One-pot synthesis of lightly doped Zn1-x Cu x O and Au-Zn1-x Cu x O with solar light photocatalytic activity in liquid phase.

We report on the facile and low-temperature one-pot chemical synthesis of lightly doped Zn1-x Cu x O and hybrid Au-Zn1-x Cu x O photocatalysts with low Cu molar content (0 < x < 0.7%) using 1,3-propanediol polyol simultaneously as solvent, reducing and a stabilizing agent, without any final thermal treatment. The photocatalysts have been characterized by X-ray diffraction, N2 adsorption study, UV-vis diffuse reflectance spectroscopy, inductively coupled plasma optical emission spectroscopy, and transmission electron microscopy. The lightly doped hybrid Au-Zn1-x Cu x O photocatalysts consisted in faceted quasi-spherical large-size Au nanoparticle cores surrounded by closely packed small-size Zn1-x Cu x O nanoparticles. Taking the photocatalytic degradation of Diuron under solar light as liquid-phase test reaction, the lightly doped Au-Zn1-x Cu x O hybrid photocatalysts with optimized x = 0.09% Cu content showed strongly enhanced photocatalytic activity when compared to the bare ZnO counterpart. The observed 16-fold higher degradation rate constant resulted jointly from the light doping of ZnO with Cu to form Zn1-x Cu x O photocatalyst and further from the addition of gold nanoparticles allowing interfacial oxide-to-metal electron transfer within the hybrid Au-Zn1-x Cu x O photocatalyst.