We report a sensitive, selective, and fast responding room temperature chemiresistive sensor for hydrogen sulfide detection and quantification using polyaniline nanowires-gold nanoparticles hybrid network. The sensor was fabricated by facile electrochemical technique. Initially, polyaniline nanowires with a diameter of 250–320 nm bridging the gap between a pair of microfabricated gold electrodes were synthesized using templateless electrochemical polymerization using a two step galvanostatic technique. Polyaniline nanowires were then electrochemically functionalized with gold nanoparticles using cyclic voltammetry technique. These chemiresistive sensors show an excellent limit of detection (0.1 ppb), wide dynamic range (0.1–100 ppb), and very good selectivity and reproducibility.

Current review signifies recent trends and challenges in the development of electrochemical sensors based on organic conducting polymers (OCPs), carbon nanotubes (CNTs) and their composites for the determination of trace heavy metal ions in water are reviewed. OCPs and CNTs have some suitable properties, such as good electrical, mechanical, chemical and structural properties as well as environmental stability, etc. However, some of these materials still have significant limitations toward selective and sensitive detection of trace heavy metal ions. To overcome the limitations of these individual materials, OCPs/CNTs composites were developed. Application of OCPs/CNTs composite and their novel properties for the adsorption and detection of heavy metal ions outlined and discussed in this review.