Article
Chemistry, Physical
Amanda Filie, Tanya Shirman, Alexandre C. Foucher, Eric A. Stach, Michael Aizenberg, Joanna Aizenberg, Cynthia M. Friend, Robert J. Madix
Summary: Dilute alloy catalysts, particularly Pd-in-Au nanoparticle alloys, demonstrate enhanced selectivity and activity in oxidative coupling of methanol reactions. Low concentrations of palladium in bimetallic nanoparticles are effective in catalyzing the production of methyl formate with high selectivity of up to 95% under certain reaction conditions.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Dmitry B. Eremin, Alexey S. Galushko, Daniil A. Boiko, Evgeniy O. Pentsak, Igor Chistyakov, Valentine P. Ananikov
Summary: Homogeneous catalysis is well-defined, while heterogeneous nanocatalysis is often poorly defined. Supported catalysts are difficult to characterize due to their heterogeneity and large size at the nanoscale. By studying individual particles of the supported catalyst, important aspects of activity for widespread and commercially important Pd/C catalysts have been revealed.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Engineering, Environmental
Amin Delparish, Anouk W. N. de Leeuw den Bouter, Aysima Yercan, John van der Schaaf, Maria Fernanda Neira d'Angelo
Summary: The study presents a method to convert furfural into alkyl furoate using a catalytic microchannel reactor, overcoming the challenge posed by explosive mixtures. Experimental and computational investigations provide insights into the kinetics and gold-assisted oxidative esterification mechanism, contributing to rational catalyst design and process development.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Tiago A. G. Silva, Erico Teixeira-Neto, Lais R. Borges, Tomaz Neves-Garcia, Adriano H. H. Braga, Liane M. M. Rossi
Summary: The activity of bimetallic AuPd nanoparticles for alcohol oxidation reaction can be optimized by adjusting the Au/Pd molar ratio. Alloy AuPd nanoparticles of different compositions were synthesized through a sol-immobilization method. Calcination caused size increase and segregation of Pd to the surface, forming a core-shell structure. The catalytic activity increased after calcination, but decreased upon reduction, indicating the importance of PdO in the shell.
Article
Chemistry, Multidisciplinary
Pit van Bonn, Daniela Dressler, Fabian Weitenhagen, Carsten Bolm
Summary: A mechanochemical palladium-catalyzed oxidative esterification of alcohols has been developed, enabling the solvent-free synthesis of esters with high yields. The environmental performance of the developed protocol was evaluated and compared with solution-based protocols, highlighting the advantages of the mechanochemical approach.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Chemistry, Applied
Onur Bulut, M. Deniz Yilmaz
Summary: This study evaluated the catalytic activity of biocompatible chitosan-stabilized gold nanoparticles on the oxidation reaction, demonstrating high efficiency and long-term stability with low toxicity to cells. The nanoparticles showed positive correlation with concentrations of catalyst and oxidant, while negative correlation with substrate concentration. The results suggest the potential of CH-AuNPs as effective and reusable nanocatalysts for oxidation reactions.
CARBOHYDRATE POLYMERS
(2021)
Article
Engineering, Biomedical
Matthias Fach, Frederikke P. Fliedner, Paul J. Kempen, Fredrik Melander, Anders E. Hansen, Linda M. Bruun, Ulli Koster, Emanuel Sporer, Andreas Kjaer, Thomas L. Andresen, Andreas I. Jensen, Jonas R. Henriksen
Summary: The new concept of using gold-palladium alloy nanoparticles for brachytherapy shows promising results in terms of reducing invasiveness of treatment, delaying tumor growth and increasing median survival times. This innovative approach has the potential to replace current brachytherapy seeds effectively.
ADVANCED HEALTHCARE MATERIALS
(2021)
Article
Chemistry, Physical
Antonio Buonerba, Annarita Noschese, Carmine Capacchione, Alfonso Grassi
Summary: A new catalytic system based on gold nanoparticles encapsulated in a PPO matrix has been synthesized, and it showed high efficiency, stability, and selectivity in the aerobic oxidation of alcohols. The catalyst exhibited high activity values in the oxidation of primary alcohols under mild reaction conditions and achieved high yields in one-pot oxidative reactions.
Article
Multidisciplinary Sciences
Xiaoyang Huang, Ouardia Akdim, Mark Douthwaite, Kai Wang, Liang Zhao, Richard J. Lewis, Samuel Pattisson, Isaac T. Daniel, Peter J. Miedziak, Greg Shaw, David J. Morgan, Sultan M. Althahban, Thomas E. Davies, Qian He, Fei Wang, Jile Fu, Donald Bethell, Steven McIntosh, Christopher J. Kiely, Graham J. Hutchings
Summary: This study demonstrates that the reaction rate can be almost doubled by separating the gold and palladium components in bimetallic carbon-supported catalysts. The enhancement is attributed to the coupling of separate redox processes occurring at isolated gold and palladium sites.
Article
Engineering, Environmental
Joseph Brindle, Michael M. Nigra
Summary: The selective oxidation of methane is a challenging process, but AuPd nanoparticles have shown promise in activating methane at moderate temperatures and pressures. Through experimental studies, the formation of different surface intermediates and their relationship with selectivity and activity have been explored. It has been hypothesized that water and copper oxide can facilitate the selective oxidation of methane. The results indicate that AuPd catalysts are more active than monometallic Au and Pd catalysts in the presence of water, and the unprotonated formate can increase the methane oxidation rate. Additionally, copper oxide improves the selectivity of methane towards CO but decreases the overall methane consumption.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Nanoscience & Nanotechnology
Ayako Taketoshi, Yuvaraj Gangarajula, Ryusei Sodenaga, Akihiro Nakayama, Mitsutaka Okumura, Norihito Sakaguchi, Toru Murayama, Tetsuya Shimada, Shinsuke Takagi, Masatake Haruta, Botao Qiao, Junhu Wang, Tamao Ishida
Summary: Gold nanoparticles (Au NPs) interact strongly with cation-and anion-substituted hydroxyapatites (Au/sHAPs) due to oxidative strong metal-support interaction (SMSI). The catalytic performance of Au/sHAPs for oxidative esterification depends on the size of the Au NPs but not on the support used. Even when fully covered by a thin sHAP layer (<1 nm), the Au NPs can still catalyze oxidative esterification. The contact area between Au NPs and the sHAP support, maximized through SMSI, enhances the catalytic activity of Au.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Christopher Tiburski, Astrid Boje, Sara Nilsson, Zafer Say, Joachim Fritzsche, Henrik Strom, Anders Hellman, Christoph Langhammer
Summary: This study investigates the differential effects of photothermal rate enhancement on various catalysts and demonstrates how this effect can be controlled by adjusting the catalyst operation point. Experimental results show that small fluctuations in reactor temperature or temperature gradients across a sample may significantly impact photothermal rate enhancement.
Article
Chemistry, Multidisciplinary
Bon Seung Goo, Kyungrok Ham, Yeji Han, Seunghoon Lee, Hayoon Jung, Yongmin Kwon, Youngmin Kim, Jong Wook Hong, Sang Woo Han
Summary: This study successfully decouples the activity of the edge and {110}-plane atoms of Pd NCs by comparing the catalytic behaviors of edge-covered Pd NCs with pristine Pd NCs, providing a new method for more precise examination of the surface properties of various NC catalysts.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Bon Seung Goo, Kyungrok Ham, Yeji Han, Seunghoon Lee, Hayoon Jung, Yongmin Kwon, Youngmin Kim, Jong Wook Hong, Sang Woo Han
Summary: This study developed a novel approach to investigate the intrinsic catalytic reactivity of edge and terrace atoms in nanocrystal catalysts. By comparing the catalytic behaviors of edge-covered Pd NCs with those of pristine Pd NCs, researchers successfully decoupled the activity of edge and {110}-plane atoms.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Wacharee Harnying, Panyapon Sudkaow, Animesh Biswas, Albrecht Berkessel
Summary: Simple carboxylic acids, like benzoic acid, have been found to enhance the activity of N-heterocyclic carbene (NHC) catalysts in the oxidative esterification of aldehydes. A protocol using a novel N-Mes-/N-2,4,6-trichlorophenyl 1,2,4-triazolium salt as catalyst and benzoic acid as co-catalyst was developed for the transformation of a wide range of sterically hindered alpha- and beta-substituted aliphatic aldehydes/enals. The observed effect is believed to be due to the carboxylic acid-induced acceleration of acyl transfer from azolium enolate intermediates.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Correction
Chemistry, Physical
Thomas Richards, Richard J. Lewis, David J. Morgan, Graham J. Hutchings
Article
Chemistry, Physical
Thomas Richards, Richard J. Lewis, David J. Morgan, Graham J. Hutchings
Summary: The direct synthesis of H2O2 from molecular H-2 and O-2 using Pd-based catalysts has been investigated. The ratio of Pd to Au in the catalyst as well as the catalyst support were found to play important roles in controlling catalytic activity and performance. Alloying Pd with more abundant secondary metals is a potential alternative to replace expensive Au.
Article
Chemistry, Physical
Christopher D. Evans, Jonathan K. Bartley, Stuart H. Taylor, Graham J. Hutchings, Simon A. Kondrat
Summary: Exceptional selectivity of LaMnO3 supported Au catalysts for the oxidation of glycerol to tartronic acid is reported. The choice of metal nanoparticle influences the selectivity of the catalysts.
Article
Chemistry, Physical
David J. Morgan, Sharukaa Uthayasekaran
Summary: The study compared the degradation of halogenated and non-halogenated polymers using x-ray photoelectron spectroscopy with different types of spectrometers. The results showed notable differences from the degradation index proposed by Beamson and Briggs. The effects of neutralizer and spot size on degradation kinetics were explored, leading to practical recommendations for analyzing damage-susceptible polymers.
SURFACE AND INTERFACE ANALYSIS
(2023)
Review
Chemistry, Multidisciplinary
Nicholas F. Dummer, David J. Willock, Qian He, Mark J. Howard, Richard J. Lewis, Guodong Qi, Stuart H. Taylor, Jun Xu, Don Bethell, Christopher J. Kiely, Graham J. Hutchings
Summary: The direct transformation of methane to methanol at a larger scale remains challenging due to the low reactivity of methane. This review examines several promising routes to methanol and evaluates the performance targets necessary for process development. It provides critical perspectives on future operation and discusses the emergence of active heterogeneous catalysts and their reaction mechanisms.
Article
Chemistry, Physical
C. J. Lombard, C. G. C. E. van Sittert, J. N. Mugo, C. Perry, D. J. Willock
Summary: In this study, well-defined models of SiO2 surfaces were created and their interaction with Pd was investigated using dispersion-corrected DFT. The results showed that Pd prefers to adsorb onto strained four-membered siloxane rings or vicinal silanol groups on the alpha-SiO2 (101) surface.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Isaac T. T. Daniel, Liang Zhao, Donald Bethell, Mark Douthwaite, Samuel Pattisson, Richard J. J. Lewis, Ouardia Akdim, David J. J. Morgan, Steven McIntosh, Graham J. J. Hutchings
Summary: Recent studies have shown that the rate of catalytic alcohol and formyl dehydrogenation in bimetallic Au-Pd systems is closely related to the rate of oxygen reduction. In this study, the rate enhancement resulting from the coupling of these two processes is evaluated for the oxidative dehydrogenation of 5-hydroxymethylfurfural. By changing the molar ratio of Au and Pd in a physical mixture of carbon-supported catalysts, the influence of the ratio on the activity is explored. It is found that the activity of the bimetallic system exceeds the combined activity of the monometallic analogues. The kinetic analysis of the system predicts the locations of the maxima in activity for both monometallic and bimetallic systems. The accuracy of the model provides further evidence and understanding of cooperative redox enhancement effects observed in bimetallic, heterogeneous catalytic systems.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Parag M. M. Shah, Liam A. Bailey, Stuart H. Taylor
Summary: A series of ceria-manganese mixed metal oxide catalysts with different Ce:Mn ratios were prepared by coprecipitation, and their capabilities for total oxidation of propane and naphthalene were evaluated. The catalyst with a higher manganese content showed the highest activity, specifically Ce0.25Mn0.75Ox. Characterization techniques revealed that the high activity of Ce0.25Mn0.75Ox was attributed to the formation of phase-separated Mn-substituted ceria and Mn2O3 phases. The catalyst preparation technique also played a significant role, as the mechanochemical and urea catalysts exhibited greater activity than the carbonate coprecipitated catalyst.
Article
Chemistry, Physical
Xiang-Bing Fan, Dong-Wook Shin, Sanghyo Lee, Junzhi Ye, Shan Yu, David J. Morgan, Adrees Arbab, Jiajie Yang, Jeong-Wan Jo, Yoonwoo Kim, Sung-Min Jung, Philip R. Davies, Akshay Rao, Bo Hou, Jong Min Kim
Summary: InP quantum dots (QDs) are being studied as a less toxic alternative to Cd-based QDs. Aminophosphine and H2S are used to eliminate defects and reconstruct the interface between InP and ZnS, resulting in enhanced photoluminescence (PL). H2S etching can also control the size of the InP core, allowing for the production of wide band gap InP-based QDs with blue emission.
NANOSCALE HORIZONS
(2023)
Article
Chemistry, Physical
Rachel L. McLaren, Rosenildo C. da Costa, Anna C. Booth, David J. Morgan, Christian J. Laycock, Michael E. A. Warwick, Gareth R. Owen
Summary: The preparation of oleophobic materials coated with a composite based on a multi-layer graphitic scaffolding is reported. These materials demonstrate efficient oil/water separations and reusability, making them promising candidates for applications such as aircraft propellant tanks and oil-spill removal.
MOLECULAR SYSTEMS DESIGN & ENGINEERING
(2023)
Article
Chemistry, Physical
Vincent Fernandez, David Morgan, Pascal Bargiela, Neal Fairley, Jonas Baltrusaitis
Summary: Cellulose undergoes new chemistry in response to XPS, but recent studies have shown that this can be detrimental to some materials. This study analyzes cellulose spectra obtained during a degradation study, revealing that cellulose degrades through the creation of carbon chemistry involving C-O, C--O and O-C--O. The findings are relevant to any material analyzed by XPS dependent on hydrogen bonds. The analysis techniques are based on an informed vectorial approach, utilizing mathematical methods such as Principal Component Analysis and linear analysis.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Parag M. M. Shah, Liam A. A. Bailey, David J. J. Morgan, Stuart H. H. Taylor
Summary: Iron-manganese mixed metal oxide catalysts with different Fe:Mn ratios were synthesized and evaluated for total propane oxidation. The Fe0.50Mn0.50Ox catalyst showed the highest activity due to increased surface area and the formation of a Mn2O3 phase. The choice of precipitating agent was found to affect the activity, with the hydroxide-precipitated catalysts generally being more active.
Article
Chemistry, Physical
Nkululeko E. Damoyi, Holger B. Friedrich, Gert H. Kruger, David J. Willock
Summary: Supported vanadium oxides are widely used catalysts for the selective oxidative dehydrogenation of alkanes to alkenes. The activity of these catalysts is influenced by the different oxygen species involved, with singly coordinated vanadyl V(V)=O being the most reactive. Understanding the relative activity of different oxygen species can help improve catalyst design and enhance productivity and selectivity in the reaction.
MOLECULAR CATALYSIS
(2023)
Article
Chemistry, Physical
Liang Zhao, Ouardia Akdim, Xiaoyang Huang, Kai Wang, Mark Douthwaite, Samuel Pattisson, Richard J. Lewis, Runjia Lin, Bingqing Yao, David J. Morgan, Greg Shaw, Qian He, Donald Bethell, Steven McIntosh, Christopher J. Kiely, Graham J. Hutchings
Summary: The aerobic oxidation of alcohols and aldehydes over supported heterogeneous catalysts involves two interconnected processes: dehydrogenation and oxygen reduction. The rate of the reaction can be greatly enhanced by coupling these processes through electron transport between independent active sites. The ratio of Au/Pd catalysts used and their physical properties play important roles in promoting alcohol oxidation through cooperative redox enhancement (CORE).
