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Bipul Sarkar

Bio: Bipul Sarkar is an academic researcher from Indian Institute of Petroleum. The author has contributed to research in topics: Catalysis & Mesoporous material. The author has an hindex of 16, co-authored 42 publications receiving 753 citations. Previous affiliations of Bipul Sarkar include Sungkyunkwan University & Academy of Scientific and Innovative Research.

Papers
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TL;DR: In this article, a new synthesis strategy was developed to prepare 2-5 nm metallic silver nanoparticles supported on tungsten oxide (WO3) nanorods with diameters between 30 and 40 nm, in the presence of cationic surfactant (cetyltrimethylammonium bromide: CTAB), capping agent (polyvinylpyrrolidone: PVP), and hydrazine.
Abstract: Propylene oxide (PO) is a versatile chemical intermediate, and by volume it is among the top 50 chemicals produced in the world. The catalytic conversion of propylene to PO by molecular oxygen with minimum waste production is of high significance from an academic as well as an industrial point of view. We have developed a new synthesis strategy to prepare 2–5 nm metallic silver nanoparticles (AgNPs) supported on tungsten oxide (WO3) nanorods with diameters between 30 and 40 nm, in the presence of cationic surfactant (cetyltrimethylammonium bromide: CTAB), capping agent (polyvinylpyrrolidone: PVP), and hydrazine. The synergy between the surface AgNPs and WO3 nanorods facilitates the dissociation of molecular oxygen on the metallic Ag surface to produce silver oxide, which then transfers its oxygen to the propylene to form PO selectively. The catalyst exhibits a PO production rate of 6.1 × 10–2 mol gcat–1 h–1, which is almost comparable with the industrial ethylene-to-ethylene oxide production rate.

108 citations

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TL;DR: In this paper, the authors have shown that the size of the catalyst as well as the spinel phase plays a crucial role in the activity by favoring the oxidation of toluene.

98 citations

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TL;DR: In this paper, Ni dispersion of Ni on mesoporous nitrogen-rich carbon material has been achieved using two different synthesis methods, and the material shows ⩾99% conversion to 5-(hydroxymethyl) furfural (HMF) within 6h of reaction with 98.7% selectivity.

94 citations

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TL;DR: In this paper, the effect of Cu loading and the influence of reaction parameters, such as the substrate to oxidant molar ratio and reaction time, were investigated in detail, revealing that the size of copper plays a crucial role towards the activity by favoring the oxidation of cyclohexane.

59 citations

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TL;DR: In this paper, the authors presented an easy approach to synthesize a novel hybrid material composed of highly dispersed MoO 3 nanoclusters on TiO 2 nanorods of diameter 80-150nm and length between 1-1.5μm.
Abstract: Preparation of metal oxide supported nanostructure appears to be interesting and challenging because of the well-defined morphology and highly accessible active sites responsible for catalysis. Here we present an easy approach to synthesize a novel hybrid material composed of highly dispersed MoO 3 nanoclusters on TiO 2 nanorods of diameter 80–150 nm and length between 1–1.5 μm. These hybrid nanostructure catalysts exhibited excellent oxidative dehydrogenation activity for the conversion of ethane to ethylene with an ethylene yield of 50.7% in the presence of O 2 . The result shows markedly high synergy between the surface Mo +6 and ultrathin TiO 2 nanorods, which selectively activates the C H bond of ethane for the production of ethylene.

51 citations


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01 Feb 1995
TL;DR: In this paper, the unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio using DFT, MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set.
Abstract: : The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

1,652 citations

Journal ArticleDOI
03 Nov 2016-Nature
TL;DR: It is shown that MOFs can also serve as effective selectivity regulators for the hydrogenation of α,β-unsaturated aldehydes, and it is anticipated that this basic design strategy will allow the development of other selective heterogeneous catalysts for important yet challenging transformations.
Abstract: Unsaturated alcohols, widely used in the flavouring, perfume and pharmaceutical industries, are produced by selectively hydrogenating CO groups over CC groups present in suitable starting aldehyde molecules. Developing efficient catalysts for this transformation is challenging. Here Zhiyong Tang and colleagues describe a new type of highly selective catalyst in which platinum nanoparticles are sandwiched between a core and a shell of a metalorganic framework. This arrangement results in stable catalysts that selectively hydrogenate CO groups to produce a range of value-added unsaturated alcohols. The design strategy underpinning the work should be applicable to other selective catalysts for important yet challenging chemical reactions.

1,079 citations

Journal ArticleDOI
TL;DR: In this article, the authors explored the influences of the active metal, support, promoter, preparation methods, calcination temperature, reducing environment, particle size and reactor choice on catalytic activity and carbon deposition for the dry reforming of methane.
Abstract: This review will explore the influences of the active metal, support, promoter, preparation methods, calcination temperature, reducing environment, particle size and reactor choice on catalytic activity and carbon deposition for the dry reforming of methane Bimetallic (Ni−Pt, Ni−Rh, Ni−Ce, Ni−Mo, Ni−Co) and monometallic (Ni) catalysts are preferred for dry reforming compared to noble metals (Rh, Ru and Pt) due to their low-cost Investigation of support materials indicated that ceria−zirconia mixtures, ZrO2 with alkali metals (Mg2+, Ca2+, Y2+) addition, MgO, SBA-15, ZSM-5, CeO2, BaTiO3 and Ca08Sr02TiO3 showed improved catalytic activities and decreased carbon deposition The modifying effects of cerium (Ce), magnesium (Mg) and yttrium (Y) were significant for dry reforming of methane MgO, CeO2 and La2O3 promoters for metal catalysts supported on mesoporous materials had the highest catalyst stability among all the other promoters Preparation methods played an important role in the synthesis of smaller particle size and higher dispersion of active metals Calcination temperature and treatment duration imparted significant changes to the morphology of catalysts as evident by XRD, TPR and XPS Catalyst reduction in different environments (H2, He, H2/He, O2/He, H2−N2 and CH4/O2) indicated that probably the mixture of reducing agents will lead to enhanced catalytic activities Smaller particle size (

593 citations

Journal ArticleDOI
TL;DR: In this article, the authors studied the effect of metal support and metal support-promoter combinations on the performance and stability of bi-and tri-metallic catalysts for dry reforming of methane, and concluded that a catalyst design must take into account not only the separate effects of the active metal, support and promoter, but also include the combined and mutual interactions of these components.
Abstract: The performance of catalysts used for the dry reforming of methane can strongly depend on the selection of active metals, supports and promoters. This work studies their effects on the activity and stability of selected catalysts. Designing an economically viable catalyst that maintains high catalytic activity and stability can be achieved by exploiting the synergic effects of combining noble and/or non-noble metals to form highly active and stable bi- and tri-metallic catalysts. Perovskite type catalysts can also constitute a potent and cost effective substituent. Metal oxide supports with surface Lewis base sites are able to reduce carbon formation and yield a greater stability to the catalyst, while noble metal promoters have proven to increase both catalyst activity and stability. Moreover, a successful metal-support-promoter combination should lead to higher metal-support interacrtion, lower reduction temperature and enhancement of the anti-coking and anti-amalgamation properties of the catalyst. However, the effect of each parameter on the overall performance of the catalyst is usually complex, and the catalyst designer is often faced with a tradeoff between activity, stability and ease of activation. Based on the review carried out on various studies, it is concluded that a catalyst design must take into consideration not only the separate effects of the active metal, support and promoter, but should also include the combined and mutual interactions of these components.

556 citations