Pakiza Begum - Academia.edu (original) (raw)

Papers by Pakiza Begum

Organic Letters, Apr 23, 2020

A visible-light-induced cascade cyclization of thioamides with alkynes was developed to synthesiz... more A visible-light-induced cascade cyclization of thioamides with alkynes was developed to synthesize 1,3-thiozoles. The sulfur radical generated from thioamide via single electron transfer (SET) pathway was promoted by photocatalysis as a key intermediate in this reaction. When bromoalkynes were used as substrate, the self-coupling products 1,1-dibromo-1-en-3-ynes were obtained in moderate yields, and an energy transfer pathway for this transformation promoted by visible-light photocatalysis was proposed.

ACS Catalysis, Dec 26, 2019

The stable activity of catalysts is an important issue in catalysis particularly aqueous phase re... more The stable activity of catalysts is an important issue in catalysis particularly aqueous phase reforming (APR) of renewable oxygenates, of biomass origin, to get H 2. Sintering of metal nanoparticles on supports affects catalyst stability. To alleviate this problem, a series of highly stable Ru supported catalysts with controlled metal nanoparticle sizes have been prepared via easy incipient wetness impregnation method. These catalysts were used for APR of glycerol to produce H 2. Nitrogen doped mesoporous carbons (NMCs) were utlized as supports and found to have a strong influence on the catalytic performance of the catalysts. Incorporation of nitrogen in the carbon framework significantly enhanced the catalytic activity compared to Ru catalysts on nitrogen free supports. Notably, the catalyst (5 wt% Ru-NMC-3) with optimal N content (10.9 wt%) demonstrated improved stability and H 2 selectivity, which are better than the many states of the art catalysts. Nitrogen in the carbon framework has a dual relationship with the activity of the catalyst; (i) it creates basic environment over the catalysts support and (ii) it acts as an anchoring site for metal nanoparticles. Anchoring of metal nanoparticles has helped to curb their sintering, thus leading to better stability of the catalysts under APR reaction conditions. Various characterization techniques were employed to understand the nature of active catalytic sites responsible for higher H 2 production while minimizing CO formation. In-situ CO-FTIR studies showed that the higher catalytic activity of 5wt% Ru-NMC-3 catalyst was attributed to enhanced WGS activity over this catalyst. Density functional theory (DFT) calculations were performed to understand the stabilization of metal nanoparticles by different types of N present on the support and provide insights into the prefered sites of glycerol adsorption on NMC support. Since 5wt% Ru-NMC-3 was relatively best catalyst, it was selected for the preparation of bimetallic catalysts.

Journal of Water and Health, Mar 25, 2021

Materials which are chemically, energetically and operationally acceptable for arsenic water trea... more Materials which are chemically, energetically and operationally acceptable for arsenic water treatment are highly required. In this study a hybrid material (SICC) of aminated starch, oxyhydroxide of iron and OMMT clay has been demonstrated for arsenic treatment. This new material was highly efficient in arsenic water treatment which could reduce arsenic concentration far below detection limits. All binding interactions during material preparation and arsenic sorption were exclusively characterized with FT-IR, XRD and other spectroscopic tools. A molecular modeling on the basis of density functional theory was carried out to verify the above findings. Influence of material dose, treatment time, initial ion concentration, varying temperatures, etc., on extent of sorption was studied in detail. The thermodynamic parameters viz. ΔG (>-11 kJ/mol), ΔH (42.48 kJ/mol), ΔS (177.6 JK À1 mol À1) and E a (59.16 kJ/mol) determined the feasibility of the process, its endothermic behavior and most importantly the chemical nature of the sorption accompanied by ion-exchange to some extent. The sorption followed a monolayer chemisorption pattern as determined by the Langmuir model (R 2 ¼ 0.973, R L ¼ 0.081) with a q max ¼ 2.04 at 303 K. The binding of As(III) on the material was governed by a pseudo second order kinetic model.

European Journal of Wood and Wood Products, Apr 4, 2019

Thermosetting composites were prepared from chemically modified soybean oil and wood flour by com... more Thermosetting composites were prepared from chemically modified soybean oil and wood flour by compression molding technique. Resins prepared from epoxidized soybean oil (ESO) and softwood powder were used as matrix and reinforcing agent, respectively. ESO was modified initially by methacrylic acid and finally by methacrylic anhydride. For comparison, both neat resin and resin blended with styrene were used in the composite preparation. The probable interaction among the resin, styrene and wood flour was established by Fourier transform infrared spectroscopy, supported by density functional theory calculations. Surface morphology of the composites was evaluated by scanning electron microscope. The flexural strength of composites with styrene-based co-monomer was in the range of 60.47-72.04 MPa, whereas that of composites without styrene was between 25.68 and 37.62 MPa. The tensile strength of styrene-blended composites was varied between 22.15 and 35.87 MPa, whereas the tensile strength was in the range of 13.68-20.48 MPa for styrene-free composites. Styreneblended composites showed an improvement in mechanical, thermal, water resistance and flame retardant properties over those of composites having no styrene. The higher the amount of methacrylic anhydride in the resin, the higher was the overall improvement in properties of composites.

New Journal of Chemistry, 2018

Synthesis of wood polymer composites with a polymer matrix and a reinforcing agent derived from r... more Synthesis of wood polymer composites with a polymer matrix and a reinforcing agent derived from renewable resources having satisfactory properties.

ChemistrySelect, Sep 29, 2017

We have studied the oxidation of CO on palladium monomer in three oxidation states, viz. 0, +1 an... more We have studied the oxidation of CO on palladium monomer in three oxidation states, viz. 0, +1 and +2, supported on FAU zeolite, using density functional theory. When metal complexes and clusters are attached to oxide or zeolite supports, they may well combine the industrial benefits of solid catalysts (heftiness for high temperature operation, absence of corrosiveness and comfort of separation from products) with the selectivity of soluble molecular catalysts. Further, single-atom catalysts (SACs) with discrete and isolated metal atoms anchored to supports can perform as active centres having significant and unique performances, such as drastic cost-reduction, notable catalytic activity and selectivity. CO oxidation has been extensively studied, as designing suitable catalysts is one of the foremost challenges in the field of catalytic research to remove poisonous carbon monoxide. CO oxidation over Pdn/FAU (n=0, +1 and +2) have been investigated which elucidate the effect of cluster charge state on the catalytic activity. The conventional bimolecular Langmuir-Hinshelwood mechanism with co-adsorbed CO and O2 has been considered. Our calculations indicate that Pd2+/FAU displays better catalytic activity among the considered systems. This study is anticipated to provide useful information for the development of highly active catalyst for CO oxidation.

Catalysis Letters, Dec 23, 2016

producing two NO 2 molecules from two NO molecules in presence of air. Energetic calculation reve... more producing two NO 2 molecules from two NO molecules in presence of air. Energetic calculation reveals that PdCu is the predominant catalytic system with more active Pd-site.

Theoretical Chemistry Accounts, Nov 19, 2013

The density functional theory has been employed to investigate the geometrical structures, relati... more The density functional theory has been employed to investigate the geometrical structures, relative stabilities, electronic and magnetic properties of Nb n O (n = 3-10) clusters. The ground state structure are obtained by adding one O atom to the Nb n clusters or by replacing one Nb atom by O atom in Nb n+1 clusters. The results of binding energy and the second difference in energy show Nb 7 O and Nb 9 O have strong stability. According to the natural population analysis, O atom attracts about 0.8 e charges from its neighboring Nb atoms. The magnetism of the Nb n O clusters mostly stems from the contribution of 4d orbital of Nb atoms.

ACS omega, Jun 29, 2018

A series of potassium salt-loaded MgAl hydrotalcites were synthesized by wet impregnation of KNO ... more A series of potassium salt-loaded MgAl hydrotalcites were synthesized by wet impregnation of KNO 3 , KF, KOH, K 2 CO 3 , and KHCO 3 salts over calcined MgAl hydrotalcite (Mg−Al = 3:1). The samples were characterized by X-ray diffraction, Fourier transform infrared, thermogravimetry− differential thermal analysis, scanning electron microscopy, and N 2 absorption−desorption techniques to investigate their structural properties. The results showed formation of welldeveloped hydrotalcite phase and reconstruction of layered structure after impregnation. The prepared hydrotalcites possess mesopores and micropores having pore diameters in the range of 3.3−4.0 nm and Brunauer−Emmett−Teller surface area 90− 207 m 2 g −1. Base strengths calculated from Hammett indicator method were found increasing after loading salts, where KOH-loaded hydrotalcite showed base strength in the range of 12.7 < H − < 15, which was found to be the preferred catalyst. Subsequently, KOH loading was increased from 10 to 40% (w/w) and catalytic activity was evaluated for the Knoevenagel condensation reaction at room temperature. Density functional theory calculations show that among all of the oxygen atoms present in the hydrotalcite, the O atom attached to the K atom has the highest basic character. In this study, 10% KOH-loaded hydrotalcite showing 99% conversion and 100% selectivity was selected as the preferred catalyst in terms of base strength, stability, and catalytic efficiency.

Development in Wastewater Treatment Research and Processes, 2022

Mathematics Applied to Engineering in Action, 2021

We have studied the oxidation of CO on palladium monomer in three oxidation states, viz. 0, +1 an... more We have studied the oxidation of CO on palladium monomer in three oxidation states, viz. 0, +1 and +2, supported on FAU zeolite, using density functional theory. When metal complexes and clusters are attached to oxide or zeolite supports, they may well combine the industrial benefits of solid catalysts (heftiness for high temperature operation, absence of corrosiveness and comfort of separation from products) with the selectivity of soluble molecular catalysts. Further, single-atom catalysts (SACs) with discrete and isolated metal atoms anchored to supports can perform as active centres having significant and unique performances, such as drastic cost-reduction, notable catalytic activity and selectivity. CO oxidation has been extensively studied, as designing suitable catalysts is one of the foremost challenges in the field of catalytic research to remove poisonous carbon monoxide. CO oxidation over Pdn/FAU (n=0, +1 and +2) have been investigated which elucidate the effect of cluste...

Journal of Water and Health, 2021

Materials which are chemically, energetically and operationally acceptable for arsenic water trea... more Materials which are chemically, energetically and operationally acceptable for arsenic water treatment are highly required. In this study a hybrid material (SICC) of aminated starch, oxyhydroxide of iron and OMMT clay has been demonstrated for arsenic treatment. This new material was highly efficient in arsenic water treatment which could reduce arsenic concentration far below detection limits. All binding interactions during material preparation and arsenic sorption were exclusively characterized with FT-IR, XRD and other spectroscopic tools. A molecular modeling on the basis of density functional theory was carried out to verify the above findings. Influence of material dose, treatment time, initial ion concentration, varying temperatures, etc., on extent of sorption was studied in detail. The thermodynamic parameters viz. ΔG (>–11 kJ/mol), ΔH (42.48 kJ/mol), ΔS (177.6 JK−1 mol−1) and E a (59.16 kJ/mol) determined the feasibility of the process, its endothermic behavior and mos...

European Journal of Organic Chemistry, 2020

In an oxygen atmosphere tert-butyl nitrite (TBN) reacts with unsymmetrical internal benzylic alke... more In an oxygen atmosphere tert-butyl nitrite (TBN) reacts with unsymmetrical internal benzylic alkenes giving nitro-nitratosation product exclusively. The -diaryl substituted styrenes provided better yields compared to -alkyl-aryl substituted styrenes. The higher yields for the former type of substrates is possible dictated by the additional stability of benzylic radical due to the anchimeric assistance imparted by the substituted phenyl ring. During oxidative nitration, the nitro (NO2) group adds at the non-benzylic site, whereas the nitrato group (ONO2) is attached at the relatively stable benzylic position. Under similar reaction conditions, α,β-unsaturated carboxylic acids, afforded nitroalkenes as the sole product.

ACS Catalysis, 2019

The stable activity of catalysts is an important issue in catalysis particularly aqueous phase re... more The stable activity of catalysts is an important issue in catalysis particularly aqueous phase reforming (APR) of renewable oxygenates, of biomass origin, to get H 2. Sintering of metal nanoparticles on supports affects catalyst stability. To alleviate this problem, a series of highly stable Ru supported catalysts with controlled metal nanoparticle sizes have been prepared via easy incipient wetness impregnation method. These catalysts were used for APR of glycerol to produce H 2. Nitrogen doped mesoporous carbons (NMCs) were utlized as supports and found to have a strong influence on the catalytic performance of the catalysts. Incorporation of nitrogen in the carbon framework significantly enhanced the catalytic activity compared to Ru catalysts on nitrogen free supports. Notably, the catalyst (5 wt% Ru-NMC-3) with optimal N content (10.9 wt%) demonstrated improved stability and H 2 selectivity, which are better than the many states of the art catalysts. Nitrogen in the carbon framework has a dual relationship with the activity of the catalyst; (i) it creates basic environment over the catalysts support and (ii) it acts as an anchoring site for metal nanoparticles. Anchoring of metal nanoparticles has helped to curb their sintering, thus leading to better stability of the catalysts under APR reaction conditions. Various characterization techniques were employed to understand the nature of active catalytic sites responsible for higher H 2 production while minimizing CO formation. In-situ CO-FTIR studies showed that the higher catalytic activity of 5wt% Ru-NMC-3 catalyst was attributed to enhanced WGS activity over this catalyst. Density functional theory (DFT) calculations were performed to understand the stabilization of metal nanoparticles by different types of N present on the support and provide insights into the prefered sites of glycerol adsorption on NMC support. Since 5wt% Ru-NMC-3 was relatively best catalyst, it was selected for the preparation of bimetallic catalysts.

Organic Letters, Apr 23, 2020

A visible-light-induced cascade cyclization of thioamides with alkynes was developed to synthesiz... more A visible-light-induced cascade cyclization of thioamides with alkynes was developed to synthesize 1,3-thiozoles. The sulfur radical generated from thioamide via single electron transfer (SET) pathway was promoted by photocatalysis as a key intermediate in this reaction. When bromoalkynes were used as substrate, the self-coupling products 1,1-dibromo-1-en-3-ynes were obtained in moderate yields, and an energy transfer pathway for this transformation promoted by visible-light photocatalysis was proposed.

ACS Catalysis, Dec 26, 2019

The stable activity of catalysts is an important issue in catalysis particularly aqueous phase re... more The stable activity of catalysts is an important issue in catalysis particularly aqueous phase reforming (APR) of renewable oxygenates, of biomass origin, to get H 2. Sintering of metal nanoparticles on supports affects catalyst stability. To alleviate this problem, a series of highly stable Ru supported catalysts with controlled metal nanoparticle sizes have been prepared via easy incipient wetness impregnation method. These catalysts were used for APR of glycerol to produce H 2. Nitrogen doped mesoporous carbons (NMCs) were utlized as supports and found to have a strong influence on the catalytic performance of the catalysts. Incorporation of nitrogen in the carbon framework significantly enhanced the catalytic activity compared to Ru catalysts on nitrogen free supports. Notably, the catalyst (5 wt% Ru-NMC-3) with optimal N content (10.9 wt%) demonstrated improved stability and H 2 selectivity, which are better than the many states of the art catalysts. Nitrogen in the carbon framework has a dual relationship with the activity of the catalyst; (i) it creates basic environment over the catalysts support and (ii) it acts as an anchoring site for metal nanoparticles. Anchoring of metal nanoparticles has helped to curb their sintering, thus leading to better stability of the catalysts under APR reaction conditions. Various characterization techniques were employed to understand the nature of active catalytic sites responsible for higher H 2 production while minimizing CO formation. In-situ CO-FTIR studies showed that the higher catalytic activity of 5wt% Ru-NMC-3 catalyst was attributed to enhanced WGS activity over this catalyst. Density functional theory (DFT) calculations were performed to understand the stabilization of metal nanoparticles by different types of N present on the support and provide insights into the prefered sites of glycerol adsorption on NMC support. Since 5wt% Ru-NMC-3 was relatively best catalyst, it was selected for the preparation of bimetallic catalysts.

Journal of Water and Health, Mar 25, 2021

Materials which are chemically, energetically and operationally acceptable for arsenic water trea... more Materials which are chemically, energetically and operationally acceptable for arsenic water treatment are highly required. In this study a hybrid material (SICC) of aminated starch, oxyhydroxide of iron and OMMT clay has been demonstrated for arsenic treatment. This new material was highly efficient in arsenic water treatment which could reduce arsenic concentration far below detection limits. All binding interactions during material preparation and arsenic sorption were exclusively characterized with FT-IR, XRD and other spectroscopic tools. A molecular modeling on the basis of density functional theory was carried out to verify the above findings. Influence of material dose, treatment time, initial ion concentration, varying temperatures, etc., on extent of sorption was studied in detail. The thermodynamic parameters viz. ΔG (>-11 kJ/mol), ΔH (42.48 kJ/mol), ΔS (177.6 JK À1 mol À1) and E a (59.16 kJ/mol) determined the feasibility of the process, its endothermic behavior and most importantly the chemical nature of the sorption accompanied by ion-exchange to some extent. The sorption followed a monolayer chemisorption pattern as determined by the Langmuir model (R 2 ¼ 0.973, R L ¼ 0.081) with a q max ¼ 2.04 at 303 K. The binding of As(III) on the material was governed by a pseudo second order kinetic model.

European Journal of Wood and Wood Products, Apr 4, 2019

Thermosetting composites were prepared from chemically modified soybean oil and wood flour by com... more Thermosetting composites were prepared from chemically modified soybean oil and wood flour by compression molding technique. Resins prepared from epoxidized soybean oil (ESO) and softwood powder were used as matrix and reinforcing agent, respectively. ESO was modified initially by methacrylic acid and finally by methacrylic anhydride. For comparison, both neat resin and resin blended with styrene were used in the composite preparation. The probable interaction among the resin, styrene and wood flour was established by Fourier transform infrared spectroscopy, supported by density functional theory calculations. Surface morphology of the composites was evaluated by scanning electron microscope. The flexural strength of composites with styrene-based co-monomer was in the range of 60.47-72.04 MPa, whereas that of composites without styrene was between 25.68 and 37.62 MPa. The tensile strength of styrene-blended composites was varied between 22.15 and 35.87 MPa, whereas the tensile strength was in the range of 13.68-20.48 MPa for styrene-free composites. Styreneblended composites showed an improvement in mechanical, thermal, water resistance and flame retardant properties over those of composites having no styrene. The higher the amount of methacrylic anhydride in the resin, the higher was the overall improvement in properties of composites.

New Journal of Chemistry, 2018

Synthesis of wood polymer composites with a polymer matrix and a reinforcing agent derived from r... more Synthesis of wood polymer composites with a polymer matrix and a reinforcing agent derived from renewable resources having satisfactory properties.

ChemistrySelect, Sep 29, 2017

We have studied the oxidation of CO on palladium monomer in three oxidation states, viz. 0, +1 an... more We have studied the oxidation of CO on palladium monomer in three oxidation states, viz. 0, +1 and +2, supported on FAU zeolite, using density functional theory. When metal complexes and clusters are attached to oxide or zeolite supports, they may well combine the industrial benefits of solid catalysts (heftiness for high temperature operation, absence of corrosiveness and comfort of separation from products) with the selectivity of soluble molecular catalysts. Further, single-atom catalysts (SACs) with discrete and isolated metal atoms anchored to supports can perform as active centres having significant and unique performances, such as drastic cost-reduction, notable catalytic activity and selectivity. CO oxidation has been extensively studied, as designing suitable catalysts is one of the foremost challenges in the field of catalytic research to remove poisonous carbon monoxide. CO oxidation over Pdn/FAU (n=0, +1 and +2) have been investigated which elucidate the effect of cluster charge state on the catalytic activity. The conventional bimolecular Langmuir-Hinshelwood mechanism with co-adsorbed CO and O2 has been considered. Our calculations indicate that Pd2+/FAU displays better catalytic activity among the considered systems. This study is anticipated to provide useful information for the development of highly active catalyst for CO oxidation.

Catalysis Letters, Dec 23, 2016

producing two NO 2 molecules from two NO molecules in presence of air. Energetic calculation reve... more producing two NO 2 molecules from two NO molecules in presence of air. Energetic calculation reveals that PdCu is the predominant catalytic system with more active Pd-site.

Theoretical Chemistry Accounts, Nov 19, 2013

The density functional theory has been employed to investigate the geometrical structures, relati... more The density functional theory has been employed to investigate the geometrical structures, relative stabilities, electronic and magnetic properties of Nb n O (n = 3-10) clusters. The ground state structure are obtained by adding one O atom to the Nb n clusters or by replacing one Nb atom by O atom in Nb n+1 clusters. The results of binding energy and the second difference in energy show Nb 7 O and Nb 9 O have strong stability. According to the natural population analysis, O atom attracts about 0.8 e charges from its neighboring Nb atoms. The magnetism of the Nb n O clusters mostly stems from the contribution of 4d orbital of Nb atoms.

ACS omega, Jun 29, 2018

A series of potassium salt-loaded MgAl hydrotalcites were synthesized by wet impregnation of KNO ... more A series of potassium salt-loaded MgAl hydrotalcites were synthesized by wet impregnation of KNO 3 , KF, KOH, K 2 CO 3 , and KHCO 3 salts over calcined MgAl hydrotalcite (Mg−Al = 3:1). The samples were characterized by X-ray diffraction, Fourier transform infrared, thermogravimetry− differential thermal analysis, scanning electron microscopy, and N 2 absorption−desorption techniques to investigate their structural properties. The results showed formation of welldeveloped hydrotalcite phase and reconstruction of layered structure after impregnation. The prepared hydrotalcites possess mesopores and micropores having pore diameters in the range of 3.3−4.0 nm and Brunauer−Emmett−Teller surface area 90− 207 m 2 g −1. Base strengths calculated from Hammett indicator method were found increasing after loading salts, where KOH-loaded hydrotalcite showed base strength in the range of 12.7 < H − < 15, which was found to be the preferred catalyst. Subsequently, KOH loading was increased from 10 to 40% (w/w) and catalytic activity was evaluated for the Knoevenagel condensation reaction at room temperature. Density functional theory calculations show that among all of the oxygen atoms present in the hydrotalcite, the O atom attached to the K atom has the highest basic character. In this study, 10% KOH-loaded hydrotalcite showing 99% conversion and 100% selectivity was selected as the preferred catalyst in terms of base strength, stability, and catalytic efficiency.

Development in Wastewater Treatment Research and Processes, 2022

Mathematics Applied to Engineering in Action, 2021

We have studied the oxidation of CO on palladium monomer in three oxidation states, viz. 0, +1 an... more We have studied the oxidation of CO on palladium monomer in three oxidation states, viz. 0, +1 and +2, supported on FAU zeolite, using density functional theory. When metal complexes and clusters are attached to oxide or zeolite supports, they may well combine the industrial benefits of solid catalysts (heftiness for high temperature operation, absence of corrosiveness and comfort of separation from products) with the selectivity of soluble molecular catalysts. Further, single-atom catalysts (SACs) with discrete and isolated metal atoms anchored to supports can perform as active centres having significant and unique performances, such as drastic cost-reduction, notable catalytic activity and selectivity. CO oxidation has been extensively studied, as designing suitable catalysts is one of the foremost challenges in the field of catalytic research to remove poisonous carbon monoxide. CO oxidation over Pdn/FAU (n=0, +1 and +2) have been investigated which elucidate the effect of cluste...

Journal of Water and Health, 2021

Materials which are chemically, energetically and operationally acceptable for arsenic water trea... more Materials which are chemically, energetically and operationally acceptable for arsenic water treatment are highly required. In this study a hybrid material (SICC) of aminated starch, oxyhydroxide of iron and OMMT clay has been demonstrated for arsenic treatment. This new material was highly efficient in arsenic water treatment which could reduce arsenic concentration far below detection limits. All binding interactions during material preparation and arsenic sorption were exclusively characterized with FT-IR, XRD and other spectroscopic tools. A molecular modeling on the basis of density functional theory was carried out to verify the above findings. Influence of material dose, treatment time, initial ion concentration, varying temperatures, etc., on extent of sorption was studied in detail. The thermodynamic parameters viz. ΔG (>–11 kJ/mol), ΔH (42.48 kJ/mol), ΔS (177.6 JK−1 mol−1) and E a (59.16 kJ/mol) determined the feasibility of the process, its endothermic behavior and mos...

European Journal of Organic Chemistry, 2020

In an oxygen atmosphere tert-butyl nitrite (TBN) reacts with unsymmetrical internal benzylic alke... more In an oxygen atmosphere tert-butyl nitrite (TBN) reacts with unsymmetrical internal benzylic alkenes giving nitro-nitratosation product exclusively. The -diaryl substituted styrenes provided better yields compared to -alkyl-aryl substituted styrenes. The higher yields for the former type of substrates is possible dictated by the additional stability of benzylic radical due to the anchimeric assistance imparted by the substituted phenyl ring. During oxidative nitration, the nitro (NO2) group adds at the non-benzylic site, whereas the nitrato group (ONO2) is attached at the relatively stable benzylic position. Under similar reaction conditions, α,β-unsaturated carboxylic acids, afforded nitroalkenes as the sole product.

ACS Catalysis, 2019

The stable activity of catalysts is an important issue in catalysis particularly aqueous phase re... more The stable activity of catalysts is an important issue in catalysis particularly aqueous phase reforming (APR) of renewable oxygenates, of biomass origin, to get H 2. Sintering of metal nanoparticles on supports affects catalyst stability. To alleviate this problem, a series of highly stable Ru supported catalysts with controlled metal nanoparticle sizes have been prepared via easy incipient wetness impregnation method. These catalysts were used for APR of glycerol to produce H 2. Nitrogen doped mesoporous carbons (NMCs) were utlized as supports and found to have a strong influence on the catalytic performance of the catalysts. Incorporation of nitrogen in the carbon framework significantly enhanced the catalytic activity compared to Ru catalysts on nitrogen free supports. Notably, the catalyst (5 wt% Ru-NMC-3) with optimal N content (10.9 wt%) demonstrated improved stability and H 2 selectivity, which are better than the many states of the art catalysts. Nitrogen in the carbon framework has a dual relationship with the activity of the catalyst; (i) it creates basic environment over the catalysts support and (ii) it acts as an anchoring site for metal nanoparticles. Anchoring of metal nanoparticles has helped to curb their sintering, thus leading to better stability of the catalysts under APR reaction conditions. Various characterization techniques were employed to understand the nature of active catalytic sites responsible for higher H 2 production while minimizing CO formation. In-situ CO-FTIR studies showed that the higher catalytic activity of 5wt% Ru-NMC-3 catalyst was attributed to enhanced WGS activity over this catalyst. Density functional theory (DFT) calculations were performed to understand the stabilization of metal nanoparticles by different types of N present on the support and provide insights into the prefered sites of glycerol adsorption on NMC support. Since 5wt% Ru-NMC-3 was relatively best catalyst, it was selected for the preparation of bimetallic catalysts.