Table 1. Redox Characteristic Peak and Electroactive Surface Area for the CuONPs/ZY/SPEs.

electrode	Epa(V)	Epc(V)	ΔE(V)	Ipa(μA)	Ipc(A)	Ipc/Ipa(A)	active area (cm2) ± SEa
SPE	0.401	0.33	0.071	0.0608	–0.0694	1.14	0.0250 ± 0.002
CuO 1.0%	0.401	0.33	0.071	0.0973	–0.1020	1.05	0.0280 ± 0.003
CuO 2.0%	0.395	0.324	0.071	0.1860	–0.2000	1.08	0.0358 ± 0.003
CuO 5.0%	0.395	0.318	0.077	0.339	–0.3380	0.997	0.0795 ± 0.006
CuO 8.0%	0.407	0.33	0.077	0.4300	–0.4750	1.10	0.0950 ± 0.005
ZY 5.0%	0.395	0.33	0.065	0.171	–0.2000	1.17	0.0495 ± 0.003
CuO/ZY	0.395	0.324	0.071	0.7070	–0.8250	1.17	0.1250 ± 0.007

^aSE for three tropical measurements.