@article { ISI:000240258600018, title = {Crystallization and phase transformation kinetics of poly(1-butene)/MWCNT nanocomposites}, journal = {Polymer}, volume = {47}, number = {18}, year = {2006}, month = {AUG}, pages = {6414-6421}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Poly(1-butene)/MWCNT nanocomposites were prepared by simple melt processing technique. Crystallization, crystal-to-crystal phase transformation and spherulitic morphology were studied using differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and optical microscopy (OM). The non-isothermal crystallization exhibited higher values of Z, derived from Avrami theory and lower values of F(T) obtained from Avrami-Ozawa analysis, while the isothermal crystallization revealed a significant increase in crystallization temperatures and lower crystallization half times compared to pristine PB. The observed changes in the crystallization kinetics were ascribed to the enhanced nucleation of PB in the presence of MWCNT. The nucleating activity calculated from the non-isothermal crystallization data revealed that the MWCNTs provide an active surface for the nucleation of PB. The optical micrographs exhibited significantly smaller crystallites with disordered morphology for the nanocomposites compared to the well defined spherulitic morphology for pristine PB. The rate of phase transformation from kinetically favored tetragonal to thermodynamically stable hexagonal form was noticeably enhanced as evidenced by the reduction in the half time for phase transformation from 58 h to 25 h for PB reinforced with 7\% MWCNT. (c) 2006 Elsevier Ltd. All rights reserved.

}, keywords = {MWCNT, Phase transformation, poly(1-butene)}, issn = {0032-3861}, doi = {10.1016/j.polymer.2006.07.011}, author = {Wanjale, Santosh D. and Jog, Jyoti Prakash} } @article { ISI:000281996100013, title = {Transformation of chemically fine tuned zeolite A precursor into dense lithium aluminosilicates - a comprehensive phase evolution and sintering study}, journal = {Microporous and Mesoporous Materials}, volume = {135}, number = {1-3}, year = {2010}, month = {NOV}, pages = {82-89}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Beyond their conventional revelation as catalysts, zeolites are being perceived as more challenging materials for modern applications. Thermal recrystallization of zeolite precursors is an efficient method for the preparation of dense aluminosilicate ceramics. However, factors viz., nature of the precursor and the way of firing it etc., influence the product quality. The present report is a systematic and detailed account of a phase transformation of Li modified zeolite A precursor using powder X-ray diffraction (PXRD), thermogravimetry (TG), differential thermal analysis (DTA), scanning electron micrographs (SEM), atomic absorption spectroscopy (MS), energy dispersive X-ray (EDX) and density measurement techniques. It involves an amorphisation followed by a recrystallization into lithium aluminosilicate (LAS). A comprehensive correlation of PXRD, TG/DTA, SEM, EDX and density data explains the complexity of high temperature phase transition (25-1200 degrees C). A qualitative phase analysis revealed the mediation of formation of LAS ceramic, beta-spodumene by few satellite transitions of SiO(2). (C) 2010 Elsevier Inc. All rights reserved.

}, keywords = {LAS silicate, Phase evolution, Phase transformation, Powder XRD, zeolite}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2010.06.014}, author = {Selvaraj, Kaliaperumal} } @article {48098, title = {Strain-enhanced phase transformation of iron oxide for higher alcohol production from CO2}, journal = {ACS Catalysis}, volume = {12}, year = {2022}, month = {SEP}, pages = {11118-11128}, type = {Article}, abstract = {

Conversion of CO2 to higher alcohols (HAs) and higher hydrocarbons (HCs) has a greater advantage compared to C1 products because of their high energy density and wide range of applications in daily life. Despite the immense potential of these chemicals, not much of scientific research has been focused on the conversion of CO2 to HAs. In the present work, we have introduced the concept of strain in designing the material to enhance the CO(2 )to HA performance. We introduced strain in a traditional iron-based catalyst, Fe2O3, by the introduction of indium (In), which facilitates the selective conversion of CO2 to HA. An optimum strain favored a 36.7\% CO2 conversion with a 42\% HA selectivity, and a record yield of 15.42\%. The strain has been tuned further with the introduction of K as a promoter. The introduced strain upon In substitution and K promotion favored the conversion of CO2, which is mapped by powder X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy. Further, the change in the mechanism upon In incorporation and K promotion has been probed by in situ diffuse reflectance infrared fourier transform spectroscopy, and it is found that the OCHx intermediate, which produces HAs, is more prominent upon In substitution, which favored the enhancement of HA production compared to that of pristine Fe2O3.

}, keywords = {CO2 to HA, Fischer-Tropsch synthesis (FTS), Phase transformation, reverse water gas shift (RWGS) reaction, strain}, issn = {2155-5435}, doi = {10.1021/acscatal.2c0318311118}, author = {Goud, Devender and Churipard, Sathyapal R. and Bagchi, Debabrata and Singh, Ashutosh Kumar and Riyaz, Mohd and Vinod, C. P. and Peter, Sebastian C.} } @article {48802, title = {Unleashing methylammonium-guanidinium lead iodide hybrid perovskite spherulitic microstructures: a structural and morphological investigation}, journal = {MRS Communications}, volume = {13}, year = {2023}, month = {JUN}, pages = {406-415}, type = {Article}, abstract = {

Perovskites can offer an attractive replacement option for existing commercial solar technologies. Herein microstructure plays an important role in improving the efficiency and stability of solar cells. Previously unidentified spherulitic microstructures of self-assembled polycrystalline perovskites are explored in this report. For this an intermediate phase of a promising guanidinium (GUAI)-rich perovskite has been investigated for its structural and morphological properties. This study infuses new insight into the evolution of perovskite microstructure from heterogeneity to homogeneity, as a result unravels the structure of perovskite embryonic spherulites, lamellar arrangements, transcrystalline nature, novel spherulites bridging, hole nucleation, impingement, and defects.

}, keywords = {Microstructure, Morphology, Nucleation \& growth, Perovskites, Phase transformation, X-ray diffraction (XRD)}, issn = {2159-6859}, doi = {10.1557/s43579-023-00375-w}, author = {Mukul, Monika and Kaliaperumal, Selvaraj and Rani, Mamta and Tripathi, Surya Kant} }