Synthesis of ZnO and CuO co-decorated porous carbon spheres with simultaneous accessibility to small biomelucules

ZnO and CuO co-decorated porous carbon spheres (PCS) were prepared via a simple hydrothermal method, denoted as ZnO-CuO/PCS. An electrochemical sensor based on the ZnO-CuO/PCS was fabricated for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Three well-resolved anodic peaks along with greatly increased peak currents were obtained at the ZnO-CuO/PCS modified glassy carbon electrode (GCE) on the differential pulse voltammograms. The anodic peak separations at the ZnO-CuO/PCS/GCE were 204 mV between AA and DA and 132 mV between DA and UA. Notably, the analytical performances of the ZnO-CuO/PCS outperform those of ZnO/PCS and CuO/PCS, which can be attributed to the synergistic effect of the two metallic oxides, i.e., the formation of p-n heterojunctions between p-type CuO and n-type ZnO allows sensitive transduction into remarkable changes in the electrochemical signals. The ZnO-CuO/PCS/GCE also presented high anti-interference ability, storage stability and repeatability in the determination of AA, DA and UA. Finally, the practical applicability of the prepared sensor was successfully demonstrated by the simultaneous determination of AA, DA and UA in human urine samples.