Abstract
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•Doped Cu-codoped ZnO prepared by facile wet-chemical method.•Highly sensitive HCHO sensor by reliable electrochemical method.•Selective enzyme-less formaldehyde sensor development.•Analyzed the real human serum samples.•Effective sensor for healthcare and biomedical fields.
An aggregated copper codoped zinc oxide (CZO; CuO.ZnO) nanomaterial was synthesized to detect formaldehyde (HCHO) from aqueous solution via electrochemical reactions. The as-grown CZO nanostructures have a typical diameter of 140 ± 15 nm in size. From the spectroscopic and electrochemical studies it was revealed that the CZO nanomaterials exhibit completely different electrochemical and electro-catalytic properties from the constituents. In terms of electro-catalytic oxidation reactions, the best reactivity was noticed at the 7.0 pH value. At the CZO surface, when HCHO molecules come in contact with the CZO surface, a coupled two electron two protons transfer reaction occur. This CZO/GCE sensor showed an excellent sensitivity (5.427 μAμM−1 cm-2), extremely low limit of detection (LOD: 4.1 ± 0.1 nM; S/N = 3), limit of quantification (LOQ: 13.67), long-term stability, and decent repeatability. In the investigative study, a linear calibration plot was found for a wide range of concentration of HCHO (0.002 μM–6000 μM; r2 = 0.9982). Compared to the bare ZnO NPs and CuO NPs, the response value at the CZO NPs toward 2.25 μM HCHO is more than ten-fold higher. This method could be an effective method of sensitive and selective electrochemical sensor development to detect hazardous and carcinogenic chemicals in aqueous medium for the safety of environmental and healthcare fields in broad scales.