Large‐Scale Synthesis of Silver Nanocubes: The Role of HCl in Promoting Cube Perfection and Monodispersity

One lump or two! Selective etching of twinned seeds, mediated by HCl and the oxygen in air, resulted in high yields of perfect single-crystal silver nanocubes in a range of sizes (30–130 nm). The chloride ion enhances oxidation and prevents aggregation, while the proton decreases the rate of reduction and facilitates etching through the formation of nitric acid.