Facile synthesis and shape evolution of oleic acid decorated Cu2O microcrystals

•A facile synthetic method of oleic acid decorated Cu2O microcrystals was developed.•The synthetic method does not require a reducing agent to attend.•The synthetic method enhances antioxidant properties of Cu2O and dispersity in paraffin.•The phase structure and morphology of Cu2O microcrystals were investigated.•Shape evolution of oleic acid decorated Cu2O microcrystals was studied. A facile synthetic method of oleic acid decorated Cu2O microcrystals has been developed by thermal decomposition of copper formate-octylamine complexes in paraffin using oleic acid as dispersing agent. This new method showed many advantages, which include free-reducing agent, enhancing antioxidant properties of Cu2O and good dispersity in paraffin, etc. The phase structure and morphology were investigated by means of XRD, SEM and TEM. It is found that the reaction time and temperature play the important roles in the crystallite morphology. With the increase of the reaction time, the Cu2O rhombic dodecahedron is gradually transformed into the spherical particle by intraparticle ripening. The shape evolution of Cu2O microcrystals can be accelerated with the increase of temperature.