Frontiers in Chemistry (Dec 2021)

Metal-Free Pyrene-Based Conjugated Microporous Polymer Catalyst Bearing N- and S-Sites for Photoelectrochemical Oxygen Evolution Reaction

  • Sabuj Kanti Das,
  • Sabuj Kanti Das,
  • Sanjib Shyamal,
  • Manisha Das,
  • Saptarsi Mondal,
  • Saptarsi Mondal,
  • Avik Chowdhury,
  • Debabrata Chakraborty,
  • Ramendra Sundar Dey,
  • Asim Bhaumik

DOI
https://doi.org/10.3389/fchem.2021.803860
Journal volume & issue
Vol. 9

Abstract

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The development of an efficient, sustainable, and inexpensive metal-free catalyst for oxygen evolution reaction (OER) via photoelectrochemical water splitting is very demanding for energy conversion processes such as green fuel generators, fuel cells, and metal-air batteries. Herein, we have developed a metal-free pyrene-based nitrogen and sulfur containing conjugated microporous polymer having a high Brunauer-Emmett-Teller surface area (761 m2 g−1) and a low bandgap of 2.09 eV for oxygen evolution reaction (OER) in alkaline solution. The π-conjugated as-synthesized porous organic material (PBTDZ) has been characterized by Fourier transform infrared spectroscopy (FT-IR), solid-state 13C (cross-polarization magic angle spinning-nuclear magnetic resonance) CP-MAS NMR, N2 adsorption/desorption analysis, field-emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) experiments. The material acts as an efficient catalyst for photoelectrochemical OER with a current density of 80 mA/cm2 at 0.8 V vs. Ag/AgCl and delivered 104 µmol of oxygen in a 2 h run. The presence of low bandgap energy, π-conjugated conducting polymeric skeleton bearing donor heteroatoms (N and S), and higher specific surface area associated with inherent microporosity are responsible for this admirable photoelectrocatalytic activity of PBTDZ catalyst.

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