Rodolfo Fini,Marina Magnani,Celso V Santilli,Sandra H Pulcinelli
{"title":"Tuning the Formation and Growth of Platinum Nanoparticles Using Surfactant: In Situ SAXS Study of the Aggregative Growth Mechanism.","authors":"Rodolfo Fini,Marina Magnani,Celso V Santilli,Sandra H Pulcinelli","doi":"10.1021/acsami.5c05268","DOIUrl":"https://doi.org/10.1021/acsami.5c05268","url":null,"abstract":"The synthesis of platinum nanoparticles (Pt NP) via chemical reduction with ascorbic acid (AA) and kinetic stabilization with the cationic surfactant tetradecyltrimethylammonium bromide (TTAB) was investigated, with emphasis on the influence of the TTAB/Pt2+ ratio on particle size and growth behavior. Based on small-angle X-ray scattering (SAXS), ultraviolet-visible (UV-vis), and transmission electron microscopy (TEM) analyses, a four-stage mechanism was proposed for Pt NP formation, starting from nucleation and initial growth of primary nanoparticles (NPp), followed by a hierarchical aggregation process governed by the interplay between attractive and repulsive forces. While the ascorbic acid governs the reduction pathway and remains central to defining the morphology of Pt NP, the addition of TTAB was found to significantly modulate aggregation kinetics and structural organization, even though it does not act as a direct shape-directing agent. The higher the TTAB concentrations, the smaller and more monodisperse the primary NP, the enhanced the electrosteric stabilization, and the denser the aggregates with lower porosity. These changes were closely correlated with a decrease in the aggregation rate and an increase in the activation barrier for aggregation. This work advances the understanding of how cationic surfactants, even when not acting as shape-directing agents, can critically influence the assembly and final architecture of Pt nanostructures, providing valuable insights into the rational design of nanoparticle-based materials.","PeriodicalId":5,"journal":{"name":"ACS Applied Materials & Interfaces","volume":"7 1","pages":""},"PeriodicalIF":9.5,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144533595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seonmyeong Yu, Hyeyun Kim, Jaeho Shin, Junsu Kim, Won Il Kim, Hyungyu Cho, Sohyun Heo, Chun-Jae Yoo, Wooseok Yang, Hyesung Cho, Kwang Ho Kim*, Ho Seok Park* and Kahyun Hur*,
{"title":"","authors":"Seonmyeong Yu, Hyeyun Kim, Jaeho Shin, Junsu Kim, Won Il Kim, Hyungyu Cho, Sohyun Heo, Chun-Jae Yoo, Wooseok Yang, Hyesung Cho, Kwang Ho Kim*, Ho Seok Park* and Kahyun Hur*, ","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":5,"journal":{"name":"ACS Applied Materials & Interfaces","volume":"17 26","pages":"XXX-XXX 962–968"},"PeriodicalIF":8.3,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acsami.5c07304","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144521795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tim Kratky,Jürgen Kraus,Paul M Leidinger,Patrick Zeller,Francesca Genuzio,Alessandro Sala,Tevfik Onur Menteş,Andrea Locatelli,Sebastian Günther
{"title":"Making Use of Si Contaminants during Chemical Vapor Deposition of Graphene on Cu: Synthesis of a Stable Material with the Textbook-like Band Structure of Free-Standing Graphene.","authors":"Tim Kratky,Jürgen Kraus,Paul M Leidinger,Patrick Zeller,Francesca Genuzio,Alessandro Sala,Tevfik Onur Menteş,Andrea Locatelli,Sebastian Günther","doi":"10.1021/acsami.5c06939","DOIUrl":"https://doi.org/10.1021/acsami.5c06939","url":null,"abstract":"We report on a gentle procedure for the complete electronic decoupling of graphene from Cu. The procedure can be added to the growth protocol of graphene synthesis by chemical vapor deposition making use of the widely unnoticed silicon release from hot wall quartz tube reactors. So far, Si release was observed if the effect was large, so that it deteriorates the grown graphene. However, the effect can also be used to turn the electronic band structure of CVD-grown graphene on Cu into that of free-standing graphene as shown in a combined spectroscopic photoelectron and low energy electron microscopy study. Adding a foil pretreatment to the synthesis protocol in the reactor turns the polycrystalline foil into (111)-textured Cu, and the electronic band structure of CVD-grown graphene on Cu(111) is achieved with n-doping by -0.4 eV and band gap formation of 0.3 eV. If, however, graphene is synthesized on a Si-loaded Cu foil, subsequent oxygen exposure in the reactor segregates the dissolved Si to the surface and converts it to intercalated silica without destroying the covering graphene. The graphene decouples electronically, and the textbook-like electronic band structure of free-standing graphene emerges. The alternating stacking of 30°-rotated layers in thicker graphene leads to electronically noninteracting layers. Moreover, in angle-resolved photoemission, replica bands due to Umklapp processes emerge without the opening of an energy gap.","PeriodicalId":5,"journal":{"name":"ACS Applied Materials & Interfaces","volume":"47 1","pages":""},"PeriodicalIF":9.5,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144533592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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