Smart Synthesis of Hollow Microporous Organic Capsules with a Polyaniline Modified Shell.

In this work, novel hypercrosslinked polymer-based hollow microporous organic capsules with a polyaniline (PANI)-modified shell (PANI@S-HMOCs) are prepared by in-situ polymerization of aniline in the porous structure of the sulfonated hollow microporous organic capsules (S-HMOCs). PANI@S-HMOC1, PANI@S-HMOC2, and PANI@S-HMOC3 are made by adjusting S-HMOCs and aniline weight ratios of 4:1 and 3:1, and 2:1, respectively. The characterizations of PANI@S-HMOCs demonstrate that electrostatic interaction between aniline and sulfonic acid groups plays an important role in encapsulating PANI in the pores of the shell. The content of PANI shows an evident effect on the porosity of PANI@S-HMOCs, and an appropriate polyaniline loading amount may increase the surface area. PANI@S-HMOC1 and PANI@S-HMOC2 have higher BET surface areas (529 and 503 m2 g-1 ) than S-HMOCs (424 m2 g-1 ), but PANI@S-HMOC3 has lower BET surface area (380 m2 g-1 ). Based on the structural and textural features, PANI@S-HMOC2 shows good adsorption performance for Cr(VI) from aqueous media (156 mg g-1 , pH = 2, and 27 mg g-1 , pH = 7).

Selective Synthesis of Bismuth or Bismuth Selenide Nanosheets from a Metal Organic Precursor: Investigation of their Catalytic Performance for Water Splitting.

The development of cost-effective, functional materials that can be efficiently used for sustainable energy generation is highly desirable. Herein, a new molecular precursor of bismuth (tris(selenobenzoato)bismuth(III), [Bi(SeOCPh)3]), has been used to prepare selectively Bi or Bi2Se3 nanosheets via a colloidal route by the judicious control of the reaction parameters. The Bi formation mechanism was investigated, and it was observed that the trioctylphosphine (TOP) plays a crucial role in the formation of Bi. Employing the vapor deposition method resulted in the formation of exclusively Bi2Se3 films at different temperatures. The synthesized nanomaterials and films were characterized by p-XRD, TEM, Raman, SEM, EDX, AFM, XPS, and UV-vis spectroscopy. A minimum sheet thickness of 3.6 nm (i.e., a thickness of 8-9 layers) was observed for bismuth, whereas a thickness of 4 nm (i.e., a thickness of 4 layers) was observed for Bi2Se3 nanosheets. XPS showed surface oxidation of both materials and indicated an uncapped surface of Bi, whereas Bi2Se3 had a capping layer of oleylamine, resulting in reduced surface oxidation. The potential of Bi and Bi2Se3 nanosheets was tested for overall water-splitting application. The OER and HER catalytic performances of Bi2Se3 indicate overpotentials of 385 mV at 10 mA cm-2 and 220 mV, with Tafel slopes of 122 and 178 mV dec-1, respectively. In comparison, Bi showed a much lower OER activity (506 mV at 10 mA cm-2) but a slightly better HER (214 mV at 10 mA cm-2) performance. Similarly, Bi2Se3 nanosheets were observed to exhibit cathodic photocurrent in photoelectrocatalytic activity, which indicated their p-type behavior.

Facile Synthesis of Hypercrosslinked Hollow Microporous Organic Capsules for Electrochemical Sensing of CuII Ions.

A very simple and facile methodology is used to prepare dithiocarbamate-functionalized hollow microporous organic capsules (HMOCs-DTC), which exhibit excellent stability, a high surface area, and appropriate microporous architecture. In this strategy, SiO2 particles are used as templates to construct PS-DVB-MAA microspheres, and then dithiocarbamate groups are grafted onto them. The dithiocarbamate-functionalized hypercrosslinked microporous organic capsules (HMOCs-DTC/GC) are then used as an electrode material for the detection of CuII ions. Cyclic voltammetry (CV) and electron impedance spectroscopy (EIS) are exploited to study the electrochemical potential of the designed material. The placement of functional groups (dithiocarbamate) at the mesopore interface effectively enhances the mass transfer, which facilitates the more selective detection of CuII ions. The high sensitivity of the modified electrode is expressed in terms of current (Ip ) enhancement at extremely low concentrations of CuII ions. Thus, a functional and robust porous material (HMOCs-DTC) presents a sensitive sensing ability, displaying the calibration response over a wide linear range (2.50×10-11 -3.50×10-10 m), with a lowest limit of detection of 1.02×10-11 m. Indeed, these HMOCs present a new class of porous polymers possessing extraordinarily high scalability but avoiding complex and expensive synthetic methodologies, promoting its practical utilization.

Fabrication of Hollow Microporous Carbon Spheres from Hyper-Crosslinked Microporous Polymers.

Porous carbon materials prepared from the porous organic polymers are currently the subject of extensive investigation. On the basis of their interesting applications, it is highly desirable to develop new synthetic methodologies to obtain carbon materials with controllable pore size and morphology. Herein, a facile synthesis of hollow microporous carbon spheres (HCSs) from hollow microporous organic capsules (HMOCs) with a good control over the pore morphology, hollow cavity, and the shell thickness is reported. The highly porous hollow carbon spheres are prepared by the pyrolysis of HMOCs-based microporous polymers. The synthetic parameters, such as hypercrosslinking and pyrolysis conditions, are optimized to modify the porous structures and the properties. The morphology and porosity as well as energy storage applications of the microporous structures HCSs, derived through a combination of divinylbenzene-crosslinking and micropore-generating hypercrosslinking, are discussed. These findings provide a new benchmark for fabricating well-defined HCSs with great promise for various applications.

Correction: Development of a chromium oxide loaded mesoporous silica as an efficient catalyst for carbon dioxide-free production of ethylene oxide.

[This corrects the article DOI: 10.1039/D3RA05858A.].

PVDF-Based Piezo-Catalytic Membranes-A Net-Zero Emission Approach towards Textile Wastewater Purification.

Among the various water purification techniques, advancements in membrane technology, with better fabrication and analysis, are receiving the most research attention. The piezo-catalytic degradation of water pollutants is an emerging area of research in water purification technology. This review article focuses on piezoelectric polyvinylidene difluoride (PVDF) polymer-based membranes and their nanocomposites for textile wastewater remediation. At the beginning of this article, the classification of piezoelectric materials is discussed. Among the various membrane-forming polymers, PVDF is a piezoelectric polymer discussed in detail due to its exceptional piezoelectric properties. Polyvinylidene difluoride can show excellent piezoelectric properties in the beta phase. Therefore, various methods of ß-phase enhancement within the PVDF polymer and various factors that have a critical impact on its piezo-catalytic activity are briefly explained. This review article also highlights the major aspects of piezoelectric membranes in the context of dye degradation and a net-zero approach. The ß-phase of the PVDF piezoelectric material generates an electron-hole pair through external vibrations. The possibility of piezo-catalytic dye degradation via mechanical vibrations and the subsequent capture of the resulting CO2 and H2 gases open up the possibility of achieving the net-zero goal.

CO2-Free Ethylene Oxide Production via Liquid-Phase Epoxidation with Fe2O3/MSM Catalyst.

In this study, we present an approach for ethylene oxide (EO) production that addresses environmental concerns by eliminating greenhouse gas emissions. Our catalyst, Fe2O3/MSM, was synthesized using a hydrothermal method, incorporating Fe2O3 nanoparticles into a well-structured mesoporous silica matrix (MSM). We selected peracetic acid as the oxidant, enabling CO2-free EO production while yielding valuable by-products such as acetic acid, monoethylene glycol, and diethylene glycol. X-ray diffraction (XRD), X- ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) analyses confirmed the heteroatom structure of the catalysts and porosity, while Transmission electron microscopy (TEM) analysis provided insights into its morphology. Then, the synthesized catalyst was used in the liquid-phase epoxidation of ethylene for EO production. Our systematic experiments involved varying critical parameters such as temperature, ethylene to oxidant ratio, catalyst dosage, and solvent to optimize EO selectivity and ethylene conversion. The results of this study demonstrated an 80.2 % ethylene conversion to EO with an EO selectivity of 87.6 %. The production process yielded valuable by-products without CO2 emissions, highlighting its environmental friendliness.

Development of a chromium oxide loaded mesoporous silica as an efficient catalyst for carbon dioxide-free production of ethylene oxide.

Ethylene oxide (EO) is a significant raw material used in many commodities for consumers, particularly ethoxylates, polymers, and certain other glycol derivatives. We synthesized a catalyst by incorporation of chromium oxide into a mesoporous silica material (Cr/MSM) via the hydrothermal method, an effective catalyst for partial ethylene oxidation for producing carbon dioxide (CO2) free EO. Subsequently, XRD, BET, XPS, and TEM were used to analyse the structural characteristics of the Cr/MSM catalyst. The catalytic performance of the synthesized catalyst was assessed in the liquid-phase epoxidation (LPE) of ethylene, utilizing peracetic acid (PAA) as an oxidant. This approach not only circumvented the generation of CO2 but also mitigated the risk of metal leaching. Confirmation of the successful production of EO was achieved through GC chromatography, where the presence of a peak with a retention time (RT) of 8.91 minutes served as conclusive evidence. We systematically explored a range of reaction parameters, including temperature, catalyst concentration, the molar ratio of ethylene to PAA, and solvent effect. This comprehensive investigation aimed to fine-tune the reaction conditions, ultimately improving ethylene conversion and enhancing the selectivity of the catalyst for EO production. This approach can effectively resolve the issues of greenhouse gas emissions and metal leaching that had been associated with previously reported catalysts.

Bismuth-Rich Co/Ni Bimetallic Metal-Organic Frameworks as Photocatalysts toward Efficient Removal of Organic Contaminants under Environmental Conditions.

Active photocatalysts with an efficiency of 99% were prepared for the degradation of the industrial dye, methylene blue (MB), under visible light irradiation. These photocatalysts comprised Co/Ni-metal-organic frameworks (MOFs), to which bismuth oxyiodide (BiOI) was added as a filler to prepare Co/Ni-MOF@BiOI composites. The composites exhibited remarkable photocatalytic degradation of MB in aqueous solutions. The effects of various parameters, including the pH, reaction time, catalyst dose, and MB concentration, on the photocatalytic activity of the prepared catalysts were also evaluated. We believe that these composites are promising photocatalysts for the removal of MB from aqueous solutions under visible light.

Facile fabrication of hypercrosslinked microporous polymer nanospheres for effective inhibition of triple negative breast cancer cells proliferation.

Treatment failure is one of the main lethal causes of human triple negative breast cancer (TNBC) patients due to inefficient drug administration. The present study demonstrated the development of functional microporous organic polymers (MOPs) as a potential drug carrier and its controlled release. Due to the existence of abundant pores and high surface area, MOPs have promoted the high drug payloads, facilitating prolonged retention time and improved drug release. Herein, porous organic polymer has been fabricated via knitting strategy using the carbonyl bridged external crosslinker. Utilizing the imine chemistry, post-functionalization at the bridging carbon with the diamine resulted in the functional porous framework which had been further modified with single stranded DNA (ssDNA). Due to the conjugated structure, the designed material incorporates the strong blue fluorescence that assists in bio-imaging. In short, the inherent features of hypercrosslinked microporous polymers nanospheres (HMPNs) enabled the high encapsulation of Epirubicin (EPI) and its controlled release in TNBC cell lines (SUM-159 and MDA-MB-231) to inhibit cancer cells proliferation. We anticipate that the further development in functionalization of hypercrosslinked polymers may lead to a breakthrough in biomedical applications.

Low temperature scalable synthetic approach enabling high bifunctional electrocatalytic performance of NiCo2S4 and CuCo2S4 thiospinels.

Ternary metal sulfides are currently in the spotlight as promising electroactive materials for high-performance energy storage and/or conversion technologies. Extensive research on metal sulfides has indicated that, amongst other factors, the electrochemical properties of the materials are strongly influenced by the synthetic protocol employed. Herein, we report the electrochemical performance of uncapped NiCo2S4 and CuCo2S4 ternary systems prepared via solventless thermolysis of the respective metal ethyl xanthate precursors at 200 and 300 °C. The structural, morphological and compositional properties of the synthesized nanoparticles were examined by powder X-ray diffraction (p-XRD), transmission electron microscopy (TEM), high-resolution TEM, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX) techniques. Electrochemical studies indicate that NiCo2S4 nanoparticles synthesized at 300 °C exhibit superior energy storage characteristics with a high specific capacitance of ca. 2650 F g-1 at 1 mV s-1, as compared to CuCo2S4 nanoparticles, which showcased a specific capacitance of ca. 1700 F g-1 at the same scan rate. At a current density of 0.5 A g-1, NiCo2S4 and CuCo2S4 nanoparticles displayed specific capacitances of 1201 and 475 F g-1, respectively. In contrast, CuCo2S4 nanoparticles presented a higher electrocatalytic activity with low overpotentials of 269 mV for oxygen evolution reaction (OER), and 224 mV for the hydrogen evolution reaction (HER), at 10 mA cm-2. The stability of the catalysts was examined for 2000 cycles in which a negligible change in both OER and HER activities was observed.

Development of functionalized hollow microporous organic capsules encapsulating morphine - an in vitro and in vivo study.

Microporous organic capsules with hollow interiors have received enormous attention due to their unusual encapsulation efficiency to confine chemicals within their hollow cavities and prompted controlled release by circumventing their ripening or poisoning. To this end, herein, we report the design and synthesis of carboxylic group functionalized hollow microporous organic capsules (HMOCs) using a facile emulsion polymerization technique that show extraordinary high encapsulation efficiency (up to 98%) of morphine·HCl and its promising prolonged release. The functionalized HMOCs are found to release the drug at a rate which is proportional to the amount of drug remaining in its interior. Due to the presence of hollow and porous morphologies, they possess high BET surface areas, i.e. up to 974 m2 g-1. Moreover, the in vivo results showed that functionalized HMOCs can offer slow release of active drug molecules and attenuate the level of writhing response over 72 h of intraperitoneal injection. The functionalized HMOCs, therefore, present a new class of potential drug delivery systems that can maintain the slow and prolonged release of analgesics by lowering the dosage and avoid frequent administration.

Design and Utility of Metal/Metal Oxide Nanoparticles Mediated by Thioether End-Functionalized Polymeric Ligands.

The past few decades have witnessed significant advances in the development of functionalized metal/metal oxide nanoparticles including those of inorganic noble metals and magnetic materials stabilized by various polymeric ligands. Recent applications of such functionalized nanoparticles, including those in bio-imaging, sensing, catalysis, drug delivery, and other biomedical applications have triggered the need for their facile and reproducible preparation with a better control over their size, shape, and surface chemistry. In this perspective, the multidentate polymer ligands containing functional groups like thiol, thioether, and ester are important surface ligands for designing and synthesizing stable nanoparticles (NPs) of metals or their oxides with reproducibility and high yield. These ligands have offered an unprecedented control over the particle size of both nanoparticles and nanoclusters with enhanced colloidal stability, having tunable solubility in aqueous and organic media, and tunable optical, magnetic, and fluorescent properties. This review summarizes the synthetic methodologies and stability of nanoparticles and fluorescent nanoclusters of metals (Au, Ag, Cu, Pt, and other transition metal oxides) prepared by using thioether based ligands and highlights their applications in bio-imaging, sensing, drug delivery, magnetic resonance imaging (MRI), and catalysis. The future applications of fluorescent metal NPs like thermal gradient optical imaging, single molecule optoelectronics, sensors, and optical components of the detector are also envisaged.