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

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.

Carbonyl-based polyimide immobilization on carbon nanotubes for aqueous zinc-ion batteries

The aqueous-based zinc-ion batteries (ZIBs) with higher safety and performance have gained great attention from scientists. Nevertheless, previous electrode materials mainly rely on inorganic metal oxides, and their structure is prone to collapse during charge and discharge, thus resulting in poor cycle stability, which severely limits the development of ZIBs. Here, a novel conjugated polyimide based conjugated microporous polymer (CMP) and multi-walled carbon nanotubes (CNT) hybrid has been gained and used as cathode material for ZIBs. The aromatic carbonyl group as active site can reversibly receive and release zinc ions, thus showing good electrochemical performance. This work provides new view for the design of high-performance ZIBs electrode materials.