Synthesis of Gold Nanosheets through Thermolysis of Mixtures of Long Chain 1‐Alkylimidazole and Hydrogen Tetrachloroaurate(III)

Micron‐sized gold nanosheets were produced through thermolysis of a mixture composed of 1‐octa‐decanylimidazole (C 18 ‐im) and HAuCl 4 in a molar ratio of 4:1 at 200 °C for 1 h. Effects of the molar ratio of [ 18 ‐im]/[HAuCl 4 ], the reaction temperature, and the N‐alkylimidazole chain length were studied. Adjusting the molar ratio of [C 18 ‐im]/[HAuCl 4 ] can tune the morphology and size of the nanostructures; the effect of reaction temperature is minimum; while using long chain imidazole tends to favor the formation of nanosheets, using 1‐methylimidazole (C 1 ‐im) produces micron‐sized polyhedra. The growth mechanism of these nanostructures was proposed. C 18 ‐im functions both as a templating and capping agent and favors the growth of nanosheets. On the other hand, C 1 ‐im functions only as a capping agent and thus favors the formation of polyhedra, especially octahedra.