Publications

@article{Sringam_2025a,

title = {Direct conversion of methane to value-added hydrocarbons using alkali metal-promoted cobalt catalysts},

author = {Sarannuch Sringam and Punyanut Thansiriphat and Thongthai Witoon and Waleeporn Donphai and Metta Chareonpanich and Chularat Wattanakit and Hiesang Sohn and Nevzat Yigit and Günther Rupprechter and Anusorn Seubsai},

doi = {10.1039/D5RA02408K},

year  = {2025},

date = {2025-07-07},

journal = {RSC Advances},

volume = {15},

issue = {28},

pages = {23103-23114},

abstract = {The oxidative coupling of methane (OCM) is a promising pathway for directly converting methane into higher hydrocarbons (C_{2+}). This research investigated the influence of alkali metal promoters (Li, Na, K, or Rb) on Co/Al_{2}O_{3} catalysts prepared based on incipient wetness impregnation for the OCM reaction. The catalyst investigations demonstrated that the catalysts promoted with K and Rb had superior performance, with the 4.6K–Co/Al_{2}O_{3} catalyst achieving a maximum C_{2+} yield of 8.1%, C_{2+} selectivity of 24.0%, and CH_{4} conversion of 32.1% at 640 °C. Catalyst characterization, based on XRD, HR-TEM, BET, XPS, CO_{2}-TPD, and H_{2}-TPR analyses, revealed the structural and physicochemical properties responsible for the enhanced catalytic activity. Specifically, K and Rb promoters increased surface basicity and enhanced the electron density of active sites, thereby promoting selective methane activation. In-situ DRIFTS and mechanistic studies highlighted the role of reactive oxygen species in promoting C_{2+} hydrocarbon formation. These results should position K–Co/Al_{2}O_{3} as a promising catalyst for OCM and provide valuable guidance for designing more efficient catalytic systems for methane utilization.},

keywords = {P08},

pubstate = {published},

tppubtype = {article}

}

@article{Phichairatanaphong_2025a,

title = {Calcium-Functionalized MgCeAl-Supported Nickel Catalysts for Enhancing Syngas Production via Dry Reforming},

author = {Orrakanya Phichairatanaphong and Nevzat Yigit and Thomas Wicht and Sanchai Kuboon and Thongthai Witoon and Günther Rupprechter and Metta Chareonpanich and Waleeporn Donphai},

doi = {10.1021/acs.iecr.5c00941},

year  = {2025},

date = {2025-06-18},

urldate = {2025-06-18},

journal = {Industrial & Engineering Chemistry Research},

volume = {64},

issue = {24},

pages = {11782–11793},

abstract = {The dry reforming reaction offers a promising pathway to transform CO_{2} and CH_{4} gases into H_{2} and CO, which serve as vital reactants and fuel gases in various industrial chemical processes. This research focused on the modification of Ni-based catalysts with alkaline earth metal for a dry reforming reaction. Nickel impregnated into mixed MgCeAl (MCA) oxide supports, tailored with calcium (Ca), was fabricated through a soft template-assisted coprecipitation technique, employing cetyltrimethylammonium chloride (CTAC) as the template. The calcium modification of MCA oxides supporting the nickel catalyst augmented the reducibility of nickel and intensified the interaction between nickel and the oxide support. In evaluating performance, Ni/0.3Ca-MCA catalyst demonstrated superior CH_{4} and CO_{2} conversions, an optimal H_{2}/CO ratio, and enhanced stability compared to other catalysts. This improvement can be attributed to the Ca addition, which likely enhances the basic sites on the catalyst, promoting CO_{2} adsorption and its simultaneous dissociation and thereby reducing coke formation.},

keywords = {P08},

pubstate = {published},

tppubtype = {article}

}

@article{Birschitzky_2024b,

title = {Machine Learning Small Polaron Dynamics},

author = {Viktor C. Birschitzky and Luca Leoni and Michele Reticcioli and Cesare Franchini},

url = {https://doi.org/10.1103/PhysRevLett.134.216301},

year  = {2025},

date = {2025-05-27},

urldate = {2024-09-24},

journal = {Physical Review Letters},

volume = {134},

issue = {21},

pages = {216301},

abstract = {Polarons are crucial for charge transport in semiconductors, significantly impacting material properties and device performance. The dynamics of small polarons can be investigated using first-principles molecular dynamics. However, the limited timescale of these simulations presents a challenge for adequately sampling infrequent polaron hopping events. Here, we introduce a message-passing neural network combined with first-principles molecular dynamics within the Born-Oppenheimer approximation that learns the polaronic potential energy surface by encoding the polaronic state, allowing for simulations of polaron hopping dynamics at the nanosecond scale. By leveraging the statistical significance of the long timescale, our framework can accurately estimate polaron (anisotropic) mobilities and activation barriers in prototypical polaronic oxides across different scenarios (hole polarons in rocksalt MgO and electron polarons in pristine and F-doped rutile TiO_{2}) within experimentally measured ranges.},

keywords = {P07},

pubstate = {published},

tppubtype = {article}

}

@article{Sokolovic_2025a,

title = {Duality and degeneracy lifting in two-dimensional electron liquids on SrTiO_{3}(001)},

author = {Igor Sokolović and Eduardo B. Guedes and Thomas P. van Waas and Fei Guo and Samuel Poncé and Craig Polley and Michael Schmid and Ulrike Diebold and Milan Radović and Martin Setvín and J. Hugo Dil},

url = {https://doi.org/10.1038/s41467-025-59258-4},

year  = {2025},

date = {2025-05-17},

journal = {Nature Communications},

volume = {16},

issue = {1},

pages = {4594},

abstract = {Two-dimensional electron liquids (2DELs) have increasing technological relevance for ultrafast electronics and spintronics, yet significant gaps in their fundamental understanding are exemplified on the prototypical SrTiO_{3}. We correlate the exact SrTiO_{3}(001) surface structure with distinct 2DELs through combined microscopic angle-resolved photoemission spectroscopy and non-contact atomic force microscopy on truly bulk-terminated surfaces that alleviate structural uncertainties inherent to this long-studied system. The SrO termination is shown to develop a 2DEL following the creation of oxygen vacancies, unlike the intrinsically metallic TiO_{2} termination. Differences in degeneracy of the 2DELs, with nearly the same band filling and identical band bending, are assigned to polar distortions of the Ti atoms in combination with spin order, supported with the extraction of fundamental electron-phonon coupling strength. These results not only resolve the ambiguities regarding 2DELs on SrTiO_{3} thus far, but also pave the way to manipulating band filling and spin order in oxide 2DELs in general.},

keywords = {P02},

pubstate = {published},

tppubtype = {article}

}

@article{Sringam_2024a,

title = {Effect of calcination temperature on the performance of K-Co/Al_{2}O_{3} catalyst for oxidative coupling of methane},

author = {Sarannuch Sringam and Thongthai Witoon and Chularat Wattanakit and Waleeporn Donphai and Metta Chareonpanich and Günther Rupprechter and Anusorn Seubsai},

url = {https://doi.org/10.1016/j.crcon.2024.100261},

doi = {10.1016/j.crcon.2024.100261},

issn = {2588-9133},

year  = {2025},

date = {2025-05-17},

urldate = {2024-05-28},

journal = {Carbon Resources Conversion},

volume = {8},

issue = {2},

pages = {100261},

abstract = {The oxidative coupling of methane (OCM) involves directly converting methane to C_{2+} hydrocarbons (such as ethylene and ethane) via a reaction with oxygen. This study elucidated the effect of the calcination temperature on the structure and catalytic performance of potassium-doped-cobalt oxide supported on an alumina (K-Co/Al_{2}O_{3}) catalyst for the OCM reaction. The catalyst was highly active at relatively low reactor temperatures (500–640 °C). Four calcination temperatures (400, 500, 600, and 700 °C) were investigated, with the results showing that the calcination temperature strongly affected catalytic properties, such as the crystalline phases, elemental distribution, physical properties, and catalytic basicity, leading to a wide range in catalytic performances. The catalyst calcined at 400 °C was superior among the catalysts, with 8.3 % C_{2+} yield, 24.8 % C_{2+} selectivity, and 33.6 % CH_{4} conversion at 640 °C. Furthermore, the catalyst was robust over 24 h of testing.},

keywords = {P08},

pubstate = {published},

tppubtype = {article}

}

@article{Tangpakonsab_2025a,

title = {Mechanistic Insights into CO and H_{2} Oxidation on Cu/CeO_{2} Single Atom Catalysts: A Computational Investigation},

author = {Parinya Tangpakonsab and Alexander Genest and Gareth S. Parkinson and Günther Rupprechter},

url = {https://doi.org/10.1007/s11244-025-02102-2},

doi = {10.1007/s11244-025-02102-2},

year  = {2025},

date = {2025-05-15},

urldate = {2025-05-15},

journal = {Topics in Catalysis},

abstract = {Single atom catalysts (SACs) have attracted significant interest due to their unique properties and potential for enhancing catalytic performance in various chemical reactions. In this study, we atomistically explore adsorption properties and catalytic performance of single Cu atoms anchored at low-index CeO_{2} surfaces, focusing on the oxidation of CO and H_{2}. Utilizing density functional theory (DFT) calculations, we report that Cu adatoms bind favorably on different CeO_{2} surfaces, following a stability order of (100) > (110) > (111). The charge transfer from a single adsorbed Cu atom to Ce leads to the reduction of Ce^{4+} to Ce^{3+} and the oxidation of Cu^{0} to Cu^{+}. This strengthens molecular bonds at Cu sites, particularly for CO, while H_{2} shows a by ~ 1 eV weaker adsorption. CO oxidation is energetically more favorable than H_{2} oxidation on the Cu/CeO_{2}(111) surface. The rate-controlling steps for the Mars–van Krevelen mechanism involve the formation of a bent CO_{2} intermediate for CO and H_{2}O for H_{2}. The lattice oxygen atom at the interface plays a key role for both oxidation processes. Our findings highlight the potential of single atom catalyst, Cu/CeO_{2}, for selective CO adsorption and its subsequent oxidation in heterogeneous catalysis.},

keywords = {P04, P08},

pubstate = {published},

tppubtype = {article}

}

@article{Coretti2022,

title = {Learning Mappings between Equilibrium States of Liquid Systems Using Normalizing Flows},

author = {Alessandro Coretti and Sebastian Falkner and Phillip Geissler and Christoph Dellago},

doi = {10.1063/5.0253034},

year  = {2025},

date = {2025-05-08},

urldate = {2022-08-22},

journal = {The Journal of Chemical Physics},

volume = {162},

issue = {18},

pages = {184102},

abstract = {Generative models and, in particular, normalizing flows are a promising tool in statistical mechanics to address the sampling problem in condensed-matter systems. In this work, we investigate the potential of normalizing flows to learn a transformation to map different liquid systems into each other while allowing at the same time to obtain an unbiased equilibrium distribution. We apply this methodology to the mapping of a small system of fully repulsive disks modeled via the Weeks–Chandler–Andersen potential into a Lennard-Jones system in the liquid phase at different coordinates in the phase diagram. We obtain an improvement in the relative effective sample size of the generated distribution up to a factor of six compared to direct reweighting. We show that this factor can have a strong dependency on the thermodynamic parameters of the source and target system.},

keywords = {P12},

pubstate = {published},

tppubtype = {article}

}

@article{Cao_2025a,

title = {Quantum Delocalization Enables Water Dissociation on Ru(0001)},

author = {Yu Cao and Jiantao Wang and Mingfeng Liu and Yan Liu and Hui Ma and Cesare Franchini and Yan Sun and Georg Kresse and Xing-Qiu Chen and Peitao Liu},

doi = {10.1103/PhysRevLett.134.178001},

year  = {2025},

date = {2025-04-30},

journal = {Physical Review Letters},

volume = {134},

issue = {17},

pages = {178001},

abstract = {We revisit the long-standing question of whether water molecules dissociate on the Ru(0001) surface through nanosecond-scale path-integral molecular dynamics simulations on a sizable supercell. This is made possible through the development of an efficient and reliable machine-learning potential with near first-principles accuracy, overcoming the limitations of previous ab initio studies. We show that the quantum delocalization associated with nuclear quantum effects enables rapid and frequent proton transfers between water molecules, thereby facilitating the water dissociation on Ru(0001). This work provides the direct theoretical evidence of water dissociation on Ru(0001), resolving the enduring issue in surface sciences and offering crucial atomistic insights into water-metal interfaces.},

keywords = {P03, P07},

pubstate = {published},

tppubtype = {article}

}

@article{Sokolovic_2024a,

title = {How to cleave cubic perovskite oxides},

author = {Igor Sokolović and Michael Schmid and Ulrike Diebold and Martin Setvín},

doi = {10.1063/5.0233747},

year  = {2025},

date = {2025-03-20},

urldate = {2025-03-20},

journal = {Review of Scientific Instruments},

volume = {96},

issue = {3},

pages = {035113},

abstract = {Surfaces of cubic perovskite oxides attract significant attention for their physical tunability and high potential for technical applications. Bulk-terminated surfaces are desirable for theoretical modeling and experimental reproducibility, yet there is a lack of methods for preparing such well-defined surfaces. We discuss a method for strain-assisted cleaving of perovskite single crystals, using a setup easily transferable between different experimental systems. The details of the cleaving device and the procedure were optimized in a systematic study on the model cubic perovskite oxide SrTiO_{3}. The large-area morphology and typical distribution of surface terminations on cleaved SrTiO_{3}(001) are presented, with specific guidelines on how to distinguish well-cleaved surfaces from conchoidally fractured ones. The cleaving is applicable to other cubic perovskites, as demonstrated on KTaO_{3}(001) and BaTiO_{3}(001). This approach opens up a pathway for obtaining high-quality surfaces of this promising class of materials.},

keywords = {P02},

pubstate = {published},

tppubtype = {article}

}

@article{Sombut_2025a,

title = {The surface phase diagram of Fe_{3}O_{4}(001) revisited},

author = {Panukorn Sombut and Matthias Meier and Moritz Eder and Thomas Angerler and Oscar Gamba and Michael Schmid and Ulrike Diebold and Cesare Franchini and Gareth S. Parkinson},

doi = {10.1039/D5LF00022J},

year  = {2025},

date = {2025-03-14},

urldate = {2025-03-14},

journal = {RSC Applied Interfaces},

volume = {2},

issue = {3},

pages = {673-683},

abstract = {Understanding how the physical and electronic structures of metal-oxide surfaces evolve under varying conditions is crucial for optimizing their performance in applications such as catalysis. In this study, we compute the surface phase diagram of the Fe_{3}O_{4}(001) facet using density functional theory (DFT)-based calculations, with an emphasis on understanding the terminations observed in surface science experiments. Our results reveal two stable terminations in addition to the subsurface cation vacancy (SCV) structure, which dominates under oxidizing conditions. The commonly reported octahedral Fe pair, also known as the Fe-dimer termination, is stable within an oxygen chemical potential range of −3.1 eV < μ_{O} < −2.3 eV. We identify the lowest-energy structure of this surface as the one proposed by J. R. Rustad, E. Wasserman and A. R. Felmy, A Molecular Dynamics Investigation of Surface Reconstruction on Magnetite (001), \textit{Surf. Sci.}, 1999, \textbf{432}, 1–2, where a tetrahedrally coordinated Fe_{A} atom is replaced by two octahedrally coordinated Fe_{B} atoms in the surface layer. This transformation serves as a precursor to the emergence of an FeO-like termination under highly reducing conditions. A key insight from our study is the importance of thoroughly sampling different charge-order configurations to identify the global minima across varying stoichiometries.},

keywords = {P02, P04, P07},

pubstate = {published},

tppubtype = {article}

}