Substantial Cyano‐Substituted Fully sp²‐Carbon‐Linked Framework: Metal‐Free Approach and Visible‐Light‐Driven Hydrogen Evolution

Abstract

Polymeric semiconductors are emerging as a kind of competitive photocatalysts for hydrogen evolution due to their well-tunable structures, versatile functionalization, and low-cost processibility. In this work, a series of conjugated porous polymers with substantial cyano-substituted fully sp 2 -carbon frameworks are efficiently synthesized by using electron-deficient tricyanomesitylene as a key building block to promote an organic base-catalyzed Knoevenagel condensation with various aldehyde-substituted arenes. The resulting porous polymers feature donor-acceptor structures with π-extended conjugation, rendering them with distinct semiconducting properties. They possess hierarchically porous structures, nanoscale morphologies, and intriguing wettability. These promising physical characters, finely tailorable by varying the arene units, are essentially relevant to the abundant cynao substituents over the whole frameworks. The as-prepared porous polymers exhibit excellent visible-light-driven photocatalytic activity for water-splitting hydrogen evolution with apparent quantum yield up to 2.0% at 420 nm or 1.9% at 470 nm, among the highest values yet reported for porous polymerbased photocatalysts, also representing the first example of such kinds of catalysts formed through a metal-free-catalyzed carbon-carbon coupling reaction.

Interfacial Approach toward Benzene‐Bridged Polypyrrole Film–Based Micro‐Supercapacitors with Ultrahigh Volumetric Power Density

“…The work function of the material was determined by ultraviolet photoelectron spectroscopy (UPS, Figure a), which is 5.47 eV. Furthermore, the optical bandgap could be calculated from the absorption edge of the ultraviolet–visible absorption spectrum (Figure S11, Supporting Information) . A Tauc plot reveals a bandgap of ≈2.0 eV (Figure b,c) .…”

An Olefin‐Linked Covalent Organic Framework as a Flexible Thin‐Film Electrode for a High‐Performance Micro‐Supercapacitor

“…[5] Thus,f orming unsubstituted C = Cb ond linkages should be favorable for improving the p-delocalization of a2Dsp 2 -carbon-linked framework. [6] Meanwhile,searching for functional monomers which are accessible to forming such linkages is of crucial importance.…”

Rational Design of Carbon‐Rich Materials for Energy Storage and Conversion

“…After thermal and activation treatments, the as‐prepared 2DPPV was facilely converted into porous carbon nanosheets, which could serve as the electrocatalysts for oxygen reduction reaction (ORR) and the electrodes for supercapacitors. Subsequently, substantial cyano‐substituted fully sp 2 ‐carbon π‐conjugated frameworks were capitalized on to act as visible‐light‐driven photocatalysts for water‐splitting hydrogen evolution . Apart from the CC bond formation, the construction of sp 2 hybridized carbon skeletons via CC coupling reactions executed by endogenous polymerization between phenazine‐based monomers has also been reported (Figure b) .…”