- Dr. Arijit Bag get his Master's Degree in Chemistryfrom University of Calcutta, West Bengal, India in2001. He joined ... moreDr. Arijit Bag get his Master's Degree in Chemistryfrom University of Calcutta, West Bengal, India in2001. He joined as a lecturer at SundarbanMahavidyalaya in 2001 and continued his teaching tillDecember 2003. In 2004, he joined Dr. Sourav Pal'sgroup of theoretical chemistry at National Chemical Laboratory,Pune, India. He did his Ph. D. in Linear response approach tocalculate molecular properties using Fock-space Multi-referenceCoupled Cluster Singles and Doubles (FSMRCCSD). At present heis doing his post doctorate research at Indian Institute of ScienceEducation and Research Kolkata, West Bengal, India. So far, hehad published 12 research papers in several international journalsincluding ELSEVIER Journal of Catalysis, AIP Journal ofChemical Physics, RSC Advances etc. He is a multidimensionalresearcher having reputed publications in Astrophysics, Quantummechanics, Molecular and Theoretical Biology, Sociology andHumanities, Molecular Simulation and Drug Designing, Catalysisand Medical methodology. Beside scientific works, he hadpublished three books of poem and two books of drama (inBengali). He edited a Bengali science magazine for schoolchildren. He had also published a music album in which he himselfacts as a lyricist, musician and vocalist. He was honored as the winnerof Bijan Bhattacharya Smriti Puraskar given by All IndianChildren Association in 2012 for his collection of short dramas –Haste Haste Bhabi.edit
Synthesis of two unique μ oxo-bridged complexes MC2 and MC3 from a metalloligand MC1 results to efficient dye degradation efficacy and effective schottkey device.
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Successful utilization of piperazine appended Schiff base chemosensor (HL) for selective recognition of Zn(ii) ion in 9 : 1 ethanol–water medium and Cd(ii), Hg(ii) in near aqueous medium among several competitive cations and their real... more
Successful utilization of piperazine appended Schiff base chemosensor (HL) for selective recognition of Zn(ii) ion in 9 : 1 ethanol–water medium and Cd(ii), Hg(ii) in near aqueous medium among several competitive cations and their real applications.
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The sequestering and complete conversion of SO2 to valuable chemicals in a metal-free pathway is highly demanded. The recent success of SO2 fixation by N-heterocyclic carbenes instigated further studies in this regard. Previous reports... more
The sequestering and complete conversion of SO2 to valuable chemicals in a metal-free pathway is highly demanded. The recent success of SO2 fixation by N-heterocyclic carbenes instigated further studies in this regard. Previous reports were confined within the carbene-SO2 reaction mechanism and the stability of oxathiirane S-oxide derivatives. The complete conversion of captured SO2 to precious chemicals was not studied. The present inquisition has accomplished the scarcity of the earlier studies. It is observed that in the presence of an excess amount of carbene, the registered SO2 is converted to the ketone derivative and thiocarbonyl S-oxide derivative. An electronic level investigation of these reactions is carried out. From the change of the molecular orbitals along the reaction path, it is concluded that the reaction between the oxathiirane S-oxide derivative and carbene follows a frog's hunting mechanism.
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Recent DFT based molecular engineering to obtain stable oxathiirane S-oxide derivatives evokes the recommencement of the use of carbenes for the sequestering of SO2, which has been kept separate so far. Carbene is one of the key chemicals... more
Recent DFT based molecular engineering to obtain stable oxathiirane S-oxide derivatives evokes the recommencement of the use of carbenes for the sequestering of SO2, which has been kept separate so far. Carbene is one of the key chemicals for the sequestering of various premier greenhouse gases like CO2, CO, N2O, etc. In this respect, a comparative study of the reactivity of carbenes with variant greenhouse gases is highly demanding. The present investigation is engrossed in the comparative reactivity of SO2 and NO2 with carbenes. All three selected carbenes are highly susceptible to SO2 and NO2. Through an immaculate mechanistic study, we are able to corroborate that the end product of the carbene-SO2 reaction is an adduct which has a preferable structure having a six-membered ring with hydrogen bonding instead of ketone and SO with higher thermodynamic stability than the corresponding oxathiirane S-oxide derivative. Carbene reacts with NO2 to form a stable carbene N, N-dioxide derivative which forms vibrationally excited oxaziridine N-oxide which rapidly dissociates to form a ketone derivative. The formation of carbene S, S-dioxide and carbene N, N-dioxide is a barrierless process. The dissociation of oxaziridene N-oxide is also a barrierless process.
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Dry reforming of methane is considered a potential reaction for the utilization of waste greenhouse gases to generate valuable chemicals. However, catalyst deactivation under a harsh reaction condi...
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A novel catalyst composed of silver nanoparticles grafted on WCNx has been prepared by using a facile pH‐adjusted method. The material reported in this study presents a non‐mineral acid route for the synthesis of the industrially... more
A novel catalyst composed of silver nanoparticles grafted on WCNx has been prepared by using a facile pH‐adjusted method. The material reported in this study presents a non‐mineral acid route for the synthesis of the industrially significant monomer adipic acid through the selective oxidation of cyclohexene. Ag has been stabilized in the hydrophobic matrix during the formation of the mesoporous silica material by using aniline as stabilizing agent. A cyclohexene conversion of 92.2 % with 96.2 % selectivity for adipic acid was observed with the AgWCNx‐2 catalyst, therefore, the AgWCNx catalyst was found to be efficient for the direct conversion to adipic acid with respect to their monometallic counterparts. The energy profile diagrams for each reaction path by using the AgWCNx catalyst were studied along with their monometallic counterparts by using the Gaussian 09 package. The reported material can avoid the use of harmful phase‐transfer catalysts (PTC) and/or chlorinated additives, which are two among other benefits of the reported work.
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Highly stable gold nanoparticles (GNPs) around 5–6 nm have been prepared by in situ reduction of chloroauric acid on the surface of nitrogen‐rich mesoporous carbon (MCN) without adding any extra stabilizing agent. The synthesized... more
Highly stable gold nanoparticles (GNPs) around 5–6 nm have been prepared by in situ reduction of chloroauric acid on the surface of nitrogen‐rich mesoporous carbon (MCN) without adding any extra stabilizing agent. The synthesized materials have been efficiently utilized as a catalyst for the truly heterogeneous hydroamination of phenylacetylene with aniline. Large turnover numbers (42×106) were achieved by suitably adjusting the gold/support (w/w) ratio, time, temperature, and solvent, leading to 98 % selectivity towards the Markovnikov product. Density functional theory (DFT) studies have been performed to predict the mechanistic pathway of hydroamination with Au0 in GNP@MCN. To understand the structure–activity relationship, the catalyst was characterized by using different techniques such as X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen physisorption studies (BET), X‐ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy.
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A boron- and nitrogen-co-doped mesoporous carbon (BxCN) material with a hierarchical pore structure has been synthesized from a new boron precursor via a nanocasting approach.
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Abstract Methyl 2′-aminobiphenyl-4-carboxylate, an optical chloride sensor has been synthesized via Suzuki-Miyaura cross-coupling followed by regioselective nitration. In general biphenyl systems are prone to undergo poly nitration... more
Abstract Methyl 2′-aminobiphenyl-4-carboxylate, an optical chloride sensor has been synthesized via Suzuki-Miyaura cross-coupling followed by regioselective nitration. In general biphenyl systems are prone to undergo poly nitration whenever they are subjected to nitration via different nitrating agents. But in this present work, a highly selective nitration in the 2′ position of methyl biphenyl-4-carboxylate was achieved using 70% HNO3 and acetic anhydride to derive 3. Upon reduction, 3 produces 4 which shows bright blue emission in different organic solvents. In presence of chloride ion the blue emission of the sensor changes to enhanced bright green emission. The chloride sensing has also been explored using other spectroscopic techniques such as 1H NMR, UV–vis spectroscopy, and theoretical study.
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Abstract This present work deals with the synthesis of a series of organogel derived from substituted tyrosine derivatives via applying the concept of molecular engineering. Phenylalanine and tyrosine are structurally very similar amino... more
Abstract This present work deals with the synthesis of a series of organogel derived from substituted tyrosine derivatives via applying the concept of molecular engineering. Phenylalanine and tyrosine are structurally very similar amino acids. But only phenylalanine forms gels in both water and organic solvents. That is why the challenge was taken to transform tyrosine into a gelator and the concept of molecular engineering was applied. It was observed that a single nitro group is sufficient enough to transform it into a gelator. Not only a Boc-protected amino acid but also dipeptide and tripeptide were also found to produce organogel. Theoretical studies were also performed to understand the interactions involved during the gelation process. The gels derived from 1, 2, and 4 were found to be responsive towards a strong base like hydroxide which also helped us to get information regarding the gel model.
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In this paper, a novel composite photocatalyst, ferric oxide–bismuth oxyhalide (Fe2O3‐BiOCl0.5Br0.5) has been synthesized, characterized, and used for the degradation of methyl orange through advanced oxidation process under ambient... more
In this paper, a novel composite photocatalyst, ferric oxide–bismuth oxyhalide (Fe2O3‐BiOCl0.5Br0.5) has been synthesized, characterized, and used for the degradation of methyl orange through advanced oxidation process under ambient conditions (sunlight, pH 7.0, and temperature 25°C). The catalyst has been characterized by using UV‐Vis spectrophotometer, Fourier transform infrared (FTIR) spectroscopy, Raman spectrometer, scanning electron microscopy (SEM), energy dispersive X‐ray analysis (EDX), and X‐ray diffractometer (XRD) techniques. The catalyst shows appreciable activities under natural sunlight conditions. From the XRD patterns and SEM images, it is observed that the elongation along the z axis in the crystal lattice of BiOCl0.5Br0.5 in the catalyst can lead to a lattice distortion induced internal electric field which can help in charge carrier separation and transport. The Fe2O3‐BiOCl0.5Br0.5 catalyst shows more than 90% photodegradation efficiency of methyl orange in 90 min of sunlight exposure. The presence of magnetic ferric oxide in the composite photocatalyst helps to isolate the catalyst from the reaction mixture by using an external magnet, and thus, the Fe2O3‐BiOCl0.5Br0.5 catalyst can be reused repeatedly, towards degradation of organic pollutants.
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Nitridated NiO/Al2O3 appears to be a highly efficient and extremely coke resistive catalyst toward methane reforming with CO2 under near real feed conditions confirmed from both experimental observation and density functional theory (DFT)... more
Nitridated NiO/Al2O3 appears to be a highly efficient and extremely coke resistive catalyst toward methane reforming with CO2 under near real feed conditions confirmed from both experimental observation and density functional theory (DFT) calculation.
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The solvent dependent investigation for the bathochromic emission has an extensive report whereas the report on solvent independent material is limited. With approach for invention of photoluminescent material, the hydrothiolation was... more
The solvent dependent investigation for the bathochromic emission has an extensive report whereas the report on solvent independent material is limited. With approach for invention of photoluminescent material, the hydrothiolation was invoked for the growth of thermally clicked energy tuneable crosslinked photoluminescent polymeric materials. The observed CIE co‐ordinates for the crosslinked polymers were Poly‐BnNpAll (0.31, 0.48) and Poly‐BnNpAlk (0.34, 0.51). The respective quantum efficiency (Φ) for Poly‐BnNpAll and Poly‐BnNpAlk were 9.73 % and 6.14 %. The energy tunability and optical responses were validated through DFT calculations and fluorescence Mueller matrix (FLMM) analysis. From FLMM, the optical parameters ‐ fluorescence diattenuation and fluorescence polarizance revealed the excited molecular orientation is more organized relative to ground state. Such materials have scope for application as promoter during photocatalysis, chemosensing, etc.
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Objective: The aim of the study was to determine the association between sleep quality with headache frequency in migraine patients and also to evaluate migraine trigger and non-headache symptoms in episodic and chronic migraine groups... more
Objective: The aim of the study was to determine the association between sleep quality with headache frequency in migraine patients and also to evaluate migraine trigger and non-headache symptoms in episodic and chronic migraine groups and evaluation of the same in poor and good sleepers (GSs) in migraine population. Materials and Methods: In a cross-sectional and observational study in a tertiary care hospital of East India between January 2018 and September 2020, migraine patients were evaluated. Migraine patients were divided into two groups: Episodic migraine (EM) and chronic migraine (CM) group according to ICHD 3 b classification and into poor sleepers (PSs, Global Pittsburgh Sleep Quality Index [PSQI] >5) and GSs (Global PSQI ≤5). Sleep was evaluated using PQSI – a self-rated questionnaire and disease pattern, associated non-headache symptoms, and triggers were evaluated in between groups. Demographic, headache character, and sleep parameters including seven “component” scores: Subjective sleep quality, sleep latency, sleeps duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction and global PQSI were compared between groups (EM and CM). Similar parameters were also compared between PSs and GSs group. Statistical analysis was performed using the χ2 test for categorical variables and the t-test and Wilcoxon rank-sum test for continuous variables. Correlation between two normally distributed numerical was tested by Pearson correlation coefficient assessment. Results: One hundred migraine patients were analyzed, among which 57 were PSs and 43 were GSs and 51 patients had EM and 49 patients had CM. Moderately significant “r” value noted in between headache frequency and global PQSI score (r = 0.45, P < 0.01). In non-headache symptoms, blurring of vision (EM 8 [16%] and CM 16 [33%] P = 0.05), nasal congestion (EM – 3 [6%] and CM – 12 [24%], P = 0.01), and cervical muscle tenderness (EM– 23 [45%] and CM – 34 [69%], P = 0.01) were more prevalent in chronic headache group along with allodynia (EM – 11 [22%] and CM – 25 [51%], P < 0.01). Conclusion: Chronic headache group had poor subjective sleep quality, increased sleep latency, decreased sleep duration, decreased sleep efficiency, and increased sleep disturbance in comparison to episodic group which has therapeutic implication. The non-headache symptoms which are more prevalent in CM patients increase the overall disability.
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Background: IC50 is one of the most important parameters of a drug. But, it is very difficult to predict this value of a new compound without experiment. There are only a few QSAR based methods available for IC50 prediction, which is also... more
Background: IC50 is one of the most important parameters of a drug. But, it is very difficult to predict this value of a new compound without experiment. There are only a few QSAR based methods available for IC50 prediction, which is also highly dependable on a huge number of known data. Thus, there is an immense demand for a sophisticated computational method of IC50 prediction in the field of in silico drug designing. Objective: Recently developed quantum computation based method of IC50 prediction by Bag and Ghorai requires an affordable known data. In present research work, further development of this method is carried out such that the requisite number of known data being minimal. Methods: To retrench the cardinal data span and shrink the effects of variant biological parameters on the computed value of IC50, a relative approach of IC50 computation is pursued in the present method. To predict an approximate value of IC50 of a small molecule, only the IC50 of a similar kind of molecule is required for this method. Results: The present method of IC50 computation is tested for both organic and organometallic compounds as HIV-1 capsid A inhibitor and cancer drugs. Computed results match very well with the experiment. Conclusion: This method is easily applicable to both organic and organometallic compounds with acceptable accuracy. Since this method requires only the dipole moments of an unknown compound and the reference compound, IC50 based drug search is possible with this method. An algorithm is proposed here for IC50 based drug search.
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Abstract A schiff base chemosensor HL [4-chloro-(((2-(piperidine-1-yl)imino)methyl)phenol], constructed by one step condensation of 2-aminoethyl piperidine and 5- Chloro Salicylaldehyde is illustrated to have its usefulness for selective... more
Abstract A schiff base chemosensor HL [4-chloro-(((2-(piperidine-1-yl)imino)methyl)phenol], constructed by one step condensation of 2-aminoethyl piperidine and 5- Chloro Salicylaldehyde is illustrated to have its usefulness for selective and sensitive detection of Zn(II) among other metal ions in aqueous solution (HEPES buffer) displaying the colour changes from light blue to turquoise under UV light. The specific detection phenomena of Zn (II) is monitored by the remarkable fluorescence enhancement and notable change in NMR spectral data of fluorescence active HL after addition of Zn(II) to it.. The impressive high binding constant in 106 orders, determined by electronic spectral titration after introduction of Zn(II) to HL assure the formation of a Zinc complex during sensing phenomena. In order to check whether the nuclearity of the constructed complex can be increased or not fluorescence enhancement phenomenon is further monitored in presence of different bridging ligands and the results display that only in presence of azide a significant enhancement of Zn(II)-HL domain is exposed where as for other bridging ligand the spectra remain unaltered. This observation insists to conduct the reaction between HL and ZnCl2 in presence of sodium azide which lead the formation of a Zn complex [Zn2(HL)2(N3)4] (complex 1) employing azide as the secondary anionic residue instead of bridging. The single crystal structure of the complex unveils the unique protonation of the piperidine N during the crystallization of the dinuclear motif of the complex 1. Furthermore the Zn complex due to the presence of remarkable luminescence property have been effectively used for selective sensing of Al(III) ion as metalloreceptor in HEPES buffer solution via turn of fluorescence with remarkable fluorescence quenching constant. In aqueous solution, complex 1 induces a 1:2 complex formation with Al(III) ion indicated by Job’s plot analysis. The DFT study suggests the formation of bimetal complex during sensing of Al(III) with complex 1 as metalloreceptor. The in vitro cell imaging study gives a authentic hints for in vivo biomedical application of HL as a selective and easy Zn(II) sensor. The two step sensing phenomena of HL and complex 1 is further established by advanced molecular logic gate formation.
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In this work, two Schiff-base-based chemosensors L1 and L2 containing electron-rich quinoline and anthracene rings were designed. L1 is AIEE active in a MeOH-H2O solvent system while formed aggregates as confirmed by the DLS measurements... more
In this work, two Schiff-base-based chemosensors L1 and L2 containing electron-rich quinoline and anthracene rings were designed. L1 is AIEE active in a MeOH-H2O solvent system while formed aggregates as confirmed by the DLS measurements and fluorescence lifetime studies. The chemosensor L1 was used for the sensitive, selective, and reversible ‘turn-on’ detection of Al3+ and Ga3+ ions as well as Aspartic Acid (Asp). Chemosensor L2, an isomer of L1, was able to selectively detect Ga3+ ion even in the presence of Al3+ ions and thus was able to discriminate between the two ions. The binding mode of chemosensors with analytes was substantiated through a combination of 1H NMR spectra, mass spectra, and DFT studies. The ‘turn-on’ nature of fluorescence sensing by the two chemosensors enabled the development of colorimetric detection, filter-paper-based test strips, and polystyrene film-based detection techniques.
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The selective detection of Zn(ii) and Ni(ii) by chemosensor HL leads to the development of two mononuclear metal complexes having ATP detection ability only by Zn complex.
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Objective: The aim of the study was to determine the association between sleep quality with headache frequency in migraine patients and also to evaluate migraine trigger and non-headache symptoms in episodic and chronic migraine groups... more
Objective: The aim of the study was to determine the association between sleep quality with headache frequency in migraine patients and also to evaluate migraine trigger and non-headache symptoms in episodic and chronic migraine groups and evaluation of the same in poor and good sleepers (GSs) in migraine population. Materials and Methods: In a cross-sectional and observational study in a tertiary care hospital of East India between January 2018 and September 2020, migraine patients were evaluated. Migraine patients were divided into two groups: Episodic migraine (EM) and chronic migraine (CM) group according to ICHD 3 b classification and into poor sleepers (PSs, Global Pittsburgh Sleep Quality Index [PSQI] >5) and GSs (Global PSQI ≤5). Sleep was evaluated using PQSI – a self-rated questionnaire and disease pattern, associated non-headache symptoms, and triggers were evaluated in between groups. Demographic, headache character, and sleep parameters including seven “component” sc...
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The structural pressure-induced ionization process is implemented to produce Zn(III) complex for the first time and possible potential applications for technological advances are reported in this article. The inversion of the electron... more
The structural pressure-induced ionization process is implemented to produce Zn(III) complex for the first time and possible potential applications for technological advances are reported in this article. The inversion of the electron population observed at the ground state of the newly synthesized complex corroborates an unexplored material response property towards electrical and magnetic fields. The first-time report of a true transition metal behavior of zinc fetches new thoughts about zinc-based bio-enzymatic and bio-catalytic processes along with its material applications in untouched files like live cell imaging contrast agents, photocatalytic water splitting, etc. The methodology of the ‘ structural pressure-induced ionization process’ may be implemented for the synthesis of more unusual oxidation states of metals.
Detection of the real-time growth rate of cancer and visualization of the effectiveness of chemotherapy using live cell imaging techniques are yet to be invented. However, these could be conducive to monitoring the cancer treatment more... more
Detection of the real-time growth rate of cancer and visualization of the effectiveness of chemotherapy using live cell imaging techniques are yet to be invented. However, these could be conducive to monitoring the cancer treatment more precisely. In the present article, a new technique is proposed that will be able to accomplish the necessity mentioned earlier. The recent development and success of organometallic carbonyl clusters as photoacoustic contrast agents and cancer drugs have fetched a few freedom for the fate of new technologies towards the invention of time-dependent photoacoustic tomography (TD-PAT) that could ease the detection and treatment of cancer using advanced clinical chemotherapy.
Molecular level understanding of liposome-gene interaction is immensely important for the research progress and technological advancement of gene delivery, which is highly significant due to a wide range of applications of gene therapy.... more
Molecular level understanding of liposome-gene interaction is immensely important for the research progress and technological advancement of gene delivery, which is highly significant due to a wide range of applications of gene therapy. The liposomal gene delivery method is one of the most promising techniques due to its efficacy to easily fuse with the cell membrane and its lower toxicity. In vivo gene delivery using liposomes is reported to be extremely successful. However, the success of gene delivery depends on various factors including the chemical nature of the structural unit of the liposome. To explore the regulative factor(s) for liposomal gene delivery, we systematically analyze the linker orientation effect on the gene delivery efficiency of liposomes through a density functional theory (DFT) study. Interestingly, it is observed that the liposome-gene interaction is not the regulating factor for successful gene delivery. The success depends on the gel to liquid melting temperature of the liposome.
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An unavoidable lockdown situation due to the spread of COVID-19 around the globe, economics of different countries has been severely hammered irrespective of its previous status. Indian economic growth had a negative slope before the... more
An unavoidable lockdown situation due to the spread of COVID-19 around the globe, economics of different countries has been severely hammered irrespective of its previous status. Indian economic growth had a negative slope before the pandemic which certainly is in the worst condition at the present situation due to the lockdown as well as other related activities. The effect of the lockdown on the Indian economy is studied and presented in this article. In this study quantum economic formulation is implemented to know the in-depth economic status of our society along with the traditional method. With the help of quantum economics, the GDP of India during the lockdown period (April – June 2020) and just after the reopening period (July – September 2020) are computed and reported. The computed GDP values in percentage are -0.4 and 2.22 respectively.
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A synergistic approach was made to develop a highly stable and carbon resistant catalyst system based on cobalt and nickel supported over modified mesoporous silica for the dry reforming of methane (DRM). Modified mesoporous silica is... more
A synergistic approach was made to develop a highly stable and carbon resistant catalyst system based on cobalt and nickel supported over modified mesoporous silica for the dry reforming of methane (DRM). Modified mesoporous silica is prepared by a hydrothermal method, and the total Co & Ni composition is taken at around 5% by using the deposition-precipitation technique. CO2 reforming with methane was performed at 400-800 °C under atmospheric pressure as well as at a pressure of 1 MPa, keeping the CH4/CO2 ratio equal to unity. The catalyst assembly before and after the reaction was thoroughly characterized by a wide range of analytical techniques including N2 physisorption, XRD, TPR, TPO, TPH, XPS, SEM, TEM, elemental mapping, TG-DTG. The physicochemical characterization results confirmed the homogeneous distribution of nanosized metal particles into the hexagonal framework of modified silica, which plays a vital role towards a stronger metal support interaction that renders carbon...