Article
Chemistry, Physical
Selwyn Hanselman, Federico Calle-Vallejo, Marc T. M. Koper
Summary: Surface platinum hydride structures on Pt(111) play a potentially important role in electrocatalysis and cathodic corrosion. Using thermodynamic methods and density functional theory, multiple surface hydride structures on Pt(111) were compared. These structures contain multiple monolayers of hydrogen that can bind subsurface or reconstruct the surface. Stable configurations share one monolayer of subsurface H stacking between the top two Pt layers. Our work provides insight into the operando surface state during low-potential reduction reactions on Pt(111) and shows a plausible precursor for cathodic corrosion.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Stephen Massicot, Tomoya Sasaki, Matthias Lexow, Sunghwan Shin, Florian Maier, Susumu Kuwabata, Hans-Peter Steinruck
Summary: The study focuses on the adsorption, wetting, growth, and thermal evolution of protic IL on Au(111) and Ag(111), revealing different behaviors on the two surfaces with the [dema][TfO] compound.
Article
Nanoscience & Nanotechnology
Sila Alemdar, Aleyna Basak, Onder Metin
Summary: In this study, binary red phosphorus/graphitic carbon nitride heterojunctions decorated with Pt nanoparticles were fabricated, showing improved photophysical properties compared to the pristine components. The incorporation of Pt NPs further improved the optical properties and enabled a high hydrogen gas generation rate under visible light irradiation. The interaction between Pt NPs and red phosphorus in the ternary heterojunction was found to be more favorable than that with graphitic carbon nitride. The band alignment and charge carrier flow of the ternary heterojunction catalyst were also studied. The mechanism of the photo-assisted hydrogen production from ammonia borane was proposed to involve both traditional B-N bond dissociation and the oxidizing action of OH radicals formed by the heterojunction photocatalyst.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Mengran Wang, Yongchul Kim, Liyuan Zhang, Won Kyung Seong, Minhyeok Kim, Shahana Chatterjee, Meihui Wang, Yunqing Li, Pavel Bakharev, Geunsik Lee, Sun Hwa Lee, Rodney S. Ruoff
Summary: This study reports the growth of amorphous carbon nanowalls on home-made Cu(111) foil using molten salt electrolytes and a carbonate carbon source, and investigates how the structure of the nanowalls can be controlled by varying electrolysis parameters.
Article
Chemistry, Physical
Merve Aksoy, Sibel Eken Korkut, Onder Metin
Summary: The enhancement of catalytic activity of Pt-based nanocatalysts in the hydrolysis of ammonia borane (AB) was achieved through in-situ synthesis of bimetallic AuPt alloy nanoparticles. The synergistic effects aroused in the AuPt alloy nanoparticles and heterojunctions formed between gCN and AuPt alloy nanoparticles contributed to the higher catalytic activity. The improved charge kinetics, higher light absorption, and effective electron transfer channels were found to be the key factors for the boosted catalytic activity.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Minoo Tasbihi, Fernando Fresno, Ignacio Alvarez-Prada, Amitava Acharjya, Arne Thomas, Lluis Escriche, Nuria Romero, Xavier Sala, Victor A. de la Pena O'Shea, Jordi Garcia-Anton
Summary: Platinum nanoparticles were directly synthesized onto mesoporous graphitic carbon nitride semiconductor through the organometallic approach, showing improved selectivity in photocatalytic CO2 reduction and contributing to the development of direct solar-to-chemical energy conversion technology.
JOURNAL OF CO2 UTILIZATION
(2021)
Article
Chemistry, Physical
Yu Wang, Meng-Ting Chen, Xin Ye, Ai-Jun Wang, Gao-Mei Tu, Lu Zhang, Jiu-Ju Feng
Summary: The study successfully synthesized a highly efficient and stable electrocatalyst for oxygen reduction reaction (ORR), which exhibited excellent activity and durability in alkaline environment. The results provide valuable guidelines for the development of advanced transition metal-based carbon catalysts in energy storage and conversion devices.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Xiaoting Chen, Marc T. M. Koper
Summary: Using in situ electrochemical atomic force microscopy (EC-AFM), we observed that the presence of Na+ cations is necessary to trigger cathodic etching of polycrystalline Pt electrode; during cathodic corrosion, the surface structure of single-crystalline Pt electrode undergoes significant changes, resulting in a highly roughened surface.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Multidisciplinary Sciences
Alex Inayeh, Ryan R. K. Groome, Ishwar Singh, Alex J. Veinot, Felipe Crasto de Lima, Roberto H. Miwa, Cathleen M. Crudden, Alastair B. McLean
Summary: N-heterocyclic carbenes (NHCs) have emerged as a promising alternative to sulfur-based ligands for self-assembly on gold surfaces, but there are still many unanswered questions about their behavior on surfaces. This study examines fundamental questions such as NHC orientation, mobility, and self-assembly by analyzing NHC overlayers on Au(111).
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Alex Sandre Kilian, Guilherme Jean Abreu, Abner de Siervo, Richard Landers, Jonder Morais
Summary: This work presents a comprehensive investigation of the surface atomic structure of a Pt/Cr2O3/Ag(111) model catalyst. The Pt/Cr2O3 model system was achieved using molecular beam epitaxy (MBE), and in situ characterization techniques including X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED), and X-ray photoelectron diffraction (XPD) were performed to probe the properties of its outermost layers. The results from XPD, along with simulations, suggest the formation of Pt nanoislands on the Cr2O3/Ag(111) surface, consisting of three Pt monolayer thick clusters with structural variations in their interatomic layer distances. This atomic rearrangement may explain the observed high reactivity in heterogeneous catalysts containing Pt nanoparticles on oxide substrates.
Article
Chemistry, Multidisciplinary
Bogdan Jurca, Lu Peng, Ana Primo, Alvaro Gordillo, Amarajothi Dhakshinamoorthy, Vasile Parvulescu, Hermenegildo Garcia
Summary: This study investigates the influence of metallic and non-metallic elements on the catalytic activity of Co-Fe@C catalysts. Pd enhances CO2 conversion and CH4 selectivity, while Ce reduces CO selectivity. The presence of Ca remarkably increases CO2 conversion and CH4 selectivity, while sulfur acts as a strong poison. The combination of sulfur and alkali metals maintains selectivity and increases conversion.
Article
Chemistry, Physical
Kalli Sai Bhavani, Tummala Anusha, Pradeep Kumar Brahman
Summary: This study presents an eco-friendly route to design and synthesize a novel nanocomposite catalyst based on platinum nanoparticles anchored on a binary support. The catalyst showed greatly enhanced electrooxidation of butanol and holds promising potential applications for high-performance alkaline fuel cells.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Multidisciplinary
Nigel J. Mason, Maria Pintea, Istvan Csarnovics, Tamas Fodor, Zita Szikszai, Zsofia Kertesz
Summary: The focused electron beam-induced deposition (FEBID) process using a GeminiSEM with a beam characteristic of 1 keV and 24 pA was employed to deposit pillars and line-shaped nanostructures, with heights ranging from 9 nm to 1 μm and widths from 5 nm to 0.5 μm. The composition of all structures was analyzed, with a desired Si/O/C content ratio of 1:2:0. It was found that the older deposits had C content over 60% when stored in air (at room temperature), while deposits aged only 12 hours had less than 50% C content. When Si(OEt)4 was deposited at high rates and under 0°C, the obtained Si content in the structures ranged from 10 to 15 atom % (compositional percentage). The FEBID structures were deposited on Au(111)/SiO2, with Au(111) chosen as a substrate due to its structural and morphological properties. The behavior of Au(111) surface during Si(OEt)4 deposition showed an increase in O ratio and a reduction in nanodeposit heights.
Article
Chemistry, Physical
Xi Dong, Tuan Anh Pham, Chunqiang Xu, Yining He, Wei Lai, Xianglin Ke, Pengpeng Zhang
Summary: In this study, the growth and electronic properties of SnSe2 films on the 3 x 3 reconstructed (111)-oriented SrTiO(3) surface were investigated using scanning tunneling microscopy/spectroscopy. A coverage-dependent growth mode, which is correlated with the spatial distribution of the electronic properties of SnSe2 films, was identified. It was also demonstrated that interfacial modification using a van der Waals-layered material of low work function (1T-WSe2) effectively alters the growth and electronic structures of SnSe2.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Lei Huang, Ya-Qiong Su, Ruijuan Qi, Dai Dang, Yanyang Qin, Shibo Xi, Shahid Zaman, Bo You, Shujiang Ding, Bao Yu Xia
Summary: Integrated fabrication of porous Pt-rich alloy encapsulated by graphitic carbon via integration engineering exhibits optimized reaction pathway and improved oxygen reduction reaction performance. The hybrid catalyst outperforms commercial Pt/C catalyst in full-cell assessment, attributed to the mutual assistance between porous Pt alloy and Co-N-C.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Multidisciplinary Sciences
Marti Lopez, Kai S. Exner, Francesc Vines, Francesc Illas
Summary: MXenes, a new family of 2D carbides and nitrides, have shown promise in electrocatalysis. The surface terminations of MXenes play a crucial role in their electrocatalytic performance and can change depending on reaction conditions. Experimental determination of Pourbaix diagrams can be challenging, but first-principles studies provide reliable insights. This study provides Pourbaix diagrams for representative MXenes and discusses their implications for theoretical electrocatalysis studies and experiments.
ADVANCED THEORY AND SIMULATIONS
(2023)
Article
Chemistry, Physical
David Vazquez-Parga, Anabel Jurado, Alberto Roldan, Francesc Vines
Summary: The adsorption and dissociation behaviors of carbon monoxide (CO) on 81 different transition metal surfaces were studied using density functional theory calculations. The study found that late-stage face-centered cubic transition metals weakly adsorb CO perpendicularly, while early-stage body-centered cubic transition metals have strong adsorption capacity. The d-band center was identified as the most effective descriptor for predicting the adsorption and co-adsorption behavior of CO, as well as activation energies.
APPLIED SURFACE SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
B. Moses Abraham, Oriol Pique, Mohd Aamir Khan, Francesc Vines, Francesc Illas, Jayant K. Singh
Summary: Fusing high-throughput quantum mechanical screening techniques with modern artificial intelligence strategies has the potential to revolutionize catalyst discovery. In this study, this strategy was applied to identify key descriptors for CO2 activation on two-dimensional transition metal (MXenes) carbides/nitrides. Machine learning models were developed and the random forest regressor scheme exhibited the best predictive performance with mean absolute errors of 0.16 ± 0.01 and 0.42 ± 0.06 eV for training and test data sets, respectively. Key descriptors for CO2 activation were identified as d-band center (ε(d)), surface metal electronegativity (χ(M)), and valence electron number of metal atoms (M (V)).
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Marti Lopez, Kai S. Exner, Francesc Vines, Francesc Illas
Summary: Both experimental and theoretical studies have shown that the MXene family has promising capabilities for the hydrogen evolution reaction (HER). However, the theoretical approach has relied on thermodynamic descriptors, while experimental studies have focused on kinetic information. This study aims to bridge the gap between theory and experiments by exploring HER pathways on V2C (0001) MXene and constructing free-energy diagrams to simulate Tafel plots. The results suggest that the V2C-H surface is kinetically favorable for the HER.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Elena M. Slavinskaya, Andrey I. Stadnichenko, Jon E. Quinlivan Dominguez, Olga A. Stonkus, Mykhailo Vorokhta, Bretislav Smid, Pablo Castro-Latorre, Albert Bruix, Konstantin M. Neyman, Andrei I. Boronin
Summary: Pt/CeO2 catalysts were characterized under reductive and oxidative pre-treatments and CO oxidation reaction conditions. Metallic Pt particles were found to be precursors for the formation of more stable PtOx particles that exhibit catalytic activity for CO oxidation below room temperature. These findings highlight the complex response of catalytic materials to reaction conditions and suggest potential strategies for improving Pt/CeO2 and similar catalysts.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Carlos Jimenez-Orozco, Elizabeth Florez, Francesc Vines, Jose A. Rodriguez, Francesc Illas
Summary: The ethylene hydrogenation catalyzed by MoCy nanoparticles was studied using density functional theory methods and several models. The effect of hydrogen coverage was examined in detail, and it was found that ethylene hydrogenation is feasible on specific MoCy nanostructures under different hydrogen coverages. The results also showed that C2H4 adsorption is feasible in a certain temperature and pressure range. The findings provide insights into the catalytic behavior of MoCy catalysts and offer a basis for future experimental studies.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Nestor Garcia-Romeral, Angel Morales-Garcia, Francesc Vines, Iberio de P. R. Moreira, Francesc Illas
Summary: The electronic ground state of Ti2C MXene was determined using density functional theory calculations, showing a magnetic ground state with antiferromagnetically coupled ferromagnetic layers. A spin model consistent with the nature of the chemical bond was presented, and the relevant magnetic coupling constants were extracted from energy differences using a mapping approach. The estimated Neel temperature is approximately 220 +/- 30 K, suggesting potential applications in spintronics and related fields.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Angel Morales-Garcia, Francesc Vines, Carmen Sousa, Francesc Illas
Summary: This Perspective provides a road map for computational heterogeneous photocatalysis, emphasizing the knowledge required to enhance the design of efficient photocatalysts. A plausible computational framework is suggested, focusing on the static and dynamic properties of relevant excited states and the involved chemistry in the reactions of interest. The road map involves explicitly exploring the nature of charge carriers, the excited-state potential energy surface, and its time evolution. Excited-state descriptors are introduced to locate and characterize the electrons and holes generated upon excitation. Nonadiabatic molecular dynamics simulations are proposed as a convenient tool to describe the time evolution of the photogenerated species and their propagation through the crystalline structure of the photoactive material, ultimately providing information about the charge carrier lifetime. Finally, it is claimed that a detailed understanding of the mechanisms of heterogeneously photocatalyzed reactions requires the analysis of the excited-state potential energy surface.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Multidisciplinary Sciences
Junsic Cho, Taejung Lim, Haesol Kim, Ling Meng, Jinjong Kim, Seunghoon Lee, Jong Hoon Lee, Gwan Yeong Jung, Kug-Seung Lee, Francesc Vines, Francesc Illas, Kai S. Exner, Sang Hoon Joo, Chang Hyuck Choi
Summary: Platinum single-atom catalysts show potential in heterogeneous electrocatalysis. The chemical nature of active Pt sites is not well understood, leading to discrepancies between experiments and theories. In this study, low-coordinated Pt-II species on carbon-based Pt single-atom catalysts were identified and found to play a critical role in the chlorine evolution reaction. This research offers guidelines for achieving high electrocatalytic performance in carbon-based single-atom catalysts.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Francesc Vines, Adria Calzada, Pablo Gamallo
Summary: Different nano-engineered grazynes were studied as membranes for separating methane and carbon dioxide. The study investigated the thermodynamics, kinetics, and dynamics of the process and compared the materials to others in the literature. The results showed that grazynes have low adsorption energy and diffusion energy barriers, making them excellent membranes for biogas upgrading with improved selectivity and larger quantity of separated CO2 per material gram.
JOURNAL OF CO2 UTILIZATION
(2023)
Article
Chemistry, Physical
Nestor Garcia-Romeral, Angel Morales-Garcia, Francesc Vines, Iberio de P. R. Moreira, Francesc Illas
Summary: The magnetic properties of Ti2C, Ti3C2, and Ti4C3 MXenes were studied using density functional theory. It was found that all MXenes exhibit magnetic behavior with antiferromagnetic coupling between the outer Ti layers. A spin model was proposed based on the analysis of the chemical bond, with diamagnetic Ti2+ ions in the inner layers and paramagnetic Ti+ centers on the surface. The magnetic coupling constants were found to depend on the functional used, with the nearest neighbor intralayer coupling always being ferromagnetic.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Diego Ontiveros, Francesc Vines, Carmen Sousa
Summary: MXene compounds, a newly discovered family of 2D materials, can become semiconductors and photoactive when their pristine surfaces are functionalized with an electronegative termination. This study uses density functional theory calculations to engineer the bandgap of a wide range of MXenes in order to find suitable materials for water splitting photocatalysis. The results suggest that Group III and IV MXenes are promising candidates for this application.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Chemistry, Physical
Ling Meng, Li-Kai Yan, Francesc Vines, Francesc Illas
Summary: This study investigates the surface composition and electrocatalytic mechanism of 2D MXene materials using Pourbaix diagrams. The results show that MXene materials with -O and -F surface groups exhibit higher efficiency in the hydrogen evolution reaction under specific conditions.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Chemistry, Physical
David Vazquez-Parga, Andrea Fernandez-Martinez, Francesc Vines
Summary: In density functional theory calculations for transition metals, generalized gradient approximation (GGA) xc functionals are found to be better suited than other types of xc functionals. However, some basic local density approximation xc functionals have not been assessed. The recent meta-GGA (SCAN) and Bayesian error estimation functional (BEEF) perform reasonably well.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Nestor Garcia-Romeral, Angel Morales-Garcia, Francesc Vines, Iberio de P. R. Moreira, Francesc Illas
Summary: A systematic computational study was conducted to investigate the electronic ground state nature and properties of M2C MXenes. The results revealed diverse conductivity and spin configurations for different MXenes, providing valuable insights for understanding and designing MXene materials.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)