Polyaniline-based synergetic electrocatalysts for CO2 reduction reaction: A review

The increasing impact of industrialization on climate change, primarily due to the emission of greenhouse gases such as carbon dioxide (CO2), underscores the urgent need for effective strategies for CO2 fixation and utilization. Electrochemical CO2 reduction holds promise in this regard, owing to its scalability, energy efficiency, selectivity, and operability under ambient conditions. However, the activation of CO2 requires suitable electrocatalysts to lower energy barriers. Various electrocatalysts, including metal-based systems and conducting polymers like polyaniline (PANi), have been identified to effectively lower this barrier and enhance CO2 reduction efficiency via synergistic mechanisms. PANi is particularly notable for its versatile interaction with CO2, cost-effectiveness, stability, and tunable properties, making it an excellent catalyst option for CO2 reduction reactions (CO2RR). Recent advancements in research focus on enhancing PANi conductivity and facilitating electron transfer through metal and metal oxide doping. Leveraging PANi's pi-pi electron stabilization ensures high conductivity and stability, rendering it suitable for real-time applications. Strategic dopant selection and optimization of Lewis acid-base interactions are crucial for selective CO2-to-hydrocarbon conversion. Tailored electrode modifications, especially metal/metal oxide-loaded PANi electrodes, outperform conventional approaches, underscoring the importance of catalyst design in advancing CO2 electroreduction technologies. This review provides a comprehensive analysis of the systematic methodology involved in preparing PANi-modified electrodes and explores the enhancements achieved through the incorporation of metals and metal oxides onto PANi-modified electrodes. It highlights the superior efficiency and selectivity of CO2RR facilitated by these modified electrodes through profound synergistic approach compared to conventional metal electrodes such as platinum.