Novel cuprous oxide morphologies using amino acids and carboxylic acids as structure directing agents in a simple hydrothermal method

The reactivity and catalytic performance of cuprous oxide (Cu₂O) particles rely on the size and morphology of the Cu₂O crystals. In this study, a facile and mild hydrothermal route is applied to generate novel uniform cuprous oxide microcrystals, using non-toxic and low-cost carboxylic acids (O,O-type) and amino acids (N,O-type) as structure directing agents. N,O-type complexing agents showed a higher ability to reduce the copper species compared to the O,O-type ligands. Using oxalate and citrate complexes, pure Cu₂O was obtained after 4 h at 200 °C, whereas the oxalate-based complex leads to the morphology of uniformly stepped microcubes, the citrate complex as precursor leads to flower-like octapods that evolved from microcubes.