Selective synthesis of plate-like and shrub-like micro-scale copper crystallites

Copper (Cu) plate-like and shrub-like micro-scale crystallites were synthesized by a facile hydrothermal method using formaldehyde (HCHO) as the reducing agent in NaOH aqueous solution at 180 °C. The X-ray diffraction patterns indicate that the as-synthesized Cu crystallites were well crystallized and with pure phase. FESEM and TEM images reveal that the final plate-like products consist of lager numbers of triangular and hexagonal plates with the edge length ranging from 0.5 to 4 μm and with the thickness ranging from 250 to 350 nm, and the shrub-like products are composed of some dendrites. SAED and HRTEM images prove that the Cu plates are singe crystals and covered by {1 1 1} facets. The effect of capping agent, NaOH concentration, reaction time and temperature on the morphologies of the final products has been investigated, and their possible formation mechanisms were also discussed.