Article
Chemistry, Physical
Lars Gell, Karoliina Honkala
Summary: In this study, the hydrogenation reaction of levulinic acid on ligand-modified Pt(111) was investigated using DFT. The results demonstrate that the ligand-modified surface can change the reaction mechanism and improve the selectivity and rate of the desired reaction.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Roman Eschenbacher, Christian Schuschke, Hanna Buehlmeyer, Nicola Taccardi, Peter Wasserscheid, Tanja Bauer, Tao Xu, Joerg Libuda
Summary: In this study, TP-IRAS was used to investigate the desorption behavior of CO on Pt(111) coadsorbed with four different ionic liquids (ILs). It was found that CO desorbs earlier from the surface with ILs compared to without. The desorption temperature of CO varied among different ILs, with higher IL-Pt(111) interaction leading to lower desorption temperature.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
John R. Rumptz, Charles T. Campbell
Summary: Understanding the adhesion energy between a liquid solvent and a clean solid surface can help estimate the decrease in adsorption energy of reactant molecules on the surface, aiding in the design of liquid-phase catalysts and electrocatalysts. Adhesion energies for various liquid-on-solid systems were measured using temperature-programmed desorption, showing the potential for estimating other liquid/solid adhesion energies. The adhesion energies of n-alkanes on different materials varied, with the order of increase being MgO(100) < graphene < TiO2(110) approximately equal to Pt(111).
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Tobias Wagener, Lukas Lueckemeier, Constantin G. Daniliuc, Frank Glorius
Summary: This study successfully demonstrates the synthesis of sought-after, enantioenriched delta-lactams through an interrupted hydrogenation mechanism using oxazolidinone-substituted pyridines and water.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Yanji Zhang, Jicheng Zhou
Summary: The Pt/@-ZrO2/SBA-15 catalyst demonstrated outstanding activity and selectivity for the hydrogenation of nitroarenes, achieving high turnover frequencies. The hybrid nanostructure catalyst showed high efficiency and recyclability, providing a new perspective for developing catalysts for various catalytic reactions.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Khawer Shafqat, Satu Pitkaaho, Minna Tiainen, Lenka Matejova, Riitta L. Keiski
Summary: In this study, the effect of platinum nanoparticle size on the catalytic reduction of nitrate in liquid phase was investigated using hydrogen as a reducing agent under ambient conditions. The results showed that 8 nm platinum nanoparticles exhibited the highest catalytic activity, while 4 nm platinum showed the highest selectivity for N-2 as the product. Additionally, the potential role of PVP capping agent as a promoter in the reaction was highlighted.
Article
Chemistry, Multidisciplinary
Jie Gao, Rui Ma, Lu Feng, Yuefeng Liu, Ralf Jackstell, Rajenahally V. Jagadeesh, Matthias Beller
Summary: This study introduces a general protocol for the selective hydrogenation and deuteration of alkenes, utilizing a specific nickel-graphitic shell-based core-shell-structured catalyst to achieve high yields of corresponding alkanes and deuterium-labeled alkanes at ambient conditions. The synthetic utility and practicability of this Ni-based hydrogenation protocol is demonstrated through gram-scale reactions and efficient catalyst recycling experiments.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Aleksandra Selivanova, Victoria G. Demina, Egor E. Aydakov, Andrey A. Saraev, Vasily V. Kaichev, Valerii Bukhtiyarov
Summary: The oxidation of methanol on a Pt(1 1 1) single crystal surface was found to start at around 350 K, producing mainly CO2 and methyl formate. Key intermediates in the reaction include CO and formaldehyde, with formates exhibiting low thermal stability and carbonates showing extremely high thermal stability. Carbonates, along with CO, can inhibit the oxidation of methanol on the platinum surface.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Zhongwen Luo, Jiahan Xie, Nicholas Kaylor, Diane A. Dickie, Hannah E. Ketcham, Robert J. Davis, T. Brent Gunnoe
Summary: Silica-supported Pd, Rh, and Pt metal nanoparticles catalyze the hydrogenolysis of the Pt-OPh bond of ((t)bpy)Pt(OPh)Cl to release PhOH. Kinetic studies show that Pd exhibits higher reactivity compared to Rh and Pt. The results of kinetic studies with Pd/SiO2 are consistent with a first-order dependence on the catalyst and the molecular Pt(II) complex ((t)bpy)Pt(OPh)Cl. TEM-EDS mapping and ICP-OES measurements reveal approximately 10-16% Pt deposition on the surface of Pd/SiO2 after 1 hour of hydrogenolysis of ((t)bpy)Pt(OPh)Cl.
Article
Chemistry, Applied
Byeongju Song, Jeongmyeong Kim, Iljun Chung, Yongju Yun
Summary: The catalytic properties of Pt catalysts supported on mesoporous silica were studied in the enantio-selective hydrogenation of ethyl pyruvate. The results showed that the pore structure and size of the m-SiO2 supports significantly influenced both the activity and enantioselectivity. The use of specific modifiers and H-2 pressure further improved the performance of the catalysts.
Article
Chemistry, Organic
Chi-Hang Fan, Tianyue Xu, Zhihai Ke, Ying-Yeung Yeung
Summary: In this study, Hantzsch pyridine was used as a promoter to activate Hantzsch ester for the generation of hydrogen peroxy radicals, which enables the ipso-hydroxylation of arylboronic acids to form phenols. The reaction conditions were mild and highly compatible with various functional groups.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Physical
Xiaoyan Liu, Yiqi Ren, Maodi Wang, Xiaomin Ren, Jian Liu, Qihua Yang
Summary: In this study, efficient nitrobenzothiazole hydrogenation was achieved using Pt/TiO2 as a catalyst. The presence of the strong metal-support interaction (SMSI) effect in Pt/TiO2 was found to enhance its activity compared to Pt/TiO2 without the SMSI effect. The activation of the -NO2 group mainly occurs through the oxygen vacancy (O-v) of TiOx in the presence of sulfur compounds, and H species dissociate on Pt to reduce -NO2. The cooperative effect between Pt and TiOx contributes to the high hydrogenation activity of Pt/TiO2.
Article
Chemistry, Physical
Griffin Ruehl, S. Elizabeth Harman, Liney Arnadottir, Charles T. Campbell
Summary: The study measured the heat of adsorption of acetonitrile on Pt(111) surface as a function of coverage, revealing a difference in adsorption heats at different temperatures and their impact on saturation coverage. The estimated adhesion energy for liquid acetonitrile on Pt(111) was found to be lower than water, benzene, and phenol, but higher than methanol and formic acid. This information can be useful in estimating the effect of acetonitrile as a solvent on the adsorption energies of catalytic reactants compared to gas phase.
Article
Chemistry, Multidisciplinary
Kalina Grzelak, Maciej Trejda, Anders Riisager
Summary: Copper-containing materials based on Ce- and Ca-Nb-mesocellular foam silica supports were prepared and applied as catalysts for the gas-phase reductive condensation of acetone. The properties of these materials, the interaction of metal species, and their role in the catalytic process were investigated. The results showed that the Cu/Ce-MCF catalyst exhibited high acetone conversion and MIBK selectivity at 250°C, indicating a synergistic effect of Cu2+, Cu-0, and CeO2 species.
Article
Energy & Fuels
Changxu Wang, Shuai Wang, Zhenshuai Wu, Yipin Lv, Guozhu Chen, Huaiqing Zhao, Daowei Gao
Summary: In this study, a Ga2O3-Pt two-component spatially isolated catalyst was introduced for the selective hydrogenation of furfural to furfuryl alcohol under hydrogen spillover. The confinement of Pt and Ga2O3 active sites in different pores led to a synergistic effect, resulting in enhanced catalytic activity and selectivity.
Article
Physics, Applied
Trevor L. Courtney, Nils Torge Mecker, Brian D. Patterson, Mark Linne, Christopher J. Kliewer
APPLIED PHYSICS LETTERS
(2019)
Article
Optics
Nils Torge Mecker, Trevor L. Courtney, Brian D. Patterson, David Escofet-Martin, Brian Peterson, Christopher J. Kliewer, Mark Linne
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2020)
Article
Optics
Timothy Y. Chen, Benjamin M. Goldberg, Brian D. Patterson, Egemen Kolemen, Yiguang Ju, Christopher J. Kliewer
Article
Optics
S. A. Steinmetz, C. J. Kliewer
Article
Thermodynamics
Timothy Y. Chen, Christopher J. Kliewer, Benjamin M. Goldberg, Egemen Kolemen, Yiguang Ju
Summary: In this study, a model for the CH4 nu(1) Q-branch was developed for fs/ps CARS, enabling simultaneous temperature acquisition from the CH4 and N-2 vibrational Q-branches. Accurate measurements were achieved for both molecules' spectra, with temperatures corresponding well to differences ranging from 4 to 17%. Additionally, spatially resolved one-dimensional thermometry using the CH4 Q-branch demonstrated a spatial resolution of 40 pm.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Mark Linne, Nils T. Mecker, Christopher J. Kliewer, David Escofet-Martin, Brian Peterson
Summary: This paper evaluates two commonly accepted Raman linewidth models, MEG and ECS, used to fit CARS model parameters and compares them to previous publications. The approaches presented in the literature are discussed along with the differences found in this study.
COMBUSTION AND FLAME
(2022)
Article
Chemistry, Physical
Scott A. Steinmetz, Andrew T. DeLaRiva, Christopher Riley, Paul Schrader, Abhaya Datye, Erik D. Spoerke, Christopher J. Kliewer
Summary: The role of solid surface in initiating gas-phase reactions, particularly the interaction between hydrogen atoms and surface sites, is still not well understood. This study presents the first measurements of hydrogen concentrations by laser-induced fluorescence in the gas-phase above catalytic and noncatalytic surfaces. The results show that hydrogen concentrations are highest above inert quartz surfaces compared to stainless steel and a platinum-based catalyst, and concentrations above the catalyst decrease rapidly with time on stream. These findings support the previously reported differences in bulk ethane dehydrogenation reactivity of these materials, suggesting hydrogen may serve as a good indicator for dehydrogenation activity.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Optics
Timothy Y. Chen, Ning Liu, Christopher J. Kliewer, Arthur Dogariu, Egemen Kolemen, Yiguang Ju
Summary: We report the development of a simple and sensitive two-beam hybrid femtosecond/picosecond pure rotational coherent anti-Stokes Raman scattering (fs/ps CARS) method to simultaneously measure the rotational and vibrational temperatures of diatomic molecules. This method utilizes coherence beating effects to infer the temperatures and a model for extraction. The experimental results are in good agreement with the model.
Article
Optics
S. A. Steinmetz, C. J. Kliewer
Summary: Coherent anti-Stokes Raman scattering (CARS) is commonly used for thermometry and concentration measurement of major species. However, its use for detecting minor species is limited due to the quadratic scaling of CARS signal with number density. Recent advancements in ultrafast CARS approaches, including hybrid CARS, have increased the excitation efficiencies. This study determines the detection limits of N-2, H-2, CO, and C2H4 using point-wise hybrid femtosecond (fs)/picosecond (ps) CARS to be on the order of 10(15) molecules/cm(3), and discusses the possible benefits of fs/nanosecond (ns) hybrid CARS.
Article
Chemistry, Physical
Timothy Y. Chen, Christopher J. Kliewer
Summary: Coherent anti-Stokes Raman scattering (CARS) is a reliable method for measuring temperature in reacting flows. However, the effects of non-Boltzmann vibrational state distributions and collisional dephasing at high pressures are still unclear. In this study, spectral simulations were used to investigate these effects and the applicability of coherence beating. It was found that short probe pulses can quantify non-Boltzmann vibrational state distributions and provide sensitive measurements of rotational and vibrational temperatures.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Optics
S. A. Steinmetz, T. Y. Chen, B. M. Goldberg, C. M. Limbach, C. J. Kliewer
Summary: Simultaneous measurement of rotational and vibrational temperatures in an N2 plasma using VIPA-CARS technique is demonstrated. VIPA-CARS provides more accurate measurements of non-equilibrium temperatures compared to grating-resolved rotational CARS.
Article
Thermodynamics
Madeline Vorenkamp, Scott A. Steinmetz, Timothy Y. Chen, Xingqian Mao, Andrey Starikovskiy, Christopher Kliewer, Yiguang Ju
Summary: This study investigates the effect of nanosecond dielectric barrier discharge (ns-DBD) plasma on deflagration to detonation transition (DDT) in a microchannel with a fuel-lean, DME, oxygen, and argon premixture. The results show that the plasma discharge can nonlinearly affect the onset time and distance of DDT. By adjusting the number of discharge pulses, DDT can be controlled. This research is of great importance for improving advanced propulsion engines.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Physics, Applied
David W. Chandler, Martin Fournier, Eric J. Smoll, Christopher J. Kliewer
Summary: We propose and demonstrate a method for direct imaging of gas-surface reaction products with high spatial resolution using ion imaging technique. The density of hydrogen deuteride (HD) molecules desorbed from a patterned platinum (Pt) thin film exposed to hydrogen (H-2) and deuterium (D-2) molecular beams was imaged using a 2 + 1 resonance enhanced multiphoton absorption scheme. A velocity-filtered ion imaging system with a grounded pinhole was used to improve the spatial resolution by a factor of 10.
APPLIED PHYSICS LETTERS
(2023)
Article
Optics
Madeline Vorenkamp, Scott A. Steinmetz, Timothy Y. Chen, Yiguang Ju, Christopher J. Kliewer
Summary: We propose a spatially enhanced electric-field-induced second-harmonic (SEEFISH) generation method using a chirped femtosecond beam to measure the electric field in mesoscale confined geometries. The chirped femtosecond beam effectively prevents higher-order mixing and white light generation near the beam focal point, reducing contamination of the SEEFISH signal. Successful measurements of electric field in a nanosecond dielectric barrier discharge demonstrate the effectiveness of the SEEFISH approach in eliminating spurious second-harmonic generation detected by traditional E-FISH methods.
Article
Multidisciplinary Sciences
Timothy Y. Chen, Scott A. Steinmetz, Brian D. Patterson, Ahren W. Jasper, Christopher J. Kliewer
Summary: The authors used coherent anti-Stokes Raman scattering to study collisional vibrational excitation in highly rotationally excited CO2 molecules in an optical centrifuge. They reported time and frequency-resolved ultrafast coherent Raman measurements of optically centrifuged CO2 at energies beyond its bond dissociation energy. They observed direct coherence transfer and time-resolved vibrational excitation due to rotational-to-vibrational energy transfer.
NATURE COMMUNICATIONS
(2023)
