Nanostructured copper oxides and phosphates from a new solid-state route

► Nanostructured CuO, Cu3(PO4)3 and Cu2P2O7 have been prepared by solid-state pyrolysis of macromolecular precursors. ► The use of chitosan as a solid-state template/stabilizer induces CuO and Cu2O nanoparticles. ► Cu2P2O7 forms 100 nm single-crystal dots with areal densities of 5.1-7.7 Gigadots/in.2. ► CuO nanostructures with controlled morphology and size that exhibit superparamagnetic behavior.