Search

Your search keyword '"Gibson, Emma K."' showing total 262 results
Start Over Author "Gibson, Emma K."
262 results on '"Gibson, Emma K."'

11. Towards the Operational Window for Nitridic and Carbidic Palladium Nanoparticles for Directed Catalysis

Author

Costley‐Wood, Lucy G, primary, Mohammed, Khaled, additional, Carravetta, Marina, additional, Decarolis, Donato, additional, Goguet, Alexandre, additional, Kordatos, Apostolos, additional, Vakili, Reza, additional, Manyar, Haresh, additional, McPake, Erin, additional, Skylaris, Chris‐Kriton, additional, Thompson, Paul, additional, Gibson, Emma K, additional, and Wells, Peter P., additional

Published
2023
Full Text
View/download PDF

14. Structural selectivity of supported Pd nanoparticles for catalytic NH3 oxidation resolved using combined operando spectroscopy

Author

Dann, Ellie K., Gibson, Emma K., Blackmore, Rachel H., Catlow, C. Richard A., Collier, Paul, Chutia, Arunabhiram, Erden, Tugce Eralp, Hardacre, Christopher, Kroner, Anna, Nachtegaal, Maarten, Raj, Agnes, Rogers, Scott M., Taylor, S. F. Rebecca, Thompson, Paul, Tierney, George F., Zeinalipour-Yazdi, Constantinos D., Goguet, Alexandre, and Wells, Peter P.

Published
2019
Full Text
View/download PDF

15. Amine hydrochloride salts : a problem in polyurethane synthesis

Author

Gibson, Emma K.

Subjects
547.7, QD Chemistry
Abstract

A major problem encountered during the industrial synthesis of isocyanates, is the loss of amine starting material through reaction with the hydrogen chloride (HC1) by-product. HC1 is formed by the phosgenation of polymeric amines and also by the subsequent decomposition of the carbamyl chloride, Equation (1). HC1 readily reacts with the polymeric amine to form an unwanted and highly insoluble amine hydrochloride salt. (Fig. 3620) Methylene dianiline (MDA) and 4-benzylaniline (4-BA) were used as models for the industrial amine starting material with their hydrochloride counterparts methylene dianiline dihydrochloride (MDA.2HC1) and 4-benzylaniline hydrochloride (4-BA.HC1) as models for the industrial waste material. To understand the forces controlling the structure and stability of these solid amine hydrochloride salts the sold state structures of MDA, MDA.2HCl, methylene dianiline monohydrochloride (MDA.HCl), 4-BA and 4-BA.HCl were investigated using single crystal X-ray diffraction which led to the determination of their lattice energies. The XRD studies were also used as a basis for Density Functional Theory (DFT) calculations. The information obtained from the solid state structures, combined with an investigation of the solution phase behaviour of 4-BA.HCl(s), resulted in the determination of a kinetic model for the recovery of amine starting material. The proposed reaction scheme describes the conditions under which the dissociation of 4-BA.HCl(s) can occur. Reaction in a closed system shows no amine production while reaction in an open system permits, within solubility limits, the complete consumption of solid waste to produce free amine. From these two extremes the conversion of waste hydrochloride salt in the industrial reactor can be rationalised.

Published
2007

17. Adsorption and activation of molecular oxygen over atomic copper(I/II) site on ceria

Author

Kang, Liqun, Wang, Bolun, Bing, Qiming, Zalibera, Michal, Büchel, Robert, Xu, Ruoyu, Wang, Qiming, Liu, Yiyun, Gianolio, Diego, Tang, Chiu C., Gibson, Emma K., Danaie, Mohsen, Allen, Christopher, Wu, Ke, Marlow, Sushila, Sun, Ling-dong, He, Qian, Guan, Shaoliang, Savitsky, Anton, Velasco-Vélez, Juan J., Callison, June, Kay, Christopher W. M., Pratsinis, Sotiris E., Lubitz, Wolfgang, Liu, Jing-yao, and Wang, Feng Ryan

Published
2020
Full Text
View/download PDF

22. The adsorption of nitrobenzene over an alumina-supported palladium catalyst: an infrared spectroscopic study.

Author

McCullagh, Annelouise M., Gibson, Emma K., Parker, Stewart F., Refson, Keith, and Lennon, David

Abstract

As part of an on-going programme of development of an aniline synthesis catalyst suitable for operation at elevated temperatures, the geometry of the adsorption complex for nitrobenzene on a 5 wt% Pd/Al2O3 catalyst is investigated by infrared (IR) spectroscopy. Via an appreciation of the reduced site symmetry resulting from adsorption, application of the metal surface selection rule, and observation of in-plane modes only, the adsorption complex (Pd–nitrobenzene) at 28 °C is assigned as occurring vertically or tilted with respect to the metal surface, adopting Csσv(yz) symmetry. Moreover, adsorption occurs via a single Pd–O bond. Single molecule DFT calculations and simulated IR spectra assist vibrational assignments but indicate a parallel adsorption geometry to be energetically favourable. The contradiction between calculated and observed structures is attributed to the DFT calculations corresponding to an isolated molecule adsorption complex, while IR spectra relate to multi molecule adsorption that is encountered during sustained catalytic turnover. Residual hydrogen from the catalyst reduction stage leads to aniline formation on the Pd surface at low nitrobenzene coverages but, on increasing nitrobenzene exposure, the aniline is forced on to the alumina support. A reaction scheme is proposed whereby the nitrobenzene adsorption geometry is inherently linked to the high aniline selectivity observed for Pd/Al2O3 catalysts. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

32. Tracking the solid-state incorporation of Sn into the framework of dealuminated zeolite beta, and consequences for catalyst design

Author

Navar, Ricardo, primary, Tarantino, Giulia, additional, Beynon, Owain T., additional, Padovan, Daniele, additional, Botti, Luca, additional, Gibson, Emma K., additional, Wells, Peter P., additional, Owens, Alun, additional, Kondrat, Simon A., additional, Logsdail, Andrew J., additional, and Hammond, Ceri, additional

Published
2022
Full Text
View/download PDF

33. Controlling the Production of Acid Catalyzed Products of Furfural Hydrogenation by Pd/TiO 2

Author

Tierney, George F., primary, Alijani, Shahram, additional, Panchal, Monik, additional, Decarolis, Donato, additional, de Gutierrez, Martha Briceno, additional, Mohammed, Khaled M. H., additional, Callison, June, additional, Gibson, Emma K., additional, Thompson, Paul B. J., additional, Collier, Paul, additional, Dimitratos, Nikolaos, additional, Corbos, E. Crina, additional, Pelletier, Frederic, additional, Villa, Alberto, additional, and Wells, Peter P., additional

Published
2021
Full Text
View/download PDF

34. Designed TiS2 nanosheets for efficient electrocatalytic reductive amination of biomass-derived furfurals.

Author

Zhang, Man, Xu, Shaojun, Boubeche, Mebrouka, Decarolis, Donato, Huang, Yizhe, Liu, Biying, Gibson, Emma K., Li, Xin, Wang, Yuchen, Luo, Huixia, Catlow, C. Richard A., and Yan, Kai

Subjects
FURFURAL, NANOSTRUCTURED materials, BIOMASS energy, RENEWABLE energy sources, AMINATION, TRANSMISSION electron microscopy
Abstract

Green and highly selective synthesis of organonitrogen chemicals (ONCs) using the renewable energy source biomass over noble-metal free solid catalysts under common room temperature and pressure conditions is still a major challenge. Here, we report a sustainable electrochemical method for selective synthesis of several valuable ONCs with high yields using biomass-derived furanic aldehydes over greenly fabricated TiS2 nanosheets through a facile synthesis. Based on a range of characterization techniques including high-resolution transmission electron microscopy and X-ray absorption fine structure, a well-defined structure of the TiS2 nanosheets (3.86 nm with 1T phase) was constructed. These as-prepared catalysts were applied to the electrochemical reductive amination (ERA) of three biomass-derived aldehydes, i.e. furfural (FF), 5-methylfurfural (MF) and 5-hydroxymethylfurfural (HMF), and exhibited superior performance whereby over 95% conversion of each furanic aldehyde and nearly perfect selectivity of ONCs were achieved. TiS2 nanosheets, in particular, exhibited a marked ∼2-fold increase in conversion (∼49%) compared with the monometallic Ti electrode. Besides, the reaction kinetics and rational pathway were also studied. In addition, these exfoliated TiS2 nanosheets maintained high durability over 6 h, providing a promising and versatile route for the sustainable upgrading of biomass-derived sources. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

35. Operando XAFS investigation on the effect of ash deposition on three-way catalyst used in gasoline particulate filters and the effect of the manufacturing process on the catalytic activity

Author

Panchal, Monik, primary, Callison, June, additional, Skukauskas, Vainius, additional, Gianolio, Diego, additional, Cibin, Giannantonio, additional, York, Andrew P E, additional, Schuster, Manfred E, additional, Hyde, Timothy I, additional, Collier, Paul, additional, Catlow, C Richard A, additional, and Gibson, Emma K, additional

Published
2021
Full Text
View/download PDF

36. Investigation of MoO x/Al 2 O 3 under cyclic operation for oxidative and non-oxidative dehydrogenation of propane

Author

Matam, Santhosh K., Moffat, Caitlin, Hellier, Pip, Bowker, Michael, Silverwood, Ian P., Catlow, C. Richard A., Jackson, S. David, Craswell, James, Wells, Peter P., Parker, Stewart F., and Gibson, Emma K.

Abstract

A MoOx/Al2O3 catalyst was synthesised and tested for oxidative (ODP) and non-oxidative (DP) dehydrogenation of propane in a reaction cycle of ODP followed by DP and a second ODP run. Characterisation results show that the fresh catalyst contains highly dispersed Mo oxide species in the +6 oxidation state with tetrahedral coordination as [MoVIO4]2− moieties. In situ X-ray Absorption Spectroscopy (XAS) shows that [MoVIO4]2− is present during the first ODP run of the reaction cycle and is reduced to MoIVO2 in the following DP run. The reduced species are partly re-oxidised in the subsequent second ODP run of the reaction cycle. The partly re-oxidised species exhibit oxidation and coordination states that are lower than 6 but higher than 4 and are referred to as MoxOy. These species significantly improved propene formation (relatively 27% higher) in the second ODP run at similar propane conversion activity. Accordingly, the initial tetrahedral [MoVIO4]2− present during the first ODP run of the reaction cycle is active for propane conversion; however, it is unselective for propene. The reduced MoIVO2 species are relatively less active and selective for DP. It is suggested that the MoxOy species generated by the reaction cycle are active and selective for ODP. The vibrational spectroscopic data indicate that the retained surface species are amorphous carbon deposits with a higher proportion of aromatic/olefinic like species.

Published
2020

37. Co3O4/TiO2catalysts studied in situduring the preferential oxidation of carbon monoxide: the effect of different TiO2polymorphsElectronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d2cy01699k

Author

Nyathi, Thulani M., Fadlalla, Mohamed I., Fischer, Nico, York, Andrew P. E., Olivier, Ezra J., Gibson, Emma K., Wells, Peter P., and Claeys, Michael

Abstract

Co3O4nanoparticles were supported on different TiO2polymorphs, namely, rutile, anatase, and a 15 : 85 mixture of rutile and anatase (also known as P25), viaincipient wetness impregnation. The Co3O4/TiO2catalysts were evaluated in the preferential oxidation of CO (CO-PrOx) in a H2-rich gas environment and characterised in situusing PXRD and magnetometry. Our results show that supporting Co3O4on P25 resulted in better catalytic performance, that is, a higher maximum CO conversion to CO2of 72.7% at 200 °C was achieved than on rutile (60.7%) and anatase (51.5%). However, the degree of reduction (DoR) of Co3O4to Co0was highest on P25 (91.9% at 450 °C), with no CoTiO3detected in the spent catalyst. The DoR of Co3O4was lowest on anatase (76.4%), with the presence of TixOy-encapsulated CoOxnanoparticles and bulk CoTiO3(13.8%) also confirmed in the spent catalyst. Relatively low amounts of CoTiO3(8.9%) were detected in the spent rutile-supported catalyst, while a higher DoR (85.9%) was reached under reaction conditions. The Co0nanoparticles formed on P25 and rutile existed in the fcc and hcp crystal phases, while only fcc Co0was detected on anatase. Furthermore, undesired CH4formation took place over the Co0present in the P25- and rutile-supported catalysts, while CH4was not formed over the Co0on anatase possibly due to encapsulation by TixOyspecies. For the first time, this study revealed the influence of different TiO2polymorphs (used as catalyst supports) on the chemical and crystal phase transformations of Co3O4, which in turn affect its activity and selectivity during CO-PrOx.

Published
2023
Full Text
View/download PDF

39. Redox?Active Hybrid Polyoxometalate?Stabilised Gold Nanoparticles

Author

Martin, Carmen, Kastner, Katharina, Cameron, Jamie M., Hampson, Elizabeth, Alves Fernandes, Jesum, Gibson, Emma K., Walsh, Darren A., Sans, Victor, and Newton, Graham N.

Subjects
General Chemistry, Catalysis
Abstract

We report the design and preparation of multifunctional hybrid nanomaterials through the stabilization of gold nanoparticles with thiol‐functionalised hybrid organic–inorganic polyoxometalates (POMs). The covalent attachment of the hybrid POM forms new nanocomposites that are stable at temperatures and pH values which destroy analogous electrostatically functionalised nanocomposites. Photoelectrochemical analysis revealed the unique photochemical and redox properties of these systems.

Published
2020

44. Synchrotron Radiation and Catalytic Science

Author

Hardacre, Christopher, primary, Beale, Andrew M., additional, Gibson, Emma K., additional, Goodall, Josephine B. M., additional, Goguet, Alex, additional, Kondrat, Simon A., additional, Malta,, Grazia, additional, Stere, Cristina, additional, Wells, Peter P., additional, Hutchings, Graham J., additional, and Catlow, C. Richard A., additional

Published
2020
Full Text
View/download PDF

46. In situ K-edge X-ray absorption spectroscopy of the ligand environment of single-site Au/C catalysts during acetylene hydrochlorination

Author

Malta, Grazia, primary, Kondrat, Simon A., additional, Freakley, Simon J., additional, Morgan, David J., additional, Gibson, Emma K., additional, Wells, Peter P., additional, Aramini, Matteo, additional, Gianolio, Diego, additional, Thompson, Paul B. J., additional, Johnston, Peter, additional, and Hutchings, Graham J., additional

Published
2020
Full Text
View/download PDF

47. Controlling the Production of Acid Catalyzed Products of Furfural Hydrogenation by Pd/TiO2.

Author

Tierney, George F., Alijani, Shahram, Panchal, Monik, Decarolis, Donato, de Gutierrez, Martha Briceno, Mohammed, Khaled M. H., Callison, June, Gibson, Emma K., Thompson, Paul B. J., Collier, Paul, Dimitratos, Nikolaos, Corbos, E. Crina, Pelletier, Frederic, Villa, Alberto, and Wells, Peter P.

Subjects
FURFURAL, CATALYSTS, PRODUCTION control, HYDROGENATION, CATALYST selectivity, POLYVINYL alcohol, SUSTAINABLE chemistry
Abstract

We demonstrate a modified sol‐immobilization procedure using (MeOH)x/(H2O)1‐x solvent mixtures to prepare Pd/TiO2 catalysts that are able to reduce the formation of acid catalyzed products, e. g. ethers, for the hydrogenation of furfural. Transmission electron microscopy found a significant increase in polyvinyl alcohol (PVA) deposition at the metal‐support interface and temperature programmed reduction found a reduced uptake of hydrogen, compared to an established Pd/TiO2 preparation. We propose that the additional PVA hinders hydrogen spillover onto the TiO2 support and limits the formation of Brønsted acid sites, required to produce ethers. Elsewhere, the new preparation route was able to successfully anchor colloidal Pd to the TiO2 surface, without the need for acidification. This work demonstrates the potential for minimizing process steps as well as optimizing catalyst selectivity – both important objectives for sustainable chemistry. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

48. Understanding the CO oxidation on Pt nanoparticles supported on MOFs by operando XPS

Author

Vakili, Reza, Gibson, Emma K., Chansai, Sarayute, Xu, Shaojun, Al‐Janabi, Nadeen, Wells, Peter P., Hardacre, Christopher, Walton, Alex, and Fan, Xiaolei

Subjects
Confinement Effect, Operando Near Ambient Pressure XPS (NAP-XPS), Pt Catalysts, Communication, Metal-Organic Frameworks (MOFs), CO Oxidation, Communications
Abstract

Metal-organic frameworks (MOFs) are playing a key role in developing the next generation of heterogeneous catalysts. In this work, near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) is applied to study in operando the CO oxidation on Pt@MOFs (UiO-67) and Pt@ZrO2 catalysts, revealing the same Pt surface dynamics under the stoichiometric CO/O2 ambient at 3 mbar. Upon the ignition at ca. 200°C, the signature Pt binding energy (BE) shift towards the lower BE (from 71.8 to 71.2 eV) is observed for all catalysts, confirming metallic Pt nanoparticles (NPs) as the active phase. Additionally, the plug-flow light-off experiments show the superior activity of the Pt@MOFs catalyst in CO oxidation than the control Pt@ZrO2 catalyst with ca. 28% drop in the T50% light-off temperature, as well as high stability, due to their sintering-resistance feature. These results provide evidence that the uniqueness of MOFs as the catalyst supports lies in the structural confinement effect.

Published
2018

Catalog

Books, media, physical & digital resources
See catalog results