Enhancing the photoelectrochemical hydrogen evolution activity of polyaniline through small molecular acid doping to introduce polariton-enhanced active sites

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-01, Vol.480, p.148321, Article 148321
• Main Authors: Nie, Weixing, Ruan, Mengnan, Liu, Xiaowei, Ruan, Ke, Sun, Yuxin, Liu, Zhifeng
• Format: Article
• Language: English
• Subjects: DFT calculation; H2 evolution; Polarons; Polyaniline; Small molecule acid
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2023.148321

•Partially crystallized spherical PANI was synthesized in an alkaline environment.•Electrochemical doping was employed to introduce small molecule acids into PANI.•Small molecule acid doping introduces polaron and bipolaron active sites for PANI.•Polaron active sites greatly enhance the surface activity of PANI.•DFT calculations verify that doping improves the H2 evolution efficiency of PANI. Development of organic polymer photoelectrodes with high surface activity is the key to efficient water splitting for hydrogen production. Polyaniline (PANI) prepared under alkaline conditions has semiconducting properties, but high reaction rates are difficult to achieve due to its poor surface activity. In this study, electrochemical doping was used to introduce small molecular acids (2,3-hydroxybutanedioic acid (TA), 2-hydroxybutanedioic acid (MA), and succinic acid (SA)) containing different numbers of hydroxyl groups into the PANI backbone to form polarizers, dipolarizers and active sites. Density Functional Theory (DFT) shows that small molecular acids interact with the imine (=N-) structure of the PANI backbone via electron cloud stacking to form complex active sites. Meanwhile, the transition from polarons to dipolarons under light conditions increases the polarity of the PANI molecular chain, which further improves the photoelectrocatalytic performance. This study will bring new ideas for efficient photoelectrocatalysis based on organic polymers.