Photo-Responsive Signatures in a Porous Organic Polymer Enable Visible Light-Driven CO₂ Photofixation

Abstract

Porous organic polymers (POPs) continue to garner immense attention for CO 2 capture and sequestration (CCS) as well as CO 2 fixation to generate useful chemicals for alleviating global warming. Functionally engineered, visible light responsive organic photopolymers with extended π-conjugation and abundant heteroatoms enable photogenerated charge carriers, enhancement in visible light absorption, higher charge separation, and reduction in charge recombination during photocatalysis. In this work, we have explored the construction of a chemically stable, pyridine-equipped, and imine-linked porous organic polymer (Py-POP) by template-free Schiff base condensation of 1,3,5-tris(4aminophenyl) benzene (APB) and 2,6-pyridinedicarboxaldehyde (PDC). This donor−acceptor Py-POP with extensive π-conjugations enables photocatalytic fixation of CO 2 with styrene epoxide (STE) under visible light illumination. We have achieved an impressive conversion of STE to styrene carbonate (STC) (∼99%) under optimized reaction conditions using tert-butyl ammonium bromide (TBAB) as a promoter. Both the efficient CO 2 adsorption and activation for photocatalytic fixation reaction are enabled by the existence of both imine and pyridine moieties in Py-POP. The interaction between Py-POP and CO 2 is further illustrated by density functional theory (DFT) calculations that show that all the POP-CO 2 interactions are favorable and exergonic. Using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) characterization techniques, we elucidate the mechanistic pathways of active key surface species in CO 2 photofixation with Py-POP. Our results provide mechanistic insight into the effectiveness of efficient, sustainable porous organic photocatalysts in visible light-driven CO 2 conversion for various energy applications.

Tweaking Photo CO2 Reduction by Altering Lewis Acidic Sites in Metalated‐Porous Organic Polymer for Adjustable H2/CO Ratio in Syngas Production

“…[15] N 2adsorption-desorption isotherms of both M-POPs feature mainly type IV with gradual gas uptake at higher P/P 0 regions (Figure S13). [16] The calculated Brunauer-Emmett-Teller specific surface areas (S BET ) of Zn-POP and Co-POP are 364 & 278 m 2 g À 1 respectively. The pore size distribution (PSD) reveals the existence of both meso and micropores in the M-POP framework (Figure S14).…”

A critical review on emerging photoactive porous materials for sulfide oxidation and sulfur mustard decontamination

“…Many materials have been employed to detoxify sulfur mustard and its analogous derivatives; in this context, owing to its attenable functionality, superior chemical and thermal stability, and enhanced porosity, POPs emerge as a judicious choice. 97 POPs are a class of advanced functional materials with structural tailorability, inherent porosity, and high flexibility, which have served for several applications like CO 2 capture, 98,99 CO 2 reduction to solar fuels, 100,101 biomass valorisation, 102,103 organic transformation reactions, 104,105 CO 2 fixation, 99 gas and liquid separation, 106 water purification, 107,108 energy storage, 109 chemo-and biosensing 110 and HD decontamination [111][112][113][114][115] etc. (Fig.…”

Recent Progress in Photocatalytic Chemical Fixation of Carbon Dioxide

“…In the photocatalytic chemical fixation of CO 2 , two strategies often exist into two main strategies: direct reduction to CO 2 radical anion, and nucleophilic attack from organometallic complexes or carbon anions. , In the strategies, the addition of a stoichiometric photosensitizer or an inorganic metal catalyst or cocatalyst is frequently required to facilitate the reaction. There are currently three main activation mechanisms for these different structures of photocatalysts for reaction substrates, namely, single electron transfer, hydrogen atom seizure, or energy transfer.…”