In this work, we report the preparation of one-dimensional (1D) bimetallic zinc-cobalt BTC (BTC = 1,3,5-benzenetricarboxylate) metal–organic frameworks (MOFs) with varying Zn/Co ratios and their conversion to hierarchical porous Co/C hybrids with a trace amount of Zn (<0.05 wt%). The crystallinity, surface area, and degree of graphitization of the resulting Co/C hybrid are governed by the Zn/Co ratio of the parent Zn-Co BTC MOF. The Co/C product derived from the Zn-rich Zn-Co BTC MOF (ZC31-BTC with a Zn/Co precursor ratio of 3:1) shows higher surface area and more amorphous structure than that derived from the Co-rich Zn-Co BTC MOF (ZC13-BTC with a Zn/Co precursor ratio of 1:3). When used for the electrochemical sensing of dopamine (DA), the glassy carbon electrode (GCE) modified with ZC31-BTC700°C (ZC31-BTC carbonized at 700 °C) shows a sensitivity of 0.0995nA nM−1 cm−2, a wide linear range of 0.1–500 µM, and a low limit of detection (LoD) of 0.04 µM (signal-to-noise ratio (S/N) = 3). The superior DA sensing performance of ZC31-BTC700°C is attributed to its high density of defects (evidenced by the high ID/IG ratio), rich mesopores (including small (<5 nm) and large mesopores (>5 nm)), and high surface area, leading to improved ion/electron transfer (based on the EIS analysis), and more electrochemically active sites (confirmed by ECSA measurements) to promote a greater oxidation of DA molecules. The anti-interference test of this ZC31-BTC700°C-modified GCE (ZC31-BTC700°C/GCE) indicates its high selectivity toward DA even in the presence of interferents, such as glucose, ascorbic acid, and uric acid. Moreover, the stability test indicates the good retainment of the current response of ZC31-BTC700°C/GCE toward DA over a period of 2 weeks.

This work reports the incorporation of coordinated water into Ni-BTC nanorods (Ni-BTC-O) which induces their structural transformation to Ni-BTC nanofibres (Ni-BTC-F). The carbonization of the NiBTC nanofibres at 600 degrees C results in the formation of carbon nanotube (CNT)-decorated hierarchical porous nickel/carbon hybrid (labelled as Ni/C-600) with enlarged pores. In contrast, the Ni/C hybrid obtained from the carbonization of the original (unmodified) Ni-BTC nanorods (Ni-BTC-O) at 600 degrees C (labelled as Ni-BTC-O-600) exhibits smaller pore size and does not show the formation of CNTs. The Ni/C-600 hybrid derived from Ni-BTC-F shows a very high adsorption capacity of 686.8 mg g-1 toward methyl blue (MB) dye. This is approximately 4.8 times higher than the adsorption capacity of Ni-BTC-O-600 (144.1 mg g-1). The higher adsorption performance of Ni/C-600 relative to Ni-BTC-O-600 can be attributed to its larger pore volume, hierarchical porosity, and additional adsorption sites provided by the CNTs. In addition, the Ni/C-600 hybrid can maintain 90% of its adsorption capacity after 5 consecutive cycles, demonstrating its potential as an efficient and recyclable adsorbent for MB dye. (c) 2023 Elsevier Inc. All rights reserved.

Enlargement of micropores in zeolitic imidazolate framework particles into mesopores is achieved via an ethylene glycol-assisted aqueous etching method. The etched carbon shows a higher specific capacitance than unetched one at high scan rates.

This work reports the template- and etching-free fabrication of hollow bimetallic nickel-cobalt benzenetricarboxylic acid (Ni Co BTC) hexagonal nanoplates by a polyvinylpyrrolidone (PVP)-assisted approach. The incorporation of PVP can reduce the stacking of these nanoplates along the vertical direction and generate depletion forces between them to reduce aggregation. When employed for the quartz crystal micmbalance (QCM) sensing of ammonia (NH3), the hollow Ni Co BTC hexagonal nanoplates exhibit 1.6, 3.8, and 7.5 times higher sensitivity to 69.5 ppm of NH(3 )than non-hollow Ni Co BTC nanoplates, Ni-BTC nanobelts, and Co-BTC microrods, respectively, and a low limit of detection (LOD) of 1.53 ppm. Additionally, they show good selectivity to NH3 in the presence of other interfering compounds and excellent stability with only a very small decrease of 2.86 % in sensitivity after 6 months. The NH3 adsorption on the hollow Ni Co BTC hexagonal nanoplates follows a pseudo first-order kinetic model with the adsorption rate being 6.1 and 7.1 times faster than Ni-BTC nanobelts and Co-BTC microrods, respectively. The good sensing performance of the hollow Ni-Co BTC hexagonal nanoplates to NH3 is attributed to the existence of carboxyl and hydroxyl groups which can provide energetic sites for the chemisorption of NH(3 )molecules and the increased adsorption sites provided by the hollow two-dimensional structure and the bimetallic composition of this MOF.

This work demonstrates the fabrication of a nanoporous iron carbide-iron oxide/reduced graphene oxide (IC-IO/ rGO) hybrid via a controlled one-step thermal treatment of Prussian blue (PB)/GO hybrid at 450 °C under N2 flow. The PB/GO hybrid is initially prepared through the in-situ deposition of PB nanoparticles on the GO sheets through electrostatic interactions. The morphological analysis of the hybrid reveals the uniform coverage of the rGO sheets by IC-IO nanoparticles and the even distribution of carbon (C), oxygen (O), and iron (Fe) on the rGO nanosheets. As a result of the hybrid composition and controlled morphology, the surface area of the obtained IC-IO/rGO hybrid (~40 m2/g) is significantly enhanced compared to those of the calcined GO sheets and PB nanoparticles (without GO).

Over the past decades, the development of porous materials has directly or indirectly affected industrial production methods. Metal-organic frameworks (MOFs) as an emerging class of porous materials exhibit some unique advantages, including controllable composition, a large surface area, high porosity, and so on. These attractive characteristics of MOFs have led to their potential applications in energy storage and conversion devices, drug delivery, adsorption and storage, sensors, and other areas. However, powdered MOFs have limited practical applications owing to poor processability, safety hazards from dust formation, and poor recyclability. In addition, the inherent micro/mesoporosities of MOFs also reduce the accessibility and diffusion kinetics for large molecules. To improve their processability for practical applications, MOFs are often deposited as MOF layers Or films (i.e., MOF-coated composites) on supporting materials or are formed into 3D structured composites, such as aerogels and hydrogels. In this article, we review recent researches on these MOF composites, including their synthetic methods and potential applications in energy storage devices, heavy metal ion adsorption, and water purification. Finally, the future outlook and challenges associated with the large-scale fabrication of MOF-based composites for practical applications are discussed.

Sulfate radical (SO4 center dot-)-based advanced oxidation processes (SR-AOPs) hold great promise for water purification due to their strong oxidizing and high selectivity. Recently, metal-organic frameworks (MOFs) as catalysts for peroxymonosulfate (PMS) activation to generate SO4 center dot- have shown a bright future. However, the intrinsic nature of powder MOF nanocrystals, such as brittleness and poor processability, largely disturb their large-scale applications in practical. Herein, we develop an in situ growth method to prepare MOF fillers. ZIF-67 in situ growth on the polyacrylonitrile (PAN) fibers lead to the ZIF-67/PAN composite fibers with high loading (up to 50 wt %). The loading ZIF-67 can retain their morphology and structure, which is comparable with that of pristine ZIF-67 powder. The ZIF-67/PAN filter demonstrates a high efficiency for organic pollutants removal by PMS activation. Furthermore, through the fabrication of filtration device, the dynamic catalysis results show the ZIF-67/PAN filter is a promising material for water purification. This work provides a new method for applying MOFs-based functional materials to practical water remediation and other separation applications.

Porous materials are widely studied for water purification and treatment as they can function as efficient adsorbents for harmful chemical wastes with their high specific surface areas. Among various types of porous materials, metal-organic frameworks (MOFs) have emerged as promising adsorbents for organic pollutants although the general powder form of MOFs largely limits their recyclability in practical applications. Herein, highly crystalline MOF particles are incorporated into agarose (AG) to fabricate highly recyclable MOF aerogels. Along with greatly improved recyclability, these MOF aerogels also achieve eco-friendliness and cost-effectiveness because AG is highly abundant in nature and can be easily modified. Typically, MOF aerogels are synthesized by uniformly dispersing MOF particles into the AG solution. The resulting MOF aerogels show significantly improved efficiency for dye adsorption. It is believed that this fabrication method for the preparation of MOF aerogels is highly versatile and it can be extended to other types of MOFs for different applications including environmental remediation, energy storage and conversion, and sensing.