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1.
Nanotechnology ; 35(41)2024 Jul 26.
Article in English | MEDLINE | ID: mdl-39019050

ABSTRACT

Metal-organic frameworks (MOFs) are believed to be promising precursors for constructing novel and efficient catalysts for glucose sensing. Herein, HKUST-1 precursors are first fabricated using a one-pot hydrothermal approach, and then HKUST-1 is converted into porous Cu2S/CuO octahedrons through conformal sulfidation with the help of OH-ions. The as-obtained Cu2S/CuO composite can provide rich electrochemical active sites and promoted electric transfer kinetics. Benefiting from these combined merits, the as-fabricated Cu2S/CuO composite is confirmed to be a high-performance catalyst, with high sensitivities of 8269.45 and 4140.82µA mM-1cm-2in the corresponding ranges of 0.05 ∼ 0.6 mM and 0.6 ∼ 1.2 mM, respectively. Moreover, the as-prepared electrode materials possess good anti-interference ability, reproducibility and long-term stability. This work opens up new avenues for the design and preparation of transition metal sulfide composites.

2.
Chemosphere ; 362: 142676, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38936487

ABSTRACT

A MOF-on-MOF composite derivative material named ZIF-67@Ce-MOF-600 was designed and synthesized. The preparation of ZIF-67@Ce-MOF-600 was optimized from the aspects of the ratio of metal and ligand, heat-treatment temperature. It was demonstrated by XRD, FT-IR, SEM-EDS and TEM. The optimum conditions for the activation of PMS by ZIF-67@Ce-MOF-600 for the degradation of tetracycline (TC) were investigated by adjusting the catalyst dosage, TC, pH, peoxymonosulfate (PMS) concentration, and different kinds of water, co-existing anions and pollution. Under optimal conditions (20 mg catalysts and 50 mg PMS added) in 100 mL of tetracyclines (TC) solvent (20 mg TC/L), the removal rate could reach up to 99.2% and after five cycles was 70.5%. The EPR results indicated the presence of free radicals and non-free radical, among which free radicals intended to play a major role in the degradation process. Its possible degradation pathways and attack sites were analyzed by liquid-phase mass spectrometry and DFT analysis.


Subject(s)
Metal-Organic Frameworks , Peroxides , Tetracycline , Water Pollutants, Chemical , Metal-Organic Frameworks/chemistry , Water Pollutants, Chemical/chemistry , Tetracycline/chemistry , Peroxides/chemistry , Water Purification/methods , Catalysis , Water/chemistry
3.
Talanta ; 277: 126339, 2024 Sep 01.
Article in English | MEDLINE | ID: mdl-38823321

ABSTRACT

Bisphenols and benzophenones are two typical kinds of endocrine-disrupting compounds (EDCs) that have been extensively detected in water environments, posing unanticipated risks to aquatic organisms and humans. It is urgent to develop efficient sample pretreatment methods for precise measurement of such EDCs. In this study, a magnetic and multi-shelled metal-organic framework derivative material has been prepared to extract and enrich trace bisphenols and benzophenones from water. Via a solvothermal reaction induced by sodium citrate followed by a carbonization treatment, a ZIF-67@ZIF-8 derived CoZn-magnetic hierarchical carbon (CoZn-MHC) material has been synthesized as a high-performance magnetic solid-phase extraction (MSPE) adsorbent. This adsorbent exhibited a good specific surface area (213.80 m2⋅g-1) and a saturation magnetization of 63.2 emu·g-1. After the optimization of several parameters (including adsorbent dosage, extraction time, pH, ionic strength, desorption solvent, and solvent volume), an efficient MSPE method for several EDCs (comprising bisphenols and benzophenones) was developed with a good linear range (R2 ≥ 0.990), a high sensitivity range (LODs: 0.793-5.37 ng⋅L-1), and good reusability (RSD ≤4.67 % in five consecutive tests). Furthermore, the material exhibited commendable resistance to matrix interference in natural water samples with the recovery rates of target compounds ranging from 74.8 % to 107 %. We envision that the preparation strategy of this functional metal-organic framework (MOF)-based adsorbent for EDCs may provide insights for relevant research in the future.


Subject(s)
Endocrine Disruptors , Metal-Organic Frameworks , Solid Phase Extraction , Water Pollutants, Chemical , Solid Phase Extraction/methods , Endocrine Disruptors/analysis , Endocrine Disruptors/isolation & purification , Endocrine Disruptors/chemistry , Metal-Organic Frameworks/chemistry , Adsorption , Water Pollutants, Chemical/isolation & purification , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/chemistry , Phenols/analysis , Phenols/isolation & purification , Phenols/chemistry , Benzophenones/chemistry , Benzophenones/isolation & purification
4.
Mikrochim Acta ; 191(6): 312, 2024 05 08.
Article in English | MEDLINE | ID: mdl-38717599

ABSTRACT

Phytosterols (PSs), a class of naturally occurring bioactive lipid compounds, have been found to possess a significant cholesterol-lowering effect. In developing countries, the consumption of rapeseed oil is the primary pathway of PS intake for the general population. However, developing low-cost, real-time, and high-throughput screening techniques for PSs remains a challenge. Here, a Cu-based nanocomposite CuOx@C was synthesized via a simple method of the calcination of HKUST-1 and systematically characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The CuOx@C demonstrated excellent peroxidase-like (POD-like) activity, functioning as a peroxidase mimic to facilitate the catalysis of 3,3',5,5'-tetramethylbenzidine (TMB) into its oxidized form (oxTMB), thereby initiating a discernible color response. On the basis of this discovery, a CuOx@C-based colorimetric method for detecting total sterols in rapeseed was successfully constructed via cascade reactions. After optimizing the conditions, the high-throughput screening of total sterols in rapeseed could be completed in only 21 min, which significantly facilitated the sensing of PSs. A linear range of 0.6-6 mg/g was achieved for the detection of total sterols in rapeseed samples, thereby satisfying the requirements for detection. In addition, due to the high stability of CuOx@C and the specificity of cholesterol oxidase, the developed method had excellent stability and selectivity toward PSs, indicating that this work has huge prospects for commercial application. This innovative work overcomes the limitation of the instrumental method and provides a portable and reliable tool for total sterols detection. It can also facilitate the development of oilseeds with a high content of PSs.


Subject(s)
Benzidines , Colorimetry , Copper , Phytosterols , Colorimetry/methods , Phytosterols/analysis , Phytosterols/chemistry , Copper/chemistry , Benzidines/chemistry , Metal-Organic Frameworks/chemistry , Limit of Detection , Catalysis , Nanocomposites/chemistry , Oxidation-Reduction
5.
Small ; 20(29): e2309577, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38348936

ABSTRACT

Inspired by energy conversion and waste reuse, hybridized Ni-MOF derivative-CdS-DETA/g-C3N5, a type-II heterojunction photocatalyst, is synthesized by a hydrothermal method for simultaneous and highly efficient photocatalytic degradation and hydrogen evolution in dye wastewater. Without the addition of cocatalysts and sacrificial agents, the optimal MOF-CD(2)/CN5 (i.e. Ni-MOF derivative-CdS-DETA (20 wt.%)/g-C3N5) exhibit good bifunctional catalytic activity, with a H2 evolution rate of 2974.4 µmol g-1 h-1 during the degradation of rhodamine B (RhB), and a removal rate of 99.97% for RhB. In the process of H2-evolution-only, triethanolamine is used as a sacrificial agent, exhibiting a high H2 evolution rate (19663.1 µmol g-1 h-1) in the absence of a cocatalyst, and outperforming most similar related materials (such as MOF/g-C3N5, MOF-CdS, CdS/g-C3N5). With the help of type-II heterojunction, holes are scavenged for the oxidative degradation of RhB, and electrons are used in the decomposition of water for H2 evolution during illumination. This work opens a new path for photocatalysts with dual functions of simultaneous efficient degradation and hydrogen evolution.

6.
J Colloid Interface Sci ; 662: 796-806, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38382364

ABSTRACT

Electromagnetic (EM) pollution can disrupt the functioning of advanced electronic devices, hence it's necessary to design EM wave absorbers with high-level absorption capabilities. The Ti3C2Tx (MXene) is classified as a potential EM absorbing material; nevertheless, the lack of magnetic loss mechanism leads to its inadequate EM absorbing performance. On this basis, a novel composite design with promising EM absorption properties is hypothesized to be the integration of few-layer MXene and heterogeneous magnetic MOF derivatives (Fe3O4/C) with complementary advantages. Herein, we synthesized two-dimensional (2D) interfacial-polarization-enhanced MXene hybrid (Fe3O4/C/MXene) by electrostatic assembly. It is notable that the interfacial polarization is realized by adding a small amount of magnetic Fe3O4/C. Furthermore, the Fe3O4/C/ MXene demonstrates an astonishing effective absorption bandwidth (EAB) of 10.7 GHz and an excellent EM wave absorption performance (RLmin) of -66.9 dB. Moreover, the radar cross section (RCS) of Fe3O4/C/MXene is lower than -15.1 dB m2 from -90° to 90° with a minimum RCS value of -52.6 dB m2 at 32°. In addition, the significant attenuation of the EM wave is due to the synergistic effect of improved impedance matching, dielectric loss, and magnetic loss. Thus, the magnetized Fe3O4/C/MXene hybrid is expected to emerge as a strong contender for high-performance EM wave absorbers.

7.
Small ; 20(26): e2309806, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38243852

ABSTRACT

The impedance matching and high loss capabilities of composites with homogeneous distribution are limited owing to high addition and lack of structural design. Developing composites with heterogeneous distribution can achieve strong and wide electromagnetic (EM) wave absorption. However, challenges such as complex design and unclear absorption mechanisms still exist. Herein, a novel composite with a heterogeneous distribution gradient is successfully constructed via MOF derivatives Co@ nitrogen-doped carbon (Co@NC) anchored on carbon foam (CF) matrix (MDCF). Notably, the concentration of MOF can easily control the gradient structure. In particular, the morphologies of MOF derivatives on the surface of CF undergo a transition from the collapse of the inner layer to the integrity of the outer layer, accompanied by a continuous reduction in the size of Co nanoparticles. Correspondingly, enhanced interface polarization from the core-shell of Co@NC and good impedance matching of MDCF can be obtained. The optimized MDCF exhibits the minimum reflection loss of -68.18 dB at 2.01 mm and effective absorption bandwidth covering the entire X-band. Moreover, MDCF exhibits lightweight characteristics, excellent compressive strength, and low radar cross-section reduction. This work highlights the immense potential of composites with heterogeneous distribution for achieving high-performance EM wave absorption.

8.
Environ Res ; 246: 118153, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38191036

ABSTRACT

The future of energy technology is significantly influenced by hydrogen (H2) energy. However, hydrogen energy production through water-splitting entirely depends on the catalyst's performance. Modifying the morphological structure and increasing the number of active sites by changing the metal composition are pivotal factors in enhancing the catalytic activity for the hydrogen evolution reaction (HER). In this context, we introduce the impact of metal-organic framework (MOF) strategies for decorating CoP petals onto α-Fe2O3 and FeCoP-NC (NC-nitrogen-doped carbon) nanoflowers. This method results in an excellent electrocatalyst for HER. The study demonstrated the influence of different MOF precursors, the impact of calcination temperatures, and the importance of composition percentages in Fe1-xCoxP-NC. As a result, FeCoP-NC shows excellent electrochemical performance potential (η) of 57 mV, a rapid kinetic Tafel value of 61 mV/dec, and remarkable electrochemical stability of around 2000 cycles and 20 h in stand potential. Additionally, the composite has numerous active surfaces at 4.7 mF/cm2 during the electrochemical reactions. This work concludes that MOF-assisted FeCoP-NC nanoflowers are an ideal electrocatalyst for HER in an alkaline medium.


Subject(s)
Metal-Organic Frameworks , Nanospheres , Carbon , Hydrogen , Kinetics
9.
ACS Appl Mater Interfaces ; 15(47): 54353-54372, 2023 Nov 29.
Article in English | MEDLINE | ID: mdl-37963084

ABSTRACT

Catalytic CO2 hydrogenation is an effective approach to producing clean fuels, but this process is expensive, in addition to the low efficiency of catalysts. Thus, photothermal CO2 hydrogenation can effectively utilize solar energy for CH4 production. Metal-organic framework (MOF) derived materials with a controlled structure and morphology are promising to give a high number of active sites and photostability in thermal catalytic reactions. For the first time, a novel heterostructure catalyst was synthesized using a facile approach to in situ grow MOF-derived 0D Co3O4 over 1D TiO2 nanowires (NWs). The original 3D dodecahedral structure of the MOF is engineered into novel 0D Co3O4 nanospheres, which were uniformly embedded over Ni-dispersed 1D TiO2 NWs. In situ prepared 10Ni-7Co3O4@TiO2 NWs-I achieved an excellent photothermal CH4 evolution rate of 8.28 mmol/h at 250 °C under low-intensity visible light, whereas UV light treatment further increased activity by 1.2-fold. UV irradiations promoted high CH4 production while improving the susceptibility of the catalyst to visible light irradiation. The photothermal effect is prominent at lower temperatures, due to the harmonization of both solar and thermal energy. By paralleling with mechanically assembled 10Ni-7Co3O4/TiO2 NWs-M, the catalytic performance of the in situ approach is far superior, attributing to the morphological transformation of 0D Co3O4, which induced intimate interfacial interactions, formation of oxygen vacancies and boosted photo-to-thermal effects. The co-existence of metallic/metal oxide Ni-Co provided beneficial synergies, enhanced photo-to-thermal effects, and improved charge transfer kinetics of the composite. This work uncovers a facile approach to engineering the morphology of MOF derivatives for efficient photothermal CO2 methanation.

10.
ACS Appl Mater Interfaces ; 15(30): 36143-36153, 2023 Aug 02.
Article in English | MEDLINE | ID: mdl-37486015

ABSTRACT

Layered double hydroxides (LDHs) have come to the foreground recently, considering their unique layered structure and short ion channels when they act as electrode materials for supercapacitors (SCs). However, due to their poor rate and cycle performance, they are not highly sought after in the market. Therefore, a flower-like hierarchical NiCo-LDH@C nanostructure with flake NiCo-LDH anchored on the carbon skeleton has emerged here, which is constructed by calcination and hydrothermal reaction and applying flake ZIF-67 as a precursor. In this structure, NiCo-LDH grows outward with abundant and homogeneously distributed Co nanoparticles on Co@C as nucleation sites, forming a hierarchical structure that is combined tightly with the carbon skeleton. The flower-like hierarchical nanostructures formed by the composite of metal-organic frameworks (MOFs) and LDHs have successfully enhanced the cycle and rate performance of LDH materials on the strength of strong structural stability, large specific surface area, and unique cooperative effect. The NiCo-LDH@C electrode displays superb electrochemical performance, with a specific capacitance of 2210.6 F g-1 at 1 A g-1 and 88.8% capacitance retention at 10 A g-1. Furthermore, the asymmetric supercapacitor (ASC) constructed with NiCo-LDH@C//RGO reveals a remarkable energy density of 45.02 W h kg-1 with a power density of 799.96 W kg-1. This project aims to propose a novel avenue to exploit NiCo-LDH electrode materials and provide theory and methodological guidance for deriving complex structures from MOF derivatives.

11.
J Colloid Interface Sci ; 627: 90-101, 2022 Dec.
Article in English | MEDLINE | ID: mdl-35842969

ABSTRACT

Metal-organic framework materials (MOF) have become a new generation of microwave absorption (MA) materials. However, it is still challenging to design an appropriate microstructure that can efficiently adjust the microwave absorbing characteristics. Herein, a novel bimetal-doped core-shell carbon derived from nickel-cobalt dual-ligand MOF has been successfully prepared. By changing the ratio of the second ligand, the morphology can change from sea urchin-like to rod-like and petal-like shapes, thereby regulating the final wave absorption performance of MOF derivatives. The Bi-MOF-1 exhibited strong microwave absorption (up to -70.70 dB), while Bi-MOF-2 presented broad effective absorption bandwidth (5.92 GHz). The analyses indicated that the excellent impedance matching can be attributed to the double-layer magnetic loss and multiple dielectric loss of the core-shell structure. This work provides a feasible approach for the design and preparation of functional composite structures based on MOF derivatives with controllable microwave absorbing properties.

12.
J Hazard Mater ; 439: 129584, 2022 10 05.
Article in English | MEDLINE | ID: mdl-35868084

ABSTRACT

Bisphenols have extensively been found in various environmental matrices and caused public concerns due to their endocrine-disrupting potential. Herein, we developed a ZIF-67@ZIF-8-derived CoZn/nitrogen-doped carbon (CoZn/NC) as a robust adsorbent for bisphenols in wastewaters. The self-generating carbon nanotubes and the open metal sites provided sufficient adsorption sites. The Co component endowed the derivative with strong magnetism facilitating its separation from water. CoZn/NC exhibited exceeding water stability in pH 3 - 12 solution and withstood water up to 15 days. The great applicability of CoZn/NC was validated with 16 real wastewaters from different sources (recoveries exceeding 97.9%). Fast adsorption kinetics were observed with removal efficiencies above 96.5% within 1 min. The adsorption isotherms were well fitted with the Langmuir model, with adsorption capacities of 222, 200, 193, and 321 mg g-1 for bisphenol A, bisphenol F, bisphenol S, and bisphenol AF, respectively. Variations in external conditions, including pH 3 - 9, humic acid (50 mg L-1), and NaCl (0.1 mol L-1), had negligible impacts on the adsorption process. The characterizations and density functional theory computation demonstrated that electrostatic, hydrophobic, π - π, and cation- π interactions are the driving forces in this system. The as-prepared CoZn/NC exhibits great promise in real wastewater treatment.


Subject(s)
Nanotubes, Carbon , Water Pollutants, Chemical , Adsorption , Benzhydryl Compounds , Kinetics , Magnetic Phenomena , Phenols , Wastewater , Water , Water Pollutants, Chemical/analysis
13.
Nanomaterials (Basel) ; 12(6)2022 Mar 09.
Article in English | MEDLINE | ID: mdl-35335718

ABSTRACT

A porous ball-flower-like Co3O4/Fe2O3 heterostructural photocatalyst was synthesized via a facile metal-organic-framework-templated method, and showed an excellent degradation performance in the model molecule rhodamine B under visible light irradiation. This enhanced photocatalytic activity can be attributed to abundant photo-generated holes and hydroxyl radicals, and the combined effects involving a porous structure, strong visible-light absorption, and improved interfacial charge separation. It is notable that the ecotoxicity of the treated reaction solution was also evaluated, confirming that an as-synthesized Co3O4/Fe2O3 catalyst could afford the sunlight-driven long-term recyclable degradation of dye-contaminated wastewater into non-toxic and colorless wastewater.

14.
J Colloid Interface Sci ; 609: 794-806, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34857378

ABSTRACT

Improving resilience, enhancing fire safety and adsorption properties were the key points for the preparation of high-performance flexible polyurethane foam (FPUF). Here, MOF-derived petal-like Co/Mg-double metal hydroxide (Co/Mg-LDH) and 3-aminopropyltriethoxysilane (APTES) were selected to modify the hydroxylated boron nitride (BNNS-OH) to obtain a hydrophobic BN@MOF-LDH@APTES. Compared with the previous work, BN@MOF-LDH@APTES demonstrated extremely high filler efficiency in reducing the heat release per unit mass (THR/TM) (18.2 % reduction) and smoke production per unit mass (TSP/TM) (19.1% reduction) of FUPF during combustion. In addition, the obtained FPUF nanocomposite exhibited high absorption capacity while achieving remarkable thermal stability and fire safety. Moreover, the FPUF nanocomposite containing 1 wt% BN@MOF-LDH@APTES achieved a 71% increase in compressive strength, indicating excellent resilience. Therefore, this work provided a new material for the preparation of high-resilience FPUF with both flame retardancy and adsorption capacity.


Subject(s)
Flame Retardants , Adsorption , Polyurethanes , Propylamines , Silanes
15.
Mikrochim Acta ; 188(10): 328, 2021 Sep 08.
Article in English | MEDLINE | ID: mdl-34495380

ABSTRACT

HKUST-1 MOFs and its derivative HKUST-CuO were coupled with TiO2 nanoparticles to form the heterogeneous composites of HKUST-1/TiO2 and HKUST-CuO/TiO2 based on their well-suitable bandgap energies (Eg). Compared with mono-component HKUST-1 or HKUST-CuO, the prepared composites displayed photoelectrochemical (PEC) response due to the synergistic effect from their heterogeneous structure. Higher photocurrent response was obtained on HKUST-CuO/TiO2-modified ITO electrode (HKUST-CuO/TiO2/ITO), which could be attributed to the hollow structure with a thin shell of HKUST-CuO greatly enhancing visible spectra harvesting. The CuO component in HKUST-CuO not only could accelerate electron transfer on the heterojunction interface but also effectively separate the photo-generated charge carriers (e-1/h+). Based on the excellent PEC performance of prepared photoactive composite material, under visible-light excitation (λ ≥ 420 nm) and with a working potential of 0 V (vs. Ag/AgCl), the S1 (probe DNA)/HKUST-CuO/TiO2/ITO PEC platform was successfully fabricated for colitoxin DNA detection without using ascorbic acid (AA) as an electron donor. Compared with the analysis results on S1/HKUST-1/TiO2/ITO electrode, S1/HKUST-CuO/TiO2/ITO displayed a wider linear response range from 1.0 × 10-6 to 4.0 × 10-1 nM with a lower detection limit of 3.73 × 10-7 nM (S/N = 3), the linear regression equation was ΔI (10-6 A) =0.5549-0.1858 log (CS2/M), which confirmed the HKUST-CuO could improve sensitivity because of its prominent PEC property. The relative standard deviation (RSD) of the PEC sensor for target DNA detection of 2.0 × 10-4 nM was 7.4%. The proposed DNA biosensor also possessed good specificity and stability. Hence, this reported work was a promising strategy for molecular diagnosis in the bio-analysis field. (A) Schematic illustration of the preparation process of the proposed PEC biosensors for colitoxin DNA detection. (B) The preparation process of HKUST-1 and HKUST-CuO.


Subject(s)
Biosensing Techniques/methods , Copper/chemistry , DNA/analysis , Electrochemical Techniques/methods , Metal-Organic Frameworks/chemistry , Titanium/chemistry , Bacterial Toxins/genetics , Biosensing Techniques/instrumentation , Copper/radiation effects , DNA Probes/chemistry , Electrochemical Techniques/instrumentation , Electrodes , Escherichia coli/chemistry , Escherichia coli Proteins/genetics , Immobilized Nucleic Acids/chemistry , Light , Limit of Detection , Metal Nanoparticles/chemistry , Metal Nanoparticles/radiation effects , Metal-Organic Frameworks/radiation effects , Photochemical Processes , Titanium/radiation effects
16.
Article in English | MEDLINE | ID: mdl-32266239

ABSTRACT

Smart fabrics that integrate electronic devices with textiles are emerging as potential candidate for apparel and electronics industries. Soft actuators based on conducting polymers are promising for smart fabrics because of light weight, flexibility, and large deformation under low voltage. However, due to the distinct characteristics of textile and electronic components, the connection between textiles and electronic devices still keeps a challenge in development of smart fabrics. Here, we report an new strategy to prepare a flexible and electroactive textile actuator. The fabric electrolyte was directly coated with an electrode ink, which is composed of Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) doped with carbonized carbon nanotubes wired zeolite imidazolate framework-8 composite. A pre-treatment of the fabric was made by soaking hydrophobic poly(vinylidene fluoride-co-hexafluoropropylene) to increase the ionic conductivity (6.72 mS cm-1) and prevent the electrode ink from penetrating through the fabric. It was found that the textile actuator could work in air stably under a low voltage of 3 V and operate at frequencies from 0.1 to 10 Hz with large strain difference (0.28% at 0.1 Hz), fast strain rate (2.8% s-1 at 10 Hz) and good blocking force (0.62 mN at 0.1 Hz). The key to high performance originates from high ionic conductivity of fabric electrolyte and large specific surface area, good mechanical properties of the metal-organic framework derivative-based composite electrodes, which present insights into preparing other smart fabrics such as textiles sensors, flexible displays, and textile energy storage devices.

17.
ACS Appl Mater Interfaces ; 12(15): 17436-17442, 2020 Apr 15.
Article in English | MEDLINE | ID: mdl-32195562

ABSTRACT

We report the preparation of porous hydrous zirconia by treatment of zirconium-based metal-organic framework (MOF) UiO-66 with a strong base. Microporosity of the original MOF was partially retained in the resultant porous hydrous zirconia. NiII centers were then adsorbed onto the OH-rich hydrous zirconia and in situ converted to highly dispersed Ni0 for CO2 hydrogenation to CH4. The activated catalyst after an induction period showed a turnover frequency of 345 h-1 or a space-time yield of 5851 mmol·gNi-1·h-1 with a CH4 selectivity of over 99%. The catalyst was tested for 100 h on stream, showing only a 4% decrease in activity, and was found to convert atmospheric CO2 to CH4 via CO2 collection through Na2CO3/NaHCO3 cycling. Thermal decomposition of NaHCO3 released CO2 for hydrogenation to CH4, and the resultant Na2CO3 absorbed CO2 from air to form NaHCO3. This work highlights the opportunity in using MOFs as precursors to prepare highly porous metal oxide/hydroxide supports for solid-gas phase catalysis.

18.
ACS Appl Mater Interfaces ; 10(26): 22311-22319, 2018 Jul 05.
Article in English | MEDLINE | ID: mdl-29888588

ABSTRACT

Water oxidation is the key process for many sustainable energy technologies containing artificial photosynthesis and metal-air batteries. Engineering inexpensive yet active electrocatalysts for water oxidation is mandatory for the cost-effective generation of solar fuels. Herein, we propose a novel hierarchical porous Ni-Co-mixed metal sulfide (denoted as NiCoS) on Ti3C2T x MXene via a metal-organic framework (MOF)-based approach. Benefiting from the unique structure and strong interfacial interaction between NiCoS and Ti3C2T x sheets, the hybrid guarantees an enhanced active surface area with prominent charge-transfer conductivity and thus a superior activity toward oxygen evolution reactions (OERs). Impressively, the hierarchical NiCoS in the hybrid is converted to nickel/cobalt oxyhydroxide-NiCoS assembly (denoted as NiCoOOH-NiCoS) by OER measurement, where NiCoOOH on the surface is confirmed as the intrinsic active species for the consequent water oxidation. The hybrid material is further applied to an air cathode for a rechargeable zinc-air battery, which exhibits low charging/discharging overpotential and long-term stability. Our work underscores the tuned structure and electrocatalytic OER performance of MOF derivatives by the versatility of MXenes and provides insight into the structure-activity relationship for noble metal-free catalysts.

19.
ACS Appl Mater Interfaces ; 8(40): 26902-26907, 2016 Oct 12.
Article in English | MEDLINE | ID: mdl-27642808

ABSTRACT

Developing highly active electrocatalysts with low cost and high efficiency for oxygen evolution reactions (OER) is important for the practical implementations of hydrogen energy. Here, we report a Zn-doped CoSe2 nanosheets grown on free-standing carbon fabric collector (CFC), which was synthesized by using a metal-organic framework (MOF) as precursor and followed by a selenylation process. Importantly, the Zn-doped CoSe2/CFC electrode exhibited an obviously enhanced catalytic activity for OER in 1 M KOH aqueous solution compared with CoSe2/CFC, showing a small overpotential of 356 mV for a current density of 10 mA cm-2, a small Tafel slope of 88 mV dec-1, and an excellent stability. The robust and free-standing electrode shows great potential as an economic catalyst for OER applications.

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