Catalytic Recyclability Research Articles

Photocatalytic Degradation of Typical Bisphenol Compounds Using Zr‐NiFe2O4@ZIF‐67/ZIF‐8 in Collaboration With Peroxydisulfate/Peroxymonosulfate

ABSTRACTAs the amount of tetrachlorobisphenol A (TCBPA) that causes potential adverse effects on human health in the environment is continually increasing. It is therefore important to develop new materials for the adsorption or degradation of these compounds using various techniques. In this study, two novel magnetic recyclable composite catalysts Zr–NiFe2O4@ZIF‐67 and Zr–NiFe2O4@ZIF‐8 were synthesized. These catalysts degraded tetrachlorobisphenol A (TCBPA) in water by activating peroxydisulfate (PDS)/peroxymonosulfate (PMS), respectively. The results show that the Zr–NiFe2O4@ZIF‐67‐5%/LED/(NH4)2S2O8 system can degrade 95% of TCBPA (20 mg/L) within 30 min, whereas the Zr–NiFe2O4@ZIF‐8‐10%/LED/KHSO5 system degrades 90% of TCBPA within 30 min. In instances of metal leaching at low concentrations, nickel and iron ions declined to 0.008 mg·L−1, TCBPA exhibits highly efficient and sustainable catalytic properties, maintaining over 80% efficacy across six cycles. The online infrared test experiment results showed the major functional groups disappearing within approximately 130 s. The results of electron paramagnetic resonance and free‐radical‐quenching experiments showed that SO4˙−, ˙OH, 1O2, and O2˙− were involved in the degradation of TCBPA. The possible degradation paths are isomerization polymerization, dechlorination, hydroxylation, ring‐opening by oxidation, and further transformation into small molecules of acids, aldehydes, alcohols and other compounds. Thus, in this study, a reliable technique for the degradation of halogenated bisphenol compounds is developed. Overall, the photocatalytic degradation of organic pollutants in water utilizing polymetallic composites as catalysts represents an innovative approach to water treatment, demonstrating enhanced catalytic activity and recyclability, with promising prospects for significant advancements in both theoretical research and practical applications.

Immobilization of snailase and β-glucosidase on L-aspartic acid-modified magnetic amorphous ZIF for efficiently and sustainably producing ginsenoside compound K.

Improving the catalytic efficiency and recyclability of immobilized enzyme remained a serious challenge in industrial applications. Enzyme immobilization in the amorphous zeolite imidazolate framework (aZIF) preserved high enzyme activity, but still faced separation difficulties and a low catalytic efficiency in practice. In this study, a one-pot co-precipitation method was used to form the enzyme-aZIF/magnetic nanoparticle (MNP) biocomposite by rapidly precipitating snailase (Sna) and β-glucosidase (β-G) with metal/ligand on MNP and modifying with L-aspartic acid (Asp). Thanks to Asp modification protecting the natural conformation of internal protein molecules and MNP stabilizing the conformation of active enzymes after immobilizing, Sna&β-G in the carrier had more stable conformations and higher catalytic efficiency than those in conventional ZIF-8, increasing the catalytic efficiency for converting ginsenoside Rb1 to rare ginsenoside compound K (CK) to 79.16%. Moreover, while improving the stability of Sna&β-G, owing to the magnetism imparted by MNP, the immobilized enzyme maintained high enzyme activity and recovery after 7cycles by rapid magnetic separation. The results provided guidance for developing immobilized Sna&β-G biocomposites with ideal catalytic efficiency and easy recovery to catalyze ginsenoside Rb1 to rare ginsenoside CK.

Ligand-Shell Cooperativity in a Bilayer Silica-Sandwiched Mixed-Metals Nanocatalyst Design for Absolute Selectivity Switch.

Unlike homogeneous metal complexes, achieving absolute control over reaction selectivity in heterogeneous catalysts remains a formidable challenge due to the unguided molecular adsorption/desorption on metal-surface sites. Conventional organic surface modifiers or ligands and rigid inorganic and metal-organic porous shells are not fully effective. Here, we introduce the concept of "ligand-porous shell cooperativity" to desirably switch reaction selectivity in heterogeneous catalysis. We present a nanocatalyst design strategy consisting of bilayer silica-sandwiched 2D mixed metal islands. The intimate 2D/2D nanoscale interfacing between porous silica layers and flat island-like mixed-metal sites, combined with organic ligands, creates a nanoconfined microenvironment that enables reliable control of molecular orientation-dependent reactivity, affording the desired product in 100% selectivity. This design simultaneously leverages the hydrophobicity and flexibility of organic ligands and the nanoscale geometric rigidity of the pores inside the inorganic silica shell. Our strategy is effective with simple amorphous silica, random Cu-alloy, and commonly used metal-coordinating ligands. We demonstrate the applicability in industrially significant reactions: selective hydrogenation of alkynes, α,β-unsaturated esters/aldehydes, and nitroarenes. Our findings offer the valuable scope of a multicomponent compact nanoscale design strategy in next-generation switchable, sustainable, and recyclable catalysis.

N-Phenylphenothiazine-based Hyper-cross-linked Polymers for Recyclable, Heterogeneous Photocatalysis of Organic Transformations: A Strategy to Access 6-Difluoromethyl-phenanthridines.

Herein, a N-phenylphenothiazine-based hyper-cross-linked polymer (PTH-HCP) was finely designed and constructed, which serves as a metal-free heterogeneous photocatalyst for organic transformations. Characterization experiments have shown that this polymer demonstrates outstanding stability, extensive surface area, and exceptional photoelectric response properties. Moreover, PTH-HCP showed good catalytic efficiency and recyclability in the photochemically driven difluoromethylation/cyclization reactions. This work provides a strategy for the design and construction of polymer photocatalysts and offers support for their broad prospects in synthetic applications.

Enhancing molecular oxygen activation by nitrogen-doped carbon encapsulating FeNi alloys with ultra-low Pt loading.

Modulating the electronic structure of noble metals via electronic metal-support interaction (EMSI) has been proven effectively for facilitating molecular oxygen activation and catalytic oxidation reactions. Nevertheless, the investigation of the fundamental mechanisms underlying activity enhancement has primarily focused on metal oxides as supports, especially in the catalytic degradation of volatile organic compounds. In this study, a novel Pt catalyst supported on nitrogen-doped carbon encapsulating FeNi alloy, featuring ultrafine Pt nanoparticles, was synthesized. This catalyst demonstrated exceptional catalytic activity (92%), recyclability, and water tolerance for the deep oxidation of formaldehyde at room temperature. Structural analyses and theoretical calculations revealed a directional electron transfer from FeNi alloy to Pt, even there is no direct contact between them. This electron penetration effect, mediated by carbon, conferred electron-rich properties to Pt, leading to the activation of molecular oxygen by elongating O-O bond length (1.405 Å). Consequently, efficient formaldehyde removal was achieved with an ultra-low Pt loading. This investigation offers a novel perspective on modulating the electronic structure of Pt by engineering a unique EMSI effect between a nonoxide support and active species, thereby enabling efficient oxygen activation for air purification.

In situ synthesis of gold nanoparticles embedded in a magnetic nanocomposite of glucosamine/alginate for enhancing recyclable catalysis performance of nitrophenol reduction.

In this study, we introduce an in situ synthesis technique for incorporating gold nanoparticles (AuNPs) into a magnetic nanocomposite made of glucosamine and alginate (GluN/Alg) via ionotropic gelation. GluN acted as a reducing agent for gold ions, leading to the formation of AuNPs which embedded in the nanocomposite Fe3O4@GluN/Alg. Analytical techniques confirmed the crystallite structure of the nanocomposite AuNPs/Fe3O4@GluN/Alg, which had an average size of 30-40 nm. This nanocomposite demonstrated high catalytic efficiency in reducing 2-, 3-, and 4-nitrophenols, exhibiting rapid kinetics with pseudo-first order rate constants between 1.16 × 10-3 s-1 and 2.29 × 10-3 s-1. The reduction rates and recyclability for nitrophenols followed the order: 4-nitrophenol > 2-nitrophenol ∼ 3-nitrophenol. These results indicate that the nanocomposite holds significant promise for customized applications in environment and medicine, positioning it as a highly versatile material.

Synthesis of High-Quality TS-1 Zeolites Using Precursors of Diol-Based Polymer and Tetrapropylammonium Bromide for 1-Hexene Epoxidation

To synthesize high-quality TS-1 zeolites with enhanced catalytic performance for 1-hexene epoxidation is highly attractive for meeting the increased need for sustainable chemistry. Herein, we report that a series of framework Ti-enriched TS-1 zeolites with high crystallinity can be effectively synthesized by the hydrothermal crystallization of a composite precursor composed of diol-based polymer (containing titanium and silicon) and tetrapropylammonium bromide (TPABr). The pre-addition of a certain amount of TPABr into the polymer-based precursor plays a very positive role in maintaining the high crystallinity and framework Ti incorporation rate of TS-1 zeolites under the premise that a relatively low concentration of tetrapropylammonium hydroxide (TPAOH) template is adopted in the following hydrothermal crystallization process. The condition-optimized TS-1 zeolite with a smaller particle size (300–500 nm) shows excellent catalytic activity, selectivity, and recyclability for the epoxidation of 1-hexene with H2O2 as an oxidant, which can achieve a 75.4% conversion of 1-hexene and a 99% selectivity of epoxide at a reaction temperature of 60 °C, which is much better than the TS-1 zeolites reported in the previous literature. The relatively small particle size of the resultant TS-1 crystals may enhance the accessibility of the catalytically active framework Ti species to reagents, and the absence of non-framework Ti species, like anatase TiO2, and low polymerized six-coordinated Ti species could effectively inhibit the ineffective decomposition of H2O2 and the occurrence of side reactions, leading to an improvement in the catalytic efficiency for the epoxidation of 1-hexente with H2O2.

Robust core−shell ZIF-67@PDB-Br as synergetic catalyst for chemical fixation of CO2 without co-catalysts

Metal-organic frameworks (MOFs) are widely studied for cycloaddition of CO2 as a heterogeneous catalyst, because of their potential Lewis acidic sites and adjustable porous structure. However, most of them exhibit good catalytic performance need the assistance of nucleophilic co-catalysts. Herein, a novel MOFs and porous organic polymers (POPs) hybrid catalyst, core-shell ZIF-67@PDB-Br, is constructed by a convenient synthetic strategy, which possesses abundant Lewis acidic sites, imidazole cations and nucleophilic centers and shows robust chemical and thermal stability. This material demonstrates high-efficient catalytic activities and recyclability in the cycloaddition of CO2 and propylene oxide without co-catalysts, the conversion and selectivity can reach 94.1 % and 99.0 %, respectively (100 °C, 1.0 MPa CO2 pressure). Furthermore, the effects of the temperature, pressure, amount of catalyst and thickness of POPs shell on the catalytic activity were investigated. This study provides a viable direction for the development of synergistic heterogeneous catalysts for fixation of CO2 without co-catalysts.

Amino-Functionalized Metal-Organic Framework-Mediated Cellulose Aerogels for Efficient Cr(VI) Reduction.

Industrialization activities have increased the discharge of wastewater that is polluted with hexavalent chromium (Cr(VI)), posing risks to ecosystems and humans. The photocatalytic reduction of Cr(VI) is viewed as a promising method for the removal of Cr(VI) species. However, developing photocatalysts with the desired catalytic activity, recyclability, and reusability remains a challenge. Herein, a composite aerogel was designed and fabricated with a Ti-based metal-organic framework (MIL-125-NH2) and carboxylated nanocellulose. MIL-125-NH2 presents a strong visible-light response, and the interactions between the amino groups of MIL-125-NH2 and the carboxyl groups of cellulose produce a strong interface affinity in the composites. The as-prepared aerogels exhibited a micro/macroporous structure. At an optimal MIL-125-NH2 loading of 55 wt%, the MC-5 sample showed a specific surface area of 582 m2·g-1. MC-5 achieved a photocatalytic Cr(VI) removal efficiency of 99.8%. Meanwhile, the aerogel-type photocatalysts demonstrated good stability and recycling ability, as MC-5 maintained a removal rate of 82% after 10 cycles. This work sheds light on the preparation of novel photocatalysts with three-dimensional structures for environmental remediation.

Synthesis of NaLTA zeolite confined CuO catalysts and superior catalytic properties for alkene epoxidation with H2O2 as oxidant

The NaLTA zeolite confined CuO catalyst CuO@NaLTA was prepared via the method of ligand protected in situ with Cu2+-glycine complex as Cu source, and characterized by multiple characteristic techniques. The results revealed that CuO nanoparticles were highly dispersed on NaLTA zeolite, and the catalytic properties of CuO@NaLTA were investigated in the alkene epoxidation with H2O2 as oxidant in dioxane. For styrene oxidation, catalyst CuO@NaLTA exhibited excellent catalytic activities with 83 % conversion and 63 % selectivity to styrene epoxide, and could be easily recycled several times without obvious activity loss. The excellent catalytic activities could be attributed to the highly dispersed active CuO species. Besides, multiple electronic effects and coordinative interactions exited in Cu ion and the Si-Al zeolite skeleton framework played a key role in the catalytic recyclability.

Rapid and Environmentally-Friendly Synthesis of Thiazolidinone Analogues in Deep Eutectic Solvent Complemented with Computational Studies.

A greener, safer, and more efficient methodology for the synthesis of (Z)-5-benzylidene-2-thioxothiazolidin-4-ones (3 a-u) and (Z)-5-benzylidenethiazolidine-2,4-diones (4 a-i) has been developed. The deep eutectic solvent (DES) ZnCl2/urea used as a greener solvent as well as a catalyst in this study accelerated the condensation of rhodanine and thiazolidine-2,4-dione with different aldehydes to afford the target scaffolds in excellent yields (88-98 %). The reaction methodology adopted offered significant advantages such as mild reaction conditions, functional group tolerance, quick reaction time, column-free isolation, catalytic recyclability, and applicability to gram-scale production. Moreover, density function theory calculations were carried out to investigate the global reactivity and stability profiles of these compounds. Finally, the green metrics analysis supported the greener nature of the present methodology.

Engineering sulfur doped flower-like BiOBrxI1-x solid solutions for strengthened photocatalytic activities

In this work, a series of S-doped BiOBrxI1-x solid solutions are fabricated via a simple and rapid solvothermal process. Various characterization techniques are used to thoroughly investigate the as-fabricated solid solutions. Interestingly, compared to BiOBrxI1-x, S-doped BiOBrxI1-x solid solutions exhibit a loose flower-like structure comprised of thinner nanosheets, which contributes to the enhanced specific surface area, as assessed by Brunauer-Emmett-Teller analysis. Furthermore, S-doped BiOBrxI1-x solid solutions reveal boosted visible-light response and rapid separation of photoinduced charge carriers, as verified by optical, photo-electrochemical, and electrochemical analysis. These lead to superior visible-light photocatalytic properties of S-doped BiOBrxI1-x solid solutions on pollutant removal, N2 fixation, and microplastic degradation. The crystal structure, morphology, and photocatalytic stability of the prepared samples are demonstrated by comparing their X-ray diffraction patterns, scanning electron microscopy images, and photocatalytic degradation as well as nitrogen reduction performance before and after six catalytic recycles. Furthermore, based on Density Functional Theory simulations, significant modifications in the band gap of BiOBrxI1-x solid solutions occur as iodine content increases while sulfur doping further refines the electronic features, which aligns with the results of Tauc plots. This research proves that S doping is a viable strategy for modulating the electronic structures of BiOBrxI1-x solid solutions for improving its photocatalytic performance, and provides a new route for optimizing the bandgaps of semiconductors via the non-metallic doping strategy.

Structural and morphological studies of g-C3N4-functionalized MWCNTs nanocomposite for sunlight-responsive photocatalytic activity

Photocatalytic degradation of organic contaminants has been proven to be one of the greatest economical and efficient techniques to address environmental pollution problems. Multi-walled carbon nanotubes (MWCNTs)/g-C3N4 (GCN) nanocomposites (NCs) were synthesized by a hydrothermal process aided by ultrasound to produce active photocatalysts. The effective synthesis of GCN, MWCNTs, and MWCNTs/GCN NCs was confirmed by X-ray diffraction (XRD) patterns. The fabrication of GCN nanosheets (NSs), the nanotubular structure of MWCNTs, and a network of neuron-like structures for MWCNTs/GCN NCs were all revealed by structural and morphological characterization. The elemental mapping of NCs containing the suitable quantity of MWCNTs revealed a uniform distribution of the sample's component elements. When the optical properties of the fabricated nanomaterials were examined by employing UV–visible spectroscopy, the results revealed a blue shift (a shift of maximum absorption to the UV region), which suggests that the addition of MWCNTs increased the band-gap energy. The behaviour of e––h+ pair recombination was revealed by measuring the charge carrier movement and trapping efficiency using photoluminescence (PL) spectroscopy. Crystal violet (CV) dye was photocatalytically degraded using prepared NCs in the presence of sunlight, and the synergistic effects of GCN and MWCNTs were examined. With a degradation efficiency of 99.32 %, MWCNTs/GCN NCs demonstrated the best sunlight-irradiated photocatalytic activity for CV degradation. The degradation of CV was discovered to follow pseudo-first-order kinetics. Throughout five consecutive studies, the NCs demonstrated the highest levels of catalytic efficiency and recyclability, with 5 % reduced degrading activities. The trapping tests showed that the primary reactive species involved in the breakdown of CV were the •O2– and •OH radicals.

Cerium-regulated Mg3FeO4@biochar activated persulfate to enhance degradation of aqueous tetracycline: The dominant role of cerium

The role of cerium (Ce) in Ce-regulated Mg3FeO4@biochar (CMF@BC) and the mechanism by which CMF@BC activates persulfate (PS) remain unclear. In this work, a novel CMF@BC was synthesized through the simple impregnation–pyrolysis process and utilized as a PS activator for the removal of aqueous tetracycline (TC). Under the optimal degradation conditions, the removal efficiency and mineralization rate of TC reached 92.7 % and 84.2 % within 60 min, respectively, the corresponding rate constant was 0.0487 min−1. The CMF@BC catalyst exhibited extremely high stability and excellent reusability after five cycles. The characterization results identified Fe2+ and oxygen vacancies as major catalytic sites. The Ce dopant inhibited the aggregation of metal ions of Mg3FeO4 during the high-temperature pyrolysis process and the Ce3+/Ce4+ redox cycle promoted Fe2+ regeneration, thus improving the catalyst performance. The degradation process was dominated by non-free radical (1O2) pathways. The possible TC-removal pathway was inferred from liquid chromatography–mass spectrometry results and density functional theory calculations. The toxicity of the degradation products was also evaluated. The CMF@BC catalyst displayed excellent catalytic performance and recyclability, wide pH adaptability, and a low ion-leaching rate, confirming its broad application prospects as a PS activator in antibiotic wastewater treatment.

Fully Exposed Ru Clusters for the Efficient Multi-Step Toluene Hydrogenation Reaction.

Liquid organic hydrogen carriers (LOHCs) are attractive platform molecules that play an important role in hydrogen energy storage and utilization. The multi-step hydrogenation of toluene (TOL) to methylcyclohexane (MCH) has been widely studied in the LOCHs systems, due to their relatively low toxicity and reasonable hydrogen storage capacity. Noble metal catalysts such as Ru has exhibited good performance in multi-step hydrogenation reactions, while the application is still hindered by their high cost and low specific activity. Therefore, the primary challenge lies in the development of noble metal catalysts with both robust activity and efficient atomic utilization. In this study, a series of Ru species ranging from single atoms, fully exposed clusters to nanoparticles were fabricated to investigate their structural evolution in the TOL multi-step hydrogenation reaction. The fully exposed and atomically dispersed Ru clusters, composed of an average of 3 Ru atoms, exhibit superior catalytic performance and recycle ability in TOL multi-step hydrogenation. Moreover, it delivers a high turnover frequency of 9850.3 h-1 under the relatively mild reaction (100 °C, 1.5 MPa), compared with those of single atoms and nanoparticles, and shows a notable advantage over catalysts reported in previous studies. From density functional theory (DFT) calculations, the overall barrier of the TOL multi-step hydrogenation reaction over the fully exposed Ru clusters is significantly lower than that of single atoms and nanoparticles, resulting in its higher activity. The present work provides an efficient strategy to regulate the reaction pathway of multi-step complicated catalytic reactions by designing fully exposed metal cluster catalysts.

Size‐Dependent Catalytic Activity Over MOF‐Derived Cobalt Oxide Supported PdO Nanoparticles in Suzuki Reaction

ABSTRACTPalladium nanoparticles immobilized on ZIF 67‐derived porous CoOx were prepared by wet‐impregnation method, followed by calcination at different temperatures. The calcination temperature has been employed to effectively manipulate the size of metal nanoparticles, where higher calcination temperatures resulted in larger sizes. The experimental results revealed that by manipulating the calcination temperature, the synthesis of palladium nanoparticles with varying sizes could be effectively controlled. Increasing the calcination temperature resulted in larger particle sizes. At a calcination temperature of 350°C, the synthesis process produced the smallest palladium nanoparticles, averaging 1.35 nm in size, facilitating the reaction between aryl halides and arylboronic acids with yields ranging from 83% to 99%. Furthermore, these nanoparticles demonstrated superior catalytic activity and recyclability.

A novel Ti³⁺-mediated approach for supporting palladium on anodic TiO2 nanotubes: Toward efficient and recyclable catalysis in the heck reaction

A simple electrochemical reduction technique was employed to generate Ti3+ with strong reducing property on the anodic TiO2 nanotubes (ATNTs). Utilizing Ti3+ as the reducing agent, Pd2+ was successfully reduced in situ to Pd0 on the anodic TiO2 nanotubes (Pd@ATNTs). Various characterization methods were employed to confirm that the proportion of Ti3+ and the size of Pd nanoparticles could be controlled by adjusting the electrochemical reduction voltage. The obtained Pd@ATNTs-2.5 exhibited satisfactory catalytic efficiency (TOF: 1302 h−1) in the Heck reaction between various aryl halides and olefins. Furthermore, Pd@ATNTs-2.5 demonstrated high stability, with no significant loss of catalytic activity observed even after six cycles.

Factors influencing the performance of organocatalysts immobilised on solid supports: A review.

Organocatalysis has become a powerful tool in synthetic chemistry, providing a cost-effective alternative to traditional catalytic methods. The immobilisation of organocatalysts offers the potential to increase catalyst reusability and efficiency in organic reactions. This article reviews the key parameters that influence the effectiveness of immobilised organocatalysts, including the type of support, immobilisation techniques and the resulting interactions. In addition, the influence of these factors on catalytic activity, selectivity and recyclability is discussed, providing an insight into optimising the performance of immobilised organocatalysts for practical applications in organic chemistry.

Catalytic selectivity in activating peroxymonocarbonate with a commercial MnO2 catalyst for water remediation

An in-situ formed peroxymonocarbonate (HCO4-) oxidation system from an equilibrium reaction of H2O2 and HCO3– was established for eliminating organic pollutants in water. With H2O2 as a co-existing oxidant in the system, a commercial available MnO2 was able to proceed selective catalytic activation of HCO4- to generate reactive oxygen species (ROS), such as ·OH and CO3·-. The MnO2 catalyst showed excellent catalytic ability, structural stability and recyclability in the HCO4--based oxidation system for removing tetracycline. The degradation rate of tetracycline reached 86 % and the catalyst could be used for at least 5 times with only 0.1 ppm of Mn leached in water. The kinetic study indicated that HCO4- was more related to the degradation of tetracycline and generated ·OH at the yield of 40 % was primarily from HCO4- activation rather than H2O2 activation. The evaluation of ROS and quenching experiments suggested that CO3·- was most responsible for tetracycline degradation. The catalyst characterization and reaction mechanism indicated that low-valent Mn species were the active sites for HCO4- activation. Finally, in-situ formation of HCO4- derived from CO2 in Na2CO3 solution with H2O2 was preliminarily explored, presenting a MnO2-catalzyed CO2-derived HCO4--based oxidation system for pollutant control. This study shows that a cheap and commercial available MnO2 can be an efficient, facile and selective catalyst for in-situ formed HCO4--based advanced oxidation processes.

Developing Covalent Organic Framework Biocatalysts through Enzyme Encapsulation.

Utilizing covalent organic frameworks (COFs) as porous supports to encapsulate enzyme represents an advanced strategy for constructing COFs biocatalysts, which has inspired numerous interests across various applications. As the structural advantages including ultrastable covalent-bonded linkage, tailorable pore structure, and metal-free biocompatibility, the resultant enzyme-COFs biocatalysts showcase functional enhancement in catalytic activity, chemical stability, long-term durability, and recyclability. This Concept describes the recent advances in the methodological strategies for engineering the COFs biocatalysts, with specific emphasis on the pore entrapment and in situ encapsulation strategies. The structural advantages of the COFs hybrid biocatalysts for organic synthesis, environment- and energy-associated applications are also canvassed. Additionally, the remaining challenges and the forward-looking directions in this field are also discussed. We believe that this Concept can offer useful methodological guidance for developing active and robust COFs biocatalysts.