DFT-Assisted Design of D–A Conjugated Polymers for Photocatalytic Reduction of Carbon Dioxide

Abstract

Renewable-energy-driven CO2 transformation to chemicals and fuels is promising but still challenging. Herein, with the help of a density functional theory (DFT) analysis of molecular orbital energies, a series of electron donor–acceptor (D–A) conjugated organic polymers were designed and prepared by one-step Scholl coupling of polycyclic arenes and anthraquinone. The resultant polymers exhibit high efficiency in photocatalytic CO2 reduction with water vapor in the absence of any additional sacrificial reductant under visible light irradiation. In particular, the polymer from anthraquinone and triphenylamine could afford CO with a generation rate of 69.7 μmol g–1 h–1 and selectivity of >99.9%, which is superior to most metal-free and sacrificial reductant-free systems. Molecular orbital visualizations indicate that photocatalysts show clear charge separation under visible light stimulation. In addition, control experiments and contact angle tests demonstrated that the high selectivity toward CO may come from the intrinsic hydrophobicity of the photocatalysts. This work provides new insight into the DFT-assisted design of organic polymeric photocatalysts.

Triphenylamine–anthraquinone based donor–acceptor conjugated microporous polymers for photocatalytic hydroxylation of phenylboronic acids

“…17,18 So far, TPA and anthraquinone-containing D-A CMPs have been used in photocatalytic hydrogen evolution from water, 19 in the electro-chemical oxygen reduction reaction (ORR), 20 as a cathode material in lithium ion batteries, 21,22 in supercapacitors, 23 as well as in photocatalytic CO 2 reduction. 24 Herein, we have synthesized two novel TPA-based D-A CMPs, namely PTPA-AQ and PTPA-AM (Scheme 1) via Suzuki-Miyaura cross-coupling reaction between tris(4-(4,4,5,5tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)amine (Monomer 1) as a donor moiety with 2,6-dibromoanthracene-9,10-dione (Monomer 2) and a modified 2,2 0 -(2,6-dibromoanthracene-9,10diylidene)dimalononitrile (Monomer 3) as acceptors (cf. Experimental section, Schemes S2 and S3, ESI †).…”

Exciton Dissociation and Reactive Site Synergic Modulation in 3D Sulfur-Rich Conjugated Porous Polymers for Promoted Selectivity on CO2 Photoconversion

“…In molecular electrostatic potential, the red areas represent those electron-rich areas while the blue areas represent electron-deficient areas. The electron-rich region is typically more conducive to photocatalytic CO 2 reduction . In Figure S12 (ESP maps), it was observed that the alkyne group in the proximity of the sulfur atom was characterized by an electron-rich region.…”

“…The electron-rich region is typically more conducive to photocatalytic CO 2 reduction. 35 In Figure S12 (ESP maps), it was observed that the alkyne group in the proximity of the sulfur atom was characterized by an electron-rich region. This phenomenon could be attributed to the fact that the π conjugation system inherent to the thiophene facilitated the easy egress of electron-delocalized, thus augmenting the electron cloud associated with the C atom situated in its vicinity.…”

Band structure engineering of a polyimide photocatalyst towards enhanced water splitting

“…Very recently, Liu and co-workers constructed an effective D-A conjugated polymer photocatalyst for CO 2 reduction by choosing appropriate monomers with the guidance of theoretical analysis of molecular orbital energies. 62 Based on these previous findings, we intend to improve PI's molecular structure so that it can be used effectively for water splitting, which remains largely unexplored. Herein, we modulate the band structure of PI through simply varying the content of the electron-donor and -acceptor moieties in the polymer skeleton.…”