The construction of artificial photosynthetic (AP) systems for the hydrogen evolution reaction (HER) and carbon dioxide reduction reaction (CRR) is one of the hottest topics in the field of energy ...and sustainability. A typical AP system is composed of three key components, a photosensitizer (PS) for visible light harvesting, a catalyst for redox reactions, and a sacrificial electron donor (SED) for consuming holes generated in the PS. Among these three components, the PS and catalyst affect the photocatalytic performance much. There are two main types of AP systems, heterogeneous systems using inorganic materials and homogeneous systems using molecules. In addition to these, a compromise strategy of using inorganic luminescent nanoparticles as photosensitizers and molecular metal complexes as catalysts to construct hybrid AP systems has been developed. Inorganic luminescent nanoparticles, such as colloidal quantum dots (QDs) and carbon quantum dots (CQDs), have advantages of robust photostability, multiple excitation, and easy preparation. Molecular catalysts feature high activity, modifiable structures, and atom economy. Research on the combination of these two different types of materials to construct hybrid systems for solar fuel production is blooming. In the last decade, a large number of hybrid AP systems have been reported, and various strategies for system construction were developed. Obvious improvements in the photocatalytic efficiency of solar fuel production were witnessed. This review focuses on hybrid AP systems for the HER and CRR. The mechanism, composition, system design, and photocatalytic performances of the reported hybrid AP systems are reviewed. The advances and challenges in this field are discussed.
The strategy of the combination of molecular catalysts and inorganic quantum dots for solar fuel production has shown great success for the construction of artificial photosynthetic systems in the last decade.
A novel smart fluorescent polymer polyethyleneimine‐grafted pyrene (PGP) is developed by incorporating four stimuli‐triggers at molecular level. The triggers are amphiphilicity, supramolecular ...host–guest sites, pyrene fluorescence indicator, and reversible chelation sites. PGP exhibits smart deformation and shape‐dependent fluorescence in response to external stimuli. It can deform into three typical shapes with a characteristic fluorescence color, namely, spherical core–shell micelles of cyan‐green fluorescence, standard rectangular nanosheets of yellow fluorescence, and irregular branches of deep‐blue fluorescence. A quasi‐reversible deformation between the first two shapes can be dynamically manipulated. Moreover, driven by reversible coordination and the resulting intramolecular photoinduced electron transfer, PGP can be used as an aqueous fluorescence ink with erasable and recoverable properties. The fluorescent patterns printed by PGP ink on paper can be rapidly erased and recovered by simple spraying a sequence of Cu2+ and ethylene diamine tetraacetic acid aqueous solutions. This erase/recover transformation can be repeated multiple times on the same paper. The multiple stimulus responsiveness of PGP makes it have potential applications in nanorobots, sensing, information encryption, and anticounterfeiting.
A smart single‐fluorophore polymer polyethyleneimine‐grafted pyrene (PGP) incorporating four stimuli‐triggers: amphiphilicity, supramolecular host–guest sites, pyrene fluorescence indicator, and reversible chelation sites, exhibits deformation and shape‐dependent fluorescence in response to external stimuli. Besides, PGP driven by its reversible chelation capacity can be used as an advanced fluorescent ink with erasable and recoverable properties.
An artificial photosynthetic assembly (APA) of a hollow-rod structure was successfully constructed by using synthetic building blocks to mimic the structure and function of natural photosynthetic ...bacteria. The APA was formed by the incorporation of carbon nanoparticles as light harvesters into an enzyme-like polymer,
PEI-Co
, containing cobalt complexes as redox catalytic centres. The APA features a bacteria-like shape of
ca.
2-3 μm length rods and a hollow structure positioning photosynthetic components at the surface. The APA integrates key components, the light harvester, redox catalyst, and proton relay group, of photosynthetic systems in assemblies formed from a polymeric framework. The APA system in aqueous solution converts protons to H
2
under visible light irradiation with obvious advantages. It exhibits a 50-fold improvement in hydrogen production activity and has a broader pH response of photocatalytic H
2
production compared with a non-assembled system.
An artificial photosynthetic assembly (APA) was successfully constructed by using synthetic building blocks to mimic the structure and function of natural photosynthetic bacteria for photocatalytic H
2
production.
•A binuclear catalyst C1 of rigidly linking two Co(TPA)ClCl moieties at meta positions of a benzene was synthesized.•C1 catalyzes CO2-to-CO conversion at each cobalt moiety in a homogeneous ...photocatalytic CO2 reduction system.•At an optimal condition, the TON and selectivity of CO production of C1 are 721 and 91.5%, respectively..•No synergistic effect of CO2 reduction exists in C1 due to the large distance between two Co centers and the rigid structure.•A CoICoI species generates via successive two PET steps from excited photosensitizer to C1 in the course of photocatalysis.
A novel binuclear cobalt complex C1 of rigidly linking two Co(TPA)ClCl moieties at meta positions of a benzene was synthesized and characterized as a catalyst for homogeneous photocatalytic CO2 reduction. Different from state-of-the-art binuclear catalyst catalyzing CO2 reduction with a synergistic catalysis mechanism, C1 catalyses CO2-to-CO conversion independently at each cobalt catalytic center. At an optimal condition, system of C1 produced CO with a TON of 721 (based on C1, corrsoponding to TON 360 per cobalt center) and a high selectivity of 91.5%. Electrochemistry and steady state spectroscopy studies revealed that a CoICoI species, generated via successive photoinduced electron transfer from excited photosensitizer to C1, is the active species of CO2 conversion. No synergistic effect of two cobalt centers exists for CO2 reduction because of larger Co-Co distance and rigid structure of C1.
Inspired by the photosynthetic system in nature, scientists proposed to construct artificial photosynthesis (AP) system to convert solar energy to chemical energy. The strategies of constructing AP ...systems has developed from simple multi-component physical mixing to supramolecular assembly. At present, the strategy is developing towards biomimetic supramolecular assembly. This review is dedicated to elaborate our understandings on the AP system construction. Three representative examples of bionic AP systems developed currently by us and others are introduced. These three examples mimic natural systems from different aspects, structural simulation, microchemical environmental construction, and phototropic simulation, which are based on strategies of hybrid supramolecular assembly or functional hydrogels’ assembling. We expect to provide new insights for the design of bionic AP systems.
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•Dual synergistic effect of nonionic photoacid components.•Polymer bound photoacids prevent the excessive acid diffusion.•The similar structure of MONS and MONMA enhances component ...miscibility.
In this paper, 4,5-dimethoxy-2-nitrobenzyl methacrylate (MONMA) was copolymerized with 2-hydroxyethyl methacrylate (HEMA) and tert-butyl methacrylate (TBMA) to obtain the terpolymer with dual sensitivity of ultraviolet (UV) light and acid, P(MONMA-HEMA-TBMA). The nonionic photosensitive ester, 4,5-dimethoxy-2-nitrobenzyl p-toluene sulfonate (MONS), is designed and synthesized as the prime photoacid generator (PAG) because of excellent photoacid generating capability of MONS and the similar substituted structure between MONS and MONMA. The ester groups in MONS PAG small molecules and the MONMA units of P(MONMA-HEMA-TBMA) disintegrate under UV irradiation to generate free diffused sulfonic acids and localized carboxylic acids, respectively. Both free and localized acids facilitate the subsequent acid-catalyzed hydrolysis of TBMA adjacent to MONMA units to induce exponential growth of carboxylic acids. Therefore, the hydrolyzed polymers containing high-content carboxylic acids become soluble in the alkaline developer. Hydrophilic HEMA is introduced to the photoresist resin to improve the interfacial affinity between the resist and the substrate. Dual synergy effect from free photoacid generator MONS and polymerized photoacid unit MONMA enhances photoacid generation and accelerates acid proliferation, which enables the decreased exposure dose and lower content of free photoacid generator MONS. A series of novel chemical amplification photoresists with various methacrylate monomer ratios are designed and synthesized to optimize the photolithographic effect of photoresist resin. The UV photolithography results demonstrate that the distinct exposed patterns are obtained at a low exposure dose using the photoresist formulation with P(MONMA50-HEMA19-TBMA31) and MONS of 9:1 w/w.
•A molecular catalyst C1, covalently linking an adamantine group to a Co(TPA)ClCl moiety, was synthesized and characterized.•CuInS2/ZnS core-shell quantum dots of grafting cyclodextrin onto the ...surface was prepared and characterized.•A self-assembling photocatalyst C1@CD-CuInS2/ZnS QDs was prepared via host-guest interaction.•The C1@CD-CuInS2/ZnS produce syngas with high stability in a CO2-saturated aqueous solution under visible light irradiation.•C1 functions as a major CO2 reduction center, CD-CuInS2/ZnS is either a hydrogen production center and a light harvester.
Simultaneously fulfilling CO2-to-CO and 2H+-to-H2 reactions in water via photocatalyst represents an alternative to produce syngas driven by solar energy. To this end, photocatalyst having ability of simultaneously producing CO and H2 with controllable ratio should be exploited. In this work, we report a self-assembly photocatalyst C1@CD-CuInS2/ZnS quantum dots (QDs) that enabling to produce syngas robustly in CO2-saturated water under visible light irradiation. C1 is a molecular catalyst of linking an adamantine moiety to Co(TPA)ClCl (TPA = tris (2-pyridylmethyl) amine), while CD-CuInS2/ZnS QDs are semiconductor QDs with structure of CuInS2 core and ZnS shell and containing β-cyclodextrin (CD) on the surface. The C1@CD-CuInS2/ZnS QDs assemblies form by anchoring molecular cobalt catalyst C1 onto cyclodextrin (CD) modified CuInS2/ZnS quantum dots (CD-CuInS2/ZnS QDs) based on host-guest interaction between adamantine in C1 and cyclodextrin in the QDs. In which, C1 functions a molecular catalytic center mainly for CO2 reduction, and CD-CuInS2/ZnS QDs functions as both a light harvester and a hydrogen production center. The C1@CD-CuInS2/ZnS QDs system maintains syngas production activity over 200 h, and produces 184.21 μmol syngas with a CO/H2 ratio of 0.74 (ca. 2:3), exhibiting obvious advantages of syngas production efficiency in comparison to the non-assembled system and pristine CD-CuInS2/ZnS QDs system. Mechanism studies revealed that photoinduced electron transfer between CD-CuInS2/ZnS QDs and C1 occurs. The host-guest interaction improves syngas production activity and stability as well as plays positive role on stability of the molecular catalyst.
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A bright white light-emitting material based on CdSe QDs was prepared by a facile post-synthetic treatment of passivating the QDs by hyperbranched polyethyleneimine (PEI) in water. The CdSe@PEI ...aqueous solution emits white light with CIE coordinates (0.334, 0.347) and a PLQY of (17.7 ± 0.1)%.
A bright white light-emitting material based on CdSe QDs was prepared by a facile post-synthetic treatment of passivating the QDs by hyperbranched polyethyleneimine (PEI) in water.
As the key material for semiconductor manufacturing, the production technology of a photoresist (PR) is complex, with many varieties and specifications. Therein, the synthesis of current resins and ...photosensitizers used for the preparation of the i-line photoresist is complicated, and the reaction products may even cause lens pollution. Herein, a kind of photodegradable polyurethane (PU) positive photoresist with a simple system was designed and prepared, in which photocleavable hexaarylbiimidazole (HABI) and tert-butylhydroquinone (TBHQ) were used as a cross-linker and a radical scavenger, respectively. The C–N bond inside the HABI unit was broken under UV irradiation, causing the reversible transformation of HABI into two triphenylimidazole radicals (TPIRs), which were subsequently quenched by TBHQ. Thus, the superpolymer formed an oligomer that could be dissolved in the developer. It was found that HABI-PU PR showed excellent photosensitivity as a positive photoresist during micro–nano manufacturing. The relationship between the content of HABI and TBHQ and resolution and the reaction mechanism between TPIR and TBHQ were studied systematically, and a linear pattern with 1 μm dimension was obtained finally.
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