Thienothiophene and triphenylbenzene based electroactive conjugated porous polymer for oxygen reduction reaction (ORR)

Catalysts based on metal-free conjugated porous polymers (CPPs) are still rare for electrochemical oxygen reduction reactions (ORR). In this study, a conjugated porous polymer, TT-TPB, based on thieno[3,2-b]thiophene (TT) and triphenylbenzene (TPB), was synthe-sized applying palladium(0) catalyzed Suzuki coupling reaction and its ORR activity was investigated in alkaline condition. It demonstrated comparable electrocatalytic performance of approximate to 0.89-0.9 V Fonset vs RHE with the commercially available Pt/C. Density-functional theory (DFT) calculations revealed that TT-TPB featured efficient electrocatalytic active sites derived from volumetric, areal, and O2 adsorbing calculations, which were in line with the experimental results. Moreover, semiconducting and surface properties of TT-TPB were investigated in detail using electro-chemical and spectrophotometric techniques. This work shows the potential application of thienothiophene-based metal-free CPP in the electrochemical conversion process.
We thank Higher Education Council of Turkey (YOK) and Scientific and Technical Research Council of Turkey (TÜBİTAK) grants to R.I. (PhD, 100/2000 YOK and 2211A BIDEP/TUBITAK). The authors thank ITU (Istanbul Technical University) and Unsped Global Lojistik, Turkey, for financial support. We also thank Dr. Sarp Kaya and KUTEM (Koc University Tupras Energy Center) for using their infrastructure. T.B. also thanks Kaan Simsek for his valuable help.