Abstract
Conjugated polymer frameworks (CPFs) have recently sparked tremendous research interest due to their broad potentials in various frontline application areas such as photocatalysis, sensing, gas storage, energy storage, etc. These framework materials, without sidechains or functional groups on their backbone, are generally insoluble in common organic solvents and less solution processable for further device applications. There are few reports on metal-free electrocatalysis, especially oxygen evolution reaction (OER) using CPF. Herein, we have developed two triazine-based donor-acceptor conjugated polymer frameworks by coupling a 3-substituted thiophene (donor) unit with a triazine ring (acceptor) through a phenyl ring spacer. Two different sidechains, alkyl and oligoethylene glycol, were rationally introduced into the 3-position of thiophene in the polymer framework to investigate the effect of side-chain functionality on the electrocatalytic property. Both the CPFs demonstrated superior electrocatalytic OER activity and long-term durability. The electrocatalytic performance of CPF2, which achieved a current density of 10 mA/cm2 at an overpotential (η) of 328 mV, is much superior to CPF1, which reached the same current density at an overpotential of 488 mV. The porous and interconnected nanostructure of the conjugated organic building blocks, which allowed for fast charge and mass transport processes, could be attributed to the higher electrocatalytic activity of both CPFs. However, the superior activity of CPF2 compared to CPF1 may be due to the presence of a more polar oxygen-containing ethylene glycol side chain, which enhances the surface hydrophilicity, promotes better ion/charge and mass transfer, and increases the accessibility of the active sites toward adsorption through lower π-π stacking compared to hexyl side chain present in CPF1. The DFT study also supports the plausible better performance toward OER for CPF2. This study confirms the promising potentiality of metal-free CPF electrocatalysts for OER and further sidechain modification to improve their electrocatalytic property.
Original language | English |
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Pages (from-to) | 29042-29051 |
Number of pages | 10 |
Journal | ACS Applied Materials and Interfaces |
Volume | 15 |
Issue number | 24 |
DOIs | |
State | Published - 21 Jun 2023 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2023 American Chemical Society.
Funding
B.K.K. acknowledges BHU for experimental facilities, DST SERB project CRG/2020/003132, and BHU IOE project R/Dev/D/IOE/incentive/ 2021-2022/32409 for financial support. C.C. acknowledges BITS Pilani Hyderabad Campus for ACRG (BITS/GAU/ACRG/2021/H0778) grant and DST, Govt. of India for DST INSPIRE Faculty award (DST/INSPIRE/04/2016/002255). C.C. also thanks the Department of Science and Technology, Government of India, for providing infrastructural facilities through PURSE Project No. SR/PURSE/2020/20 (G) at BITS Pilani Hyderabad Campus. S.H. is thankful to the DST INSPIRE Ph.D. program for fellowship. N.G. and R.P.B. acknowledge UGC for providing the fellowship. M.D. acknowledges the Core Research Grant (CRG/2020/005626) of SERB, India. M.D. also acknowledges CSIR-CLRI Communication No. 1844.
Funders | Funder number |
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DST SERB | CRG/2020/003132, BITS/GAU/ACRG/2021/H0778, R/Dev/D/IOE/incentive/ 2021-2022/32409 |
Department of Science and Technology, Ministry of Science and Technology, India | SR/PURSE/2020/20 |
University Grants Commission | CRG/2020/005626 |
Science and Engineering Research Board | |
Banaras Hindu University | |
Central Leather Research Institute | 1844 |
Keywords
- conjugated polymer
- conjugated polymer framework
- electrocatalysis
- electrochemistry
- metal-free electrocatalyst
- oxygen evolution reaction