Sonochemical synthesis of two nanostructured silver(I) coordination polymers based on semi-rigid bis(benzimidazole) ligands

Recent progress on sonochemical production for the synthesis of efficient photocatalysts and the impact of reactor design

Sonochemical-assisted synthesis has flourished recently for the design of photocatalysts. The main power used is ultrasound that allows the nanomaterials shape and size modification and control. This review highlights the effect in formation mechanism by ultrasound application and the most common photocatalysts that were prepared via sonochemical techniques. Moreover, the challenge for the suitable reactor design for the synthesis of materials or for their photocatalytic evaluation is discussed since the most prominent reactor systems, batch, and continuous flow, has both advantages and drawbacks. This work summarises the significance of sonochemical synthesis for photocatalytic materials as a green technology that needs to be further investigated for the preparation of new materials and the scale up of developed reactor systems to meet industrial needs.

2D and 3D silver-based coordination polymers with thiomorpholine-4-carbonitrile and piperazine-1,4-dicarbonitrile: structure, intermolecular interactions, photocatalysis, and thermal behavior

The reaction of the thiomorpholine-4-carbonitrile and piperazine-1,4-dicarbonitrile ligands afforded four Ag(i) coordination polymers with excellent photocatalytic activity in the degradation of the mordant blue 9 dye.

Four dual-functional luminescent Zn(ii)-MOFs based on 1,2,4,5-benzenetetracarboxylic acid with pyridylbenzimidazole ligands for detection of iron(iii) ions and acetylacetone

Four Zn-MOFs with different topological types were synthesized and characterized, MOFs 1–4 have excellent sensitivity, selectivity, recyclability and structural stabilities for detecting acac/Fe³⁺ in the naked eye range.

Facile sonochemical-assisted synthesis of Cu/ZnO/Al2O3 nanocomposites under vacuum: Optical and photocatalytic studies

This paper reports on the synthesis of Cu/ZnO/Al₂O₃ nanocomposites via a facile sonochemical-assisted approach using new starting reactants. This study was conducted to synthesis and photocatalytic evaluation of the Cu/ZnO/Al₂O₃ nanocomposite in vacuum conditions. The XRD results showed that Cu/ZnO/Al₂O₃ and CuO/ZnO/Al₂O₃ nanocomposites could be obtained after annealing at 600 °C for 3 h in vacuum conditions and in the air, respectively. The effects of Cu:Zn:Al ratio, ultrasonic irradiation, power, time, and capping agent on the product composition and morphology were also studied. Finally, the efficiency of various as-synthesized Cu/ZnO/Al₂O₃ nanocomposites for decolorization of methylene blue were evaluated. According to the results, using ultrasonic irradiation and annealing under vacuum, the efficiency is improved up to 100%. Because in this situation Cu/Cu₂O/ZnO/Al₂O₃ is formed, which has a better absorption (due to Cu₂O) and conductivity (due to Cu) than CuO/ZnO/Al₂O₃ for the photocatalysis process.

Fast ultrasound-assisted synthesis of highly crystalline MIL-88A particles and their application as ethylene adsorbents

Highly crystalline MIL-88A particles have been successfully synthesized via fast ultrasound-assisted processes. The influence of the sonication generator and synthesis time on the structure, crystallinity, morphology and surface area of the materials were studied in detail. Under this modified ultrasonic method, X-ray diffraction patterns of MIL-88A particles showed highly crystalline structures in contrast to those reported in literature. Significant differences on surface areas and microporosity were appreciated under ultrasound conditions employed. Specific surface areas in the range between 179 and 359 m² g^-1 were obtained. That material synthesized under ultrasound batch conditions during 1 h had the highest surface area and microporous character. Different particle sizes and morphologies were obtained depending on the synthesis procedure. In general, probe sonicators led to smaller particle sizes. Moreover, a comparative study of the ethylene adsorption of the MIL-88A particles and several common MOFs in the ethylene adsorption was investigated. The results suggest that the modified ultrasound-assisted procedure for the synthesis of MIL-88A is effective to obtain highly crystalline particles, which are very efficient to adsorb ethylene molecules.

Luminescence, electrochemical and photocatalytic properties of sub-micron nickel(II) and cobalt(II) coordination polymers synthesized by sonochemical process

Submicron structures of Ni^II/Co^II-based coordination polymers (CPs) [Ni(L1)(mip)·H₂O]_n (1) and {[Co(L2)(mip)]·0·.5H₂O}_n(2) (L1=1,6-bis(5,6-dimethylbenzimidazole)hexane, L2=1,6-bis(benzimidazole)hexane, H₂mip=5-methylisophthalic acid) were obtained by ultrasonic irradiation and structurally characterized by elemental analysis, powder X-ray diffraction and scanning electron microscopy. Structural analysis show that two CPs feature uninodal 3-connected 2D hcb layer, whilst CP 2 is further extended into a 3D complicated supramolecular network by C14-H14⋯O2 hydrogen bonds. Ultrasonic time and power influencing morphology of sub-micron sized CPs, were also discussed. Besides that, thermal stability, luminescence, electrochemical properties and photocatalytic activity of sub-micron sized 1 and 2 were presented in detail. Moreover, sub-micron sized 1 manifests the higher photocatalytic activity than sub-micron sized 2 for decomposition of methylene blue (MB) under UV irradiation.

Ultrasonic-promoted rapid preparation of PVC/TiO2-BSA nanocomposites: Characterization and photocatalytic degradation of methylene blue

In the present project in order to prevent agglomeration and better dispersion of TiO₂ nanoparticles (NPs) in the poly(vinyl chloride) (PVC) matrix, initially, the surface of TiO₂ NPs was covered by bovine serum albumin protein (BSA) via sonication method. Then, the TiO₂-BSA powders were embedded into the PVC matrix using ultrasonic irradiations. With mechanical and magnetic stirring homogenous mixture was not obtained. So sonication process was very essential and vital. Physical, chemical and structural properties of the samples were investigated with various tools. Morphology studies showed the well distribution of spherical TiO₂ NPs in the PVC matrix. TGA analysis showed that nanocomposites (NCs) have higher thermal stability than the pristine polymer. The photocatalytic activity tests by destroying the methylene blue dye on the pristine TiO₂ NPs, TiO₂-BSA NPs and PVC/TiO₂-BSA NC 6 wt% were examined. The results showed that the photocatalytic activity of TiO₂ NPs was reduced in the presence of BSA and PVC. It can be concluded that the TiO₂-BSA NPs and PVC/TiO₂-BSA NC 6 wt% have UV shielding properties and can protect film from degradation by UV.

Structures, luminescence and photocatalytic properties of two nanostructured cadmium(II) coordination polymers synthesized by sonochemical process

By varying the dicarboxylate coligands, two nano-sized cadmium(II) coordination polymers (CPs), [Cd(bix)(DCTP)]_n (1) and [Cd(bix)₂(BPDC)]_n (2) (bix=1,4-bis(imidazol-1-ylmethyl)benzene, H₂DCTP=2,5-dichloroterephthalic acid, H₂BPDC=biphenyl-4,4'-dicarboxylic acid) were synthesized hydrothermally and sonochemical irradiation. CPs 1-2 and their nanostructures have been characterized by elemental analysis, single-crystal X-ray diffraction, and scanning electron microscopy (SEM). CP 1 features a uninodal 4-connected 2D sql network consisting of two different helical arrays. Whilst, CP 2 displays 2D layer which constructed by the linear chains and M2L2 type discrete loops. The effect of ultrasonic power and temperature on the morphology and size of CPs 1-2 are investigated in detail. Nano-sized 1-2 show the relatively high photocatalytic performance for degradation of Methylene Blue (MB) under UV irradiation.

Ultrasonic-assisted synthesis of polyvinyl alcohol/phytic acid polymer film and its thermal stability, mechanical properties and surface resistivity

In this paper, polyvinyl alcohol/phytic acid polymer (PVA/PA polymer) was synthesized through esterification reaction of PVA and PA in the case of acidity and ultrasound irradiation and characterized, and PVA/PA polymer film was prepared by PVA/PA polymer and characterized, and the influence of dosage of PA on the thermal stability, mechanical properties and surface resistivity of PVA/PA polymer film were researched, and the influence of sonication time on the mechanical properties of PVA/PA polymer film was investigated. Based on those, it was concluded that the hydroxyl group on the chain of PVA and the phosphonic group on PA were connected together in the form of phosphonate bond, and the hydroxyl group on the chain of PVA were connected together in the form of ether bond after the intermolecular dehydration; in the meantime, it was also confirmed that PVA/PA polymer film prepared from 1.20mL of PA not only had the high thermal stability and favorable ductility but also the low surface resistivity in comparison with PVA/PA polymer film with 0.00mL of PA, and the ductility of PVA/PA polymer film was very sensitive to the sonication time.