Electrochemical incorporation of hemin in a ZnO–PPy nanocomposite on a Pt electrode as NOx sensor

Abstract

An electrochemical NO(x) sensor was fabricated based on the incorporation of hemin on a ZnO-PPy nanocomposite modified Pt electrode. Scanning electron microscopy, energy dispersive X-ray analysis and cyclic voltammetry were used to confirm the successful stepwise assembly procedure for the sensor. The electrocatalytical behavior of the sensor was investigated by cyclic voltammetry. The hemin-ZnO-PPy-Pt electrode exhibited characteristic hemin reversible redox peaks at 0.035 V and -0.11 V vs. Ag/AgCl respectively. The hemin-ZnO-PPy-Pt electrode exhibited 3-fold enhanced electrocatalytic activity towards NO(x) compared to the hemin-PPy-Pt electrode. The electrocatalytic response of the sensor was proportional to the NO(x) concentration in the range of 0.8 to 2000 μM (r(2) = 0.9974) with a sensitivity of 0.04 μA μM(-1) cm(-2) and detection limit of 0.8 μM for the hemin-ZnO-PPy-Pt electrode. The low detection limit, wide linear range and enhanced sensitivity of the present sensor make it valuable for potential applications. In addition, this sensor exhibited good reproducibility and stability.

Nanostructured Materials for Room‐Temperature Gas Sensors

“…Previous studies have demonstrated that hybrid materials are highly suitable in sensing applications, showing enhanced sensor stability, sensitivity and selectivity. The inorganic phase can be diverse, ranging from metal oxides, metal nanoparticles, carbon nanotubes and graphene . Their incorporation into conducting polymers can increase the concentration of interacting sites with the analytes, improve the intra‐ and inter‐chain mobility of charge carriers in the polymer chains or even modify the affinity of the composite to the electron‐donor or ‐acceptor molecules .…”

Organic–Inorganic Hybrid Nanocomposite-Based Gas Sensors for Environmental Monitoring

“…Kaushik et al 52 and Prakash et al 172 used WO 3 −PANI and hemin/ZnO-PPy nanocomposite thin film sensors, respectively, to detect NO x gases. The NO x gas sensing characteristics of the PPy-ZnO nanocomposites showed superior selectivity and reversibility to NO x compared to PPy.…”

Hybrid and 2D nanomaterials

“…The combinations of macrocycles, polymers, carbonaceous materials and inorganic materials are infinite, in particular if we combine more than two of them. As an example, we can cite the case of an electrochemical sensor in which hemin, an iron porphyrin complex, deposited on the surface of a Pt/ZnO/PPy structure, acts as an electrocatalyst to detect NOx at the sub micromolar level in aqueous solution [86]. Another example is that of CNT/PPy chemiresistors in which the polymer bears calix [4]arenes that ensure the selective recognition of aromatic VOCs like BTX [87].…”