Improved f‑Al13 Nanoscale Cluster Synthesis: Design of Experiments as a Method for Green Reaction Planning

Alumina films and nanoparticles are industrially relevant materials that can be difficult to prepare due to synthetic challenges relating to controlling the size of the nanoparticulates. The synthesis of an ∼1 nm “flat-Al13” (f-Al13) nanoscale alumina species was optimized through statistical analysis. Through examination of historic data sets, improved synthesis conditions were elucidated by design of experiments (DOE) and validated experimentally. These results were confirmed through dynamic light scattering (DLS) measurements, and resulted in a 4- to 12-fold increase in DLS peak intensity for the 1 nm cluster (increase from 5.3% to 23.6% and 66.2%), and an essentially quantitative conversion of mass percentage to the 1–2 nm f-Al13 cluster over larger oligomers and agglomerates. This methodology reduces the need for expansive synthetic runs, reducing the overall solvent usage and waste resulting in a greener synthetic method.