Layer-by-Layer Film Based on Sn3O4 Nanobelts as Sensing Units to Detect Heavy Metals Using a Capacitive Field-Effect Sensor Platform

Abstract

Lead and nickel, as heavy metals, are still used in industrial processes, and are classified as “environmental health hazards” due to their toxicity and polluting potential. The detection of heavy metals can prevent environmental pollution at toxic levels that are critical to human health. In this sense, the electrolyte–insulator–semiconductor (EIS) field-effect sensor is an attractive sensing platform concerning the fabrication of reusable and robust sensors to detect such substances. This study is aimed to fabricate a sensing unit on an EIS device based on Sn3O4 nanobelts embedded in a polyelectrolyte matrix of polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) using the layer-by-layer (LbL) technique. The EIS-Sn3O4 sensor exhibited enhanced electrochemical performance for detecting Pb2+ and Ni2+ ions, revealing a higher affinity for Pb2+ ions, with sensitivities of ca. 25.8 mV/decade and 2.4 mV/decade, respectively. Such results indicate that Sn3O4 nanobelts can contemplate a feasible proof-of-concept capacitive field-effect sensor for heavy metal detection, envisaging other future studies focusing on environmental monitoring.

Advancements in Polymer-Assisted Layer-by-Layer Fabrication of Wearable Sensors for Health Monitoring

“…The sensor exhibited an impressive limit of detection, with a notable sensitivity that could be attributed to the synergistic effect of the materials used in the LbL film. In another study, Morais et al [114] developed an EIS sensor modified with a LbL film for detecting Pb 2+ and Ni 2+ ions. This film was assembled by alternating layers of PAA and PVP, incorporating Sn 3 O 4 nanobelts within the structure.…”

Improved Microelectrode Array Electrode Design for Heavy Metal Detection

“…Electrode design is essential in improving the stability and accuracy of dissolved voltammetry detection. In recent years, many scholars have focused on the design and investigation of new electrodes [13,14]. With the development of micromachining, microelectrodes have become indispensable as working electrodes in electrochemical analysis [15,16].…”

Modeling the Conduction Mechanism in Chemoresistive Gas Sensor Based on Single-Crystalline Sn3O4 Nanobelts: A Phenomenological In Operando Investigation

“…Even today, it remains a key material for gas detection, along with ZnO, In 2 O 3 , and WO 3. − Among a wide range of other possible Sn x O y stoichiometries predicted by theoretical calculations, Sn 3 O 4 is a mixed-valence tin oxide (Sn 2+ , Sn 4+ , and O 2– ) that exhibits n-type semiconductor behavior and an optical bandgap of approximately 2.7 eV. − Accordingly, the functionalities of Sn 3 O 4 have been explored in many research fields. − In 2014, we reported the first results on the gas sensing properties of Sn 3 O 4 , followed by a more detailed investigation focusing on NO 2 detection . The studied material consists of single-crystalline layered Sn 3 O 4 nanobelts, which grow along the (101) plane direction of the triclinic crystal system .…”