Inorganic Nanoparticles/Metal Organic Framework Hybrid Membrane Reactors for Efficient Photocatalytic Conversion of CO2

Metal-organic frameworks incorporated with C3N4: A visible light enhanced platform for degradation of polybromodiphenyl ethers

A series of nano-photocatalysts metal-organic frameworks (MOFs)/graphitic carbon nitride (CN) (named MOFCN-x) with high activity have been synthesized by in-situ growth method. Under visible light irradiation, MOFCN-x hybrids show enhanced photocatalytic activity for the debromination of polybromodiphenyl ethers (PBDEs) compared with CN. Among all the hybrids, MOFCN-2 shows the highest reaction rate, which is 3.3 times as high as that in CN. MOFCN-x photocatalysts own stable visible light activity after recycled experiment. It indicates that a moderate amount of MOFs in MOFCN-x can largely enhance the photocatalytic ability by improved visible light absorption, larger specific surface area and better photo-generated charge carriers separation and transfer capabilities. More interestingly, the debromination pathway of PBDEs by MOFCN-x shows obvious selectivity compared with pure CN that bromines at meta-positions are much more susceptible than those at the para- and ortho-positions. The possible photoreductive mechanism has been proposed. This study shows that nanocomposite MOFCN can be an excellent candidate for dealing with halogen pollutants by solar-driven.

Facilitated Photocatalytic CO2 Reduction in Aerobic Environment on a Copper-Porphyrin Metal-Organic Framework

Herein, we fabricated a π-π stacking hybrid photocatalyst by combining two two-dimensional (2D) materials: g-C₃ N₄ and a Cu-porphyrin metal-organic framework (MOF). After an aerobic photocatalytic pretreatment, this hybrid catalyst exhibited an unprecedented ability to photocatalytically reduce CO₂ to CO and CH₄ under the typical level (20 %) of O₂ in the air. Intriguingly, the presence of O₂ did not suppress CO₂ reduction; instead, a fivefold increase compared with that in the absence of O₂ was observed. Structural analysis indicated that during aerobic pretreatment, the Cu node in the 2D-MOF moiety was hydroxylated by the hydroxyl generated from the reduction of O₂ . Then the formed hydroxylated Cu node maintained its structure during aerobic CO₂ reduction, whereas it underwent structural alteration and was reductively devitalized in the absence of O₂ . Theoretical calculations further demonstrated that CO₂ reduction, instead of O₂ reduction, occurred preferentially on the hydroxylated Cu node.

Design and application of g-C3N4-based materials for fuels photosynthesis from CO2 or H2O based on reaction pathway insights

Photocatalytic CO2 reduction reaction (CRR) and hydrogen evolution reaction (HER) based on graphitic carbon nitride (g-C3N4) that is regarded as the metal-free "holy grail" photocatalyst, provide promising strategies for producing next-generation fuels, contributing to achieving carbon neutrality, alleviating energy and environment crisis. However, the activity of CRR and HER over g-C3N4 leaves much to be desired. Therefore, numerous studies have sprung up to enhance photoactivity. A comprehensive understanding of the CRR and HER reaction pathways is crucial for designing g-C3N4-based materials, further promoting efficient fuel production. Different from previous reviews that focus on g-C3N4 modification from the viewpoint of material science. In this review, we divided the multistep processes of CRR and HER into five reaction pathways and summarized the latest advances for improving each pathway of fuels synthesis through CRR or HER. Meanwhile, the existing bottleneck issues of each step were also discussed. Finally, comprehensive conclusions, including the remaining challenges, outlooks, etc., for CRR and HER over g-C3N4 were put forward. We are sure that this review will conduce to the understanding of the structure-activity relationship between CRR, HER processes, and g-C3N4 structure, which can provide the reference for developing high-powered photocatalysts, not confined to g-C3N4.

The Progress of Metal-Organic Framework for Boosting CO2 Conversion

With the rapid development of modern society, environmental problems, including excessive amounts of CO2 released in the atmosphere, are becoming more and more serious. It is necessary to develop new materials and technologies to reduce pollution. Among them, metal–organic frameworks (MOFs) have shown potential for application in the area of catalysis due to their ultra-high specific surface area, structural versatility, and designability as well as ease of modification and post-synthesis. Herein, we summarize recent research advances by use of MOFs for boosting CO2 conversion. Furthermore, challenges and possible research directions related to further exploration are also discussed.

Biogas improvement as renewable energy through conversion into methanol: A perspective of new catalysts based on nanomaterials and metal organic frameworks

In recent years, the high cost and availability of energy sources have boosted the implementation of strategies to obtain different types of renewable energy. Among them, methane contained in biogas from anaerobic digestion has gained special relevance, since it also permits the management of a big amount of organic waste and the capture and long-term storage of carbon. However, methane from biogas presents some problems as energy source: 1) it is a gas, so its storage is costly and complex, 2) it is not pure, being carbon dioxide the main by-product of anaerobic digestion (30%–50%), 3) it is explosive with oxygen under some conditions and 4) it has a high global warming potential (27–30 times that of carbon dioxide). Consequently, the conversion of biogas to methanol is as an attractive way to overcome these problems. This process implies the conversion of both methane and carbon dioxide into methanol in one oxidation and one reduction reaction, respectively. In this dual system, the use of effective and selective catalysts for both reactions is a critical issue. In this regard, nanomaterials embedded in metal organic frameworks have been recently tested for both reactions, with very satisfactory results when compared to traditional materials. In this review paper, the recent configurations of catalysts including nanoparticles as active catalysts and metal organic frameworks as support materials are reviewed and discussed. The main challenges for the future development of this technology are also highlighted, that is, its cost in environmental and economic terms for its development at commercial scale.

Advances in metal-organic framework-based membranes

Membrane-based separations have garnered considerable attention owing to their high energy efficiency, low capital cost, small carbon footprint, and continuous operation mode. As a class of highly porous crystalline materials with well-defined pore systems and rich chemical functionalities, metal-organic frameworks (MOFs) have demonstrated great potential as promising membrane materials over the past few years. Different types of MOF-based membranes, including polycrystalline membranes, mixed matrix membranes (MMMs), and nanosheet-based membranes, have been developed for diversified applications with remarkable separation performances. In this comprehensive review, we first discuss the general classification of membranes and outline the historical development of MOF-based membranes. Subsequently, particular attention is devoted to design strategies for MOF-based membranes, along with detailed discussions on the latest advances on these membranes for various gas and liquid separation processes. Finally, challenges and future opportunities for the industrial implementation of these membranes are identified and outlined with the intent of providing insightful guidance on the design and fabrication of high-performance membranes in the future.

Insight on Reaction Pathways of Photocatalytic CO2 Conversion

Photocatalytic CO₂ conversion to value-added chemicals is a promising solution to mitigate the current energy and environmental issues but is a challenging process. The main obstacles include the inertness of CO₂ molecule, the sluggish multi-electron process, the unfavorable thermodynamics, and the selectivity control to preferable products. Furthermore, the lack of fundamental understanding of the reaction pathways accounts for the very moderate performance in the field. Therefore, in this Perspective, we attempt to discuss the possible reaction mechanisms toward all C₁ and C₂ value-added products, taking into account the experimental evidence and theoretical calculation on the surface adsorption, proton and electron transfer, and products desorption. Finally, the remaining challenges in the field, including mechanistic understanding, reactor design, economic consideration, and potential solutions, are critically discussed by us.

Metal-organic frameworks and their composites for fuel and chemical production via CO2 conversion and water splitting

Increase in the global energy demand has been leading to major energy crises in recent years. The use of excess fossil fuels for energy production is causing severe global warming, as well as energy shortage. To overcome the global energy crisis, the design of various chemical structures as efficient models for the generation of renewable energy fuels is very much crucial, and will limit the use of fossil fuels. Current challenges involve the design of Metal-Organic Framework (MOF) materials for this purpose to diminish the energy shortage. The large surface area, tunable pore environment, unique structural property and semiconducting nature of the highly porous MOF materials enhance their potential applications towards the production of enhanced energy fuels. This review is focused on the architecture of MOFs and their composites for fuels and essential chemicals production like hydrogen, methane, ethanol, methanol, acetic acid, and carbon monoxide, which can be used as renewable fuel energy sources to limit the use of fossil fuels, thereby reducing global warming.

Metal Oxides as Catalyst/Supporter for CO2 Capture and Conversion, Review

Various carbon dioxide (CO2) capture materials and processes have been developed in recent years. The absorption-based capturing process is the most significant among other processes, which is widely recognized because of its effectiveness. CO2 can be used as a feedstock for the production of valuable chemicals, which will assist in alleviating the issues caused by excessive CO2 levels in the atmosphere. However, the interaction of carbon dioxide with other substances is laborious because carbon dioxide is dynamically relatively stable. Therefore, there is a need to develop types of catalysts that can break the bond in CO2 and thus be used as feedstock to produce materials of economic value. Metal oxide-based processes that convert carbon dioxide into other compounds have recently attracted attention. Metal oxides play a pivotal role in CO2 hydrogenation, as they provide additional advantages, such as selectivity and energy efficiency. This review provides an overview of the types of metal oxides and their use for carbon dioxide adsorption and conversion applications, allowing researchers to take advantage of this information in order to develop new catalysts or methods for preparing catalysts to obtain materials of economic value.

Recent Progress in the Synthesis and Applications of Composite Photocatalysts: A Critical Review

Photocatalysis is an advanced technique that transforms solar energy into sustainable fuels and oxidizes pollutants via the aid of semiconductor photocatalysts. The main scientific and technological challenges for effective photocatalysis are the stability, robustness, and efficiency of semiconductor photocatalysts. For practical applications, researchers are trying to develop highly efficient and stable photocatalysts. Since the literature is highly scattered, it is urgent to write a critical review that summarizes the state-of-the-art progress in the design of a variety of semiconductor composite photocatalysts for energy and environmental applications. Herein, a comprehensive review is presented that summarizes an overview, history, mechanism, advantages, and challenges of semiconductor photocatalysis. Further, the recent advancements in the design of heterostructure photocatalysts including alloy quantum dots based composites, carbon based composites including carbon nanotubes, carbon quantum dots, graphitic carbon nitride, and graphene, covalent-organic frameworks based composites, metal based composites including metal carbides, metal halide perovskites, metal nitrides, metal oxides, metal phosphides, and metal sulfides, metal-organic frameworks based composites, plasmonic materials based composites and single atom based composites for CO₂ conversion, H₂ evolution, and pollutants oxidation are discussed elaborately. Finally, perspectives for further improvement in the design of composite materials for efficient photocatalysis are provided.

Recent Advances of Photocatalytic Hydrogenation of CO2 to Methanol

Constantly increasing hydrocarbon fuel combustion along with high levels of carbon dioxide emissions has given rise to a global energy crisis and environmental alterations. Photocatalysis is an effective technique for addressing this energy and environmental crisis. Clean and renewable solar energy is a very favourable path for photocatalytic CO2 reduction to value-added products to tackle problems of energy and the environment. The synthesis of various products such as CH4, CH3OH, CO, EtOH, etc., has been expanded through the photocatalytic reduction of CO2. Among these products, methanol is one of the most important and highly versatile chemicals widely used in industry and in day-to-day life. This review emphasizes the recent progress of photocatalytic CO2 hydrogenation to CH3OH. In particular, Metal organic frameworks (MOFs), mixed-metal oxide, carbon, TiO2 and plasmonic-based nanomaterials are discussed for the photocatalytic reduction of CO2 to methanol. Finally, a summary and perspectives on this emerging field are provided.

Efficient Photocatalytic Reduction of CO2 to CO Using NiFe2O4@N/C/SnO2 Derived from FeNi Metal-Organic Framework

Use of light is considered an effective approach to convert CO₂ into usable chemical energy. In the present study, an iron- and nickel-containing bimetallic metal-organic framework (MOF) was synthesized via a simple solvothermal route. SnO₂ was then composited with the said MOF, and the obtained material was calcined and annealed to fabricate a series of nanophotocatalysts. The annealed sample displayed superior photocatalytic activity to the calcined sample, possibly due to the carbon-nitrogen layer formed after annealing mediating the charge-transfer process. The results of photocatalytic experiments indicated that using [Ru(bpy)₃]Cl₂·6H₂O as a photosensitizer and triethanolamine (TEOA) and acetonitrile (MeCN) as sacrificial agents, the catalyst sample was annealed at 450 °C (NiFe₂O₄@N/C/SnO₂-450) to afford the highest CO yield from CO₂ (2057.41 μmol g^-1 h^-1). The increase in the photocatalytic ability of the nanocomposites is basically attributed to multiple synergistic effects between NiFe₂O₄ and SnO₂, which reduce the recombination probability of the photo-induced electrons and holes. Ultimately, a photocatalytic reaction mechanism is proposed for NiFe₂O₄@N/C/SnO₂ in the reduction of CO₂.

The Evolution of Photocatalytic Membrane Reactors over the Last 20 Years: A State of the Art Perspective

The research on photocatalytic membrane reactors (PMRs) started around the year 2000 with the study of wastewater treatment by degradation reactions of recalcitrant organic pollutants, and since then the evolution of our scientific knowledge has increased significantly, broadening interest in reactions such as the synthesis of organic chemicals. In this paper, we focus on some initial problems and how they have been solved/reduced over time to improve the performance of processes in PMRs. Some know-how gained during these last two decades of research concerns decreasing/avoiding the degradation of the polymeric membranes, improving photocatalyst reuse, decreasing membrane fouling, enhancing visible light photocatalysts, and improving selectivity towards the reaction product(s) in synthesis reactions (partial oxidation and reduction). All these aspects are discussed in detail in this review. This technology seems quite mature in the case of water and wastewater treatment using submerged photocatalytic membrane reactors (SPMRs), while for applications concerning synthesis reactions, additional knowledge is required.

A novel UiO-66/PSF-composite membrane for the rejection of multiple antibiotics: Numerical simulation and experiment verification

UiO-66 nanoparticles were fabricated and applied to the support layer of a novel, thin-film nanocomposite membrane for treatment of wastewater containing antibiotics. The incorporation of the UiO-66 particle structure improved the stability and permeability of the membrane. When the membrane with 0.5 wt% of UiO-66 particles was used to treat antibiotic wastewater by a forward-osmosis process, the water flux reached 50.78 LMH (L·m^-2·h^-1), an increase of 46% compared with the membrane without UiO-66 particles. The rejections of six types of antibiotics improved to over 99.94%. Even trimethoprims rejection rate enhanced to 100% because antibiotics exposed on the surface of the UiO-66 nanoparticles. The forward osmosis model could explain the mechanism of permeation, and predict water flux and rejection. Thus, a novel mathematical model with Gaussian pore distribution and different potential functions was proposed to process multiple-solute transportation and rejection on the charged surface of the membrane. The rejection of six antibiotics was predicted by the iteration algorithm, and the errors of water flux, salt flux, and rejection rates were less than 1.3 LMH, 0.2 gMH (g·m^-2 h^-1), and 1.7% between the predictions and the experiments, respectively. The accuracy of the proposed model was higher than the model published before. Therefore, the experimental results and the theoretical model provide a significant insight into the synthesis thin-film composite membranes and application of water purification.

Recent advances in visible-light-driven carbon dioxide reduction by metal-organic frameworks

Metal-organic frameworks (MOFs) have emerged as promising materials and have attracted researchers due to their unique chemical and physical properties-design flexibility, tuneable pore channels, a high surface-to-volume ratio that allow their distinct application in diverse research fields-gas storage, gas separation, catalysis, adsorption, drug delivery, ion exchange, sensing, etc. The rapidly growing CO₂ in the atmosphere is a global concern due to the excessive use of fossil fuels in the current era. CO₂ is the prime cause of global warming and should be ameliorated either through adsorption or conversion into value-added products to protect the environment and mankind. Nowadays, MOFs are exploited as a photocatalyst for applications of CO₂ reduction. Since the use of semiconductors limits the use of visible light for photocatalytic reduction of CO₂, MOFs are promising options. The current review describes recent development in the application of MOFs as host, composites, and their derivatives in photocatalytic reduction of CO₂ to CO and different organic chemicals (HCOOH, CH₃OH, CH₄). Efficient charge separation and visible light absorption by incorporation of active sites for efficient photocatalysis have been discussed. The selection of material for high CO₂ uptake and potential strategies for the rational design and development of high-performance catalysts are outlined. Major challenges and future perspectives have also been discussed at the last of the review.

Mechanistic insight into photocatalytic CO2 reduction by a Z-scheme g-C3N4/TiO2 heterostructure

The Z-scheme g-C₃N₄/TiO₂ heterostructure has remarkable catalytic activity for reducing CO₂ to CH₄ and CH₃OH.

A review of the research status of CO2 photocatalytic conversion technology based on bibliometrics

In order to clarify the research status, hot spots and development trend in the field of conversion of carbon dioxide, a large amount of literature data set in the scientific network database was analyzed by bibliometrics.

Metal-Organic Frameworks as a Platform for CO2 Capture and Chemical Processes: Adsorption, Membrane Separation, Catalytic-Conversion, and Electrochemical Reduction of CO2

The continuous rise in the atmospheric concentration of carbon dioxide gas (CO2) is of significant global concern. Several methodologies and technologies are proposed and applied by the industries to mitigate the emissions of CO2 into the atmosphere. This review article offers a large number of studies that aim to capture, convert, or reduce CO2 by using a superb porous class of materials (metal-organic frameworks, MOFs), aiming to tackle this worldwide issue. MOFs possess several remarkable features ranging from high surface area and porosity to functionality and morphology. As a result of these unique features, MOFs were selected as the main class of porous material in this review article. MOFs act as an ideal candidate for the CO2 capture process. The main approaches for capturing CO2 are pre-combustion capture, post-combustion capture, and oxy-fuel combustion capture. The applications of MOFs in the carbon capture processes were extensively overviewed. In addition, the applications of MOFs in the adsorption, membrane separation, catalytic conversion, and electrochemical reduction processes of CO2 were also studied in order to provide new practical and efficient techniques for CO2 mitigation.

De Novo synthesis of platinum-nanoparticle-encapsulated UiO-66-NH2 for photocatalytic thin film fabrication with enhanced performance of phenol degradation

The structural and chemical stability of UiO-66-NH₂ and its simulated solar irradiation responsive characteristic make it a suitable metal-organic framework (MOF) candidate as photocatalytic material. Platinum nanoparticles (Pt NPs) are typically immobilized in MOF to enhance the photocatalytic efficiency. However, introducing high metal content in MOF with high dispersion is still challenging using conventional methods. In this paper, we present de novo synthesis of Pt@UiO-66-NH₂, which can reach a highest metal content of 16 wt% with an average nanoparticle size of around 2 nm as confirmed by ICP-MS analysis and TEM images. The presence of benzoic acid plays multiple important roles in Pt@UiO-66-NH₂ formation, including binding formation with Zr clusters, facilitating Pt dispersion, and being a modulator in MOF construction. In addition, the Pt@UiO-66-NH₂ is fabricated on the α-Al₂O₃ substrate as a photocatalytic membrane reactor (PMR) for phenol degradation, which shows over 70 % removal efficiency under light irradiation and H₂O₂ addition. The recycle test shows that the PMR can maintain high catalytic efficiency. The facile de novo synthesis method proposed in this study enables effective immobilization of high metal content in MOF, and construction of membrane-based photocatalyst for scale-up application.

Porous Copper/Zinc Bimetallic Oxides Derived from MOFs for Efficient Photocatalytic Reduction of CO2 to Methanol

A novel metal organic framework (MOF)-derived porous copper/zinc bimetallic oxide catalyst was developed for the photoreduction of CO2 to methanol at a very fast rate of 3.71 mmol gcat−1 h−1. This kind of photocatalyst with high activity, selectivity and a simple preparation catalyst provides promising photocatalyst candidates for reducing CO2 to methanol.

High gas permeability of nanoZIF-8/polymer-based mixed matrix membranes intended for biogas purification

The production of biomethane from the biogas purification process depends on the capacity of the separation technique employed to separate methane from carbon dioxide. Mixed matrix membranes (MMMs) combine the benefits of polymeric and inorganic materials, and it is believed that the trade-off between gas permeability and selectivity in polymeric membranes can be hampered by MMMs. Until recently, the development of MMMs for the biogas purification process has been constrained in lab scales. To be applied in large scales, the increase in gas permeability as well as the membrane performance under the influence of CO2 plasticization needs to be investigated. This paper reports the evaluation of gas permeability and CO2/CH4 gas separation performances of nano zeolitic imidazolate framework (ZIF)-8/Pebax-1657 to be used for biogas purification processes. In addition, the study on the CO2 plasticization behavior of MMMs fabricated with co-polymer Pebax was investigated. The incorporation of nanoZIF-8 particles inhibited the increase of CO2 permeability due to the reduced polymer flexibility. In addition, the diffusional selectivity of ZIF-8 improves the permeation behavior of both gases through MMMs. With nanoZIF-8/Pebax-1657 MMMs, the incorporation of particles improves the gas permeability with a slight decrease in gas selectivity, indicating a potentiality of the membranes used for biogas purification processes.

Enhanced d–d transitions in HKUST/Bi2WO6 nanocomposite mediated visible-light driven selective conversion of benzyl alcohol to benzaldehyde

Graphical representation of the involvement of the d–d transition in the photocatalytic conversion of benzyl alcohol to benzaldehyde.

Vacancy induced photocatalytic activity of La doped In(OH)3 for CO2 reduction with water vapor

A possible mechanism to explain the impact of La doping on electron transfer process in wide band gap semiconductor In(OH)₃.

Synthesis of MIL-53 thin films by vapour-assisted conversion

Using a vapour-assisted conversion approach it is possible to prepare homogeneous MIL-53 thin films on a variety of substrates.

Recent Innovation of Metal-Organic Frameworks for Carbon Dioxide Photocatalytic Reduction

The accumulation of carbon dioxide (CO2) pollutants in the atmosphere begets global warming, forcing us to face tangible catastrophes worldwide. Environmental affability, affordability, and efficient CO2 metamorphotic capacity are critical factors for photocatalysts; metal-organic frameworks (MOFs) are one of the best candidates. MOFs, as hybrid organic ligand and inorganic nodal metal with tailorable morphological texture and adaptable electronic structure, are contemporary artificial photocatalysts. The semiconducting nature and porous topology of MOFs, respectively, assists with photogenerated multi-exciton injection and adsorption of substrate proximate to void cavities, thereby converting CO2. The vitality of the employment of MOFs in CO2 photolytic reaction has emerged from the fact that they are not only an inherently eco-friendly weapon for pollutant extermination, but also a potential tool for alleviating foreseeable fuel crises. The excellent synergistic interaction between the central metal and organic linker allows decisive implementation for the design, integration, and application of the catalytic bundle. In this review, we presented recent MOF headway focusing on reports of the last three years, exhaustively categorized based on central metal-type, and novel discussion, from material preparation to photocatalytic, simulated performance recordings of respective as-synthesized materials. The selective CO2 reduction capacities into syngas or formate of standalone or composite MOFs with definite photocatalytic reaction conditions was considered and compared.

Unusual adsorption behaviours and responsive structural dynamics via selective gate effects of an hourglass porous metal-organic framework

An hourglass porous metal–organic framework, LIFM-12, constructed on a T-shaped flexible ligand with Cu²⁺ paddle-wheel clusters, shows temperature and gas adsorption responsive structural dynamics upon reversible molecular guest binding. Temperature-dependent single crystal and powder X-ray diffraction experiments show that the open gate status of the framework with adaptive behaviours facilitates kinetic diffusion of gas molecules resulting in the sequential filling of pores of different sizes, thus creating a breathing behaviour reminiscent of the observation of several steps in adsorption isotherms. In addition, adsorption studies revealed that LIFM-12 performs exceptional adsorption selectivity of 10–25 for CO₂versus light gases N₂, CH₄, and CO and up to 200 for C₃H₆versus CH₄.

A Cu²⁺ based metal–organic framework exhibits dynamic behaviour upon guest inclusion/release process, and performing stepwise sorption isotherms for various gas. We elucidate detailed mechanisms under its exceptional sorption behavior.

Carbon-Based Nanomaterials in Sensors for Food Safety

Food safety is one of the most important and widespread research topics worldwide. The development of relevant analytical methods or devices for detection of unsafe factors in foods is necessary to ensure food safety and an important aspect of the studies of food safety. In recent years, developing high-performance sensors used for food safety analysis has made remarkable progress. The combination of carbon-based nanomaterials with excellent properties is a specific type of sensor for enhancing the signal conversion and thus improving detection accuracy and sensitivity, thus reaching unprecedented levels and having good application potential. This review describes the roles and contributions of typical carbon-based nanomaterials, such as mesoporous carbon, single- or multi-walled carbon nanotubes, graphene and carbon quantum dots, in the construction and performance improvement of various chemo- and biosensors for various signals. Additionally, this review focuses on the progress of applications of this type of sensor in food safety inspection, especially for the analysis and detection of all types of toxic and harmful substances in foods.

Recent Advances in MOF-based Nanocatalysts for Photo-Promoted CO2 Reduction Applications

The conversion of CO2 to valuable substances (methane, methanol, formic acid, etc.) by photocatalytic reduction has important significance for both the sustainable energy supply and clean environment technologies. This review systematically summarized recent progress in this field and pointed out the current challenges of photocatalytic CO2 reduction while using metal-organic frameworks (MOFs)-based materials. Firstly, we described the unique advantages of MOFs based materials for photocatalytic reduction of CO2 and its capacity to solve the existing problems. Subsequently, the latest research progress in photocatalytic CO2 reduction has been documented in detail. The catalytic reaction process, conversion efficiency, as well as the product selectivity of photocatalytic CO2 reduction while using MOFs based materials are thoroughly discussed. Specifically, in this review paper, we provide the catalytic mechanism of CO2 reduction with the aid of electronic structure investigations. Finally, the future development trend and prospect of photocatalytic CO2 reduction are anticipated.

Tuning the Size and Shape of NanoMOFs via Templated Electrodeposition and Subsequent Electrochemical Oxidation

The control over the size and shape of nanoMOFs is essential for their exploitation in integrated devices such as sensors, membranes for gas separation, photoelectrodes, etc. Here, we demonstrate the synthesis of nanowires and three-dimensionally interconnected nanowire networks of Cu-based metal-organic frameworks (MOFs) by a combination of ion-track technology and electrochemical methods. In particular, Cu nanowires and nanowire networks were electrodeposited inside polymeric etched ion-track membranes and subsequently converted by electrochemical oxidation into different Cu-based MOFs such as the well-known Cu₃(BTC)₂ (also known as HKUST-1) and the lesser-known MOF Cu(INA)₂. The MOFs are formed inside the template, therefore adopting the shape of the host nanochannels. The synthesized MOF nanowires exhibit tunable diameters between 80 and 260 nm. Characterization by X-ray diffraction, thermogravimetric analysis/differential scanning calorimetry, scanning electron microscopy, and transmission electron microscopy indicates that the employed electrochemical conversion includes the formation of Cu₂O as an intermediate, as well as the initial formation of an amorphous MOF phase, which crystallizes upon longer reaction times.