Donor-Acceptor Conjugated Acetylenic Polymers for High- Performance Bifunctional Photoelectrodes

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Contributors

Abstract

Due to the drastic required thermodynamical requirements, a photoelectrode material that can function as both a photocathode and a photoanode remains elusive. In this work, we demonstrate for the first time that, under simulated solar light and without co-catalysts, donor-acceptor conjugated acetylenic polymers (CAPs) exhibit both impressive oxygen evolution (OER) and hydrogen evolution (HER) photocurrents in alkaline and neutral medium, respectively. In particular, poly(2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine) (pTET) provides a benchmark OER photocurrent density of ~200 μA cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE) at pH 13 and a remarkable HER photocurrent density of ~190 μA cm−2 at 0.3 V vs. RHE at pH 6.8. By combining theoretical investigations and electrochemical-operando Resonance Raman spectroscopy, we show that the OER proceeds with two different mechanisms, with the electron-depleted triple bonds acting as single-site OER in combination with the C4-C5 atoms of the phenyl rings as dual sites. The HER, instead, occurs via an electron transfer from the tri-acetylenic linkages to the triazine rings, which act as the HER active sites. This work represents a novel application of organic-based materials and contributes to the development of high-performance photoelectrochemical catalysts for the solar fuels’ generation.

Details

Original languageEnglish
Article numbere202301170
Number of pages6
JournalChemSusChem
Volume17
Issue number7
Early online date18 Dec 2023
Publication statusPublished - 8 Apr 2024
Peer-reviewedYes

External IDs

Scopus 85180001177

Keywords

Subject groups, research areas, subject areas according to Destatis

Sustainable Development Goals

Keywords

  • bifunctional photoelectrodes, conjugated polymers, hydrogen evolution, oxygen evolution, resonance Raman, Conjugated polymers, Hydrogen Evolution, Oxygen evolution, Resonance Raman, bifunctional photoelectrodes