Fabrication of superhydrophilic Cu2O and CuO membranes

The present work demonstrates a simple method on the direct preparation of Cu2O and CuO membranes with super-hydrophilic property via calcination or reduction of the parent film of Cu(OH)2. By controlling the reaction conditions, Cu(OH)2 membranes with different surface patterns composed of nano-belts, whiskers, or stick-bundles were first prepared. Cu2O and CuO membranes were obtained from Cu(OH)2 membranes by subsequent reduction and dehydration, respectively. The patterns of the parent film of Cu(OH)2 were kept in the as-prepared Cu2O and CuO membranes. Interestingly, the Cu(OH)2 crystals with various morphologies on the as-prepared film were all transformed to close-packed Cu2O nanoparticles after the reduction. Wettability investigation reveals that both Cu2O and CuO membranes have super-hydrophilic properties.