Synthesis, characterisation and stability of Cu₂O nanoparticles produced via reverse micelles microemulsion

Cuprite (Cu₂O) nanoparticles were synthesized at room temperature via reduction of CuCl₂·2H₂O by NaBH₄ in water/n-heptane microemulsion stabilised by the non-ionic Brij30 surfactant. Whole Powder Pattern Modelling of the X-ray diffraction patterns shows the presence of a bimodal size distribution in the nanopowders, with a fraction of domains in the 10-40 nm range and a smaller one below 10 nm. Linear and planar defects are absent. A relationship between the average size of the larger particles and the quantity of water in the system was obtained. The stability of cuprite under visible light irradiation both during the synthesis and after the preparation was investigated, showing that a self-catalytic conversion of Cu₂O into CuO takes place in water.