Pub Date : 2024-09-17DOI: 10.1016/j.susc.2024.122616
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":"","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":null,"pages":null},"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
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":"","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":null,"pages":null},"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}
Pub Date : 2024-09-15DOI: 10.1016/j.susc.2024.122613
The adsorbate-induced formation of sub-nanometer clusters on transition-metal single crystals observed in previous high-pressure microscopic studies hinted at the in-situ formation of unique active sites even on large nanoparticle catalysts. We propose that the adatom formation energy can be used as an energetic descriptor for the initial step toward the adsorbate-induced metal-cluster formation process. This descriptor can be efficiently computed using density functional theory (DFT) calculations and applied for screening and identification of metal catalysts where this phenomenon may play an important role in generating active sites in-situ. As a proof of concept, here, we construct an adatom formation energy database for three AuxCuy alloys (x:y = 3:1, 1:1, or 1:3) and eighteen adsorbates (H, C, N, O, F, S, Cl, Br, I, CHx, NHx (x = 1 – 3), CO, NO, and OH) commonly involved in catalytic reactions. The energetics of adatom formation were examined in all cases where the (111) terrace, (211) step-edge, and (874) kink were the sources of the adatom. We demonstrate that the presence of an adsorbate could alter not only the energetics for adatom formation but also the elemental nature of the preferred adatom being formed. Using our database, we identified promising systems which favor adsorbate-induced adatom formation under near-ambient conditions. Specifically, CO-induced adatom formation on all three Au-Cu alloy surfaces could occur under CO2 electroreduction (CO2RR) conditions. This phenomenon offers a qualitative explanation for the experimentally observed CO2RR activity on Au-Cu alloy catalysts. Our methodology offers an easily expandable and efficient approach for large-scale catalyst screening with regards to adatom/cluster formation under reaction conditions and provides insight into the possible nature of active sites on alloy catalysts from a novel perspective.
{"title":"Adsorbate-induced adatom formation on Au-Cu bimetallic alloys and its possible consequences for CO2 electroreduction","authors":"","doi":"10.1016/j.susc.2024.122613","DOIUrl":"10.1016/j.susc.2024.122613","url":null,"abstract":"<div><div>The adsorbate-induced formation of sub-nanometer clusters on transition-metal single crystals observed in previous high-pressure microscopic studies hinted at the <em>in-situ</em> formation of unique active sites even on large nanoparticle catalysts. We propose that the adatom formation energy can be used as an energetic descriptor for the initial step toward the adsorbate-induced metal-cluster formation process. This descriptor can be efficiently computed using density functional theory (DFT) calculations and applied for screening and identification of metal catalysts where this phenomenon may play an important role in generating active sites <em>in-situ</em>. As a proof of concept, here, we construct an adatom formation energy database for three Au<sub>x</sub>Cu<sub>y</sub> alloys (<em>x:y</em> = 3:1, 1:1, or 1:3) and eighteen adsorbates (H, C, N, O, F, S, Cl, Br, I, CH<sub>x</sub>, NH<sub>x</sub> (<em>x</em> = 1 – 3), CO, NO, and OH) commonly involved in catalytic reactions. The energetics of adatom formation were examined in all cases where the (111) terrace, (211) step-edge, and (874) kink were the sources of the adatom. We demonstrate that the presence of an adsorbate could alter not only the energetics for adatom formation but also the elemental nature of the preferred adatom being formed. Using our database, we identified promising systems which favor adsorbate-induced adatom formation under near-ambient conditions. Specifically, CO-induced adatom formation on all three Au-Cu alloy surfaces could occur under CO<sub>2</sub> electroreduction (CO<sub>2</sub>RR) conditions. This phenomenon offers a qualitative explanation for the experimentally observed CO<sub>2</sub>RR activity on Au-Cu alloy catalysts. Our methodology offers an easily expandable and efficient approach for large-scale catalyst screening with regards to adatom/cluster formation under reaction conditions and provides insight into the possible nature of active sites on alloy catalysts from a novel perspective.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328029","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 : 2024-09-14DOI: 10.1016/j.susc.2024.122606
In this report we describe new findings on the structure, composition and thermal stability of FeNi nanoparticles, synthesized via a magnetron sputtering source and deposited on a clean W(110) surface. The elemental distribution of the nanoparticles was determined by energy dispersive X-ray (EDX) and electron energy loss spectroscopy (EELS). The melting behavior of the nanoparticles was studied under UHV by scanning tunneling microscopy (STM) upon heating. Notably, it has been observed that the nanoparticle’s core is characterized by an enrichment of Ni atoms, while the shell shows a higher amount of Fe atoms. Specifically, in the case of Fe0.75Ni0.25 and Fe0.25Ni0.75, where a Ni core is surrounded by a Fe shell, all nanoparticles completely liquefy after heating at 540 K. In contrast, the Fe0.50Ni0.50 nanoparticles, which exhibit a homogeneous distribution of both elements, only begin to melt around 540 K.
在本报告中,我们介绍了通过磁控溅射源合成并沉积在洁净 W(110) 表面的 FexNi1-x 纳米粒子的结构、组成和热稳定性方面的新发现。纳米粒子的元素分布是通过能量色散 X 射线(EDX)和电子能量损失光谱(EELS)测定的。在超高真空条件下,通过扫描隧道显微镜(STM)研究了纳米颗粒加热后的熔化行为。值得注意的是,我们观察到纳米粒子的核心富含镍原子,而外壳则含有较多的铁原子。具体来说,Fe0.75Ni0.25 和 Fe0.25Ni0.75(镍核被铁壳包围)纳米粒子在 540 K 的温度下加热后全部完全液化。
{"title":"Elemental Distribution and Melting Characteristics of FeNi nanoparticles on W(110) surfaces","authors":"","doi":"10.1016/j.susc.2024.122606","DOIUrl":"10.1016/j.susc.2024.122606","url":null,"abstract":"<div><p>In this report we describe new findings on the structure, composition and thermal stability of Fe<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>Ni<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span> nanoparticles, synthesized via a magnetron sputtering source and deposited on a clean W(110) surface. The elemental distribution of the nanoparticles was determined by energy dispersive X-ray (EDX) and electron energy loss spectroscopy (EELS). The melting behavior of the nanoparticles was studied under UHV by scanning tunneling microscopy (STM) upon heating. Notably, it has been observed that the nanoparticle’s core is characterized by an enrichment of Ni atoms, while the shell shows a higher amount of Fe atoms. Specifically, in the case of Fe<sub>0.75</sub>Ni<sub>0.25</sub> and Fe<sub>0.25</sub>Ni<sub>0.75</sub>, where a Ni core is surrounded by a Fe shell, all nanoparticles completely liquefy after heating at 540 K. In contrast, the Fe<sub>0.50</sub>Ni<sub>0.50</sub> nanoparticles, which exhibit a homogeneous distribution of both elements, only begin to melt around 540 K.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271191","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 : 2024-09-13DOI: 10.1016/j.susc.2024.122609
The growth of Fe on a clean Be(0001) surface is investigated on the atomic scale by a combined scanning tunneling microscopy and density functional theory study. At low Fe coverage, the nucleation of terraced nanoislands with a disordered surface is observed experimentally. Increasing the Fe coverage results in the growth of extended films exhibiting a well-ordered p superstructure. Density functional theory is applied to investigate the growth of Fe on a Be(0001) surface from individual atoms to extended films. Our studies provide strong evidence for the formation of a buckled honeycomb Fe lattice that is embedded in two Be planes with Kagome and triangular symmetry, respectively.
通过扫描隧道显微镜和密度泛函理论的综合研究,在原子尺度上对洁净的 Be(0001) 表面上铁的生长进行了研究。在低铁覆盖率下,实验观察到表面无序的阶梯状纳米岛的成核。增加铁的覆盖率会导致扩展薄膜的生长,并呈现出井然有序的 p(2×2) 超结构。应用密度泛函理论研究了 Fe 在 Be(0001) 表面从单个原子到扩展薄膜的生长过程。我们的研究有力地证明了倒扣蜂窝状铁晶格的形成,该晶格分别嵌入具有卡戈米对称性和三角形对称性的两个 Be 平面。
{"title":"Growth of an Fe buckled honeycomb lattice on Be(0001)","authors":"","doi":"10.1016/j.susc.2024.122609","DOIUrl":"10.1016/j.susc.2024.122609","url":null,"abstract":"<div><div>The growth of Fe on a clean Be(0001) surface is investigated on the atomic scale by a combined scanning tunneling microscopy and density functional theory study. At low Fe coverage, the nucleation of terraced nanoislands with a disordered surface is observed experimentally. Increasing the Fe coverage results in the growth of extended films exhibiting a well-ordered p<span><math><mrow><mo>(</mo><mn>2</mn><mo>×</mo><mn>2</mn><mo>)</mo></mrow></math></span> superstructure. Density functional theory is applied to investigate the growth of Fe on a Be(0001) surface from individual atoms to extended films. Our studies provide strong evidence for the formation of a buckled honeycomb Fe lattice that is embedded in two Be planes with Kagome and triangular symmetry, respectively.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553520","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 : 2024-09-12DOI: 10.1016/j.susc.2024.122608
The growth of Pt islands at submonolayer coverages on Ag(111) at room temperature were investigated with scanning tunneling microscopy. A two-step mechanism for growth of the islands is proposed. First, Pt replaces Ag substrate atoms through a place-exchange process. Next, Pt adatoms nucleate at substitutional Pt sites and Pt islands subsequently grow from these sites. At room temperature, Ag atoms migrate to cover Pt islands, creating vacancy pits on the terraces and bays on the step edges. Ag atoms nucleate at corner sites of the Pt islands, and the layer of Ag atoms on the Pt islands grow from these sites.
{"title":"Growth and Ag-encapsulation of Pt islands on Ag(111) at room temperature","authors":"","doi":"10.1016/j.susc.2024.122608","DOIUrl":"10.1016/j.susc.2024.122608","url":null,"abstract":"<div><p>The growth of Pt islands at submonolayer coverages on Ag(111) at room temperature were investigated with scanning tunneling microscopy. A two-step mechanism for growth of the islands is proposed. First, Pt replaces Ag substrate atoms through a place-exchange process. Next, Pt adatoms nucleate at substitutional Pt sites and Pt islands subsequently grow from these sites. At room temperature, Ag atoms migrate to cover Pt islands, creating vacancy pits on the terraces and bays on the step edges. Ag atoms nucleate at corner sites of the Pt islands, and the layer of Ag atoms on the Pt islands grow from these sites.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240394","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 : 2024-09-06DOI: 10.1016/j.susc.2024.122598
Calcite (calcium carbonate) is the most abundant carbonate in the Earth's crust. Due to its omnipresence it plays a prominent role in fields such as geochemistry, biomineralization and industrial processes. Moreover, the interaction of water with the most stable cleavage plane, calcite (10.4), has been studied intensively, elucidating atomic-scale details of water binding and structure formation on this surface. Interestingly, calcite (10.4) reconstructs under ultrahigh vacuum conditions, exhibiting a (2 × 1) surface unit cell. Although first indications of this reconstruction have been presented more than 20 years ago, a clear confirmation of the existence has been provided only very recently. Here, we study the tip-assisted diffusion of water molecules on calcite (10.4) under ultrahigh vacuum conditions. By recording images series using dynamic atomic force microscopy we follow the movement of water molecules on the surface kept at 140 K. Analyzing the change in consecutive images allows for elucidating details of the molecular movement on the surface. Most notably, the analysis reveals that water molecules occupy one type of adsorption position exclusively, while the other type is not adopted. Our analysis thus demonstrates that the (2 × 1) reconstruction manifests itself in the movement of single water molecules on this surface.
方解石(碳酸钙)是地壳中含量最丰富的碳酸盐。由于方解石无处不在,它在地球化学、生物矿化和工业过程等领域发挥着重要作用。此外,人们对水与最稳定的裂解面方解石(10.4)的相互作用进行了深入研究,阐明了该表面上水结合和结构形成的原子尺度细节。有趣的是,方解石(10.4)在超高真空条件下会发生重构,显示出一个(2 × 1)表面单元格。虽然这种重构的最初迹象早在 20 多年前就已出现,但直到最近才得到明确证实。在这里,我们研究了在超高真空条件下方解石(10.4)上水分子的尖端辅助扩散。通过使用动态原子力显微镜记录系列图像,我们跟踪了保持在 140 K 的表面上水分子的运动。分析连续图像的变化,可以阐明表面上分子运动的细节。最值得注意的是,分析表明水分子只占据一种吸附位置,而另一种吸附位置则没有被采用。因此,我们的分析表明,(2 × 1)重构表现为单个水分子在该表面上的运动。
{"title":"Reconstruction of calcite (10.4) manifests itself in the tip-assisted diffusion of water","authors":"","doi":"10.1016/j.susc.2024.122598","DOIUrl":"10.1016/j.susc.2024.122598","url":null,"abstract":"<div><p>Calcite (calcium carbonate) is the most abundant carbonate in the Earth's crust. Due to its omnipresence it plays a prominent role in fields such as geochemistry, biomineralization and industrial processes. Moreover, the interaction of water with the most stable cleavage plane, calcite (10.4), has been studied intensively, elucidating atomic-scale details of water binding and structure formation on this surface. Interestingly, calcite (10.4) reconstructs under ultrahigh vacuum conditions, exhibiting a (2 × 1) surface unit cell. Although first indications of this reconstruction have been presented more than 20 years ago, a clear confirmation of the existence has been provided only very recently. Here, we study the tip-assisted diffusion of water molecules on calcite (10.4) under ultrahigh vacuum conditions. By recording images series using dynamic atomic force microscopy we follow the movement of water molecules on the surface kept at 140 K. Analyzing the change in consecutive images allows for elucidating details of the molecular movement on the surface. Most notably, the analysis reveals that water molecules occupy one type of adsorption position exclusively, while the other type is not adopted. Our analysis thus demonstrates that the (2 × 1) reconstruction manifests itself in the movement of single water molecules on this surface.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0039602824001493/pdfft?md5=3556086ff04a23d149cbe25dcc58ffcb&pid=1-s2.0-S0039602824001493-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142232030","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 : 2024-09-05DOI: 10.1016/j.susc.2024.122597
We investigate tracer diffusion at the domain boundaries in an adsorption layer, an effect that corresponds to grain boundary diffusion in 3D polycrystalline solids. Experiments were performed on adsorbed O atoms on a Ru(0001) surface in a layer of CO molecules. The CO molecules form a structure which displays translational domains. High-speed scanning tunneling microscopy (STM) was used to image the motion of the O atoms. The data show that single O atoms preferentially move along the domain walls which in the STM movies appear as disordered, fluctuating stripes between the ordered domains. The diffusion coefficient of the O atoms is one order of magnitude higher than the diffusion coefficient in the ordered domains. By comparison with previous experiments on completely disordered CO layers, it is concluded that the diffusion is similarly promoted by the enhanced fluctuations in the disordered domain walls.
我们研究了吸附层中畴边界的示踪剂扩散,这种效应相当于三维多晶固体中的晶界扩散。实验是在 Ru(0001) 表面的 CO 分子层中吸附 O 原子。CO 分子形成了 (3x3)R30∘ 结构,显示出平移域。利用高速扫描隧道显微镜 (STM) 对 O 原子的运动进行了成像。数据显示,单个 O 原子优先沿着畴壁运动,在 STM 电影中,畴壁表现为有序畴之间的无序波动条纹。O 原子的扩散系数比有序畴内的扩散系数高一个数量级。通过与之前在完全无序的 CO 层上进行的实验进行比较,可以得出结论:无序畴壁的波动增强同样促进了扩散。
{"title":"An STM study on the diffusion of O atoms on a CO-covered Ru(0001) surface—The role of domain boundaries","authors":"","doi":"10.1016/j.susc.2024.122597","DOIUrl":"10.1016/j.susc.2024.122597","url":null,"abstract":"<div><p>We investigate tracer diffusion at the domain boundaries in an adsorption layer, an effect that corresponds to grain boundary diffusion in 3D polycrystalline solids. Experiments were performed on adsorbed O atoms on a Ru(0001) surface in a layer of CO molecules. The CO molecules form a <span><math><mrow><mrow><mo>(</mo><mrow><msqrt><mn>3</mn></msqrt><mspace></mspace><mi>x</mi><mspace></mspace><msqrt><mn>3</mn></msqrt></mrow><mo>)</mo></mrow><mi>R</mi><msup><mn>30</mn><mo>∘</mo></msup></mrow></math></span> structure which displays translational domains. High-speed scanning tunneling microscopy (STM) was used to image the motion of the O atoms. The data show that single O atoms preferentially move along the domain walls which in the STM movies appear as disordered, fluctuating stripes between the ordered domains. The diffusion coefficient of the O atoms is one order of magnitude higher than the diffusion coefficient in the ordered domains. By comparison with previous experiments on completely disordered CO layers, it is concluded that the diffusion is similarly promoted by the enhanced fluctuations in the disordered domain walls.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0039602824001481/pdfft?md5=56584dd5332ca4fc5c5a34180b11b3f8&pid=1-s2.0-S0039602824001481-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142167951","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 : 2024-09-05DOI: 10.1016/j.susc.2024.122596
Surface site activation enhances the sensing properties of the CeO2 (110) surface. Herein, the adsorption of nitrogen dioxide (NO2) on pristine and modified CeO2 (110) surfaces has been studied in detail using quantum chemical calculation. The introduction of the single praseodymium atom on the CeO2 surface reduces its band gap from 1.93 to 0.53 eV, which in turn enhances the adsorption energy from -0.58 (pristine) to -1.34 eV (doped) and also prolongs the desorption time, indicating stronger adsorption ability. The density of states (DOS) and projected density of states (PDOS) analyses reveal that Pr doping modifies the electronic properties of the CeO2 (110) surface which improves NO2 sensitivity. Further, it is also observed that 0.57 eV increase in the work function for NO₂ adsorption on Pr doped CeO2 surface, indicating stronger interaction compared to the pristine CeO2. In contrast, reduced CeO2 surfaces do not exhibit any significant change in sensing properties. Thus, it is understood that Pr-doped CeO2 (Pr/CeO2) surfaces exhibit better stability and sensitivity towards NO2 adsorption compared to pristine and reduced surfaces. Therefore, this study provides insight into the rational design of advanced gas sensing materials based on modified CeO2 (110) surfaces, contributing to the development of an efficient air quality monitoring system.
{"title":"A comparative DFT study on NO2 adsorption and sensing activities of pristine, reduced and Pr3+-doped CeO2 (110) surface","authors":"","doi":"10.1016/j.susc.2024.122596","DOIUrl":"10.1016/j.susc.2024.122596","url":null,"abstract":"<div><p>Surface site activation enhances the sensing properties of the CeO<sub>2</sub> (110) surface. Herein, the adsorption of nitrogen dioxide (NO<sub>2</sub>) on pristine and modified CeO<sub>2</sub> (110) surfaces has been studied in detail using quantum chemical calculation. The introduction of the single praseodymium atom on the CeO<sub>2</sub> surface reduces its band gap from 1.93 to 0.53 eV, which in turn enhances the adsorption energy from -0.58 (pristine) to -1.34 eV (doped) and also prolongs the desorption time, indicating stronger adsorption ability. The density of states (DOS) and projected density of states (PDOS) analyses reveal that Pr doping modifies the electronic properties of the CeO<sub>2</sub> (110) surface which improves NO<sub>2</sub> sensitivity. Further, it is also observed that 0.57 eV increase in the work function for NO₂ adsorption on Pr doped CeO<sub>2</sub> surface, indicating stronger interaction compared to the pristine CeO<sub>2</sub>. In contrast, reduced CeO<sub>2</sub> surfaces do not exhibit any significant change in sensing properties. Thus, it is understood that Pr-doped CeO<sub>2</sub> (Pr/CeO<sub>2</sub>) surfaces exhibit better stability and sensitivity towards NO<sub>2</sub> adsorption compared to pristine and reduced surfaces. Therefore, this study provides insight into the rational design of advanced gas sensing materials based on modified CeO<sub>2</sub> (110) surfaces, contributing to the development of an efficient air quality monitoring system.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S003960282400147X/pdfft?md5=da5d6fe58d0c46afcf6053356f53d89c&pid=1-s2.0-S003960282400147X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142163699","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 : 2024-09-01DOI: 10.1016/j.susc.2024.122595
Carboxylic acid-modified anatase TiO-water interfaces are widely relevant, yet understanding of their molecular scale structure is limited. To help improve this understanding, we here construct a deep neural network potential (DP) that accurately represents the potential energy surface of the formic (FA) and acetic acid (AA)-covered anatase TiO(101) (A101) interfaces with water predicted by Density Functional Theory (DFT) with the SCAN exchange–correlation functional. Long time-scale (ns) Molecular Dynamics simulations employing such DP provide insight into the hydration structure at the interface, showing how the water density profile and radial distribution functions depend on the coverage and adsorption configurations of the acids. The developed model sets the stage for estimating the adsorption energetics of these small carboxylic acids on the A101 surface in an aqueous environment.
{"title":"Long timescale molecular dynamics simulations of carboxylic acid-modified anatase TiO2(101)-water interfaces using ab-initio deep neural network potentials","authors":"","doi":"10.1016/j.susc.2024.122595","DOIUrl":"10.1016/j.susc.2024.122595","url":null,"abstract":"<div><p>Carboxylic acid-modified anatase TiO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-water interfaces are widely relevant, yet understanding of their molecular scale structure is limited. To help improve this understanding, we here construct a deep neural network potential (DP) that accurately represents the potential energy surface of the formic (FA) and acetic acid (AA)-covered anatase TiO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>(101) (A101) interfaces with water predicted by Density Functional Theory (DFT) with the SCAN exchange–correlation functional. Long time-scale (ns) Molecular Dynamics simulations employing such DP provide insight into the hydration structure at the interface, showing how the water density profile and radial distribution functions depend on the coverage and adsorption configurations of the acids. The developed model sets the stage for estimating the adsorption energetics of these small carboxylic acids on the A101 surface in an aqueous environment.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151355","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}