A5039722442- Advanced Chemical Physics Studies
- Catalysis and Oxidation Reactions
- Zeolite Catalysis and Synthesis
- Photochemistry and Electron Transfer Studies
- Mass Spectrometry Techniques and Applications
- Catalytic Processes in Materials Science
- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Spectroscopy and Laser Applications
- Lignin and Wood Chemistry
- Catalysis and Hydrodesulfurization Studies
- Biochemical and biochemical processes
- Chemical Thermodynamics and Molecular Structure
- Catalysis for Biomass Conversion
- Atomic and Molecular Physics
- Laser-Matter Interactions and Applications
- Fermentation and Sensory Analysis
- Spectroscopy and Quantum Chemical Studies
- Ion-surface interactions and analysis
- Molecular Spectroscopy and Structure
- Inorganic Fluorides and Related Compounds
- Free Radicals and Antioxidants
- Analytical Chemistry and Chromatography
- Oxidative Organic Chemistry Reactions
- Environmental remediation with nanomaterials
Anhui Institute of Optics and Fine Mechanics
2019-2025
Chinese Academy of Sciences
2019-2025
Hefei Institutes of Physical Science
2024-2025
Shandong Marine Resource and Environment Research Institute
2025
Shandong University
2025
Paul Scherrer Institute
2019-2024
Hefei National Center for Physical Sciences at Nanoscale
2016-2024
University of Science and Technology of China
2005-2024
Hefei University
2017-2020
Collaborative Innovation Center of Chemistry for Energy Materials
2018-2019
Oxidative dehydrogenation of propane (ODHP) is an emerging technology to meet the global propylene demand with boron nitride (BN) catalysts likely play a pivotal role. It widely accepted that gas-phase chemistry plays fundamental role in BN-catalyzed ODHP. However, mechanism remains elusive because short-lived intermediates are difficult capture. We detect free radicals (CH3•, C3H5•) and reactive oxygenates, C2-4 ketenes C2-3 enols, ODHP over BN by operando synchrotron photoelectron photoion...
Resistively heated silicon carbide microreactors are widely applied as continuous sources to selectively prepare elusive and reactive intermediates with astrochemical, catalytic, or combustion relevance measure their photoelectron spectrum. These reactors also provide deep mechanistic insights into uni- bimolecular chemistry. However, the sampling conditions effects have not been fully characterized. We use cation velocity map imaging distribution of molecular beam signal quantify scattered,...
Unveiling catalytic mechanisms at a molecular level aids rational catalyst design and selectivity control for process optimization. In this study, we find that the Brønsted acid site density of zeolite efficiently controls guaiacol pyrolysis mechanism. Guaiacol demethylation to catechol initiates reaction, as evidenced by detected methyl radicals. The mechanism branches form either fulvenone (c-C5H4 = C O), reactive ketene intermediate, dehydration, or phenol acid-catalyzed dehydroxylation....
Ketene (CH
Formaldehyde, which is formed as the primary product from methanol, has a profound impact on distribution and catalyst deactivation in industrially-relevant methanol-to-hydrocarbons conversion.
Pyrolysis and low-temperature oxidation of dimethoxymethane (methylal, MeOCH2OMe) play an important role in the ignition blended diesel fuels, but underlying mechanisms are still debated. In these kinetic models, bimolecular hydrogen abstraction or unimolecular C–O bond fission considered as primary initial steps, while MeOCH2OMe isomerization is sometimes disregarded. this work, we investigate pyrolysis combining imaging photoelectron photoion coincidence spectroscopy with vacuum...
Abstract C1 coupling reactions over zeolite catalysts are central to sustainable chemical production strategies. However, questions persist regarding the involvement of CO in ketene formation, and impact this elusive oxygenate intermediate on reactivity patterns. Using operando photoelectron photoion coincidence spectroscopy (PEPICO), we investigate role methyl chloride conversion hydrocarbons (MCTH), a prospective process for methane valorization with reaction network akin methanol (MTH)...
The catalytic pyrolysis of guaiacol-based lignin monomers, vanillin, syringol, and eugenol over commercial HZSM-5 has been investigated using
The vacuum ultraviolet photoionization and dissociative of isomeric radicals, acetyl (CH3CO) vinoxy (CH2CHO), have been studied using synchrotron radiation double imaging photoelectron photoion coincidence (i2PEPICO) spectroscopy. Mass-selected threshold spectra (ms-TPES) corresponding to the parent cations (m/z = 43, CH3CO+ CH2CHO+) their fragment ions 15, CH3+) are measured assigned based on theoretical calculations. first second bands ms-TPES m/z 43 mainly unstructured due large molecular...
We reveal dechlorination channels and pathways to olefins aromatics in the catalytic pyrolysis of polyvinylchloride (PVC) model compound 1,3‐dichlorobutane by operando photoelectron photoion coincidence (PEPICO) spectroscopy. Experimental computational results agree that primary pathway involves double dehydrochlorination producing 1,3‐butadiene HCl. Minor radical are evidenced detection chloromethyl, methyl, propargyl radicals thermal decomposition, while chlorine absent. HZSM‐5 zeolites...
The dissociation of internal energy selected dimethyl carbonate (DMC) cations was studied by imaging photoelectron photoion coincidence spectroscopy (iPEPICO) in the 10.3-12.5 eV photon range. Vibrational fine structure is observed ground state band threshold spectrum up to threshold, and Franck-Condon simulations identify O-C-O bend mode, particular combination with C═O stretch be active. DMC ionization determined 10.47 ± 0.01 eV. first dissociative photoionization product, CH2OH+,...
The Active Thermochemical Tables (ATcT) yield 8.477 ± 0.007 eV as the ionization energy of vinyl radical, which agrees with wave function theory results. photoionization spectrum yielded 8.59 0.03 eV, while photoelectron 8.25 0.05 for adiabatic energy. In order to reconcile these contradictory measurements, we produced radical by flash pyrolysis divinyl sulfone, and recorded its (PI) threshold (TPE) in 8.10-10.45 photon range at Swiss Light Source first time using double imaging photoion...
Abstract Ketene (CH 2 =C=O) has been postulated as a key intermediate for the first olefin production in zeolite‐catalyzed chemistry of methanol‐to‐olefins (MTO) and syngas‐to‐olefins (STO) processes. The reaction mechanism remains elusive, because short‐lived ethenone ketene its derivatives are difficult to detect, which is further complicated by low expected concentration. We report on experimental detection methylketene 3 −CH=C=O) formed methylation HZSM‐5 via operando synchrotron...
Photoionization and dissociative photoionization of acetaldehyde (CH
We studied the thermal decomposition of vanillin in a low-pressure pyrolysis microreactor by photoelectron photoion coincidence spectroscopy. The products were identified isomer-selectively mass-selected threshold spectra (ms-TPES) based on Franck–Condon simulations and reference spectra. Methyl loss homolytic C–O bond fission methoxy group is initial unimolecular step. primary intermediate, 2-hydroxy-5-formyl-phenoxy radical (m/z 137), may undergo multiple decarbonylation steps lose...
PEPICO determines conformer-dependent ionization energies and unveils the fragmentation mechanism of C<sub>6</sub>H<sub>11</sub>F<sup>+</sup>.
Threshold photoelectron-photoion coincidence (TPEPICO) is a powerful method to prepare and analyze internal energy- or state-selected ions. Here, we review the state-of-the-art TPEPICO imaging technique combining with tunable vacuum ultraviolet (VUV) synchrotron radiation its recent applications at Hefei Light Source (HLS), especially on fundamental data measurement dissociation dynamics of By applying double velocity map for both electrons ions in coincidence, collection efficiency charged...
We studied the valence photoionization of vanillin by photoelectron photoion coincidence spectroscopy in 8.20–19.80 eV photon energy range. Vertical ionization energies EOM-IP-CCSD calculations reproduce spectral features. Composite method and Franck–Condon simulation weak, ground-state band yield adiabatic most stable conformer as 8.306(20) eV. The lowest dissociative channels correspond to hydrogen atom, carbon monoxide, methyl losses, which form dominant C8H7O3+ (m/z 151) less intense...
The threshold photoelectron spectrum (TPES) of halocyclohexanes C6H11X (X = Cl, Br, and I) was recorded at the Swiss Light Source assigned with help density functional theory equation-of-motion ionization potential coupled cluster calculations. Dyson orbitals show that first two electronic states cation arise by symmetry breaking doubly degenerate eg in cyclohexane as perturbed halogen or perturbation lone pair ring scaffold case light heavy substituents, respectively. When resulting (A″ A′)...
The thermal decomposition of the three anisaldehyde isomers was studied by photoelectron photoion coincidence spectroscopy. pyrolysis products were identified isomer-selectively their mass-selected threshold spectrum in comparison to reference spectra. C–O bond fission at methoxy group generates methyl and aldehyde phenoxy radicals initial fragmentation step for all isomers. For para meta isomers, these can produce either 1-formyl-2,4-cyclopentadiene-1-yl radical or low-energy removal CO...
The N-NO bond fission of N
The dissociative photoionization of CF3Cl was investigated in the photon energy range 12.30-18.50 eV. low-lying electronic states CF3Cl+ cations were prepared by method threshold photoelectron-photoion coincidence (TPEPICO). photoelectron spectrum and coincident time-of-flight mass spectra at specific energies recorded. Only a CF3+ fragment observed lower energy, while CF2Cl+ appeared for C2E D2E states. As Cl-loss from ground ionic state is statistical, total kinetic release distribution...