Recent progress in polyaniline-based catalysts for electrochemical energy conversion

Although platinum (Pt) is an excellent electrocatalyst, its high price hinders its widespread application. So, developing a clean and efficient noble metal-free electrocatalyst is urgent for electrochemical energy conversion. Recently, researchers have focused on polyaniline (PANI)-based catalysts to replace noble metal catalysts for targeted >2e^- product reactions crucial for electrochemical energy conversion. This review introduces the importance of PANI, especially the catalytic performance of PANI-based catalysts in different electrochemical reactions, including the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), CO₂ reduction reaction (CO₂RR), etc. Because of its unique redox properties, high conductivity, high stability, ease of synthesis, and low cost, PANI can serve as an effective support for catalysts to enhance their catalytic performance. Then, based on our understanding of the catalytic mechanism, we discuss regulatory strategies for improving catalytic performance by enhancing the intrinsic activity of active sites and increasing the active surface area through the use of PANI. Finally, in response to the shortcomings of PANI composite catalysts in each catalytic reaction, we have identified the key issues and challenges for their future development.