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.
The design of smart stimuli‐responsive photoluminescent materials capable of multi‐level encryption and complex information storage is highly sought after in the current information era. Here, a ...novel adamantyl‐capped CsPbBr3 (AD‐CsPbBr3) perovskite NCs, along with its supramolecular host‐guest assembly partner a modified β‐CD (mCD), mCD@AD‐CsPbBr3, are designed and prepared. By dispersing these two materials in different solvents, namely, AD‐CsPbBr3 in toluene, mCD@AD‐CsPbBr3 in toluene, and mCD@AD‐CsPbBr3 in methanol, the three solutions exhibit diverse photoluminescence (PL) turn‐on/off or PL discoloration response upon supramolecular stimulus. Based on these responses, a proof‐of‐principle programmable Multi‐Level Photoluminescence Encoding System (MPLES) is established. Three types of four‐level and three types of three‐level information encoding are achieved by the system. A layer‐by‐layer four‐level information encryption and decryption as well as a two‐level encrypted 3D code are successfully achieved.
Adamantyl‐capped AD‐CsPbBr3 perovskite nanorods and their cyclodextrin‐coated counterparts, mCD@AD‐CsPbBr3, display varied photoluminescent turn on/off or discoloration responses to four stimuli. This enables a sophisticated encoding system capable of multi‐level encryption and decryption, including intricate four‐layer encryption/decryption processes and a dual‐level 3D code.
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.
The utilization of solar energy to produce solar fuels, namely hydrogen (H2) and carbon-based fuels, represents a sustainable and clean method for fuel production. The state-of-the-art photocatalysts ...realized H2 production or CO2 reduction, separately, with high activity and stability. Syngas, a gaseous mixture of carbon monoxide (CO) and H2 is an important feedstock in petrochemical industries. Syngas with a reasonable CO : H2 ratio satisfies different product requirements in Fischer–Tropsch (F–T) synthesis. The production of syngas via photocatalysis through protons and CO2 reduction reactions is a promising strategy to obtain syngas through solar-to-chemical energy conversion. Herein, we report a novel ternary photocatalyst, CoPh/CdSe@TiO2, by assembling a molecular CO2 reduction catalyst CoPh, CdSe quantum dots (QDs), and TiO2 nanoparticles (NPs) together via facile self-assembly. The CoPh/CdSe@TiO2 photocatalyst enables the catalysis of proton and CO2 reduction reactions and produces syngas under visible light irradiation. The CoPh/CdSe@TiO2 photocatalyst simultaneously produces CO and H2 for over 140 hours under visible light irradiation. The efficiencies of CO and H2 production are 571 μmol g−1 and 1554 μmol g−1, respectively. The CO : H2 ratio maintains in the range of 1 : 0.6–1 : 2.7, satisfying syngas ratio requirements for F–T synthesis. Mechanism studies revealed that CdSe QD, TiO2 NP, and CoPh function mainly as a visible light harvester, a H2 production catalyst, and a CO2 reduction catalyst, respectively. Photoinduced electron transfers from CdSe QD to CoPh or TiO2, separately, occur in the ternary photocatalyst. A robust photocatalytic syngas production has been achieved based on the successful assembly of three functional components in one photocatalyst.
•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.
Colloidal quantum dots (QDs) as photocatalysts enable catalysis of CO2-to-CO conversion in the presence of electron donors. The surface and/or interfacial chemical environment of the QDs is essential ...for the activity and selectivity of the CO2 photoreduction. Various strategies, including exposing active metal sites or anchoring functional organic ligands, have been applied to tune the QDs’ surface chemical environment and thus to improve both activity and selectivity of CO2 photoreduction, which occurs at surface of the QDs. However, the efficient and selective photocatalytic CO2 reduction with QD photocatalysts in water is still a challenging task due to low CO2 solubility and robust competing reaction of proton reduction in water. Different from state-of-the-art QDs’ surface manipulation, we proposed to ameliorate the interfacial chemical environment of CdSe QDs via assembling the QDs into functional polymeric micelles in water. Herein, CdSe@PEI-LA assemblies were constructed by loading CdSe QDs into polymeric micelles formed by PEI-LA, a polyethylenimine (PEI)-based functional amphiphilic polymer. Due to self-assembly and high CO2 adsorption capacity of PEI-LA in water, the photocatalytic CO2-to-CO conversion efficiency and selectivity of the CdSe@PEI-LA assemblies in water were dramatically improved to 28.0 mmol g–1 and 87.5%, respectively. These two values increased 57 times and 1.5 times, respectively, compared with those of the pristine CdSe QDs. Mechanism studies revealed that CdSe QDs locate in polymeric micelles of high CO2 local concentration and the photoinduced electron transfer from the conduction band of CdSe QDs to Cd–CO2* species is thermodynamically and kinetically improved in the presence of PEI-LA. The CdSe@PEI-LA system represents a successful example of using a functionalized amphiphilic polymer to ameliorate interfacial microenvironments of nanocrystal photocatalysts and realizing efficient and selective CO2 photoreduction in water.
The design of smart stimuli-responsive photoluminescent materials capable of multi-level encryption and complex information storage is highly sought after in the current information era. Here, a ...novel adamantyl-capped CsPbBr
(AD-CsPbBr
) perovskite NCs, along with its supramolecular host-guest assembly partner a modified β-CD (mCD), mCD@AD-CsPbBr
, are designed and prepared. By dispersing these two materials in different solvents, namely, AD-CsPbBr
in toluene, mCD@AD-CsPbBr
in toluene, and mCD@AD-CsPbBr
in methanol, the three solutions exhibit diverse photoluminescence (PL) turn-on/off or PL discoloration response upon supramolecular stimulus. Based on these responses, a proof-of-principle programmable Multi-Level Photoluminescence Encoding System (MPLES) is established. Three types of four-level and three types of three-level information encoding are achieved by the system. A layer-by-layer four-level information encryption and decryption as well as a two-level encrypted 3D code are successfully achieved.
•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.
Display omitted
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.
PDF