Molecular Porous Photosystems Tailored for Long‐Term Photocatalytic CO₂ Reduction

Abstract

The molecular‐level structuration of two full photosystems into conjugated porous organic polymers is reported. The strategy of heterogenization gives rise to photosystems which are still fully active after 4 days of continuous illumination. Those materials catalyze the carbon dioxide photoreduction driven by visible light to produce up to three grams of formate per gram of catalyst. The covalent tethering of the two active sites into a single framework is shown to play a key role in the visible light activation of the catalyst. The unprecedented long‐term efficiency arises from an optimal photoinduced electron transfer from the light harvesting moiety to the catalytic site as anticipated by quantum mechanical calculations and evidenced by in situ ultrafast time‐resolved spectroscopy.

Finding the Sweet Spot of Photocatalysis─A Case Study Using Bipyridine-Based CTFs

“…To obtain a detailed and quantitative insight into the composition of the CTFs, 13 C ComPmultiCP MAS NMR spectra were recorded. 14,35,36 The signal around 170 ppm can be attributed to the triazine core carbon atom, confirming the successful condensation and oxidation of amidine and aldehydes to the triazine core in all materials (Figure 2a). The absence of any signal in the 13 C NMR spectra at about 190 ppm and 163 ppm highlights the complete transformation of aldehyde and amidine moieties in all materials (see Figure S13).…”

“…While some interesting results have been achieved in photocatalysis, [12][13][14][15][16] typically by adding electron acceptor (p-doping) or electron donor atoms or moieties (n-doping) in the final composition of the material, 6,13,17,18 the correlation of material's structure with the observed catalytic performance remains phenomenological, 17,19,20 as the observed changes in electronic properties, geometry and morphology seemed too intertwined to rationalize the changes in catalytic activity. 21,22 One frontier in preparing photoactive multifunctional materials by modular design thus lies in the control and comprehension from the material's molecular structure up to the macroscopic scale, understanding material's performances in its entirety, beyond the description of its molecular units.…”

Porous Organic Polymers for Photocatalytic Carbon Dioxide Reduction

“…In order to solve this problem, Wisser et al . linked the perylene with bipyridine by C−C bonds to form fully conjugated polymers (Cp*Rh@PerBpyCMP) (Figure 4b) [33] . The Rh complexes are loaded into the conjugated porous polymer to achieve efficient and ultra‐fast electron energy transfer.…”

Unravelling the molecular structure and confinement of an or-ganometallic catalyst heterogenized within amorphous porous polymers

“…In fact, the heterogenization of molecular complexes within porous supports allows for reactivities, productivities and selectivities inaccessible in the homogeneous phase due to the controlled confinement of the active site into a three-dimensional porous framework. [1][2][3][4][5][6][7][8][9][10] The knowledge acquired about the homogeneous molecular catalysts structure-activity relationship is now so pre-cise that computational chemistry can be used to predict reactivity and selectivity. 11,12 Unfortunately, this level of maturity has not yet been reached for heterogenized molecular catalysts.…”