center dot xEtOH). The above molecular adduct has been subjected to a variety of structural, spectroscopic and morphological characterization techniques. The results of the solid state C-13 CPMAS NMR technique suggests the coordination of 9FM to MgCl2. Observation of a low angle diffraction peak at 2 theta = 5.7 degrees (d = 15.5 angstrom) underscores the coordination of 9FM along the z-axis, and ethanol in the molecular adduct. Active Ziegler-Natta catalysts were prepared by two different synthesis methods; the conventional method to obtain a high surface area active catalyst, and other one with 9FM as an integral part of the active catalyst in order to study the influence of 9FM as an IED over the active sites. The active catalysts were also characterized thoroughly with different analytical tools. The XRD results show (003) facets of delta-MgCl2 (alpha-MgCl2) for the conventional (non-conventional) titanated catalyst. Results of the ethylene polymerization activity study reveals that the conventionally prepared highly porous active catalyst shows 1.7-2.5 times higher activity than the non-conventional prepared catalyst; however, the latter shows a low molecular weight distribution and confirms the role of the Lewis base as an IED.

}, issn = {1477-9226}, doi = {10.1039/c4dt00793j}, author = {Gnanakumar, Edwin S. and Chokkapu, Eswara Rao and Kunjir, Shrikant and Ajithkumar, Thalasseril G. and Rajamohanan, P. R. and Chakraborty, Debashis and Gopinath, Chinnakonda S.} } @article { ISI:000344330800015, title = {Role of nanointerfaces in Cu- and Cu plus Au-based near-ambient-temperature CO oxidation catalysts}, journal = {ChemCatChem}, volume = {6}, number = {11}, year = {2014}, month = {NOV}, pages = {3116-3124}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Disordered mesoporous Cu-doped ceria-zirconia (Cu0.1Ce0.85Zr0.05O2), and gold deposited (Au/Cu0.1Ce0.85Zr0.05O2) catalysts were synthesized and evaluated for CO oxidation. Onset of CO oxidation activity, and 50\% (100\%) CO2 formation occurs at room temperature (RT), and 77 (120)degrees C, respectively, with Cu0.1Ce0.85Zr0.05O2. A small amount of gold on Cu0.1Ce0.85Zr0.05O2 induces the sustainable oxidation catalysis around RT. Onset of copper reduction temperature decreases from 110 degrees C on Cu0.1Ce0.85Zr0.05O2 to 48 degrees C with Au/Cu0.1Ce0.85Zr0.05O2, highlighting the direct interaction between Cu and Au through a Cu-Au interface. Au particles with a (00 1) facet deposit on an oxygen-deficient site of (111) facet of CeO2-ZrO2. Any decrease in surface Cu-content with increasing Au-content further supports the Au-Cu-Ce/Zr interface interactions. Nanointerfaces of Au clusters on Cu next to oxygen-deficient sites of CeO2-ZrO2 facilitate all the elementary steps of the CO + O-2 reaction to occur in close proximity at ambient conditions.

}, keywords = {carbon monoxide, Gold, heterogeneous catalysis, Oxidation, redox}, issn = {1867-3880}, doi = {10.1002/cctc.201402581}, author = {Gnanakumar, Edwin S. and Naik, Jarpla Madhusudhan and Manikandan, Marimuthu and Raja, Thirumalaiswamy and Gopinath, Chinnakonda S.} } @article {42861, title = {Porous thin films towards bridging the material gap in heterogeneous catalysis}, journal = {Catalysis, Structure \& Reactivity}, volume = {2}, year = {2016}, month = {MAR}, pages = {1-12}, type = {Article}, abstract = {

An attempt has been made to bridge the material gap, existing between ideal single crystals and real-world powder nanocatalyst employed in surface science and heterogeneous catalysis, respectively. Simple wet chemical method (sol{\textendash}gel and spin-coating deposition) has been applied to make continuous Ce1 - xZrxO2 (x = 0{\textendash}1) (CZ) thin films with uniform thickness (~40 nm) and smooth surface characteristics. Uniform thickness and surface smoothness of the films over a large area was supported by a variety of measurements. Molecular beam (MB) studies of O2 adsorption on CZ surfaces reveals the oxygen storage capacity (OSC), and sticking coefficient increases from 400 to 800 K. Porous nature of Ce-rich CZ compositions enhances O2 adsorption and OSC, predominantly due to O-diffusion and redox nature, even at 400 K. A good correlation exists between MB measurements made on CZ films for oxygen adsorption, and OSC, and ambient pressure CO oxidation on powder form of CZ; this demonstrates the large potential to bridge the material gap. CZ was particularly chosen as a model system for the present studies, since it has been well-studied and a correlation between surface science properties made on thin films and catalysis on powder CZ materials could be a litmus test. Ambient catalysis on ceria-zirconia nanocatalyst correlates well with surface properties measured through molecular beam on thinfilm and close the material gap.

}, doi = {10.1080/2055074X.2015.1133269}, author = {Dubey, Anjani and Kolekar, Sadhu K. and Gnanakumar, Edwin S. and Roy, Kanak and Vinod, C. P. and Gopinath, Chinnakonda S.} } @article {43358, title = {Mechanistic aspects of wet and dry CO oxidation on Co3O4 nanorod surfaces: a NAP-UPS study}, journal = {ACS Omega}, volume = {2}, year = {2017}, month = {MAR}, pages = {828-834}, type = {Jouranl Article}, abstract = {

Catalytic activity, electronic structure, and the mechanistic aspects of Co3O4 nanorod (NR) surfaces have been explored for CO oxidation in dry and wet atmosphere using near-ambient pressure ultraviolet photoelectron spectroscopy. Presence of water with CO + O2 plummets the catalytic activity because of the change in the electronic nature from predominantly oxide (without water in feed) to a Co3O4 surface covered by a few intermediates. However, at >=375 K, the Co3O4 surface recovers and regains the oxidation activity, at least partially, even in the presence of water. This is fully supported by the changes observed in the work function of Co3O4 under wet (H2O + CO + O2) conditions compared with dry (CO + O2) conditions. This study focuses on the comparative CO oxidation rate on Co3O4 NR surfaces and highlights the changes in the electronic structure that occur in the catalyst during the CO oxidation reaction.

}, keywords = {Catalyst, Nano Structures, Power X-Ray Diffraction, spectra, Water Vapor}, doi = {10.1021/acsomega.6b00471}, author = {Ruchi Jain and Gnanakumar, Edwin S. and Gopinath, Chinnakonda S.} }