{"title":"TiO2(110) 和 SiOx 上铜簇界面的电荷转移","authors":"","doi":"10.1016/j.susc.2024.122547","DOIUrl":null,"url":null,"abstract":"<div><p>Metal nanoparticles supported on different oxidic supports are the most common materials in heterogeneous (photo-)catalysis. This work presents a systematic investigation of copper clusters deposited onto slightly and highly reduced rutile TiO<sub>2</sub>(110) single crystals and silicon wafers with native oxide films. The focus is on the electronic properties of the copper clusters and possible metal-support interactions as these can change the catalytic behavior of the catalyst. Specifically, we examine coverage-dependent core-level binding energy shifts and kinetic energy Auger signal shifts of the Cu2p<sub>3/2</sub> and CuLMM signals in X-ray photoelectron spectroscopy as well as a Wagner plot analysis, Auger parameter analysis, and analyze the main support signals. The final-state-induced binding energy shifts dominant at lower coverages are related to the imperfect core-hole shielding of the positive charge remaining after photoemission. At higher copper coverages the more metallic character of the clusters, apparent from dominating initial-state effects, is more prominent. The shift in binding energy, kinetic energy, and Auger parameter are larger for copper on silica than for copper on reduced titania. The formation of Ti<sup>3+</sup> or Si<sup>3+</sup> indicates a charge transfer from the metal clusters to the support. For the first nominal monolayer of copper on titania a constant number of Ti<sup>3+</sup> interstitials of 6% to 8% were observed regardless of the initial reduction degree of the titania. At the highest copper coverage, the local Ti<sup>3+</sup> density at the (sub)surface increases to 11.0% and 11.7%. For the SiO<sub>x</sub> surface the same could be observed as the Si<sup>3+</sup>/Si<sup>4+</sup> ratio increased from 4% at the lowest copper coverage to 73% at the highest. For the inert SiO<sub>x</sub> surface, we suggest an interaction of the copper with defects in the amorphous thin film.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1000,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0039602824000980/pdfft?md5=f591f88bf8fa5527d3967ce11ef36ce2&pid=1-s2.0-S0039602824000980-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Charge transfer at interfaces of copper clusters on TiO2(110) and SiOx\",\"authors\":\"\",\"doi\":\"10.1016/j.susc.2024.122547\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Metal nanoparticles supported on different oxidic supports are the most common materials in heterogeneous (photo-)catalysis. This work presents a systematic investigation of copper clusters deposited onto slightly and highly reduced rutile TiO<sub>2</sub>(110) single crystals and silicon wafers with native oxide films. The focus is on the electronic properties of the copper clusters and possible metal-support interactions as these can change the catalytic behavior of the catalyst. Specifically, we examine coverage-dependent core-level binding energy shifts and kinetic energy Auger signal shifts of the Cu2p<sub>3/2</sub> and CuLMM signals in X-ray photoelectron spectroscopy as well as a Wagner plot analysis, Auger parameter analysis, and analyze the main support signals. The final-state-induced binding energy shifts dominant at lower coverages are related to the imperfect core-hole shielding of the positive charge remaining after photoemission. At higher copper coverages the more metallic character of the clusters, apparent from dominating initial-state effects, is more prominent. The shift in binding energy, kinetic energy, and Auger parameter are larger for copper on silica than for copper on reduced titania. The formation of Ti<sup>3+</sup> or Si<sup>3+</sup> indicates a charge transfer from the metal clusters to the support. For the first nominal monolayer of copper on titania a constant number of Ti<sup>3+</sup> interstitials of 6% to 8% were observed regardless of the initial reduction degree of the titania. At the highest copper coverage, the local Ti<sup>3+</sup> density at the (sub)surface increases to 11.0% and 11.7%. For the SiO<sub>x</sub> surface the same could be observed as the Si<sup>3+</sup>/Si<sup>4+</sup> ratio increased from 4% at the lowest copper coverage to 73% at the highest. For the inert SiO<sub>x</sub> surface, we suggest an interaction of the copper with defects in the amorphous thin film.</p></div>\",\"PeriodicalId\":22100,\"journal\":{\"name\":\"Surface Science\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.1000,\"publicationDate\":\"2024-07-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.sciencedirect.com/science/article/pii/S0039602824000980/pdfft?md5=f591f88bf8fa5527d3967ce11ef36ce2&pid=1-s2.0-S0039602824000980-main.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Surface Science\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0039602824000980\",\"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/S0039602824000980","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Charge transfer at interfaces of copper clusters on TiO2(110) and SiOx
Metal nanoparticles supported on different oxidic supports are the most common materials in heterogeneous (photo-)catalysis. This work presents a systematic investigation of copper clusters deposited onto slightly and highly reduced rutile TiO2(110) single crystals and silicon wafers with native oxide films. The focus is on the electronic properties of the copper clusters and possible metal-support interactions as these can change the catalytic behavior of the catalyst. Specifically, we examine coverage-dependent core-level binding energy shifts and kinetic energy Auger signal shifts of the Cu2p3/2 and CuLMM signals in X-ray photoelectron spectroscopy as well as a Wagner plot analysis, Auger parameter analysis, and analyze the main support signals. The final-state-induced binding energy shifts dominant at lower coverages are related to the imperfect core-hole shielding of the positive charge remaining after photoemission. At higher copper coverages the more metallic character of the clusters, apparent from dominating initial-state effects, is more prominent. The shift in binding energy, kinetic energy, and Auger parameter are larger for copper on silica than for copper on reduced titania. The formation of Ti3+ or Si3+ indicates a charge transfer from the metal clusters to the support. For the first nominal monolayer of copper on titania a constant number of Ti3+ interstitials of 6% to 8% were observed regardless of the initial reduction degree of the titania. At the highest copper coverage, the local Ti3+ density at the (sub)surface increases to 11.0% and 11.7%. For the SiOx surface the same could be observed as the Si3+/Si4+ ratio increased from 4% at the lowest copper coverage to 73% at the highest. For the inert SiOx surface, we suggest an interaction of the copper with defects in the amorphous thin film.
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.