Xiangkun Wu
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View article: Facile Decarbonylation Suppresses the <i>Ortho</i> Effect and Ketene Formation in the Catalytic Pyrolysis of Substituted Benzaldehyde Lignin Model Compounds
Facile Decarbonylation Suppresses the <i>Ortho</i> Effect and Ketene Formation in the Catalytic Pyrolysis of Substituted Benzaldehyde Lignin Model Compounds Open
Ketene intermediates lead to branching and lower phenol selectivities in the catalytic pyrolysis of lignin model compounds, which makes understanding their formation mechanism key to enable targeted process optimization. While gas-phase py…
View article: Vacuum ultraviolet photoionization and dissociative photoionization of acetyl (CH3CO) and vinoxy (CH2CHO) radicals
Vacuum ultraviolet photoionization and dissociative photoionization of acetyl (CH3CO) and vinoxy (CH2CHO) radicals Open
The vacuum ultraviolet photoionization and dissociative photoionization of isomeric radicals, acetyl (CH3CO) and vinoxy (CH2CHO), have been studied using synchrotron radiation double imaging photoelectron photoion coincidence (i2PEPICO) sp…
View article: Pathways to Aromatics in the Catalytic Pyrolysis of a Polyvinylchloride Model Compound Revealed by Operando Photoelectron Photoion Coincidence Spectroscopy
Pathways to Aromatics in the Catalytic Pyrolysis of a Polyvinylchloride Model Compound Revealed by Operando Photoelectron Photoion Coincidence Spectroscopy Open
Dechlorination channels and pathways to olefins and aromatics in the catalytic pyrolysis of the polyvinylchloride (PVC) model compound 1,3‐dichlorobutane are revealed using operando photoelectron photoion coincidence (PEPICO) spectroscopy.…
View article: A review of the development of miniature mass spectrometry for planetary exploration
A review of the development of miniature mass spectrometry for planetary exploration Open
Over the past five decades, miniature mass spectrometry plays a crucial role in planetary exploration, offering the sensitivity, resolution and precision required to analyze elements and isotopes, detect trace gases, and study the composit…
View article: A solution for 4-propylguaiacol hydrodeoxygenation without ring saturation
A solution for 4-propylguaiacol hydrodeoxygenation without ring saturation Open
View article: Photoionization and Dissociative Photoionization of Acetaldehyde in the 10.0–13.7 eV Range by Synchrotron Photoelectron Photoion Coincidence Spectroscopy
Photoionization and Dissociative Photoionization of Acetaldehyde in the 10.0–13.7 eV Range by Synchrotron Photoelectron Photoion Coincidence Spectroscopy Open
Photoionization and dissociative photoionization of acetaldehyde (CH 3 CHO) in the 10.0–13.7 eV energy range are studied by using synchrotron radiation double imaging photoelectron photoion coincidence spectroscopy (i 2 PEPICO). The X 2 A′…
View article: CO Cofeeding Affects Product Distribution in CH<sub>3</sub>Cl Coupling over ZSM‐5 Zeolite: Pressure Twists the Plot
CO Cofeeding Affects Product Distribution in CH<sub>3</sub>Cl Coupling over ZSM‐5 Zeolite: Pressure Twists the Plot Open
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 the impact of this elusive oxygenate intermediate o…
View article: CO Cofeeding Affects Product Distribution in CH<sub>3</sub>Cl Coupling over ZSM‐5 Zeolite: Pressure Twists the Plot
CO Cofeeding Affects Product Distribution in CH<sub>3</sub>Cl Coupling over ZSM‐5 Zeolite: Pressure Twists the Plot Open
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 the impact of this elusive oxygenate intermediate o…
View article: The formation, reactivity and transformation pathways of formaldehyde in the methanol-to-hydrocarbon conversion
The formation, reactivity and transformation pathways of formaldehyde in the methanol-to-hydrocarbon conversion Open
Formaldehyde, which is formed as the primary product from methanol, has a profound impact on product distribution and catalyst deactivation in the industrially-relevant methanol-to-hydrocarbons conversion.
View article: Catalytic pyrolysis mechanism of lignin moieties driven by aldehyde, hydroxyl, methoxy, and allyl functionalization: the role of reactive quinone methide and ketene intermediates
Catalytic pyrolysis mechanism of lignin moieties driven by aldehyde, hydroxyl, methoxy, and allyl functionalization: the role of reactive quinone methide and ketene intermediates Open
The complex catalytic pyrolysis mechanism of key lignin monomers demonstrates how functional groups dictate product pathways, revealing insights to enhance desired chemical yields and minimize catalyst deactivation.
View article: Enlightening salt: enthalpy of formation of gaseous sodium chloride by photoelectron photoion coincidence spectroscopy
Enlightening salt: enthalpy of formation of gaseous sodium chloride by photoelectron photoion coincidence spectroscopy Open
An in-vacuum flash pyrolysis microreactor was used to seed a molecular beam with gaseous sodium chloride. The vapour was ionised with tuneable synchrotron vacuum ultraviolet radiation to determine the 0 K appearance energy of the sodium ca…
View article: Beyond vanilla: The dissociation mechanism of vanillin in four charge states
Beyond vanilla: The dissociation mechanism of vanillin in four charge states Open
We compare the unimolecular decay mechanism of vanillin in four charge states. The unimolecular thermal decomposition of the neutral and dissociative ionization reactions in the cation have already been addressed in synchrotron-based photo…
View article: Photoion Mass-Selected Threshold Photoelectron Spectroscopy to Detect Reactive Intermediates in Catalysis: From Instrumentation and Examples to Peculiarities and a Database
Photoion Mass-Selected Threshold Photoelectron Spectroscopy to Detect Reactive Intermediates in Catalysis: From Instrumentation and Examples to Peculiarities and a Database Open
Photoion mass-selected threshold photoelectron spectroscopy (ms-TPES) is a synchrotron-based, universal, sensitive, and multiplexed detection tool applied in the areas of catalysis, combustion, and gas-phase reactions. Isomer-selective vib…
View article: On the origin of initial hydrocarbons in methanol-to-hydrocarbons reaction
On the origin of initial hydrocarbons in methanol-to-hydrocarbons reaction Open
View article: Tuning the zeolite acidity enables selectivity control by suppressing ketene formation in lignin catalytic pyrolysis
Tuning the zeolite acidity enables selectivity control by suppressing ketene formation in lignin catalytic pyrolysis Open
View article: Selective conversion of methanol to monocyclic aromatics via catalysis relay
Selective conversion of methanol to monocyclic aromatics via catalysis relay Open
View article: Unraveling Radical and Oxygenate Routes in the Oxidative Dehydrogenation of Propane over Boron Nitride
Unraveling Radical and Oxygenate Routes in the Oxidative Dehydrogenation of Propane over Boron Nitride Open
Oxidative dehydrogenation of propane (ODHP) is an emerging technology to meet the global propylene demand with boron nitride (BN) catalysts likely to play a pivotal role. It is widely accepted that gas-phase chemistry plays a fundamental r…
View article: A direct liquid sampling interface for photoelectron photoion coincidence spectroscopy
A direct liquid sampling interface for photoelectron photoion coincidence spectroscopy Open
We introduce an effective and flexible high vacuum interface to probe the liquid phase with photoelectron photoion coincidence (liq-PEPICO) spectroscopy at the vacuum ultraviolet (VUV) beamline of the Swiss Light Source. The interface comp…
View article: Frontispiz: Ketenes in the Induction of the Methanol‐to‐Olefins Process
Frontispiz: Ketenes in the Induction of the Methanol‐to‐Olefins Process Open
Heterogene Katalyse. In ihrer Zuschrift (e202207777) nutzen Patrick Hemberger et al. PEPICO-Spektroskopie zur Identifizierung von Keten- und Methylketen-Intermediaten in der Methylacetat-Umwandlung über HZSM-5-Zeolith.
View article: Frontispiece: Ketenes in the Induction of the Methanol‐to‐Olefins Process
Frontispiece: Ketenes in the Induction of the Methanol‐to‐Olefins Process Open
Heterogeneous Catalysis. In their Communication (e202207777), Patrick Hemberger et al. employed PEPICO spectroscopy to identify ketene and methylketene intermediates in methyl acetate conversion over the HZSM-5 zeolite.
View article: Ketenes in the Induction of the Methanol‐to‐Olefins Process
Ketenes in the Induction of the Methanol‐to‐Olefins Process Open
Ketene (CH 2 =C=O) has been postulated as a key intermediate for the first olefin production in the zeolite‐catalyzed chemistry of methanol‐to‐olefins (MTO) and syngas‐to‐olefins (STO) processes. The reaction mechanism remains elusive, bec…
View article: Ketenes in the Induction of the Methanol‐to‐Olefins Process
Ketenes in the Induction of the Methanol‐to‐Olefins Process Open
Ketene (CH 2 =C=O) has been postulated as a key intermediate for the first olefin production in the zeolite‐catalyzed chemistry of methanol‐to‐olefins (MTO) and syngas‐to‐olefins (STO) processes. The reaction mechanism remains elusive, bec…
View article: A plethora of isomerization processes and hydrogen scrambling in the fragmentation of the methanol dimer cation: a PEPICO study
A plethora of isomerization processes and hydrogen scrambling in the fragmentation of the methanol dimer cation: a PEPICO study Open
Photoelectron photoion coincidence reveals two new dissociative ionization channels in the methanol dimer, including C–C bond formation, and establishes the H-scrambling mechanism by partial deuteration.
View article: Unimolecular thermal decarbonylation of vanillin stifled by the bimolecular reactivity of methyl-loss intermediate
Unimolecular thermal decarbonylation of vanillin stifled by the bimolecular reactivity of methyl-loss intermediate Open
We studied the thermal decomposition of vanillin in a low-pressure pyrolysis microreactor by photoelectron photoion coincidence spectroscopy. The pyrolysis products were identified isomer-selectively by photoion mass-selected threshold pho…
View article: Neutrophil-to-Lymphocyte Ratio Better Than High-Sensitivity C-Reactive Protein in Predicting Stroke-Associated Pneumonia in Afebrile Patients
Neutrophil-to-Lymphocyte Ratio Better Than High-Sensitivity C-Reactive Protein in Predicting Stroke-Associated Pneumonia in Afebrile Patients Open
We found that compared with hs-CRP, NLR was significantly associated with the occurrence of SAP in patients with AIS without fever and showed a more effective predictive value for SAP.
View article: Characterisation of the first electronically excited state of protonated acetylene C<sub>2</sub>H<sub>3</sub><sup>+</sup> by coincident imaging photoelectron spectroscopy
Characterisation of the first electronically excited state of protonated acetylene C<sub>2</sub>H<sub>3</sub><sup>+</sup> by coincident imaging photoelectron spectroscopy Open
We present a combined experimental and theoretical study of the threshold photoelectron spectroscopy of the vinyl radical encompassing the first triplet excited state of the vinyl cation. The radicals were produced in a flow-tube reactor b…
View article: Hydrogen migration as a potential driving force in the thermal decomposition of dimethoxymethane: New insights from pyrolysis imaging photoelectron photoion coincidence spectroscopy and computations
Hydrogen migration as a potential driving force in the thermal decomposition of dimethoxymethane: New insights from pyrolysis imaging photoelectron photoion coincidence spectroscopy and computations Open
Pyrolysis and low-temperature oxidation of dimethoxymethane (methylal, MeOCH2OMe) play an important role in the ignition of blended diesel fuels, but the underlying mechanisms are still debated. In these kinetic models, bimolecu…
View article: Dissociation dynamics of energy-selected ions using threshold photoelectron-photoion coincidence velocity imaging
Dissociation dynamics of energy-selected ions using threshold photoelectron-photoion coincidence velocity imaging Open
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 ultrav…
View article: Pyrolysis of n-butane investigated using synchrotron threshold photoelectron photoion coincidence spectroscopy
Pyrolysis of n-butane investigated using synchrotron threshold photoelectron photoion coincidence spectroscopy Open
Synchrotron TPEPICO and a flash pyrolysis micro-reactor were utilized to investigate thermal decomposition of n-butane and its reaction mechanisms were revealed.