Metal-organic Framework Precursor Research Articles

Metal Organic Framework Cubosomes.

We demonstrate a general strategy for the synthesis of ordered bicontinuous-structured metal organic frameworks (MOFs) by using polymer cubosomes (PCs) with a double primitive structure (Im m symmetry) as the template. The filling of MOF precursors in the open channel of PCs, followed by their coordination and removal of the template, generates MOF cubosomes with a single primitive topology (Pm m) and average mesopore diameters of 60-65 nm. Mechanism study reveals that the formation of ZIF-8 cubosomes undergoes a new MOF growth process, which involves the formation of individual MOF seeds in the template, their growth and eventual fusion into the cubosomes. Their growth kinetics follows the Avrami equation with an Avrami exponent of n=3 and a growth rate of k=1.33×10-4 , indicating their fast 3D heterogeneous growth mode. Serving as a bioreactor, the ZIF-8 cubosomes show high loading of trypsin enzyme, leading to a high catalytic activity in the proteolysis of bovine serum albumin.

Insight into radical-nonradical coupling activation pathways of peroxymonosulfate by CuxO for antibiotics degradation

In this work, a heterogeneous catalyst of CuxO was rationally designed by using Cu-based metal organic frameworks (marked Cu-BDC) as the template, and was used to degrade tetracycline (TC) via activation of peroxymonosulfate (PMS). The optimal CuxO-350 showed excellent catalytic efficiency for TC degradation, and the reaction rate constant (0.104 min−1) was 8 times higher than that (0.013 min−1) of raw Cu-BDC. The characterization observations confirmed that CuxO-350 possessed multiple valence states (CuO and Cu2O) and oxygen vacancies (Ov), both of which were favorable for the activation of PMS, resulting in promoting the generation of active species in the CuxO-350 + PMS system. Different from the free radical pathway in Cu-BDC + PMS system, a radical-nonradical coupling process was detected in the CuxO-350 + PMS system, which was confirmed by quenching experiments and EPR measurements. Moreover, the toxicity prediction showed that the toxicity of degradation intermediates declined compared with TC. This work not only opened up a new strategy for the rational design and preparation of high-efficient catalysts by employing metal organic frameworks precursors, but also offered an insight into the reaction mechanism of PMS activation through a radical-nonradical coupling process catalyzed by CuxO-350 derived from Cu-BDC.

A novel MnTi mixed oxide catalyst engineered by metal–organic framework precursor for enhancing NOx removal performance

In this research, MnTi metal–organic frameworks (MnTi‐MOFs) were successfully prepared, and derived catalysts were innovatively applied to the removal of NOx by selective catalytic reduction with NH3 (NH3‐SCR). The test results show that the one‐step controllable synthesis of MnTi‐MOFs material is achieved through adjusting the Mn/Ti molar ratios and the proportion of metal to organic ligands, in which the ratio of organic ligands is vitally significant for the synthesis of MnTi‐MOFs (MnTi‐MOFs can only be synthesized with the ligand to metal molar ratio in the range of 3–4). Owing to the special heterogeneity of MOFs, the catalyst sample derived from the MnTi‐MOFs precursor prepared with suitable raw material ratio exhibits the best SCR performance. Series of characterization analyses show that the catalysts derived from MOFs precursors with ordered lattice structure exhibit an appropriate surface chemical adsorption oxygen, an increased Mn4+/Mnn+ content, and enhanced acidity of the surface of the sample. This research affords an innovative method to the controllable preparation of dual metal MOFs and expands the development of catalysts in the field of low‐temperature de‐NOx.

MOF-derived NiCo-LDH Nanocages on CuO Nanorod Arrays for Robust and High Energy Density Asymmetric Supercapacitors.

Layered double hydroxide (LDH) is widely explored in supercapacitors on account of its high capacity, adjustable composition and easy synthesis process. Unfortunately, solitary LDH still has great limitations as an electrode material due to its shortcomings, such as poor conductivity and easy agglomeration. Herein, nanoflakes assembled NiCo-LDH hollow nanocages derived from a metal-organic framework (MOF) precursor are strung by CuO nanorods formed from etching and oxidation of copper foam (CF), forming hierarchical CuO@NiCo-LDH heterostructures. The as-synthesized CuO@NiCo-LDH/CF shows a large capacitance (5607 mF cm-2 at 1 mA cm-2 ), superior rate performance (88.3 % retention at 10 mA cm-2 ) and impressive cycling durability (93.1 % capacitance is retained after 5000 cycles), which is significantly superior to control CuO/CF, CuO@ZIF-67/CF, NiCo-LDH/CF and Cu(OH)2 @NiCo-LDH/CF electrodes. Besides, an asymmetrical supercapacitor consists of CuO@NiCo-LDH/CF and activated carbon displays a maximum energy density of 47.3 Wh kg-1 , and its capacitance only declines by 6.8 % after 10000 cycles, demonstrating remarkable cycling durability. The advantages of highly conductive and robust CuO nanorods, MOF-derived hollow structure and the core-shell heterostructure contribute to the outstanding electrochemical performance. This synthesis strategy can be extended to design various core-shell heterostructures adopted in versatile electrochemical energy storage applications.

Metal-organic framework derived functional MnO2 via an in-situ oxidation strategy for advanced quasi-solid-state supercapacitors

Accurately controlling the morphology and structure of metal oxides faces huge challenges, which also limits their applications in different fields. Here, we report an in-situ oxidization strategy to design hollow spherical MnO2 (HS–MnO2) at room temperature based on the Mn-based metal-organic framework precursor. During the in-situ oxidization process, the obtained HS-MnO2 remains a hollow spherical structure with abundant pre-inserted Na+ and oxygen vacancies, which contributes to addressing its issues of volume expansion, low ionic diffusion rate, and low electronic conductivity. Consequently, the HS-MnO2 electrode exhibits high reversible capacitance (304.3 F g−1, 0.5 A g−1), high cycle stability (77.6% capacity retention for over 20,000 cycles at 10 A g−1), and excellent rate performance in supercapacitor applications. Importantly, the MnO2-based quasi-solid-state supercapacitor can power different devices, which shows its good application prospect. Our work provides new insights into the preparation of transition metal oxides with controllable structures via a mass-productive strategy with low cost to fulfill their potential in energy storage devices.

Functional Metal/Carbon Composites Derived from Metal–Organic Frameworks: Insight into Structures, Properties, Performances, and Mechanisms

Metal–organic frameworks (MOFs) have extensively emerged as promising templates/precursors to prepare functional derivatives for various purposes because of their ultrahigh porosity, large specific surface area, and excellent user-configuration flexibility. Among these derivatives, MOFs-derived metal/carbon composites surmount the shortcomings of the individual components and produce synergistic effects, showing great potential in environmental remediation and energy storage and conversion. Herein, this work systematically discusses the synthetic strategies of MOFs-derived metal/carbon composites from the perspective of different MOF precursors, including pristine MOFs, heteroatom-doped MOFs, and MOFs composited with substrates. The unique advantages of MOFs-derived metal/carbon composites with exceptional stability, conductivity, and catalytic activity are then particularly summarized. On the basis of these advantages, their recent progress in the environment and energy fields is elaborated, with special emphasis on the elucidation of their mechanisms. Finally, the challenges and opportunities for future research are presented, which is expected to provide references for the design of multipurpose MOFs-derived metal/carbon composites.

Monodispersed Pt Sites Supported on NiFe-LDH from Synchronous Anchoring and Reduction for High Efficiency Overall Water Splitting.

Precise design of low-cost, efficient and definite electrocatalysts is the key to sustainable renewable energy. Herein, this work develops a targeted-anchored and subsequent spontaneous-redox strategy to synthesize nickel-iron layered double hydroxide (LDH) nanosheets anchored with monodispersed platinum (Pt) sites (Pt@LDH). Intermediate metal-organic frameworks (MOF)/LDH heterostructure not only provides numerous confine points to guarantee the stability of Pt sites, but also excites the spontaneous reduction for PtII . Electronic structure, charge transfer ability and reaction kinetics of Pt@LDH can be effectively facilitated by the monodispersed Pt moieties. As a result, the optimized Pt@LDH that with the 5% ultra-low content Pt exhibits the significant increment in electrochemical water splitting performance in alkaline media, which only afford low overpotentials of 58mV at 10 mAcm-2 for hydrogen evolution reaction (HER) and 239mV at 10 mAcm-2 for oxygen evolution reaction (OER), respectively. In a real device, Pt@LDH can drive an overall water-splitting at low cell voltage of 1.49V at 10 mAcm-2 , which can be superior to most reported similar LDH-based catalysts. Moreover, the versatility of the method is extended to other MOF precursors and noble metals for the design of ultrathin LDH supported monodispersed noble metal electrocatalysts promoting research interest in material design.

Reticular Coordination Induced Interfacial Interstitial Carbon Atoms on Ni Nanocatalysts for Highly Selective Hydrogenation of Bio-Based Furfural under Facile Conditions.

A rational design of transition metal catalysts to achieve selective hydrogenation of furfural (FFR) to tetrahydrofurfuryl alcohol (THFA) under facile conditions is a promising option. In this work, a series of Ni catalysts were synthesized by controlled thermal treatment of Ni-based metal-organic frameworks (MOFs), with the purpose of modulating the interface of nickel nanoparticles by the reticular coordination in MOF precursors. The catalytic performance indicates that Ni/C catalyst obtained at 400 °C exhibits efficient conversion of FFR (>99%) and high selectivity to THFA (96.1%), under facile conditions (80 °C, 3 MPa H2, 4.0 h). The decomposition of MOF at low temperatures results in highly dispersed Ni0 particles and interfacial charge transfer from metal to interstitial carbon atoms induced by coordination in MOF. The electron-deficient Ni species on the Ni surface results in an electropositive surface of Ni nanoparticles in Ni/C-400, which ameliorates furfural adsorption and enhances the hydrogen heterolysis process, finally achieving facile hydrogenation of FFR to THFA.

N-doped carbon–iron heterointerfaces for boosted electrocatalytic active and selective ammonia production

The electrochemical conversion of waste nitrate (NO3-) to valuable ammonia (NH3) is an economical and environmentally friendly technology for sustainable NH3 production. It is beneficial for environmental nitrogen pollution management and is also an appealing alternative to the current Haber-Bosch process for NH3 production. However, owing to the competing hydrogen evolution reaction, it is necessary to design highly efficient and stable electrocatalysts with high selectivity. Herein, we report a rational design of Fe nanoparticles wrapped in N-doped carbon (Fe@N10-C) as a high NH3 selective and efficient electrocatalyst using a metal-organic framework precursor. We constructed a catalyst with new active sites by doping with nitrogen, which activated neighboring carbon atoms and enhanced metal-to-carbon electron transfer, resulting in high catalytic activity. These doped N sites play a key role in the NO3- electroreduction. As a result, the Fe@N10-C nanoparticles with optimal doping of N demonstrated remarkable performance, with a record-high NO3- removal capacity of 125.8 ± 0.5 mg N gcat-1 h-1 and nearly 100 % (99.7 ± 0.1%) selectivity. The catalyst also delivers an impressive NH3 production rate of 2647.7 μg h-1 cm-2 and high faradaic efficiency of 91.8 ± 0.1%. This work provides a new route for N-doped carbon-iron catalysis application and paves the way for addressing energy and environmental issues.

Regulation of electronic structure in medium-entropy metal sulfides nanoparticles as highly efficient bifunctional electrocatalysts for zinc-air battery

Medium/high-entropy materials have attracted more and more attention in catalytic field in view of their unique properties, yet the related catalytic mechanisms remain ambiguous. Herein, we demonstrate a two-step method for the preparations of medium-entropy metal sulfides (MESs) nanoparticles through the sulfuration of metal-organic frameworks (MOFs) precursors. Compared with the MOF precursor, MES has better electrocatalytic performance in oxygen evolution and reduction reactions (OER/ORR). Electron energy loss spectroscopy (EELS) and X-ray photoelectron spectroscopy (XPS) characterization indicate that the sulfidation can lead metallic ions to possessing higher valence states. Furthermore, the regulation of electronic structure are further proved by density functional theory (DFT) calculations. Rechargeable zinc-air batteries assembled with the Fe1.2(CoNi)1.8S6 MES nanoparticles catalyst superior performances outperforming the commercial catalyst (Pt/C+RuO2). The reported two-step method of fabrication strategy for preparing medium-entropy metal sulfides may further contribute to fundamental research into and industrial applications of medium-entropy materials in the rechargeable zinc-air batteries.

Layered porous Mn0.18V2O5@C with manganese and carbon provided by a metal-organic framework precursor as a cathode material for aqueous zinc-ion batteries.

At present, vanadium-based cathodes for aqueous zinc-ion batteries (AZIBs) are limited by their slow reaction kinetics, poor electrical conductivity, and low capacity retention. To overcome these problems, here, we design a layered porous Mn0.18V2O5@C as the cathode material for AZIBs using a manganese-containing metal-organic framework as a template through a simple solvothermal method. Such an electrode delivers an excellent specific capacity (380 mA h g-1 at 0.1 A g-1) accompanied by superior cycling stability (about 85% capacity retention for 2000 cycles at 6 A g-1). The excellent electrochemical performance of Mn0.18V2O5@C is ascribed to the improved interface activity including smooth zinc ion transport, abundant ion reaction active sites and accelerated charge transfer resulting from the coordination of the porous structure, doped conductive carbon, and the stable channel structure derived from the pillar effect of doping manganese ions, preventing a premature collapse of the electrode structure. It is also revealed by structural evolution analysis that the residual zinc ions also combine with the original Mn0.18V2O5 to form a ZnxMnyV2O5 phase, which serves as an additional structural pillar and in the meantime, also participates in the following cycles. These favorable electrochemical results suggest that Mn0.18V2O5@C is a suitable cathode material for AZIBs.

Metal-organic framework-derived Cu nanoparticle binder-free monolithic electrodes with multiple support structures for electrocatalytic nitrate reduction to ammonia.

Electrocatalytic nitrate reduction to ammonia, which removes nitrates from aquatic ecosystems, is a potential alternative to the classical Haber-Bosch process. Nevertheless, the selectivity of ammonia is often affected by the toxic by-product nitrite. Here, the polyhedral-supported Cu nanoparticle binder-free monolithic electrode (Cu-BTC-Cu) is synthesized by the in situ electroreduction of Cu metal-organic framework (Cu-MOF) precursors. The Cu-BTC-Cu displays a high ammonia yield of 4.00 mg h-1 cm-2cat and a faradaic efficiency of 83.8% in 0.05 M K2SO4 (pH = 7), greatly outperforming the rod-supported (Cu-BTEC-Cu) and unsupported (Cu-BDC-Cu) Cu nanoparticle monolithic electrodes. Impressively, the Cu-BTC-Cu can inhibit significantly the release of by-product NO2- and present favourable stability after 10 consecutive cycles. These preeminent properties can be attributed to the polyhedral structure, which enables better dispersion of Cu nanoparticles and brings more active sites. Moreover, the reaction mechanism of Cu-BTC-Cu is analysed by electrochemical in situ characterization and several key intermediates are captured. This work provides new insights into the modification of the electrocatalytic nitrate reduction activity of Cu-based catalysts and ideas for the design of high-efficiency electrodes.

Solvothermal synthesis of organoclay/Cu-MOF composite and its application in film modified GCE for simultaneous electrochemical detection of deoxyepinephrine, acetaminophen and tyrosine.

An organoclay/copper-based metal-organic framework (MOF) composite was synthesized using a solvothermal method by growing a Cu-BTC (copper(ii) benzene-1,3,5-tricarboxylate) MOF from a mixture of the MOF precursor solution in which various amounts of organoclay had been dispersed. The organoclay was obtained by intercalating a cationic dye, namely thionin, into a natural Cameroonian clay sampled in Sagba deposit (North West of Cameroon). The organoclay and the as-synthesized composites were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and Brunauer, Emmett and Teller (BET) techniques. From Scherrer's equation, the crystallite size of the composite was found to be between 55 and 58 nm, twice as large as the pristine MOF's crystallite size. The organoclay/Cu-MOF composite (Sa-TN50/Cu3(BTC)2) exhibiting a BET surface area of 192 m2 g-1, about twice that of pristine clay and about one seventh that of pristine MOF, was then utilized to form a stable thin film onto glassy carbon electrodes (GCE) by drop coating (Sa-TN50/Cu3(BTC)2/GCE). These electrodes demonstrated electrocatalytic behavior toward deoxyepinephrine (DXEP) and thus enabled selective and simultaneous sensitive detection of three analytes: DXEP, acetaminophen (AC) and tyrosine (TYR) compared with bare GCE and clay modified electrode. Under optimum conditions, Sa-TN50/Cu3(BTC)2/GCE exhibited good performance including large calibration curves ranging from 5.0 μM to 138.0 μM for DXEP, 4.0 μM to 153.0 μM for AC and 1.0 μM to 29.4 μM for TYR. The detection limits were found to be, 0.4 μM, 0.7 μM and 0.2 μM for DXEP, AC and TYR, respectively. The developed sensors have been applied successfully in the quantification of AC in a commercial tablet of AC, and DXEP, AC and TYR in tap water.

Iridium-titanium oxides for efficient oxygen evolution reaction in acidic media

Active and highly stable oxygen evolution reaction (OER) electrocatalyst for PEM-based water electrolysis are currently in high demand. Herein, we report a rutile iridium-titanium oxide solid solution (IrTiOx) through a facile one-step annealing of a Ti-based metal-organic framework precursor. The composite exhibits excellent OER activity and stability in acidic media, with a low overpotential of 296 mV at 10 mA cm−2 while the OER activity was retained during a 100-h galvanostatic stability test at a constant current of 10 mA cm−2 in 0.5 M H2SO4, outperforming the state-of-the-art IrO2-based electrocatalysts. We further demonstrate the structure evolution of iridium-titanium oxide during OER operations. In contrast to the initial uniform distribution of Ir and Ti over the entire architecture, after OER stability test, a hollow morphology is formed, in which the particle surface is covered with an IrOx-rich layer and entire particle becomes hollow. We ascribe the structure evolution to the Ir/Ti leaching and redeposition during the OER operations. We propose that the structure evolution of iridium-titanium oxide during the electrochemical process is responsible for the high OER activity and stability of IrTiOx.

Hollow Co9S8 cores encapsulated in hierarchical MXene@Bi2O3 multiple shells for constructing binder-free electrodes of foldable supercapacitors

Rational structure design and regulation are of paramount importance for obtaining electrode materials with desirable electrochemical performance. Here, a novel binder-free electrode with the hollow Co9S8 core@multi-shell structure (CS-x@MXene@Bi2O3) derived from metal-organic frameworks (MOFs) precursor is well designed by the electrospinning, sulfuration, carbonization, and hydrothermal processes. In this architecture, the concentration of Co9S8 (CS-x) is optimized for an ideal flexible substrate, which alleviates the dimensional variation for long cycle life. The unique cores and the MXene flakes engineered by Bi2O3 multiple shells can be responsible for the superior characteristics, including a fast electronic pathway, large specific surface area, enhanced electrical conductivity, and improved electrochemical performance. As expected, the obtained CS-2@MXene@Bi2O3 binder-free electrode exhibits a high discharge capacitance of 646.1 F g–1 (1 A g–1). Two binder-free electrodes can be assembled into a solid-state supercapacitor with desirable energy and power density, and long-term cyclic stability is demonstrated through 5000 cycles. Given these advantages, the CS-2@MXene@Bi2O3 is selected as the electrode in a foldable supercapacitor. More importantly, the specific capacitance is reserved after various deformations. Therefore, it is expected that binder-free electrode materials with the unique core@shell structure design could be applied in wearable and portable energy conversion devices.

3D flower-shape Co/Cu bimetallic nanocomposites with excellent wideband electromagnetic microwave absorption

Electromagnetic wave (EMW) absorbing materials prepared by Metal-organic-frameworks (MOFs) derived two-dimensional sheet carbon materials and magnetic metal composites have been widely studied because of their advantages of low density and large specific surface area. However, it is still a challenge to design the microstructure and composition of materials effectively to obtain the best EMW absorption properties. In this work, 3D flower-shape Co/Cu bimetallic nanocomposites were synthesized by calcination of MOFs precursors. By tuning the ratio of Co and Cu salts, nanocomposites with different morphology, size and pore structure were obtained. Impedance matching can be improved by adjusting the synergistic effect of magnetic loss and dielectric loss. When the molar ratio of Co and Cu salts was 4:1, the best EMW absorption performance of the CoCu-CNF-10 composite was achieved. The minimum reflection loss reaches − 51.7 dB at 12.6 GHz with a thin thickness of 2.7 mm, while the effective absorption bandwidth is as broad as 6.4 GHz (9.7–16.1 GHz). This work provides a new idea for the rational design of MOFs-derived materials with excellent EMW absorption properties.

MOF-derived inverse opal Cu3P@C with multi-stage pore structure as the superior anode material for lithium ion battery

Copper phosphide has shown remarkable development potential in the anode materials of lithium ion batteries (LIBs) due to its high mass/volume ratio capacity. Nevertheless, the low conductivity and volumetric expansion in the cycling process restrict its practical application. Herein, we ingeniously designed and successfully prepared copper phosphide (Cu3P)@carbon (C) nanocomposite with multi-stage pore inverse opals (Cu3P@C MSPIOs), including possessed the ordered macropores with the mean aperture of ∼100 nm induced by polystyrene (PS) sphere templates and the mesoporous structure with the pore size range of 3.0-9.5 nm and 16–27 nm derived from metal-organic framework (MOF) precursor. Compared to the Cu3P@C particles prepared without PS sphere templates, the Cu3P@C MSPIOs as the anode materials demonstrated exceptional lithium storage performance. At a high current density of 2 A g-1, the discharge specific capacity of Cu3P@C MSPIOs was 295 mA h g-1 in the 1st cycle while that dropped to 204 mA h g-1 during the 2nd one, and then gradually stabilized. After 1500 cycles, the discharge specific capacity can still reach to 166.3 mA h g-1, maintaining 81% capacity compared to the 2nd discharge specific capacity, which indicates the Cu3P@C MSPIOs as the anode material presented good cycling stability. Apparently, the multi-stage pore structure, which can effectively resolve the volumetric change problem during lithium ion (Li+) intercalation/deintercalation as well as facilitate contact between electrolyte and anode, is primarily responsible of the superior Li-ion storage property of Cu3P@C MSPIOs. At the same time, MOF derived carbon can improve electrical conductivity, accelerate the formation of a stable solid electrolyte interface membrane and also provide buffer layers to further alleviate volumetric expansion.

Hierarchical nickel cobalt sulfide nanoparticles encapsulated in rose-shaped carbon spheres as high-performance anode materials for lithium-ion batteries

A rose-shaped binary Ni/Co metal-organic framework (Ni/Co-MOF) precursor assembled from numerous cross-linked 2D nanosheets was prepared via a facile hydrothermal reaction. The hierarchical structure was inherited by a one-step carbonization and sulfurization of the precursor and derived nickel cobalt bimetal sulfide nanoparticles encapsulated in rose-shaped carbon spheres (NiS2/CoS2@RCSs) composite. As an anode material for lithium-ion batteries (LIBs), the final composite material could improve conductivity, facilitate electrolyte penetration, and alleviate volume change. Beneficial from the unique nano-architecture plus the bimetallic synergistic effect, the obtained anode electrode achieves an exceptional cycling stability (747.7 mA h g−1 at 1.0 A g−1 after 400 cycles) with a superior rate capability (500.9 mAh g−1 at 4.0 A g−1).

Toxin-Blocking Textiles: Rapid, Benign, Roll-to-Roll Production of Robust MOF-Fabric Composites for Organophosphate Separation and Hydrolysis.

Current approaches to create zirconium-based metal-organic framework (MOF) fabric composites for catalysis, water purification, wound healing, gas sorption, and other applications often rely on toxic solvents, long reaction/post processing times, and batch methods hindering process scalability. Here, a novel mechanism was reported for rapid UiO-66-NH2 synthesis in common low-boiling-point solvents (water, ethanol, and acetic acid) and revealed acid-base chemistry promoting full linker dissolution and vapor-based crystallization. The mechanism enabled scalable roll-to-roll production of mechanically resilient UiO-66-NH2 fabrics with superior chemical protective capability. Solvent choice and segregated spray delivery of organic linker and metal salt MOF precursor solutions allowed for rapid MOF nucleation on the fiber surface and decreased the energy and time needed for post-processing, producing an activated composite in less than 165 min, far outpacing conventional MOF-fabric synthesis approaches. The MOF-fabric hydrolyzed and blocked permeation of the chemical warfare agent soman, outperforming the protection-standard activated carbon cloth. This work presents both chemical insights into Zr-MOF powder and fabric composite formation by a rapid, industrially relevant approach and demonstrates its practicality and affordability for high-performing personal protective equipment.

Bacterial cellulose flakes loaded with Bi2MoO6 nanoparticles and quantum dots for the photodegradation of antibiotic and dye pollutants

Effective strategies to improve charge separation in semiconductor particles are critical for improving the photodegradation of organic pollutants at levels sufficient for environmental applications. Herein, Bi2MoO6 (BMOMOF), comprising both nanoparticles (NPs) and quantum dots (QDs), was synthesized from a bismuth-based metal-organic framework (Bi-MOF) precursor. Surface defects on BMOMOF, the combination of NPs and QDs, and modified energy band edges improved photogenerated charge separation and facilitated redox reactions. When compared to BMO derived from uncoordinated Bi, the BMOMOF photocatalyst (PC) was more efficient at photodegrading tetracycline hydrochloride (TCH) and ciprofloxacin (CIP), two widely-used antibiotics ubiquitous in wastewater, as well as the carcinogenic pollutant rhodamine B (RhB). BMOMOF was then loaded on the biopolymer bacterial cellulose (BC) to further enhance photocatalytic performance and facilitate the recovery of the PC after water treatment processes. The novel BMOMOF/BC photocatalytic flakes were significantly larger than pure BMOMOF, and thus easier to recuperate. Furthermore, anchoring BMOMOF on BC flakes augmented significantly the photodegradation of TCH, CIP, and RhB, mainly because hydroxyl groups in BC act as hole traps facilitating photogenerated electron-hole separation. Results obtained with BMOMOF/BC highlight promising approaches to develop optimal PCs for aqueous pollutants degradation.