The low structural stability of hydrogen‐bonded organic frameworks (HOFs) is a thorny issue retarding the development of HOFs. A rational design approach is now proposed for construction of a stable ...HOF. The resultant HOF (PFC‐1) exhibits high surface area of 2122 m2 g−1 and excellent chemical stability (intact in concentrated HCl for at least 117 days). A new method of acid‐assisted crystalline redemption is used to readily cure the thermal damage to PFC‐1. With periodic integration of photoactive pyrene in the robust framework, PFC‐1 can efficiently encapsulate Doxorubicin (Doxo) for synergistic chemo‐photodynamic therapy, showing comparable therapeutic efficacy with the commercial Doxo yet considerably lower cytotoxicity. This work demonstrates the notorious stability issue of HOFs can be properly addressed through rational design, paving a way to develop robust HOFs and offering promising application perspectives.
An ultra‐robust hydrogen‐bonded organic framework with high BET surface area and acid‐assisted crystalline recovery was developed through several rational design strategies. With periodic integration of photoactive pyrene in the framework, this material can efficiently encapsulate the drug doxorubicin for synergistic chemo‐photodynamic therapy, showing low cytotoxicity and prominent therapeutic efficacy.
Electrocatalytic CO2 reduction (ECR) is a promising technology to simultaneously alleviate CO2‐caused climate hazards and ever‐increasing energy demands, as it can utilize CO2 in the atmosphere to ...provide the required feedstocks for industrial production and daily life. In recent years, substantial progress in ECR systems has been achieved by the exploitation of various novel electrode materials. The anodic materials and cathodic catalysts that have, respectively, led to high‐efficiency energy input and effective heterogenous catalytic conversion in ECR systems are comprehensively reviewed. Based on the differences in the nature of energy sources and the role of materials used at the anode, the fundamentals of ECR systems, including photo‐anode‐assisted ECR systems and bio‐anode‐assisted ECR systems, are explained in detail. Additionally, the cathodic reaction mechanisms and pathways of ECR are described along with a discussion of different design strategies for cathode catalysts to enhance conversion efficiency and selectivity. The emerging challenges and some perspective on both anode materials and cathodic catalysts are also outlined for better development of ECR systems.
Electrode materials are considered to be important components for electrocatalytic CO2 reduction systems, as they affect the energy input method and CO2 conversion efficiencies. Various photo‐anode and bio‐anode materials for lowering external bias and progress on cathode catalysts for improving CO2 conversion efficiencies are comprehensively reviewed. Moreover, enhancement strategies in the design of these electrode materials are highlighted.
Despite numerous inherent merits of metal–organic frameworks (MOFs), structural fragility has imposed great restrictions on their wider involvement in many applications, such as in catalysis. Herein, ...a strategy for enhancing stability and enabling functionality in a labile Zr(IV)‐MOF has been proposed by in situ porphyrin substitution. A size‐ and geometry‐matched robust linear porphyrin ligand 4,4′‐(porphyrin‐5,15‐diyl)dibenzolate (DCPP2−) is selected to replace the 4,4′‐(1,3,6,8‐tetraoxobenzolmn3,8phenanthroline‐2,7(1H,3H,6H,8H)‐diyl)dibenzoate (NDIDB2−) ligand in the synthesis of BUT‐109(Zr), affording BUT‐110 with varied porphyrin contents. Compared to BUT‐109(Zr), the chemical stability of BUT‐110 series is greatly improved. Metalloporphyrin incorporation endows BUT‐110 MOFs with high catalytic activity in the photoreduction of CO2, in the absence of photosensitizers. By tuning the metal species and porphyrin contents in BUT‐110, the resulting BUT‐110‐50%‐Co is demonstrated to be a good photocatalyst for selective CO2‐to‐CO reduction, via balancing the chemical stability, photocatalytic efficiency, and synthetic cost. This work highlights the advantages of in situ ligand substitution for MOF modification, by which uniform distribution and high content of the incoming ligand are accessible in the resulting MOFs. More importantly, it provides a promising approach to convert unstable MOFs, which mainly constitute the vast MOF database but have always been neglected, into robust functional materials.
The in situ porphyrin substitution strategy is developed for modifying labile interpenetrated BUT‐109(Zr), affording BUT‐110 with enhanced chemical stability and photocatalytic activity. By tuning the species and contents of metalloporphyrin in BUT‐110, some of the BUT‐110 MOFs may serve as potential photocatalysts for selective CO2‐to‐CO reduction, in the absence of photosensitizer.
Polychlorinated dibenzo-p-dioxins (PCDDs), as a class of persistent and highly toxic organic pollutants, have been posing a great threat to human health and the environment. The sensing of these ...compounds is important but challenging. Here, we report a highly stable zirconium-based metal-organic framework (MOF), Zr
O
(OH)
(HCOO)
(CPTTA)
(BUT-17) with one-dimensional hexagonal channels and phenyl-rich pore surfaces for the recognition and sensing of two representative PCDDs, 2,3-dichlorodibenzo-p-dioxin (BCDD) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), based on the fluorescence quenching. BUT-17 exhibits high sensing ability with the detection limits as low as 27 and 57 part per billion toward BCDD and TCDD, respectively, and is very selective as well without the interference of similar compounds. The recognition of BUT-17 toward BCDD is demonstrated by single-crystal structure of its guest-loaded phase, in which the fluorescence-quenched complexes form between the adsorbed BCDD molecules and the MOF host through π-π stacking and hydrogen bonding interactions.
The emergence and global spread of bacterial resistance to conventionally used antibiotics have highlighted the urgent need for new antimicrobial agents that might replace antibiotics. Currently, ...nanomaterials hold considerable promise as antimicrobial agents in anti‐inflammatory therapy. Due to their distinctive functional physicochemical characteristics and exceptional biocompatibility, carbon dots (CDs)‐based composites have attracted a lot of attention in the context of these antimicrobial nanomaterials. Here, a thorough assessment of current developments in the field of antimicrobial CDs‐based composites is provided, starting with a brief explanation of the general synthesis procedures, categorization, and physicochemical characteristics of CDs‐based composites. The many processes driving the antibacterial action of these composites are then thoroughly described, including physical destruction, oxidative stress, and the incorporation of antimicrobial agents. Finally, the obstacles that CDs‐based composites now suffer in combating infectious diseases are outlined and investigated, along with the potential applications of antimicrobial CDs‐based composites.
Carbon dots (CDs)‐based composites integrate the outstanding properties of functional modules and CDs, exhibiting remarkable optical, enzyme‐like activity, and biocompatible properties, emerging as a promising application tool in the field of bacteriostatic therapy.
Efficient removal of organic pollutants from wastewater has become a hot research topic due to its ecological and environmental importance. Traditional water treatment methods such as adsorption, ...coagulation, and membrane separation suffer from high operating costs, and even generate secondary pollutants. Photocatalysis on semiconductor catalysts (TiO
2
, ZnO, Fe
2
O
3
, CdS, GaP, and ZnS) has demonstrated efficiency in degrading a wide range of organic pollutants into biodegradable or less toxic organic compounds, as well as inorganic CO
2
, H
2
O, NO
3
−
, PO
4
3−
, and halide ions. However, the difficult post-separation, easy agglomeration, and low solar energy conversion efficiency of these inorganic catalysts limit their large scale applications. Exploitation of new catalysts has been attracting great attention in the related research communities. In the past two decades, a class of newly-developed inorganic-organic hybrid porous materials, namely metal-organic frameworks (MOFs) has generated rapid development due to their versatile applications such as in catalysis and separation. Recent research has showed that these materials, acting as catalysts, are quite effective in the photocatalytic degradation of organic pollutants. This review highlights research progress in the application of MOFs in this area. The reported examples are collected and analyzed; and the reaction mechanism, the influence of various factors on the catalytic performance, the involved challenges, and the prospect are discussed and estimated. It is clear that MOFs have a bright future in photocatalysis for pollutant degradation.
This review summarizes research advances in photocatalytic organic pollutant degradation in metal-organic frameworks.
Lead halide perovskite quantum dots (QDs) are promising electrochemiluminescence (ECL) nanoemitters due to their fascinating photophysical properties. However, due to their poor structural stability ...against the external environment, the trade‐off between their colloidal stability and carrier injection/transport efficiency is a major challenge in the advancement of perovskite‐based ECL technology. In this work, intense and stable ECL from CsPbBr3 (CPB) QDs is achieved by simultaneously encapsulating CPB QDs and coreactant (CoR) into in situ generated SiO2 matrix via hydrolysis of tetramethyl orthosilicate. The well‐designed architecture of the as‐obtained CPB‐CoR@SiO2 nanocomposites (NCs) guarantees not only greatly improved stability thanks to the peripheral SiO2 protecting matrix, but also efficient self‐enhanced ECL between CPB and the intra‐coreactants. Consequently, by elaborately selecting the CoR molecules with different tertiary/secondary amines and functional groups, multifold higher (up to 10.2 times) ECL efficiencies are obtained for the CPB‐CoR@SiO2 NCs alone in reference to the standard Ru(bpy)32+/tri‐n‐propylamine system. This work provides an efficient design strategy for obtaining stable and highly efficient ECL from perovskite QDs, and offers a new perspective for the development and application of perovskite‐based ECL system.
Ternary CsPbBr3 perovskite suprastructures with self‐enhanced electrochemiluminescence and improved stability is prepared by simultaneously encapsulating CsPbBr3 quantum dots and coreactant into in situ generated SiO2 matrix via hydrolysis of tetramethyl orthosilicate. The obtained nanocomposites exhibit higher (up to 10.2 times) electrochemiluminescence efficiencies in reference to the standard Ru(bpy)32+/tri‐n‐propylamine system.
The hollow-structured C-In2O3@MO (MO = ZnO, Co3O4, and ZnCo2O4) heterojunction photocatalysts are fabricated by the core–shell structured dual MOF template-directed strategy. The obtained ...photocatalysts exhibit high performance for CO2 photoreduction, due to the suitable energy band matching structure and high solar light unilization.
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•A dual MOFs template-directed strategy for fabricating heterojunction photocatalysts is firstly developed.•A series of C-In2O3@MO (MO = ZnO, Co3O4, and ZnCo2O4) heterojunctions are fabricated.•The sutiable energy matching and hollow structure of the C-In2O3@ZnCo2O4 promotes CO2 photoreduction activity.
Developing efficient photocatalysts for CO2 reduction into value-added chemical feedstocks is of significance. Heterojunction photocatalysts are promising candidates but still suffering from the insufficient electron-hole pair separation issues. Herein, a strategy that dual metal–organic frameworks (MOFs) template-directed fabrication of carbon-supported heterojunction, C-In2O3@MO (MO = ZnO, Co3O4, and ZnCo2O4) with tunable band matching structure was developed. The resultant hollow- structured C-In2O3@ZnCo2O4 shows high CO2 reduction activity towards CO (44.1 μmol g1 h−1) with a selectivity of 66%. The superior performance of this material could be ascribed to the suitable energy band matching and efficient internal charge transfer on p-n heterojunction, which facilitates electron-hole separation. Meanwhile, the hollow cavity not only improved light-harvesting capability through multiple light reflection and scattering in the internal voids but also provided large surface area for exposing active sites to promoting the activation of CO2. This study thus proposes a feasible approach to adjust the heterojunction structure of photocatalysts to achieve efficient CO2 reduction reaction.
The rapid detection of antibiotics in agricultural products is of great significance. In this work, two stable fluorescent metal–organic frameworks (MOFs), BUT-178 and BUT-179, are synthesized and ...used to detect tetracycline antibiotics. Among them, BUT-179 exhibits better performance in the detection of different tetracycline antibiotics in water and eggs. The limits of detection of BUT-179 toward tetracycline, aureomycin, oxytetracycline, and doxycycline all reach the nanomolar level. Furthermore, the cycling tests confirm that BUT-179 can be easily recovered and repeatedly used without an obvious performance loss. This work demonstrates the excellent application potential of MOFs for food safety, especially the fluorescence detection of antibiotics in foods.
Metal–organic frameworks (MOFs) have been developing at an unexpected rate over the last two decades. However, the unsatisfactory chemical stability of most MOFs hinders some of the fundamental ...studies in this field and the implementation of these materials for practical applications. The stability in a MOF framework is mostly believed to rely upon the robustness of the M–L (M = metal ion, L = ligand) coordination bonds. However, the role of organic linkers as agents of stability to the framework, particularly the linker rigidity/flexibility, has been mostly overlooked. In this work, we demonstrate that a ligand-rigidification strategy can enhance the stability of MOFs. Three series of ligand rotamers with the same connectivity but different flexibility were prepared. Thirteen Zr-based MOFs were constructed with the Zr6O4(OH4)(−CO2) n units (n = 8 or 12) and corresponding ligands. These MOFs allow us to evaluate the influence of ligand rigidity, connectivities, and structure on the stability of the resulting materials. It was found that the rigidity of the ligands in the framework strongly contributes to the stability of corresponding MOFs. Furthermore, water adsorption was performed on some chemically stable MOFs, showing excellent performance. It is expected that more MOFs with excellent stability could be designed and constructed by utilizing this strategy, ultimately promoting the development of MOFs with higher stability for synthetic chemistry and practical applications.
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