Article
Thermodynamics
Guoqing Wang, Shixing Wang, Thibault F. Guiberti
Summary: A novel PLIF technique using a single dye laser is proposed for simultaneous, single-shot imaging of NH3, NH, and NO in NH3-H2 flames. Three wavelength couples are used to image the three species simultaneously. The technique is then used to visualize the structure of premixed and non-premixed flames in a fuel blend of NH3 and H2.
COMBUSTION AND FLAME
(2023)
Article
Optics
Wei Zhang, Xue Dong, Zhiwei Sun, Bo Zhou, Zhenkan Wang, Mattias Richter
Summary: This study presents a computational imaging approach using convolutional neural networks for interpolating CH2O PLIF images, achieving higher temporal resolution for visualizing intermediate species in combustion. Results demonstrate the model's ability to accurately predict PLIF images at various axial positions, serving as an efficient offline model to overcome challenges in ultra-high speed PLIF techniques.
Article
Thermodynamics
Samir B. Rojas Chavez, Karl P. Chatelain, Thibault F. Guiberti, Remy Mevel, Deanna A. Lacoste
Summary: The study focuses on the impact of the excitation line on planar laser-induced fluorescence imaging of hydroxyl radical in H2-fueled detonation wave. Results show that the Q2(8)+Q1(9) excitation scheme provides the highest LIF intensity, and the maximum intensity decreases with increasing pressure. Using more favorable excitation schemes will enable better detonation flow visualization in future studies.
COMBUSTION AND FLAME
(2021)
Article
Engineering, Electrical & Electronic
Yudong Guo, Lijun Xu, Hongyao Li, Hongyu Zhang, Zhang Cao
Summary: This study introduces a planar laser-induced fluorescence (PLIF) technique that can be used to image the temperature and concentration distribution inside flames. The proposed method utilizes laser absorption spectroscopy (LAS) tomography to provide initial images of gas temperature, which are then used to update the fluorescence image iteratively. The results of numerical simulations and experiments demonstrate the effectiveness of this method, with relative errors of temperature and concentration within acceptable ranges.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Chemistry, Analytical
Siying Chen, Yuanyuan Chen, Yinchao Zhang, Pan Guo, He Chen, Huiyun Wu
Summary: In this research, a 3D modeling system based on PLIF technique is proposed to analyze the temporal and spatial variations of bioaerosol particles in a confined chamber. The system can reconstruct the 3D distribution of aerosol particles within a measurement volume of about 50 cm x 29.7 cm x 42 cm and record the diffusion process with a temporal resolution of 5 seconds. The experiments demonstrate the system's capability to visualize and analyze aerosol particles diffusion in confined spaces effectively.
Article
Chemistry, Multidisciplinary
Guohua Li, Zhenrong Zhang, Jingfeng Ye, Sheng Wang, Jun Shao, Haolong Wu, Yamin Wang, Zhiyun Hu, Jinhua Wang, Zuohua Huang
Summary: In order to address the uncertainty in the calibration process of two-color plane laser-induced fluorescence (PLIF) temperature measurement, a new calibration method is proposed, taking into account the influence of fluorescence yield. The calibration process is carried out at high and low temperature regions to restrain the bias originating from quenching. This new calibration method is validated in a jet flame with a temperature range of 1300-1800 K, and the results demonstrate its effectiveness in the combustion field, especially with a large temperature range and strong quenching coefficient.
APPLIED SCIENCES-BASEL
(2023)
Article
Thermodynamics
Minggang Wan, Jiajian Zhu, Mingbo Sun, Shu Zheng, Bo Zhou, Yuhui Huang, Hongbo Wang, Yao Liu, Ge Wu, Zhenguo Wang
Summary: Conducting CH2O PLIF imaging in scramjets is challenging due to strong flame emissions (FEs). To overcome this challenge, a CH2O PLIF imaging strategy utilizing 353.06 nm excitation and capturing two frames with a time delay was proposed. The strategy reduced FE interference and improved the signal-to-background ratio from 1-2 to 10, enabling CH2O PLIF imaging in scramjets.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Campbell D. Carter, Aaron W. Skiba, Isaac Boxx, Patton M. Allison
Summary: This study assessed the detection of formaldehyde (CH2O) in atmospheric-pressure premixed flames using planar laser-induced fluorescence (PLIF) and explored methods to improve the signal-to-noise ratio (SNR) of CH2O PLIF. The researchers compared different excitation wavelengths and schemes and identified the optimal excitation line and detection setup. They demonstrated the efficacy of high-quality CH2O PLIF in measuring premixed turbulent flames with pre-vaporized kerosene fuels.
COMBUSTION AND FLAME
(2022)
Article
Electrochemistry
Ana Gonzalez-Espinosa, Antonio Lozano, Manuel Montiel, Alvaro Ibanez, Jose E. Barranco, Felix Barreras
Summary: In this research, the flow behavior through a commercial electrode for Redox Flow Batteries (RFB) was studied using Planar Laser Induced Fluoresce imaging (PLIF). Different cell configurations were tested, and measurements of pressure drop were obtained. The results showed that a tight fitting of the electrode within its housing is crucial for the proper distribution of electrolyte, and the presence of channels affects the flow pattern significantly. The configuration with serpentine channels in the back plate was found to be the most energy-efficient, but a large portion of the electrolyte bypasses the electrode.
ELECTROCHIMICA ACTA
(2023)
Article
Thermodynamics
Yawei Song, Sheng Su, Yifeng Chen, Yushuai Liu, Zheng Zhao, Jingyan Wang, Qiangqiang Ren, Hengda Han, Kai Xu, Jun Xu, Long Jiang, Yi Wang, Song Hu, Jun Xiang
Summary: It has been found that the moisture content in coal affects its ignition and soot generation characteristics. Understanding the impact of moisture on coal ignition and soot generation is crucial for improving energy efficiency in coal utilization. Experimental results showed that both the ignition delay time and the amount of soot generated during volatile combustion increased with higher moisture content in the coal.
Article
Chemistry, Multidisciplinary
Hajime Kameo, Yudai Tanaka, Yoshihiro Shimoyama, Daisuke Izumi, Hiroyuki Matsuzaka, Yumiko Nakajima, Pierre Lavedan, Arnaud Le Gac, Didier Bourissou
Summary: A T-shaped Pt-0 complex with a diphosphine-borane (DPB) ligand was prepared. The Pt -> B interaction enhances the electrophilicity of the metal and triggers the addition of Lewis bases to give the corresponding tetracoordinate complexes. For the first time, anionic Pt-0 complexes are isolated and structurally authenticated.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
J. Antonowicz, P. Zalden, K. Sokolowski-Tinten, K. Georgarakis, R. Minikayev, A. Pietnoczka, F. Bertram, M. Chaika, M. Chojnacki, P. Dluzewski, K. Fronc, A. L. Greer, C. Jastrznbski, D. Klinger, Ch Lemke, O. M. Magnussen, B. Murphy, K. Perumal, U. Ruett, K. J. Warias, R. Sobierajski
Summary: In this study, ultrafast heating and rapid cooling processes in the devitrification of thin film Cu67Zr33 metallic glass were investigated using ultrashort pulsed laser annealing. X-ray diffraction snapshots were taken during the glass-crystal transformation, revealing the formation of a crystalline ZrO2 layer and the nucleation and growth of fcc-Cu in the amorphous matrix. At low annealing temperatures, the devitrification kinetics of ZrO2 and Cu are correlated, while at high temperatures ZrO2 forms much faster than Cu.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Vikram Mehar, Helen Edstrom, Mikhail Shipilin, Uta Hejral, Chengjun Wu, Aravind Kadiri, Stefano Albertin, Benjamin Hagman, Kim von Allmen, Tim Wiegmann, Sebastian Pfaff, Jakub Drnec, Johan Zetterberg, Edvin Lundgren, Lindsay R. Merte, Johan Gustafson, Jason F. Weaver
Summary: The structures of oxide phases on metallic catalysts during reaction have a strong influence on the catalytic oxidation of CO and CH4. It has been found that an epitaxial PdO(100) structure forms on Pd(100) at temperatures above 600 K during the oxidation process. Additionally, the oxidation behavior of Pd(100) changes from forming epitaxial PdO(101) at 500 K to simultaneously growing epitaxial PdO(100) and PdO(101) at temperatures above 600 K, resulting in a thicker and rougher oxide layer. This change is attributed to a temperature-induced change in the stability of small PdO domains that initiate the oxidation process.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Xia Zhang, Wenzhi Li, Zean Zhou, Kun Chen, Mingwei Wu, Liang Yuan
Summary: The study investigated the effects of different morphologies of CeO2 on the catalytic efficiency of Pd/CeO2, finding that rod-like CeO2 exhibited excellent performance when loaded with Pd in CO oxidation reaction. Moreover, the highly dispersed Pd on the surface of CeO2 was found to increase the concentration of Ce3+, activate lattice oxygen, and promote the generation of active centers, thereby enhancing the reaction activity.
MOLECULAR CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Maxime Van den Bossche, Jacek Goniakowski, Claudine Noguera
Summary: Ultra-thin alumina films coated on aluminum alloy surfaces are important for various applications, but their structural and stability characteristics are still not well understood. Research indicates that on NiAl(100) substrates, observed theta-alumina films correspond to thermodynamic equilibrium, rather than being influenced by kinetic effects during alloy oxidation and film growth.
Article
Chemistry, Physical
Chu Zhang, Baochang Wang, Anders Hellman, Mikhail Shipilin, Andreas Schaefer, Lindsay R. Merte, Sara Blomberg, Xueting Wang, Per-Anders Carlsson, Edvin Lundgren, Jonas Weissenrieder, Andrea Resta, Anders Mikkelsen, Jesper N. Andersen, Johan Gustafson
Summary: The study found that the oxidation of CO on a stepped Rh(553) surface occurs faster than on a flat Rh(111) surface at the same temperature, however, it is not due to reactions at the step sites but rather at the terrace sites close to the steps. This insight can provide ways to optimize the shape of nanoparticles to further improve the activity of certain reactions.
Article
Chemistry, Physical
Uta Hejral, Janis Timoshenko, David Kordus, Mauricio Lopez Luna, Nuria J. Divins, Simon Widrinna, Ioannis Zegkinoglou, Lukas Pielsticker, Hemma Mistry, Jorge Anibal Boscoboinik, Stefanie Kuehl, Beatriz Roldan Cuenya
Summary: This study investigated the catalytic mechanism of NiGa alloys in CO2 hydrogenation. It was found that Ni3Ga1 and Ni5Ga3 nanoparticles formed different phases at different temperatures under H-2 activation. Under CO2 hydrogenation conditions, Ga partially oxidized to form Ga2O3. The Ni3Ga1 NPs showed high selectivity towards methane production, while the Ni5Ga3 NPs exhibited high selectivity towards methanol production, which was attributed to the presence of the S-Ni5Ga3 phase.
JOURNAL OF CATALYSIS
(2022)
Article
Chemistry, Physical
Stefano Albertin, Lindsay R. Merte, Edvin Lundgren, Rachel Martin, Jason F. Weaver, Ann-Christin Dippel, Olof Gutowski, Uta Hejral
Summary: The oxidation and reduction reactions on the Ir(100) surface were studied using high-energy surface X-ray diffraction. Different oxide structures were observed under varied O-2 partial pressure, and the reduction process led to the formation of metallic Ir islands.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Dorotea Gajdek, Par A. T. Olsson, Sara Blomberg, Johan Gustafson, Per-Anders Carlsson, Dorthe Haase, Edvin Lundgren, Lindsay R. Merte
Summary: Grazing incidence X-ray absorption fine structure spectroscopy was used to study the CoO films on Pt(111). The results showed that the chemical state of Co changed under different oxidizing and reducing conditions, indicating the formation of cobalt hydroxide, oxyhydroxide, and bulklike Co3O4.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Christopher Sauer, Anders Loren, Andreas Schaefer, Per-Anders Carlsson
Summary: The valorization of 2,5-dimethylfuran (2,5-DMF) through catalytic fast pyrolysis (CFP) was studied using on-line FTIR-MS gas phase analysis. The selectivity towards benzene, toluene, and xylene (BTX) aromatics decreased with time on stream (TOS), while the isomerization rates of 2,5-DMF towards 2,4-dimethylfuran and cyclic ketones increased, indicating the involvement of specific active sites.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Jannis Thien, Jascha Bahlmann, Andreas Alexander, Kevin Ruwisch, Jari Rodewald, Tobias Pohlmann, Martin Hoppe, Fatih Alarslan, Martin Steinhart, Baki Altuncevahir, Padraic Shafer, Carola Meyer, Florian Bertram, Joachim Wollschlaeger, Karsten Kuepper
Summary: This study presents the magnetic properties and cation ordering of ultrathin Co-rich cobalt ferrite films. The electronic structure and distribution of cations in the films were examined using various characterization techniques. The results show a partially inverse spinel structure and an increased amount of Co3+ cations in the low-spin state for one of the films.
Article
Chemistry, Physical
Mengqiao Di, Kerry Simmance, Andreas Schaefer, Yanyue Feng, Felix Hemmingsson, Magnus Skoglundh, Tamsin Bell, David Thompsett, Lucy Idowu Ajakaiye Jensen, Sara Blomberg, Per-Anders Carlsson
Summary: Industrially relevant Pt/ceria and reference Pt/alumina catalysts with narrow Pt particle size distributions were prepared and studied for CO oxidation. The CO oxidation on highly oxidized Pt particles and at the platinum-ceria boundary was observed, while Pt/alumina showed a drop in catalytic activity due to CO self-poisoning.
JOURNAL OF CATALYSIS
(2022)
Article
Chemistry, Physical
Sebastian Pfaff, Lisa Ramisch, Sabrina M. Gericke, Alfred Larsson, Edvin Lundgren, Johan Zetterberg
Summary: Many surface science experiments in the field of heterogeneous catalysis are now conducted under more realistic conditions, i.e., at higher pressures. Under these pressures, localized gas conditions are formed within the reactor. Understanding the interaction between these gas conditions and the catalyst surface at relevant time and space scales is crucial. To address this, a combination of techniques is used to analyze the composition of gas and surface with sufficient temporal and spatial resolution. By conducting an operando experiment that combines these techniques, it is demonstrated that the spatial evolution of catalytic ignition over Pd(100) during CO oxidation at higher pressures is driven by localized gas conditions, highlighting the importance of 2D gas-phase measurements when studying model catalysts under high-pressure conditions.
Article
Chemistry, Physical
Kevin Ruwisch, Tobias Pohlmann, Florian Bertram, Christoph Schlueter, Andrei Gloskovskii, Karsten Kuepper, Joachim Wollschlaeger
Summary: In this work, we conducted a comprehensive study on real-time monitoring of the growth of epitaxial CoxFe3-xO4 thin films. Through time resolved operando HAXPES technique, we observed different growth characteristics under different oxygen partial pressures, including metallic, light oxidic, and cobalt ferrite-like growth.
Article
Chemistry, Multidisciplinary
Alessandro Greco, Vladimir Starostin, Evelyn Edel, Valentin Munteanu, Nadine Russegger, Ingrid Dax, Chen Shen, Florian Bertram, Alexander Hinderhofer, Alexander Gerlach, Frank Schreiber
Summary: This article demonstrates the optimized pipeline for automated analysis of reflectometry data using machine learning. The pipeline combines various training and data treatment techniques. The accurate predictions made by the neural network serve as good starting parameters for the subsequent data fitting.
JOURNAL OF APPLIED CRYSTALLOGRAPHY
(2022)
Article
Chemistry, Physical
Amit Kumar Chawla, Shikha Wadhwa, Arka Bikash Dey, Florian Bertram, Saif A. Khan, Ratnesh Pandey, Mukul Gupta, Vipin Chawla, Akula Umamaheswara Rao, D. K. Avasthi
Summary: This study focuses on the synthesis of Pd-Ag nano-composite films by magnetron cosputtering and the structural changes in the alloy film during hydrogenation and dehydrogenation processes. Synchrotron X-ray diffraction was used to reveal subtle structural changes occurring, showing that adding Ag to Pd can completely remove dissolved hydrogen. Lower concentrations of Ag in Pd exhibit better performance during hydrogenation/dehydrogenation processes.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Applied
Christopher Sauer, Guido J. L. de Reijer, Andreas Schaefer, Per-Anders Carlsson
Summary: The valorization of biomass-derived molecules into commodity chemicals is important for the transition to renewable feedstocks. The model platform molecule 2,5-dimethylfuran (2,5-dmf) can be converted into value-added aromatics such as benzene, toluene, and xylenes (BTX) over zeolite catalysts. Substituting gallium into the zeolite framework enhances benzene selectivity and resistance to deactivation in continuous catalytic performance tests.
TOPICS IN CATALYSIS
(2023)
Article
Instruments & Instrumentation
Ekaterina Kneschaurek, Alexander Hinderhofer, Bernd Hofferberth, Niels Scheffczyk, Linus Pithan, Paul Zimmermann, Lena Merten, Florian Bertram, Frank Schreiber
Summary: We present a compact sample environment for studying the kinetics of thin film crystallization on synchrotron beamlines, which includes atmospheric control, automated deposition, spin-coating, and annealing stages. The setup allows real-time investigation of thin film growth using grazing-incidence X-ray diffraction techniques. Sensors are used to detect humidity and oxygen levels. The spinning stage has low vertical oscillation amplitude and can be used for antisolvent application or gas quenching. Differential reflectance spectroscopy is implemented for analyzing thin film thickness and optical properties. The system can be controlled remotely by the control software at synchrotron beamlines.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Chemistry, Physical
Vikram Mehar, Helen Edstrom, Mikhail Shipilin, Uta Hejral, Chengjun Wu, Aravind Kadiri, Stefano Albertin, Benjamin Hagman, Kim von Allmen, Tim Wiegmann, Sebastian Pfaff, Jakub Drnec, Johan Zetterberg, Edvin Lundgren, Lindsay R. Merte, Johan Gustafson, Jason F. Weaver
Summary: The structures of oxide phases on metallic catalysts during reaction have a strong influence on the catalytic oxidation of CO and CH4. It has been found that an epitaxial PdO(100) structure forms on Pd(100) at temperatures above 600 K during the oxidation process. Additionally, the oxidation behavior of Pd(100) changes from forming epitaxial PdO(101) at 500 K to simultaneously growing epitaxial PdO(100) and PdO(101) at temperatures above 600 K, resulting in a thicker and rougher oxide layer. This change is attributed to a temperature-induced change in the stability of small PdO domains that initiate the oxidation process.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Applied
Mengqiao Di, Andreas Schaefer, Felix Hemmingsson, Tamsin Bell, Yanyue Feng, Magnus Skoglundh, David Thompsett, Per-Anders Carlsson
Summary: The influence of nitrogen oxide on the lean CO oxidation activity of Pt/ceria and Pt/alumina catalysts has been studied. It was found that nitrogen oxide can affect the activity of the catalysts, inhibit the oxidation reaction of ceria, and accelerate the accumulation of nitrates.
