Using Silver Nanoclusters as a New Tool in Nanotechnology: Synthesis and Photocorrosion of Different Shapes of Gold Nanoparticles

Abstract

Until now, the concept of metal (0) atomic quantum clusters or nanoclusters (NCs) and their increasing role in nanotechnology due to their novel and exceptional properties in important industrial fields (such as catalysis) has not been included at the education level. Here, syntheses of both metal nanoparticles (NPs) and metal nanoclusters (with sizes below ≈1–2 nm) are used for understanding the large differences between both types of nanomaterials. In this experiment we highlight the catalytic and photocatalytic properties of silver NCs, as well as the plasmon band, as the main optical difference between metal NPs and NCs. In the first step of the experiment, the synthesis of different sizes and shapes of AuNPs is carried out and changes in their plasmon band are discussed. In a second step, students conduct the anisotropic growth of AuNPs, catalyzed by silver NCs (Ag n , where n is the number of atoms forming the cluster), which do not display a plasmon band. Finally, it is shown that Ag n NCs can induce AuNP photocorrosion, which can be avoided by introducing molecules with more negative redox potential (called hole scavengers). Redox properties of Ag n NCs are used in this laboratory experiment to discuss with the students several important physicochemical issues, such as absolute and hydrogen redox potential scales, electronic and optical properties of nanomaterials, semiconductor band gap, photogenerated electron–hole pairs (excitons), catalysis and photocatalysis, the role of hole scavengers, or spontaneous process and free energy. This very new area at the bottom of nanotechnology is ideal to make chemistry relevant and engaging for students. It allows them to learn fundamentals by using chemistry that is at the frontier of research, and they are able to do this in an accessible way.

Nanobilim ve Nanoteknoloji Eğitimi Araştırmaları Üzerine Bir Bibliyometrik Analiz

“…The laboratories provided appropriate environments to implement hands-on experiences, and laboratory exercises represented the hands-on learning aspect of NST related studies. In addition, there were many articles focusing the fabrication, characterization, properties, and applications of nanoparticles such as AgNPs and AuNPs through laboratory experiments (e.g., Amaris et al, 2017;Cea et al, 2016;Perez-Marino et al, 2019). The authors of these articles claimed that such efforts aimed to educate a well-trained nanotechnology workforce because of the increasing applications of nanomaterials.…”

Spin Crossover Nanoparticles

“…In past years, several laboratory experiments for high school and undergraduate students have been published in this Journal in the field of nanoparticles in order to study their exceptional optical properties with respect to bulk materials. Most of these articles are based on gold and silver nanoparticles of different sizes and shapes for which the spectroscopic properties are based on plasmon resonance phenomena. − Likewise, quantum dots (QDs) embellished by the decomposition of the ligands at high temperature have been used to study the size dependent properties of nanoparticles . The appealing properties of QDs such as the coverage of the completely visible spectrum render them an exceptional platform to study size and composition effects in their optical properties as well.…”

Teaching Nanotechnology through Research Proposals

“…Nanotechnology, with its multidisciplinary character, has experienced a rise in the past few decades and has had a significant influence on almost all fields of science and technology, − including chemistry . This was also recognized in 2016 when the Nobel Prize in Chemistry was awarded to Stoddart, Sauvage, and Feringa for their remarkable work on nanomachines. , As the relevance of nanotechnology in society grew more and more obvious, its importance in education became more evident too. ,− This has been recognized at all levels of education, namely, primary, secondary, ,− and tertiary (higher) education. ,− Most contributions regarding nanotechnology in higher education, however, deal with the importance of teaching nanotechnology, , the content taught within nanotechnology courses ,,, or laboratory experiments found useful to illustrate important concepts in nanotechnology in the lab. − However, there are only several published contributions on the activities in the nanotechnology classroom ,,,,,,, at any level as most contributions focus on wh...…”