Recent progress on the utilization of polypyrrole (PPy)-based nanocomposites for electrochemical applications

Currently, polymers are receiving remarkable scientific attention for electrocatalytic applications due to their advantageous properties such as cost-effectiveness, abundance, non-toxicity, viscoelasticity, and reactivity. These polymers include polyacetylene (PA), polythiophene (PTh), polyaniline (PANI), and polypyrrole (PPy). However, bare polymers are less efficient since they have inferior conductivity compared to metals. There are several initiatives to solve this challenge including doping, nanocomposite/heterojunction formation, and defect engineering. Several studies conducted revealed that these initiatives yield nanocomposites with enhanced electronic properties, optical properties, electrocatalytic activity, stability, durability, and interestingly thermoelectric properties. In this study, the use of PPy-based nanocomposites is deemed necessary since PPy has high electrical conductivity compared to many polymers, good environmental stability, stable in the oxidized form, easily synthesized, and exhibits redox properties. These enhanced properties are normally found in certain polymer-free semiconductors such as platinum (Pt), iridium (Ir), and ruthenium (Ru). However, these metal-based electrocatalysts are exorbitant, prone to degradation, low selectivity, and challenging to control reaction pathways. This makes PPy-based catalysts significantly better alternatives. This study explores the synthesis, overall properties, and performance of electrocatalytic PPy-based nanocomposites in areas such as hydrogen evolution, oxygen reduction, carbon dioxide conversion, pollutant degradation, sensors, and supercapacitors.