Pub Date : 2024-10-01DOI: 10.1016/j.susc.2024.122612
Ulrike Küst , Julia Prumbs , Calley Eads , Weijia Wang , Virginia Boix , Alexander Klyushin , Mattia Scardamaglia , Robert Temperton , Andrey Shavorskiy , Jan Knudsen
Dynamic processes in catalysis are gaining increased attention and could very well be one of the next frontiers in surface science. One way to study such processes is to induce chemical changes on the surface for example by periodically adjusting the (electro)chemical potential in situ and identify the resulting spectral changes. Often this is referred to as Modulation Excitation Spectroscopy (MES). Using Ambient Pressure Photoelectron Spectroscopy data, we here discuss and compare the analysis of MES data using both Phase Sensitive Detection (PSD) and Fourier analysis. We discuss that PSD determines the component magnitude at a user-defined phase value while Fourier analysis provides the maximum oscillation amplitude and respective phase value of oscillating spectral features. We discuss advantages and disadvantages of the different analysis schemes and explore how the full time-evolution can be obtained.
催化的动态过程越来越受到关注，很可能成为表面科学的下一个前沿领域。研究此类过程的一种方法是诱导表面发生化学变化，例如通过在原位定期调节（电）化学势，并识别由此产生的光谱变化。这通常被称为调制激发光谱（MES）。利用常压光电子能谱数据，我们在此讨论并比较使用相敏检测（PSD）和傅立叶分析对 MES 数据进行的分析。我们讨论了 PSD 可确定用户定义相位值的分量幅度，而傅里叶分析可提供振荡光谱特征的最大振荡幅度和各自的相位值。我们讨论了不同分析方案的优缺点，并探讨了如何获得完整的时间演变。
{"title":"Comparing phase sensitive detection and Fourier analysis of modulation excitation spectroscopy data exemplified by Ambient Pressure X-ray Photoelectron Spectroscopy","authors":"Ulrike Küst , Julia Prumbs , Calley Eads , Weijia Wang , Virginia Boix , Alexander Klyushin , Mattia Scardamaglia , Robert Temperton , Andrey Shavorskiy , Jan Knudsen","doi":"10.1016/j.susc.2024.122612","DOIUrl":"10.1016/j.susc.2024.122612","url":null,"abstract":"<div><div>Dynamic processes in catalysis are gaining increased attention and could very well be one of the next frontiers in surface science. One way to study such processes is to induce chemical changes on the surface for example by periodically adjusting the (electro)chemical potential in situ and identify the resulting spectral changes. Often this is referred to as Modulation Excitation Spectroscopy (MES). Using Ambient Pressure Photoelectron Spectroscopy data, we here discuss and compare the analysis of MES data using both Phase Sensitive Detection (PSD) and Fourier analysis. We discuss that PSD determines the component magnitude at a user-defined phase value while Fourier analysis provides the maximum oscillation amplitude and respective phase value of oscillating spectral features. We discuss advantages and disadvantages of the different analysis schemes and explore how the full time-evolution can be obtained.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"751 ","pages":"Article 122612"},"PeriodicalIF":2.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.susc.2024.122622
Tianhao Hu , Burcu Karagoz , Fang Xu , Ashley R. Head , Jonas Weissenrieder , Dario Stacchiola
The chemical and electronic properties of copper combined with its large natural abundance lend this material to impact a wide range of technological applications, including heterogeneous catalysis. The reactivity of copper in its Cu1+oxidation state makes this specific configuration relevant in various chemical reactions, but the facile redox properties of copper make the isolation of individual states for fundamental studies difficult. Here we review three Cu2O model systems used to study the interaction of Cu1+ with small molecules making use of surface science techniques: Cu2O/Cu(111), thin polycrystalline Cu2O films on Cu foil, and bulk Cu2O crystals. Advantages and disadvantages of each system are discussed and exemplified through case studies of chemical adsorption and reactivity studies.
{"title":"The surface chemistry of cuprous oxide","authors":"Tianhao Hu , Burcu Karagoz , Fang Xu , Ashley R. Head , Jonas Weissenrieder , Dario Stacchiola","doi":"10.1016/j.susc.2024.122622","DOIUrl":"10.1016/j.susc.2024.122622","url":null,"abstract":"<div><div>The chemical and electronic properties of copper combined with its large natural abundance lend this material to impact a wide range of technological applications, including heterogeneous catalysis. The reactivity of copper in its Cu<sup>1+</sup>oxidation state makes this specific configuration relevant in various chemical reactions, but the facile redox properties of copper make the isolation of individual states for fundamental studies difficult. Here we review three Cu<sub>2</sub>O model systems used to study the interaction of Cu<sup>1+</sup> with small molecules making use of surface science techniques: Cu<sub>2</sub>O/Cu(111), thin polycrystalline Cu<sub>2</sub>O films on Cu foil, and bulk Cu<sub>2</sub>O crystals. Advantages and disadvantages of each system are discussed and exemplified through case studies of chemical adsorption and reactivity studies.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"751 ","pages":"Article 122622"},"PeriodicalIF":2.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-29DOI: 10.1016/j.susc.2024.122619
Connor Pope , Jungwon Yun , Rishikishore Reddy , Jovenal Jamir , Minkyu Kim , Aravind Asthagiri , Jason F. Weaver
We investigated the oxidation of CO on stoichiometric and O-rich IrO2(110) surfaces using temperature programmed reaction spectroscopy (TPRS), density functional theory (DFT) calculations and microkinetic simulations. Adsorbed CO on the s-IrO2(110) surface generates CO and CO2 peaks near 545 K during TPRS, and only about 38 % of the CO oxidized to CO2 when the initial CO layer was saturated. Pre-adsorbed O-atoms, so-called on-top oxygen (Ot), promote the oxidation of CO adsorbed on IrO2(110). On the Ot-covered surface, CO oxidation by Ot atoms produces a CO2 TPRS peak at ∼370 K, and all of the initially adsorbed CO oxidizes to CO2 when the initial Ot coverage is greater than the CO coverage. In agreement with the TPRS results, DFT calculations predict that the barrier is about 100 kJ/mol lower for CO oxidation by an Ot atom than a lattice O-atom of IrO2(110). A microkinetic model, parameterized with energy barriers computed using DFT, accurately reproduces the CO and CO2 TPRS traces only after CO binding energies are lowered to values determined using a hybrid exchange-correlation functional and the barrier for CO molecules to fill bridging O-vacancies is lowered. The simulations predict that O-vacancies play an important role in mediating the CO oxidation kinetics on s-IrO2(110), and thereby demonstrate the importance of future spectroscopic studies aimed at characterizing the nature of the surface CO and O species involved in reaction. This study provides new insights for understanding CO oxidation on IrO2(110), and provides evidence that several elementary steps can be involved in governing this chemistry.
我们利用温度编程反应光谱（TPRS）、密度泛函理论（DFT）计算和微动力学模拟研究了CO在化学计量和富含O的IrO2（110）表面上的氧化过程。在 TPRS 过程中，s-IrO2(110) 表面吸附的 CO 在 545 K 附近产生 CO 和 CO2 峰，当初始 CO 层饱和时，只有约 38% 的 CO 氧化成 CO2。预先吸附的 O 原子，即所谓的顶部氧（Ot），促进了吸附在 IrO2（110）上的 CO 的氧化。在Ot覆盖的表面上，Ot原子对CO的氧化作用会在∼370 K时产生一个CO2 TPRS峰，当初始Ot覆盖率大于CO覆盖率时，所有初始吸附的CO都会氧化成CO2。与 TPRS 结果一致，DFT 计算预测，Ot 原子氧化 CO 的势垒比 IrO2(110) 晶格 O 原子氧化 CO 的势垒低约 100 kJ/mol。只有在一氧化碳结合能降低到使用混合交换相关函数确定的值以及一氧化碳分子填充桥接 O-空位的障碍降低之后，使用 DFT 计算的能垒参数化的微动力学模型才能准确地再现一氧化碳和二氧化碳的 TPRS 轨迹。模拟预测 O-空位在介导 s-IrO2(110)上的 CO 氧化动力学中发挥了重要作用，从而证明了未来旨在确定参与反应的表面 CO 和 O 物种性质的光谱研究的重要性。这项研究为理解二氧化钛（IrO2）(110) 上的一氧化碳氧化作用提供了新的视角，并提供了证据，证明这一化学反应可能涉及几个基本步骤。
{"title":"CO oxidation on IrO2(110) surfaces","authors":"Connor Pope , Jungwon Yun , Rishikishore Reddy , Jovenal Jamir , Minkyu Kim , Aravind Asthagiri , Jason F. Weaver","doi":"10.1016/j.susc.2024.122619","DOIUrl":"10.1016/j.susc.2024.122619","url":null,"abstract":"<div><div>We investigated the oxidation of CO on stoichiometric and O-rich IrO<sub>2</sub>(110) surfaces using temperature programmed reaction spectroscopy (TPRS), density functional theory (DFT) calculations and microkinetic simulations. Adsorbed CO on the s-IrO<sub>2</sub>(110) surface generates CO and CO<sub>2</sub> peaks near 545 K during TPRS, and only about 38 % of the CO oxidized to CO<sub>2</sub> when the initial CO layer was saturated. Pre-adsorbed O-atoms, so-called on-top oxygen (O<sub>t</sub>), promote the oxidation of CO adsorbed on IrO<sub>2</sub>(110). On the O<sub>t</sub>-covered surface, CO oxidation by O<sub>t</sub> atoms produces a CO<sub>2</sub> TPRS peak at ∼370 K, and all of the initially adsorbed CO oxidizes to CO<sub>2</sub> when the initial O<sub>t</sub> coverage is greater than the CO coverage. In agreement with the TPRS results, DFT calculations predict that the barrier is about 100 kJ/mol lower for CO oxidation by an O<sub>t</sub> atom than a lattice O-atom of IrO<sub>2</sub>(110). A microkinetic model, parameterized with energy barriers computed using DFT, accurately reproduces the CO and CO<sub>2</sub> TPRS traces only after CO binding energies are lowered to values determined using a hybrid exchange-correlation functional and the barrier for CO molecules to fill bridging O-vacancies is lowered. The simulations predict that O-vacancies play an important role in mediating the CO oxidation kinetics on s-IrO<sub>2</sub>(110), and thereby demonstrate the importance of future spectroscopic studies aimed at characterizing the nature of the surface CO and O species involved in reaction. This study provides new insights for understanding CO oxidation on IrO<sub>2</sub>(110), and provides evidence that several elementary steps can be involved in governing this chemistry.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"751 ","pages":"Article 122619"},"PeriodicalIF":2.1,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-29DOI: 10.1016/j.susc.2024.122621
Peter Seidel, Sascha Pomp, Florian Schwarz, Martin Sterrer
The stability of single-crystalline monolayer FeO(111) and 10 nm thin Fe3O4(111) films on Pt(111) upon exposure to environments of increasing chemical complexity has been studied with X-ray photoelectron spectroscopy, temperature-programmed desorption, in-situ scanning tunneling microscopy, and cyclic voltammetry. The well-defined oxide films, which were prepared under ultrahigh-vacuum conditions, were exposed to aqueous solutions of different pH and electrochemical cycling in pure and catechol-containing electrolyte. The films are stable in neutral (pH 7) and alkaline (pH 13) solutions both at open circuit conditions and during electrochemical cycling within the limits of hydrogen and oxygen evolution potentials. Also in strongly acidic (pH 1) perchlorate solution the films remain intact under open circuit conditions, but they quickly dissolve on application of electrochemical potential. Especially for the ultrathin FeO(111) films, catechol enhances the dissolution at neutral pH during electrochemical cycling. A comparison of Pt(111), FeO(111) and Fe3O4(111) substrates in the electrochemical catechol oxidation reaction reveals enhanced and sustained activity of FeO in alkaline environment, while strong deactivation occurs on Pt(111) and Fe3O4(111). This is explained by the weaker interaction between catechol and FeO(111) compared to the other substrates, which hampers the formation of a barrier layer on the electrode surface.
{"title":"Stability and dissolution of single-crystalline iron oxide thin films in electrochemical environments","authors":"Peter Seidel, Sascha Pomp, Florian Schwarz, Martin Sterrer","doi":"10.1016/j.susc.2024.122621","DOIUrl":"10.1016/j.susc.2024.122621","url":null,"abstract":"<div><div>The stability of single-crystalline monolayer FeO(111) and 10 nm thin Fe<sub>3</sub>O<sub>4</sub>(111) films on Pt(111) upon exposure to environments of increasing chemical complexity has been studied with X-ray photoelectron spectroscopy, temperature-programmed desorption, in-situ scanning tunneling microscopy, and cyclic voltammetry. The well-defined oxide films, which were prepared under ultrahigh-vacuum conditions, were exposed to aqueous solutions of different pH and electrochemical cycling in pure and catechol-containing electrolyte. The films are stable in neutral (pH 7) and alkaline (pH 13) solutions both at open circuit conditions and during electrochemical cycling within the limits of hydrogen and oxygen evolution potentials. Also in strongly acidic (pH 1) perchlorate solution the films remain intact under open circuit conditions, but they quickly dissolve on application of electrochemical potential. Especially for the ultrathin FeO(111) films, catechol enhances the dissolution at neutral pH during electrochemical cycling. A comparison of Pt(111), FeO(111) and Fe<sub>3</sub>O<sub>4</sub>(111) substrates in the electrochemical catechol oxidation reaction reveals enhanced and sustained activity of FeO in alkaline environment, while strong deactivation occurs on Pt(111) and Fe<sub>3</sub>O<sub>4</sub>(111). This is explained by the weaker interaction between catechol and FeO(111) compared to the other substrates, which hampers the formation of a barrier layer on the electrode surface.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"751 ","pages":"Article 122621"},"PeriodicalIF":2.1,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-26DOI: 10.1016/j.susc.2024.122618
Thomas Haunold , Krešimir Anić , Alexander Genest , Christoph Rameshan , Matteo Roiaz , Hao Li , Thomas Wicht , Jan Knudsen , Günther Rupprechter
In the present work, we have studied the interaction of water with spinel cobalt oxide (Co3O4), an effect which has been considered a major cause of its catalytic deactivation. Employing a Co3O4(111) model thin film grown on Ir(100) in (ultra)high vacuum, and ambient pressure X-ray photoelectron spectroscopy (APXPS), hydroxylation in 0.5 mbar H2O vapor at room temperature was monitored in real time. The surface hydroxyl (OH) coverage was determined via two different models based (i) on the termination of a pristine and OH-covered Co3O4(111) surface as derived from density functional theory (DFT) calculations, and (ii) on a homogeneous cobalt oxyhydroxide (CoO(OH)) overlayer. Langmuir pseudo-second-order kinetics were applied to characterize the OH evolution with time, suggesting two regimes of chemisorption at the mosaic-like Co3O4(111) film: (i) plateaus, which were quickly saturated by OH, followed by (ii) slow hydroxylation in the “cracks” of the thin film. H2O dissociation and OH formation, blocking exposed Co2+ ions and additionally consuming surface lattice oxygen, respectively, may thus account for catalyst deactivation by H2O traces in reactive feeds.
{"title":"Hydroxylation of an ultrathin Co3O4(111) film on Ir(100) studied by in situ ambient pressure XPS and DFT","authors":"Thomas Haunold , Krešimir Anić , Alexander Genest , Christoph Rameshan , Matteo Roiaz , Hao Li , Thomas Wicht , Jan Knudsen , Günther Rupprechter","doi":"10.1016/j.susc.2024.122618","DOIUrl":"10.1016/j.susc.2024.122618","url":null,"abstract":"<div><div>In the present work, we have studied the interaction of water with spinel cobalt oxide (Co<sub>3</sub>O<sub>4</sub>), an effect which has been considered a major cause of its catalytic deactivation. Employing a Co<sub>3</sub>O<sub>4</sub>(111) model thin film grown on Ir(100) in (ultra)high vacuum, and ambient pressure X-ray photoelectron spectroscopy (APXPS), hydroxylation in 0.5 mbar H<sub>2</sub>O vapor at room temperature was monitored in real time. The surface hydroxyl (OH) coverage was determined <em>via</em> two different models based (i) on the termination of a pristine and OH-covered Co<sub>3</sub>O<sub>4</sub>(111) surface as derived from density functional theory (DFT) calculations, and (ii) on a homogeneous cobalt oxyhydroxide (CoO(OH)) overlayer. Langmuir pseudo-second-order kinetics were applied to characterize the OH evolution with time, suggesting two regimes of chemisorption at the mosaic-like Co<sub>3</sub>O<sub>4</sub>(111) film: (i) plateaus, which were quickly saturated by OH, followed by (ii) slow hydroxylation in the “cracks” of the thin film. H<sub>2</sub>O dissociation and OH formation, blocking exposed Co<sup>2+</sup> ions and additionally consuming surface lattice oxygen, respectively, may thus account for catalyst deactivation by H<sub>2</sub>O traces in reactive feeds.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"751 ","pages":"Article 122618"},"PeriodicalIF":2.1,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.susc.2024.122615
Yibing Xie , Chen Yao
The lithium perchlorate-interacted oxygen-containing carbon paper (LiClO4-OCP) is designed to act as electroactive supercapacitor electrode substrates for the energy storage application. The OCP is fabricated through hydrothermal activation treatment of carbon paper in H2O2 reaction medium. The OCP is composed of graphite pitches with ultra-thin graphene structure of top layer, showing the improved graphitization degree. The LiClO4-OCP with the polarized electrostatic force-induced interfacial adsorption reveals much more intensive interaction than LiClO4-CP with van der Waals force-induced interfacial adsorption, contributing to promoting interfacial charge transfer of LiClO4-OCP. LiClO4-OCP reveals more effective interface charge transfer and more feasible electrolyte diffusion than LiClO4-CP, contributing to higher electrochemical double-layer capacitance. LiClO4-OCP with oxygen-containing groups conducts reversible redox process to supply additional Faradaic capacitance. Mean response current is increased from 0.10 ∼ 1.34 mA cm-2 for LiClO4-CP to 0.19 ∼ 2.31 mA cm-2 for LiClO4-OCP at scan rates of 5∼100 mV s-1, indicating the improved electrochemical activity of LiClO4-OCP. The cyclic voltammetry-based capacitance increases from 19.91 ∼ 13.01 mF cm-2 mF g-1 for LiClO4-CP to 37.76 ∼ 23.06 mF cm-2 for LiClO4-OCP. The galvanostatic charge/discharge-based capacitance decreases from 13.84 ∼ 3.97 mF cm-2 for LiClO4-CP to 29.71 ∼ 12.92 mF cm-2 for LiClO4-OCP. Density-functional theory-based simulation calculation proves LiClO4-OCP with such a short molecular distance is allowed to occur strong electrostatic interaction which is caused by the perchlorate ion-induced polarization of oxygen-containing groups. The LiClO4-OCP has lower interfacial energy, lower band gap and higher density of states at Fermi energy level than LiClO4-CP, indicating the improved interfacial interaction and electrical conductivity of LiClO4-OCP. The experimental measurement and theoretical calculation achieve the consistent results of higher electrochemical activity of LiClO4-OCP electrode substrate to present its superior capacitance performance.
{"title":"Interfacial effect investigation of lithium perchlorate-interacted oxygen-containing carbon paper","authors":"Yibing Xie , Chen Yao","doi":"10.1016/j.susc.2024.122615","DOIUrl":"10.1016/j.susc.2024.122615","url":null,"abstract":"<div><div>The lithium perchlorate-interacted oxygen-containing carbon paper (LiClO4-OCP) is designed to act as electroactive supercapacitor electrode substrates for the energy storage application. The OCP is fabricated through hydrothermal activation treatment of carbon paper in H<sub>2</sub>O<sub>2</sub> reaction medium. The OCP is composed of graphite pitches with ultra-thin graphene structure of top layer, showing the improved graphitization degree. The LiClO4-OCP with the polarized electrostatic force-induced interfacial adsorption reveals much more intensive interaction than LiClO4-CP with van der Waals force-induced interfacial adsorption, contributing to promoting interfacial charge transfer of LiClO4-OCP. LiClO4-OCP reveals more effective interface charge transfer and more feasible electrolyte diffusion than LiClO4-CP, contributing to higher electrochemical double-layer capacitance. LiClO4-OCP with oxygen-containing groups conducts reversible redox process to supply additional Faradaic capacitance. Mean response current is increased from 0.10 ∼ 1.34 mA cm<sup>-2</sup> for LiClO4-CP to 0.19 ∼ 2.31 mA cm<sup>-2</sup> for LiClO4-OCP at scan rates of 5∼100 mV s<sup>-1</sup>, indicating the improved electrochemical activity of LiClO4-OCP. The cyclic voltammetry-based capacitance increases from 19.91 ∼ 13.01 mF cm<sup>-2</sup> mF g-1 for LiClO4-CP to 37.76 ∼ 23.06 mF cm<sup>-2</sup> for LiClO4-OCP. The galvanostatic charge/discharge-based capacitance decreases from 13.84 ∼ 3.97 mF cm<sup>-2</sup> for LiClO4-CP to 29.71 ∼ 12.92 mF cm<sup>-2</sup> for LiClO4-OCP. Density-functional theory-based simulation calculation proves LiClO4-OCP with such a short molecular distance is allowed to occur strong electrostatic interaction which is caused by the perchlorate ion-induced polarization of oxygen-containing groups. The LiClO4-OCP has lower interfacial energy, lower band gap and higher density of states at Fermi energy level than LiClO4-CP, indicating the improved interfacial interaction and electrical conductivity of LiClO4-OCP. The experimental measurement and theoretical calculation achieve the consistent results of higher electrochemical activity of LiClO4-OCP electrode substrate to present its superior capacitance performance.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"751 ","pages":"Article 122615"},"PeriodicalIF":2.1,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.susc.2024.122617
Mausumi Mahapatra , Marcus A. Sharp , Christopher J. Lee , Yifeng Zhu , Oliver Y. Gutiérrez , Bruce D. Kay , Zdenek Dohnálek
Single metal atoms dispersed on oxides are a new emerging class of catalysts owing to their unique electronic and chemical properties. In this study, we have prepared a series of model single-atom catalysts possessing well-characterized Rh sites that include Rh adatoms (Rhad), mixed surface layers with octahedrally-coordinated Rh (Rhoct), as well as metallic Rh clusters and nanoparticles (Rhmet) on Fe3O4(001). Using X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM), we investigated the activity of such model systems towards H2 and their stability in reducing environments. Our results show that the atomically dispersed Rhad and Rhoct species do not activate H2, which would result in the formation of surface hydroxyls on Fe3O4(001). In contrast, the presence of Rhmet in H2 results in the formation of hydroxyls and subsequent etching of the Fe3O4(001) at higher temperatures (≥ 500 K) due to water formation via the Mars−van Krevelen mechanism. Additionally, such surface etching leads to the release of the Rhoct from the surface lattice and their sintering to Rhmet. To bridge the material gap between the surface science models and high surface area catalysts, we perform parallel studies on powder Rh/Fe3O4 catalysts. The XPS characterization shows remarkable similarities between these systems. Further, our surface science studies provide an atomistic picture of the behavior of high surface area catalysts in the H2 atmosphere.
{"title":"The evolution of model Rh/Fe3O4(001) catalysts in hydrogen environments","authors":"Mausumi Mahapatra , Marcus A. Sharp , Christopher J. Lee , Yifeng Zhu , Oliver Y. Gutiérrez , Bruce D. Kay , Zdenek Dohnálek","doi":"10.1016/j.susc.2024.122617","DOIUrl":"10.1016/j.susc.2024.122617","url":null,"abstract":"<div><div>Single metal atoms dispersed on oxides are a new emerging class of catalysts owing to their unique electronic and chemical properties. In this study, we have prepared a series of model single-atom catalysts possessing well-characterized Rh sites that include Rh adatoms (Rh<sub>ad</sub>), mixed surface layers with octahedrally-coordinated Rh (Rh<sub>oct</sub>), as well as metallic Rh clusters and nanoparticles (Rh<sub>met</sub>) on Fe<sub>3</sub>O<sub>4</sub>(001). Using X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM), we investigated the activity of such model systems towards H<sub>2</sub> and their stability in reducing environments. Our results show that the atomically dispersed Rh<sub>ad</sub> and Rh<sub>oct</sub> species do not activate H<sub>2,</sub> which would result in the formation of surface hydroxyls on Fe<sub>3</sub>O<sub>4</sub>(001). In contrast, the presence of Rh<sub>met</sub> in H<sub>2</sub> results in the formation of hydroxyls and subsequent etching of the Fe<sub>3</sub>O<sub>4</sub>(001) at higher temperatures (≥ 500 K) due to water formation via the Mars−van Krevelen mechanism. Additionally, such surface etching leads to the release of the Rh<sub>oct</sub> from the surface lattice and their sintering to Rh<sub>met</sub>. To bridge the material gap between the surface science models and high surface area catalysts, we perform parallel studies on powder Rh/Fe<sub>3</sub>O<sub>4</sub> catalysts. The XPS characterization shows remarkable similarities between these systems. Further, our surface science studies provide an atomistic picture of the behavior of high surface area catalysts in the H<sub>2</sub> atmosphere.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"751 ","pages":"Article 122617"},"PeriodicalIF":2.1,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.susc.2024.122607
Dawid Jarosz , Ewa Bobko , Marcin Stachowicz , Ewa Przeździecka , Piotr Krzemiński , Marta Ruszała , Anna Juś , Małgorzata Trzyna-Sowa , Kinga Maś , Renata Wojnarowska-Nowak , Oskar Nowak , Daria Gudyka , Brajan Tabor , Michał Marchewka
This study presents a demonstration of the surface morphology behavior of gallium antimonide (GaSb) layers deposited on gallium arsenide (GaAs) (100) substrates using three different methods: metamorphic, interfacial misfit (IMF) matrix, and a method based on a Polish patent application number P.443805. The first two methods are commonly used, while the third differs in the sequence of successive steps and the presence of Be doping at the initial growth stage. By comparing GaSb layers made by these methods for the same growth parameters, the most favorable procedure for forming a GaSb buffer layer is selected. Using GaAs substrates with a GaSb buffer layer is a cheaper alternative to using GaSb substrates in infrared detector structures based on II-type superlattices T2SL, such as InAs/GaSb. The quality of the GaSb buffer layer determines the quality of the subsequent layers that form the entire T2SL and affects factors such as dark current in terms of application.
本研究展示了使用三种不同方法在砷化镓（GaAs）（100）基底上沉积锑化镓（GaSb）层的表面形态行为：变质法、界面错位（IMF）基质法和基于波兰专利申请号 P.443805 的方法。前两种方法是常用的，而第三种方法的不同之处在于连续步骤的顺序以及在初始生长阶段掺入 Be 的情况。通过比较在相同生长参数下用这些方法制造的镓硒化物层，可以选择最有利于形成镓硒化物缓冲层的程序。在基于 II 型超晶格 T2SL（如 InAs/GaSb）的红外探测器结构中，使用带有 GaSb 缓冲层的 GaAs 衬底比使用 GaSb 衬底更便宜。GaSb 缓冲层的质量决定了构成整个 T2SL 的后续层的质量，并影响暗电流等应用因素。
{"title":"Evolution of the surface morphology of GaSb epitaxial layers deposited by molecular beam epitaxy (MBE) on GaAs (100) substrates","authors":"Dawid Jarosz , Ewa Bobko , Marcin Stachowicz , Ewa Przeździecka , Piotr Krzemiński , Marta Ruszała , Anna Juś , Małgorzata Trzyna-Sowa , Kinga Maś , Renata Wojnarowska-Nowak , Oskar Nowak , Daria Gudyka , Brajan Tabor , Michał Marchewka","doi":"10.1016/j.susc.2024.122607","DOIUrl":"10.1016/j.susc.2024.122607","url":null,"abstract":"<div><p>This study presents a demonstration of the surface morphology behavior of gallium antimonide (GaSb) layers deposited on gallium arsenide (GaAs) (100) substrates using three different methods: metamorphic, interfacial misfit (IMF) matrix, and a method based on a Polish patent application number P.443805. The first two methods are commonly used, while the third differs in the sequence of successive steps and the presence of Be doping at the initial growth stage. By comparing GaSb layers made by these methods for the same growth parameters, the most favorable procedure for forming a GaSb buffer layer is selected. Using GaAs substrates with a GaSb buffer layer is a cheaper alternative to using GaSb substrates in infrared detector structures based on II-type superlattices T2SL, such as InAs/GaSb. The quality of the GaSb buffer layer determines the quality of the subsequent layers that form the entire T2SL and affects factors such as dark current in terms of application.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"751 ","pages":"Article 122607"},"PeriodicalIF":2.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0039602824001584/pdfft?md5=8c36a3bf254391ffeefbcb9b455b7662&pid=1-s2.0-S0039602824001584-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.1016/j.susc.2024.122616
Junyi Fan , Haixia Chen , Jijun Ding , Haiwei Fu , Jianhong Peng
The generation of clean energy hydrogen through solar-driven water decomposition is an effective solution to the current global energy shortage and environmental pollution. In this paper, ZnO/WS2 heterojunction is constructed based on first-principles. The effect of uniaxial strain and vacancy defects (VZn, VO, VS, V2S) on electronic and optical properties of ZnO/WS2 heterojunction are calculated. The results indicate that the bandgap of the heterojunction is decreased and the visible absorption range is expanding. Additionally, the built-in electric field of the heterojunction is determined to be oriented from ZnO to WS2, which enhances the efficiency of carrier separation. Band-edge position analysis indicates that ZnO/WS2 heterojunctions exhibit good redox water properties under an applied compressive strain of −2 %. Finally, the visible light absorption range of the heterostructures is also expanded by introducing VS and V2S vacancy defects. However, it exhibits a superior ability to oxidize and reduce water only under VZn defects. The corresponding photocatalytic mechanism of ZnO/WS2 heterojunctions is discussed.
{"title":"First principles study on photocatalytic water decomposition of ZnO/WS2 heterojunctions","authors":"Junyi Fan , Haixia Chen , Jijun Ding , Haiwei Fu , Jianhong Peng","doi":"10.1016/j.susc.2024.122616","DOIUrl":"10.1016/j.susc.2024.122616","url":null,"abstract":"<div><p>The generation of clean energy hydrogen through solar-driven water decomposition is an effective solution to the current global energy shortage and environmental pollution. In this paper, ZnO/WS<sub>2</sub> heterojunction is constructed based on first-principles. The effect of uniaxial strain and vacancy defects (V<sub>Zn</sub>, V<sub>O</sub>, V<sub>S</sub>, V<sub>2S</sub>) on electronic and optical properties of ZnO/WS<sub>2</sub> heterojunction are calculated. The results indicate that the bandgap of the heterojunction is decreased and the visible absorption range is expanding. Additionally, the built-in electric field of the heterojunction is determined to be oriented from ZnO to WS<sub>2</sub>, which enhances the efficiency of carrier separation. Band-edge position analysis indicates that ZnO/WS<sub>2</sub> heterojunctions exhibit good redox water properties under an applied compressive strain of −2 %. Finally, the visible light absorption range of the heterostructures is also expanded by introducing V<sub>S</sub> and V<sub>2S</sub> vacancy defects. However, it exhibits a superior ability to oxidize and reduce water only under V<sub>Zn</sub> defects. The corresponding photocatalytic mechanism of ZnO/WS<sub>2</sub> heterojunctions is discussed.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"751 ","pages":"Article 122616"},"PeriodicalIF":2.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1016/j.susc.2024.122614
Yuyu Huang , Jindong An , Guoqing Huang , Ruikun Wang , Huimin Liu , Ping Xiao , Shiqing Wang , Yue Zhang
Iron-based materials are promising sorbents for controlling arsenic emissions. However, the effects of SO2, especially the synergistic mechanism of As2O3 adsorption under the combined effects of O2 and SO2, remain inadequately explored. This study investigated for the first time the impact of the newly formed surface resulting from the adsorption and dissociation of O2 and SO2 on the adsorption of As2O3. The results showed that Mn3f and Fe3f sites were the active sites for the adsorption of O2 and SO2, which competed with As2O3 and hindered its adsorption. Conversely, dissociation created more reactive sites, which promoted the process. Selectivity analysis revealed that As2O3 preferentially adsorbed on the dissociated surface, highlighting the dominance of the promotion effect. Finally, starting from the adsorption sequence of O2 and SO2, the impact of arsenic adsorption and oxidation was examined on sorbents created through the sequential adsorption of O2 and SO2. Regardless of the adsorption sequence, active O atoms with catalytic effects were exposed, supporting the enhanced removal of arsenic under the synergistic effect of O2 and SO2. Building upon this analysis, a theoretical framework for efficiently removing As2O3 from O2 and SO2 flue gases using Mn-modified Fe2O3-based materials was developed.
{"title":"Mechanistic insight into the synergistic effect of O2 and SO2 for improving removal of arsenic over Mn-modified Fe2O3-based sorbent","authors":"Yuyu Huang , Jindong An , Guoqing Huang , Ruikun Wang , Huimin Liu , Ping Xiao , Shiqing Wang , Yue Zhang","doi":"10.1016/j.susc.2024.122614","DOIUrl":"10.1016/j.susc.2024.122614","url":null,"abstract":"<div><p>Iron-based materials are promising sorbents for controlling arsenic emissions. However, the effects of SO<sub>2</sub>, especially the synergistic mechanism of As<sub>2</sub>O<sub>3</sub> adsorption under the combined effects of O<sub>2</sub> and SO<sub>2</sub>, remain inadequately explored. This study investigated for the first time the impact of the newly formed surface resulting from the adsorption and dissociation of O<sub>2</sub> and SO<sub>2</sub> on the adsorption of As<sub>2</sub>O<sub>3</sub>. The results showed that Mn<sub>3f</sub> and Fe<sub>3f</sub> sites were the active sites for the adsorption of O<sub>2</sub> and SO<sub>2</sub>, which competed with As<sub>2</sub>O<sub>3</sub> and hindered its adsorption. Conversely, dissociation created more reactive sites, which promoted the process. Selectivity analysis revealed that As<sub>2</sub>O<sub>3</sub> preferentially adsorbed on the dissociated surface, highlighting the dominance of the promotion effect. Finally, starting from the adsorption sequence of O<sub>2</sub> and SO<sub>2</sub>, the impact of arsenic adsorption and oxidation was examined on sorbents created through the sequential adsorption of O<sub>2</sub> and SO<sub>2</sub>. Regardless of the adsorption sequence, active O atoms with catalytic effects were exposed, supporting the enhanced removal of arsenic under the synergistic effect of O<sub>2</sub> and SO<sub>2</sub>. Building upon this analysis, a theoretical framework for efficiently removing As<sub>2</sub>O<sub>3</sub> from O<sub>2</sub> and SO<sub>2</sub> flue gases using Mn-modified Fe<sub>2</sub>O<sub>3</sub>-based materials was developed.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"751 ","pages":"Article 122614"},"PeriodicalIF":2.1,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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