GCE of 3-mm diameter, before use, was first polished to a mirrorlike
with 1.0, 0.3 and 0.05 mm Al2O3 slurry on a polish cloth, and
rinsed with double-distilled water, then ultrasonic treat in ethanol
and double-distilled water for 5 min, respectively. The modified
process was illustrated in Scheme 1. The first step was the preparation
of nanoZnO/GCE: NanoZnO electrodeposits were grown in
Multi-Potential Steps method mode at 60 ◦C in an aqueous solution
composed of 0.1 M ZnCl2 with 0.1 M potassium chloride (KCl) as
supporting electrolyte under oxygen bubbling. For comparison purpose,
electrodeposition was also conducted at the same condition
without oxygen bubbling. The second step was the preparation of
CuNPs/nanoZnO/GCE: this process was conducted by potentiostatic
deposition at
−0.5 V for 120 s in an aqueous solution composed
of 0.01 M Cu(NO3)2 with 0.1 M KCl. The third step was the formation
of Pt nanomaterials: A template-engaged replacement reaction
between the deposited CuNPs and the aqueous H2PtCl6 solution
was carried out. Multi-Potential Steps method mode was employed
to assist the formation of PtNPs at the nanoZnO/GCE according
to gas bubble dynamic template method. The PtNPs/nanoZnO/GCE
was as stored at 4 ◦C when not in use.