Enhanced catalytic activity without the use of an external light source using microwave-synthesized CuO nanopetals.

We report enhanced catalytic activity of CuO nanopetals synthesized by microwave-assisted wet chemical synthesis. The catalytic reaction of CuO nanopetals and H ₂ O ₂ was studied with the application of external light source and also under dark conditions for the degradation of the hazardous dye methylene blue. The CuO nanopetals showed significant catalytic activity for the fast degradation of methylene blue and rhodamine B (RhB) under dark conditions, without the application of an external light source. This increased catalytic activity was attributed to the co-operative role of H ₂ O ₂ and the large specific surface area (≈40 m ² ·g ^-1 ) of the nanopetals. We propose a detail mechanism for this fast degradation. A separate study of the effect of different H ₂ O ₂ concentrations for the degradation of methylene blue under dark conditions is also illustrated.