Teaching Nanochemistry Through the Lens of the Green Chemistry Principles: An Undergraduate Gold Nanoparticle Synthesis Lab

An undergraduate quantitative analysis chemistry laboratory was designed to introduce students to nanochemistry and green chemistry while fostering a sustainability mindset that aligns with the 12 Principles of Green Chemistry. Two gold nanoparticle (AuNP) syntheses were used to teach students about green chemistry and sustainability: a modified Frens synthesis, a scaled-down version of the synthesis first published in the 1970s, and a synthesis that incorporates tea as a reducing reagent inspired by Sharma et al. This laboratory experiment was carried out over two 4-h laboratory meetings spanning 2 weeks with Green Chemistry Principles integrated into each stage of learning. Students were engaged in the theme of sustainability in prelab discussion, applied it throughout the hands-on syntheses, and reflected on it through the postlab, encouraging critical thinking throughout the synthetic process. This structure provides a teaching framework that instills Green Chemistry Principles 1, 6, and 7 of Prevention, Design for Energy Efficiency, and Use of Renewable Feedstocks, which are applied directly in the lab rather than as abstract principles. Due to AuNPs’ distinct characteristic absorbance peak between 520–550 nm, populations of monodisperse, pseudospherical AuNPs were identified. Through examination of spectroscopic data, comparison of these two products yields student knowledge about AuNP properties, including size, shape, and dispersity. This laboratory provides a foundation for teaching undergraduates about nanoparticles and lays the groundwork for fostering a green and sustainable mindset along with environmental responsibility in students, which can be carried forward in the fields of academia, research, and industry.