Model Ag/HOPG Catalysis for Ethylene Epoxidation: Comparison of Methods for the Preparation of Large Ag Particles with High Surface Coverage

IF 2.5 4区化学 Q3 CHEMISTRY, PHYSICAL

Catalysis Letters Pub Date : 2026-10-07 DOI:10.1007/s10562-026-05538-7

Anna V. Nartova, Аlexandra A. Ananina, Aleksey M. Dmitrachkov, Ren I. Kvon, Maxim A. Panafidin, Boris V. Andryushechkin, Valerii I. Bukhtiyarov

{"title":"Model Ag/HOPG Catalysis for Ethylene Epoxidation: Comparison of Methods for the Preparation of Large Ag Particles with High Surface Coverage","authors":"Anna V. Nartova, Аlexandra A. Ananina, Aleksey M. Dmitrachkov, Ren I. Kvon, Maxim A. Panafidin, Boris V. Andryushechkin, Valerii I. Bukhtiyarov","doi":"10.1007/s10562-026-05538-7","DOIUrl":null,"url":null,"abstract":"<div><p>The results of the preparation of ‘Ag/HOPG’ model catalysts for ethylene epoxidation, focusing on the preparation of a high coverage of large silver particles on HOPG (highly oriented pyrolytic graphite) surface and suitable for in situ XPS (X-ray photoelectron spectroscopy) and STM (scanning tunneling microscopy) studies are presented. Several approaches to preparing Ag/HOPG samples are compared. SEM (scanning electron microscopy), STM, and XPS, combined with deep-learning analysis, were used to quantify particle-size distributions, the number of Ag particles per unit area, and the surface coverage of the support by Ag. It is shown that damaging of the basal plane of graphite (by Ar<sup>+</sup> etching) (i) is promising for film-like Ag - coating, due to the merging of closely spaced particles upon their growth; (ii) promotes Ag-C encapsulation. These effects make such samples unsuitable for reaction mechanistic studies. In contrast, thermal vacuum deposition of silver using an e-beam evaporator on freshly peeled HOPG produces uniformly distributed, relatively flat Ag particles with controlled mean sizes in the range of 30–100 nm and Ag coverages up to 0.59 of the support surface area. Annealing a sample containing 100 nm Ag particles in vacuum at 500 °C reveals Ostwald ripening. O 1s XPS line analysis confirms that prepared low-oxygen Ag/HOPG systems are suitable model catalysts for the instrumental studies of ethylene epoxidation.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":508,"journal":{"name":"Catalysis Letters","volume":"156 11","pages":""},"PeriodicalIF":2.5000,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Catalysis Letters","FirstCategoryId":"92","ListUrlMain":"https://link.springer.com/article/10.1007/s10562-026-05538-7","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}

引用次数: 0

Abstract

The results of the preparation of ‘Ag/HOPG’ model catalysts for ethylene epoxidation, focusing on the preparation of a high coverage of large silver particles on HOPG (highly oriented pyrolytic graphite) surface and suitable for in situ XPS (X-ray photoelectron spectroscopy) and STM (scanning tunneling microscopy) studies are presented. Several approaches to preparing Ag/HOPG samples are compared. SEM (scanning electron microscopy), STM, and XPS, combined with deep-learning analysis, were used to quantify particle-size distributions, the number of Ag particles per unit area, and the surface coverage of the support by Ag. It is shown that damaging of the basal plane of graphite (by Ar⁺ etching) (i) is promising for film-like Ag - coating, due to the merging of closely spaced particles upon their growth; (ii) promotes Ag-C encapsulation. These effects make such samples unsuitable for reaction mechanistic studies. In contrast, thermal vacuum deposition of silver using an e-beam evaporator on freshly peeled HOPG produces uniformly distributed, relatively flat Ag particles with controlled mean sizes in the range of 30–100 nm and Ag coverages up to 0.59 of the support surface area. Annealing a sample containing 100 nm Ag particles in vacuum at 500 °C reveals Ostwald ripening. O 1s XPS line analysis confirms that prepared low-oxygen Ag/HOPG systems are suitable model catalysts for the instrumental studies of ethylene epoxidation.

Graphical Abstract

查看原文本刊更多论文

模型Ag/HOPG催化乙烯环氧化：制备高表面覆盖率大Ag颗粒方法的比较

介绍了“Ag/HOPG”型乙烯环氧化催化剂的制备结果，重点介绍了在HOPG（高取向热解石墨）表面制备高覆盖度的大银颗粒，并适用于原位XPS （x射线光电子能谱）和STM（扫描隧道显微镜）研究。比较了几种制备Ag/HOPG样品的方法。SEM（扫描电子显微镜）、STM和XPS结合深度学习分析，量化颗粒尺寸分布、单位面积Ag颗粒数量以及Ag在载体表面的覆盖率。结果表明，通过Ar+蚀刻(i)对石墨基面进行破坏，可以形成薄膜状的Ag -涂层，这是由于在生长过程中紧密分布的颗粒合并；（ii）促进Ag-C封装。这些影响使得这些样品不适合用于反应机理的研究。相比之下，利用电子束蒸发器在新鲜剥皮的HOPG上热真空沉积银，可以得到均匀分布、相对平坦的银颗粒，其平均尺寸在30-100 nm范围内，银的覆盖面积高达支撑表面积的0.59。在500°C真空退火含有100 nm银粒子的样品显示奥斯特瓦尔德成熟。o1s XPS线分析证实制备的低氧Ag/HOPG体系是乙烯环氧化仪器研究的合适模型催化剂。图形抽象

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Catalysis Letters 化学-物理化学

CiteScore

5.70

自引率

3.60%

发文量

327

审稿时长

1 months

期刊介绍： Catalysis Letters aim is the rapid publication of outstanding and high-impact original research articles in catalysis. The scope of the journal covers a broad range of topics in all fields of both applied and theoretical catalysis, including heterogeneous, homogeneous and biocatalysis. The high-quality original research articles published in Catalysis Letters are subject to rigorous peer review. Accepted papers are published online first and subsequently in print issues. All contributions must include a graphical abstract. Manuscripts should be written in English and the responsibility lies with the authors to ensure that they are grammatically and linguistically correct. Authors for whom English is not the working language are encouraged to consider using a professional language-editing service before submitting their manuscripts.