Rhenium-Metalated Polypyridine-Based Porous Polycarbazoles for Visible-Light CO₂ Photoreduction

Abstract

Transformation of CO2 into valuable chemicals and especially fuels is deemed as a promising approach to reduce our dependence on fossil fuels and to alleviate climate change. Carbazole-based porous polymers bearing rhenium-metalated polypyridine functionalities were constructed via simple oxidative coupling reaction. These porous polymers are employed as heterogeneous supports for immobilization of catalytically active rhenium complexes and furthermore provide high CO2 adsorption capabilities and light absorption abilities, i.e., photosensitizing properties. Consequently, such rhenium-metalated microporous polycarbazole networks show high efficiencies for CO2 photoreduction upon visible-light irradiation, with a CO evolution rate up to 623 μmol g–1 h–1 and selectivity of 97.8%. The microporous solid photocatalyst shows enhanced stability and photocatalytic performance compared to the molecular catalysts during long-term use.

A stable covalent organic framework for photocatalytic carbon dioxide reduction

“…By contrast, the band gap in organic semiconductors can be tuned readily through the incorporation of a diverse range of monomers. [9][10][11] In recent years, porous organic materials such as carbon nitrides, [12][13][14] conjugated microporous polymers (CMPs), 15,16 covalent triazine-based frameworks (CTFs) 17 and hyper-crosslinked polymers (HCPs) 18 have been studied for photocatalytic CO 2 reduction. Those organic materials are typically amorphous; by contrast, covalent organic frameworks (COFs) can combine porosity with crystallinity.…”

Covalent Organic Framework Hosting Metalloporphyrin‐Based Carbon Dots for Visible‐Light‐Driven Selective CO2Reduction

“…[1][2][3][4] Photocatalytic CO 2 reduction into valuable chemicals and/or fuels is considered as one promising but challenging approach to achieve an energy sustainable society. Various molecular-or semiconductor-based systems have been developed for photocatalytic CO 2 reduction, [5][6][7][8][9][10][11] but the efficiency dots with small size and good solubility have been reported for photodynamic therapy. [37,38] It can be anticipated that the confinement of metalloporphyrin-based carbon dots in the channels of COFs will be promising solutions to achieve stable catalytic systems.…”

Molecular Porous Photosystems Tailored for Long‐Term Photocatalytic CO2 Reduction

“…Key for their success is the tunability of the properties of the polymers by copolymerization of tailored monomers for a careful control of light absorption or porosity . Also, recently the use of porous organic polymers as photosensitizers has been reported for CO 2 reduction into CO, using different transition‐metal‐based catalysts . However, long‐term stability remains an important challenge, as such photocatalysts still showed deactivation within typically less than 15 hours.…”

“…[8,10,18] Also,r ecently the use of porous organic polymers as photosensitizers has been reported for CO 2 reduction into CO,u sing different transition-metal-based catalysts. [16,[19][20][21][22] However,l ong-term stability remains an important challenge, [16] as such photocatalysts still showed deactivation within typically less than 15 hours.Furthermore, bottom-up approaches for the design of better performing heterogeneous photocatalysts are restricted, as only little is known on the fundamental mechanisms occurring during light harvesting and activation of the catalysts. [23,24] Herein we report tailor-made three-dimensional porous polymers made from molecular organic photosensitizers in which we heterogenized an efficient molecular catalyst.…”