Facile electron delivery from graphene template to ultrathin metal-organic layers for boosting CO2 photoreduction

Huang

et al. 2022

JACS Au

Self Cite

The sunlight-driven reduction of CO 2 into carbonaceous fuels can lower the atmospheric CO 2 concentration and provide renewable energy simultaneously, attracting scientists to design photocatalytic systems for facilitating this process. Significant progress has been made in designing high-performance photosensitizers and catalysts in this regard, and further improvement can be realized by installing additional interactions between the abovementioned two components, however, the design strategies and mechanistic investigations on such interactions remain challenging. Here, we present the construction of molecular models for intermolecular π–π interactions between the photosensitizer and the catalyst, via the introduction of pyrene groups into both molecular components. The presence, types, and strengths of diverse π–π interactions, as well as their roles in the photocatalytic mechanism, have been examined by 1 H NMR titration, fluorescence quenching measurements, transient absorption spectroscopy, and quantum chemical simulations. We have also explored the rare dual emission behavior of the pyrene-appended iridium photosensitizer, of which the excited state can deliver the photo-excited electron to the pyrene-decorated cobalt catalyst at a fast rate of 2.60 × 10 6 s –1 via co-facial π–π interaction, enabling a remarkable apparent quantum efficiency of 14.3 ± 0.8% at 425 nm and a high selectivity of 98% for the photocatalytic CO 2 -to-CO conversion. This research demonstrates non-covalent interaction construction as an effective strategy to achieve rapid CO 2 photoreduction besides a conventional photosensitizer/catalyst design.

Section: Resultsmentioning

confidence: 99%

Co-facial π–π Interaction Expedites Sensitizer-to-Catalyst Electron Transfer for High-Performance CO₂ Photoreduction

Huang

et al. 2022

JACS Au

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“…Harvesting sunlight for the reductive transformation of CO 2 into carbonaceous fuels has been regarded as a sustainable pathway to manufacture carbon-neutral energy, as well as the promising mitigation of greenhouse gas. With the advantages of well-defined and highly modulable molecular structures, many chemists have devoted themselves to the design of molecular systems of light-stimulated CO 2 reduction with transition metal complexes, which can function as either photosensitizer (PSs) to transporting electrons upon light excitation, or catalysts to accept electrons for catalytic CO 2 reduction 1 – 8 . Extensive efforts have been dedicated to achieving high catalytic rates 9 – 13 , i.e., turn-over frequency (TOF) or turn-over number (TON), whereas quantum efficiency (QE) also deserves significant attention as it has been considered as the prominent, intrinsic parameter to evaluate the photon-to-product efficiency for a photocatalytic system 14 .…”

Section: Introductionmentioning

confidence: 99%

Rapid electron transfer via dynamic coordinative interaction boosts quantum efficiency for photocatalytic CO2 reduction

et al. 2021

Self Cite

The fulfillment of a high quantum efficiency for photocatalytic CO2 reduction presents a key challenge, which can be overcome by developing strategies for dynamic attachment between photosensitizer and catalyst. In this context, we exploit the use of coordinate bond to connect a pyridine-appended iridium photosensitizer and molecular catalysts for CO2 reduction, which is systematically demonstrated by 1H nuclear magnetic resonance titration, theoretical calculations, and spectroscopic measurements. The mechanistic investigations reveal that the coordinative interaction between the photosensitizer and an unmodified cobalt phthalocyanine significantly accelerates the electron transfer and thus realizes a remarkable quantum efficiency of 10.2% ± 0.5% at 450 nm for photocatalytic CO2-to-CO conversion with a turn-over number of 391 ± 7 and nearly complete selectivity, over 4 times higher than a comparative system with no additional interaction (2.4%±0.2%). Moreover, the decoration of electron-donating amino groups on cobalt phthalocyanine can optimize the quantum efficiency up to 27.9% ± 0.8% at 425 nm, which is more attributable to the enhanced coordinative interaction rather than the intrinsic activity. The control experiments demonstrate that the dynamic feature of coordinative interaction is important to prevent the coordination occupancy of labile sites, also enabling the wide applicability on diverse non-noble-metal catalysts.

“…Most recently, lead halide perovskite (LHP) nanocrystals have also been actively pursued as photocatalysts due to their proper energy band structures, high tolerance of defect, long lifetime of photogenerated carrier, and excellent visible-light responses [63,64]. The integration of LHP nanocrystals and graphene oxide or g-C 3 N 4 have been explored for photocatalytic reduction CO 2 to CO and CH 4 by facilitated charge separation.…”

Section: Quantum Dots@mofsmentioning

confidence: 99%

“…The total yield is as high as 1,559 μmol•g −1 about 38-fold of that of pure MOF without perovskite quantum dots. The perovskite quantum dots@MOFs indicated an effective approach to improve the stability of quantum dots and facilitate the charge separation efficiency of MOF-based photocatalysts [64]. The halide perovskite CsPbBr 3 quantum dots@ZIF composite was also prepared for photocatalytic CO 2 reduction to CO and CH 4 through a facile in situ synthesis process of direct growth/coating of ZIF on quantum dots.…”

Section: Quantum Dots@mofsmentioning

confidence: 99%

Nanostructure@metal-organic frameworks (MOFs) for catalytic carbon dioxide (CO2) conversion in photocatalysis, electrocatalysis, and thermal catalysis

2021

Nano Res.

The catalytic conversion of carbon dioxide (CO 2 ) into high value-added chemicals is of great significance to address the pressing carbon cycle issues. Reticular chemistry of metal-organic frameworks (MOFs)-based materials exhibits great potential and effectiveness to face CO 2 challenge from capture to conversion. To date, the integrated nanocomposites of nanostructure and MOF have emerged as a powerful heterogeneous catalysts featured with multifold advantages including synergistic effects between the two interfaces, confinement effect of meso-and micropores, tandem reaction triggered by multiple active sites, high stability and dispersion, and so on. Given burgeoning carbon cycle and nanostructure@MOFs, this review highlights some of important advancements to provide a full understanding on the synthesis and design of nanostructure@MOFs composites to facilitate carbon cycle through CO 2 photocatalytic, electrocatalytic, and thermal conversion. Afterward, the catalytic applications of some representative nanostructure@MOFs composites are categorized, in which the origin of activity or structure-activity relationship is summarized. Finally, the opportunities and challenges are proposed for inspiring the future development of nanostructure@MOFs composites for carbon cycle.