Synthesis of 3D Flower-Like Ni0.6Zn0.4O Microspheres for Electrocatalytic Oxidation of Methanol

The 3D flower-like Ni 0.6 Zn 0.4 O microspheres were prepared by calcination treatment of Ni–Zn LDHs (layered double hydroxides) that were obtained through a hydrothermal method. The yielded Ni 0.6 Zn 0.4 O microspheres were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET). The results showed that the calcinated microspheres of Ni 0.6 Zn 0.4 O still well maintained the flower-like architecture of Ni–Zn LDHs. The surface area, total pore volume, and average pore diameter of the Ni 0.6 Zn 0.4 O microspheres were obtained with the values of 36.106 m 2  g −1 , 0.111 cm 3  g −1 , and 5.676 nm, respectively. As modified anode active materials, the Ni 0.6 Zn 0.4 O microspheres exhibited excellent electrocatalytic performance and fast electrochemical kinetics for methanol oxidation in strong alkaline electrolyte where the high surface area of flower-like Ni 0.6 Zn 0.4 O microspheres provides the high contact probability between catalysts and reactants. The presence of Zn also improves the electron transfer within catalysts inside. Also, the Ni 0.6 Zn 0.4 O modified electrode maintained good electrocatalytic performance during the term of 36,000 s. Diagram of the formation of the flower-like Ni 0.6 Zn 0.4 O microspheres and CVs of Ni 0.6 Zn 0.4 O/GCE (a, d), NiO/GCE (b, e), and ZnO/GCE (c, f) in KOH solution without (a–c) and with (d–f) 0.1 M methanol.