Nanostructured copper oxides and phosphates from a new solid-state route
Résumé
Nanostructured copper containing materials of CuO, Cu3(PO4)3 and Cu2P2O7 have been prepared by solid-state pyrolysis of molecular CuCl2*NC5H4OH (I), CuCl2*CNCH2C6H4OH (II), oligomeric [Cu(PPh3)Cl]4 (III), N3P3[OC6H4CH2CN*CuCl]6[PF6] (IV), N3P3[OC6H5]5[OC5H4N*Cu][PF6] (V), polymeric chitosan*(CuCl2)n (VI) and polystyrene-co-4-vinylpyridine PS-b-4-PVP*(CuCl2) (VII) precursors. The products strongly depend on the precursor used. The pyrolytic products from phosphorus-containing precursors (III), (IV) and (V) are Cu phosphates or pyrophosphates, while non-phosphorous-containing precursors (VI) and (VII), result in mainly CuO. The use of chitosan as a solid-state template/stabilizer induces the formation of CuO and Cu2O nanoparticles. Copper pyrophosphate (Cu2P2O7) deposited on Si using (IV) as the precursor exhibits single-crystal dots of average diameter 100 nm and heights equivalent to twice the unit cell b-axis (1.5-1.7 nm) and an areal density of 5.1-7.7 Gigadots/in.2. Cu2P2O7 deposited from precursor (VI) exhibits unique labyrinthine high surface area deposits. The morphology of CuO deposited on Si from pyrolysis of (VI) depends on the polymer/Cu meta ratio. Magnetic measurements performed using SQUID on CuO nanoparticle networks suggest superparamagnetic behavior. The results give insights into compositional, shape and morphological control of the as-formed nanostructures through the structure of the precursors.