{"title":"还原二维晶体 MoO3 单层","authors":"","doi":"10.1016/j.susc.2024.122579","DOIUrl":null,"url":null,"abstract":"<div><p>The atomic structure of MoO<sub>x</sub> films formed upon a gradual thermal reduction of an ordered MoO<sub>3</sub> monolayer on the Pd(100) substrate was explored via surface science characterization techniques and density functional theory (DFT) calculations. Two main reduction stages were identified. First, the initial oxygen excess was gradually eliminated by altering the domain boundary length, orientation, and atomic structure. The films nevertheless remained O-rich, with numerous terminal oxygen atoms (formation of Mo<img>O groups), and an elevated work function. Second, multiple ordered O-lean phases were formed, characterized by either very few or no terminal oxygen atoms, and a much smaller surface work function. According to calculations, the positive charging of the Pd substrate stabilizes the oxygen excess during the first stage, but during the second reduction stage, the substrate becomes negatively charged, stabilizing enhanced cation oxidation states. On their basis, the mechanisms underlying the oxygen release from the initial c(2 × 2) domains were disclosed. The experiments showed that the film reduction is perfectly reversible, which highlights the very promising properties of the MoO<sub>3</sub>/Pd system for heterogeneous catalysis.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1000,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0039602824001304/pdfft?md5=1525d168946b789b4b9dc648b293aa1e&pid=1-s2.0-S0039602824001304-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Reduction of a two-dimensional crystalline MoO3 monolayer\",\"authors\":\"\",\"doi\":\"10.1016/j.susc.2024.122579\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The atomic structure of MoO<sub>x</sub> films formed upon a gradual thermal reduction of an ordered MoO<sub>3</sub> monolayer on the Pd(100) substrate was explored via surface science characterization techniques and density functional theory (DFT) calculations. Two main reduction stages were identified. First, the initial oxygen excess was gradually eliminated by altering the domain boundary length, orientation, and atomic structure. The films nevertheless remained O-rich, with numerous terminal oxygen atoms (formation of Mo<img>O groups), and an elevated work function. Second, multiple ordered O-lean phases were formed, characterized by either very few or no terminal oxygen atoms, and a much smaller surface work function. According to calculations, the positive charging of the Pd substrate stabilizes the oxygen excess during the first stage, but during the second reduction stage, the substrate becomes negatively charged, stabilizing enhanced cation oxidation states. On their basis, the mechanisms underlying the oxygen release from the initial c(2 × 2) domains were disclosed. The experiments showed that the film reduction is perfectly reversible, which highlights the very promising properties of the MoO<sub>3</sub>/Pd system for heterogeneous catalysis.</p></div>\",\"PeriodicalId\":22100,\"journal\":{\"name\":\"Surface Science\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.1000,\"publicationDate\":\"2024-08-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.sciencedirect.com/science/article/pii/S0039602824001304/pdfft?md5=1525d168946b789b4b9dc648b293aa1e&pid=1-s2.0-S0039602824001304-main.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Surface Science\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0039602824001304\",\"RegionNum\":4,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Surface Science","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0039602824001304","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Reduction of a two-dimensional crystalline MoO3 monolayer
The atomic structure of MoOx films formed upon a gradual thermal reduction of an ordered MoO3 monolayer on the Pd(100) substrate was explored via surface science characterization techniques and density functional theory (DFT) calculations. Two main reduction stages were identified. First, the initial oxygen excess was gradually eliminated by altering the domain boundary length, orientation, and atomic structure. The films nevertheless remained O-rich, with numerous terminal oxygen atoms (formation of MoO groups), and an elevated work function. Second, multiple ordered O-lean phases were formed, characterized by either very few or no terminal oxygen atoms, and a much smaller surface work function. According to calculations, the positive charging of the Pd substrate stabilizes the oxygen excess during the first stage, but during the second reduction stage, the substrate becomes negatively charged, stabilizing enhanced cation oxidation states. On their basis, the mechanisms underlying the oxygen release from the initial c(2 × 2) domains were disclosed. The experiments showed that the film reduction is perfectly reversible, which highlights the very promising properties of the MoO3/Pd system for heterogeneous catalysis.
期刊介绍:
Surface Science is devoted to elucidating the fundamental aspects of chemistry and physics occurring at a wide range of surfaces and interfaces and to disseminating this knowledge fast. The journal welcomes a broad spectrum of topics, including but not limited to:
• model systems (e.g. in Ultra High Vacuum) under well-controlled reactive conditions
• nanoscale science and engineering, including manipulation of matter at the atomic/molecular scale and assembly phenomena
• reactivity of surfaces as related to various applied areas including heterogeneous catalysis, chemistry at electrified interfaces, and semiconductors functionalization
• phenomena at interfaces relevant to energy storage and conversion, and fuels production and utilization
• surface reactivity for environmental protection and pollution remediation
• interactions at surfaces of soft matter, including polymers and biomaterials.
Both experimental and theoretical work, including modeling, is within the scope of the journal. Work published in Surface Science reaches a wide readership, from chemistry and physics to biology and materials science and engineering, providing an excellent forum for cross-fertilization of ideas and broad dissemination of scientific discoveries.