Organic-inorganic Systems Research Articles

Pore accessibility by wettable fluids in overmature marine shales of China: Investigations from contrast-matching small-angle neutron scattering (CM-SANS)

The characterization of pore accessibility is essential for shale oil and gas reservoir evaluation. However, owing to the extremely low permeability and high heterogeneity of shale components, accurate nanoscale evaluation of pore accessibility remains challenging. In this study, a systematic investigation of nanoscale pore accessibility characteristics and their controlling factors was undertaken via contrast-matching small-angle neutron scattering (CM-SANS) on four overmature marine shale samples from China. In addition, a series of experiments integrating the air-liquid contact angle, spontaneous imbibition, mercury intrusion capillary pressure (MICP), and field-emission scanning electron microscopy, were conducted to determine the shale wettability and pore connectivity characteristics. A novel accessibility index was developed and utilized to analyze the accessibility of fluids with different wetting phases in nanoscale pore networks and their changes over time. The results from the CM-SANS test of Wufeng-Longmaxi shale samples indicate that higher pore volumes (pores >7 nm) were filled with toluene due to the development of organic pores and the connection between organic pores and inorganic pore systems. Meanwhile, more water-accessible pores were observed within a pore size of less than 7 nm. This result indicates that the pore volume is perhaps composed of hydrophilic pores related to clay minerals or created by the swelling of clays. Furthermore, the combination of CM-SANS on samples (before and after combustion) and MICP showed that pore accessibility to water and toluene was controlled by pore surface wettability and pore connectivity. Thus, CM-SANS is an effective means of evaluating the nanoscale pore accessibility of shale, revealing the relationship between wettability and pore connectivity, which can help better understand the migration of hydrocarbon fluids and the imbibition of fracturing fluid.

Manipulating the interlayer carrier diffusion and extraction process in organic-inorganic heterojunctions: from 2D to 3D structures

Interlayer carrier transfer at heterointerfaces plays a critical role in light to electricity conversion using organic and nanostructured materials. However, how interlayer carrier extraction at these interfaces is poorly understood, especially in organic-inorganic heterogeneous systems. Here, we provide a direct strategy for manipulating the interlayer carrier diffusion process, transfer rate and extraction efficiency in tetracene/MoS2 type-II band alignment heterostructure by constructing the 2D–3D organic-inorganic (O-I) system. As a result, the prolonged diffusion length (12.32 nm), enhanced electron transfer rate (9.53 × 109 s−1) and improved carrier extraction efficiency (60.9%) are obtained in the 2D O-I structure which may be due to the more sufficient charge transfer (CT) state generation. In addition, we have demonstrated that the interlayer carrier transfer behavior complied with the diffusion mechanism based on the one-dimensional diffusion model. The diffusion coefficients have varied from 0.0027 to 0.0036 cm2 s−1 as the organic layer changes from 3D to 2D structures. Apart from the relationship between the carrier injection and diffusion process, temperature-dependent time-resolved spectra measurement is used to reveal the trap-related recombination that may limit the interlayer carrier extraction. The controllable interlayer carrier transfer behavior enables O-I heterojunction to be optimized for optoelectronic applications.

Production of antibacterial cement composites containing ZnO/lignin and ZnO–SiO2/lignin hybrid admixtures

Inorganic–organic systems based on ZnO or ZnO–SiO2 and lignin were used for the first time to counteract the biodeterioration of cement composites. The stability of the oxide–lignin and interoxide–lignin combinations was confirmed by Fourier transform infrared spectroscopy, while electrokinetic studies confirmed the stability of the systems in the alkaline environment of the cement matrix. Moreover, lignin-enriched admixtures showed very good water wettability, which enabled their uniform dispersion in the cement matrix. Physical and mechanical tests confirmed the retarding effect of zinc oxide on the hydration of the cement binder in the initial setting period, which was manifested by lower mechanical parameters up to the 7th day of setting. The use of interoxide systems with silica balanced this adverse effect. The designed systems based on ZnO and lignin caused the inactivation of both bacterial and fungal pathogens, the effect being weaker in the case of the systems with silica.

Charge Transfer Screening and Energy Level Alignment at Complex Organic-Inorganic Interfaces: A Tractable Ab Initio GW Approach.

Complex organic-inorganic interfaces are important for device and sensing applications. Charge transfer doping is prevalent in such applications and can affect the interfacial energy level alignments (ELA), which are determined by many-body interactions. We develop an approximate ab initio many-body GW approach that can capture many-body interactions due to interfacial charge transfer. The approach uses significantly less resources than a regular GW calculation but gives excellent agreement with benchmark GW calculations on an F4TCNQ/graphene interface. We find that many-body interactions due to charge transfer screening result in gate-tunable F4TCNQ HOMO-LUMO gaps. We further predict the ELA of a large system of experimental interest-4,4'-bis(dimethylamino)bipyridine (DMAP-OED) on monolayer MoS2, where charge transfer screening results in an ∼1 eV reduction of the molecular HOMO-LUMO gap. Comparison with a two-dimensional electron gas model reveals the importance of explicitly considering the intraband transitions in determining the charge transfer screening in organic-inorganic interface systems.

Photoelectrochemical water splitting by hybrid organic-inorganic systems: Setting the path from 2% to 20% solar-to-hydrogen conversion efficiency

SummaryPromoting solar fuels as a viable alternative to hydrocarbons calls for technologies that couple efficiency, durability, and low cost. In this work we elucidate how hybrid organic-inorganic systems employing hybrid photocathodes (HPC) and perovskite solar cells (PSC) could eventually match these needs, enabling sustainable and clean hydrogen production. First, we demonstrate a system comprising an HPC, a PSC, and a Ru-based oxygen evolution catalyst reaching a solar-to-hydrogen (STH) efficiency above 2%. Moving from this experimental result, we elaborate a perspective for this technology by adapting the existing models to the specific case of an HPC-PSC tandem. We found two very promising scenarios: one with a 10% STH efficiency, achievable using the currently available semiconducting polymers and the widely used methylammonium lead iodide (MAPI) PSC, and the other one with a 20% STH efficiency, requiring dedicated development for water-splitting applications of recently reported high-performing organic semiconductors and narrow band-gap perovskites.

A data fusion approach to optimize compositional stability of halide perovskites

Summary Search for resource-efficient materials in vast compositional spaces is an outstanding challenge in creating environmentally stable perovskite semiconductors. We demonstrate a physics-constrained sequential learning framework to subsequently identify the most stable alloyed organic-inorganic perovskites. We fuse data from high-throughput degradation tests and first-principle calculations of phase thermodynamics into an end-to-end Bayesian optimization algorithm using probabilistic constraints. By sampling just 1.8% of the discretized CsxMAyFA1−x−yPbI3 (MA, methylammonium; FA, formamidinium) compositional space, perovskites centered at Cs0.17MA0.03FA0.80PbI3 show minimal optical change under increased temperature, moisture, and illumination with >17-fold stability improvement over MAPbI3. The thin films have 3-fold improved stability compared with state-of-the-art multi-halide Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3, translating into enhanced solar cell stability without compromising conversion efficiency. Synchrotron-based X-ray scattering validates the suppression of chemical decomposition and minority phase formation achieved using fewer elements and a maximum of 8% MA. We anticipate that this data fusion approach can be extended to guide materials discovery for a wide range of multinary systems.

Functionalized mesoporous silica as a fluorescence sensor for selective detection of Hg2+ in aqueous medium.

We combined the virtues of mesoporous silica and organic functional groups to develop a hybrid fluorescent sensor, PyU-SBA-15, with excellent ability to detect Hg2+ in aqueous medium with high selectivity. In this sensor, the pyrene fluorophore acts as the reporter and the urea unit acts as the receptor during Hg2+ determination. The control material, PyH-SBA-15, which lacks a carbonyl group in the receptor portion, did not display metal-ion selectivity, thereby demonstrating that introducing an additional metal-chelating unit is necessary to improve the metal-ion selectivity of the hybrid sensor. When the concentration of Hg2+ was increased, the fluorescence emission intensities of PyU-SBA-15 at 379, 398, and 476nm gradually decreased. The emission intensity at 379nm was linearly proportional to Hg2+ concentrations in the range of 0-1.0×10-4M, and the sensor was determined to have a detection limit of 9.92×10-8M. This work provides an effective strategy for improving or modulating the metal-ion selectivity of fluorescent sensors based on organic-inorganic hybrid mesoporous silica systems.

Siloxanes-Versatile Materials for Surface Functionalisation and Graft Copolymers.

Siloxanes are adaptable species that have found extensive applications as versatile materials for functionalising various surfaces and as building blocks for polymers and hybrid organic-inorganic systems. The primary goal of this review is to report on and briefly explain the most relevant recent developments related to siloxanes and their applications, particularly regarding surface modification and the synthesis of graft copolymers bearing siloxane or polysiloxane segments. The key strategies for both functionalisation and synthesis of siloxane-bearing polymers are highlighted, and the various trends in the development of siloxane-based materials and the intended directions of their applications are explored.

Prerequisites and prospects for the development of novel systems based on the Keplerate type polyoxomolybdates for the controlled release of drugs and fluorescent molecules

Synthetic approaches were proposed to the development of hybrid organic—inorganic systems based on giant Keplerate polyoxometalates (POM Mo132), biocompatible polymers, and fluorescent molecules. A concept was formulated for the production of new systems for the prolonged release of drugs bearing a constant or temporary (protonated group) positive charge and fluorescent labels for tissue staining during electrophoretic introduction. In particular, a possibility of covalent functionalization of the POM Mo132 surface by the organosilicon molecules (aminopropyltrimethoxysilane) was shown. A promising procedure of the synthesis of NHS-esters of rhodamine B for the subsequent inclusion into the hybrid system was developed. The kinetic studies of POM destruction in an aqueous medium were carried out. The influence of association of rhodamine B with Mo132 on the character of fluorescence was studied.

Zirconocene immobilization into organic-inorganic dual-shell silicas prepared by the nonhydrolytic sol-gel method for polyethylene production

Cp2ZrCl2 was entrapped in dual-layered silica by two iterated nonhydrolytic sol-gel steps with organosilanes (methyltriethoxysilane, isopropyltriethoxysilane, octyltriethoxysilane, octadecyltrimethoxysilane) and WCl6 as modifiers. For comparative reasons, organic-inorganic hybrid one-layer systems were also synthesized. The hybrid systems were evaluated for ethylene polymerization, with methylaluminoxane (MAO) as the cocatalyst. Increasing catalytic activity was observed in the case of the dual-layered silica systems. Modification of the silica surface with octadecylsilane (C8-Si) in combination with the presence of added Lewis acid centers (W) afforded the highest catalytic activity among the systems tested. The presence of organosilanes on the silica surface may affect polyethylene polydispersity. In the case of dual systems, the presence of two distinct hybrid silica layer effects, an internal silica layer modified with C18-Si and an external layer with C8-Si moieties, impinged on the broadening of polydispersity. Inverse moieties have distinct polydispersity indexes that indicate the surface modification at internal/external silica layers affects polymer characteristics. Microstructural features of hybrid silicas determined by small-angle X-ray scattering indicate that a low number of neighbors and larger correlation distances could explain higher catalytic activities. Similarly, long carbon chains in organoalkoxysilanes tend to reduce the radii of second level particles in a hierarchical structure of dual-shell systems, which in turn leads to higher catalytic activity.

From past research experiences looking to the future of sol–gel

Based on the outline of the conference that the author held in St. Petersburg for the conferment of the Life Achievement Award, some important steps in the evolution of science and sol–gel technology are revisited through examples taken from his research experiences. The goal is to reconsider what has been done in the past in light of what has been learned in the meantime. Some topics are still current and probably deserve further and more in-depth research, and new ideas for future work may be suggested. Driven by the interest of finding new materials and new fields of application, the sol–gel has evolved from the first studies on simple glass and glass–ceramic systems, to more sophisticated and complex organic–inorganic systems, multifunctional materials, and nanocomposites.

Periodic Mesoporous Organosilica Nanoparticles with BOC Group, towards HIFU Responsive Agents.

Periodic Mesoporous Organosilica Nanoparticles (PMONPs) are nanoparticles of high interest for nanomedicine applications. These nanoparticles are not composed of silica (SiO2). They belong to hybrid organic–inorganic systems. We considered using these nanoparticles for CO2 release as a contrast agent for High Intensity Focused Ultrasounds (HIFU). Three molecules (P1–P3) possessing two to four triethoxysilyl groups were synthesized through click chemistry. These molecules possess a tert-butoxycarbonyl (BOC) group whose cleavage in water at 90–100 °C releases CO2. Bis(triethoxysilyl)ethylene E was mixed with the molecules Pn (or not for P3) at a proportion of 90/10 to 75/25, and the polymerization triggered by the sol-gel procedure led to PMONPs. PMONPs were characterized by different techniques, and nanorods of 200–300 nm were obtained. These nanorods were porous at a proportion of 90/10, but non-porous at 75/25. Alternatively, molecules P3 alone led to mesoporous nanoparticles of 100 nm diameter. The BOC group was stable, but it was cleaved at pH 1 in boiling water. Molecules possessing a BOC group were successfully used for the preparation of nanoparticles for CO2 release. The BOC group was stable and we did not observe release of CO2 under HIFU at lysosomal pH of 5.5. The pH needed to be adjusted to 1 in boiling water to cleave the BOC group. Nevertheless, the concept is interesting for HIFU theranostic agents.

Magnetocaloric effect in 2D-alkylammonium copper halides layered inorganic-organic systems

Two-dimensional inorganic–organic hybrids are important due to tunable physical properties and their suitability in the data storage, memory devices, low-temperature magnetic refrigeration technology, energy storage, and other applications. The significance of such lead-free layered hybrids is in the ease of synthesis and material stability against heat, humidity, temperature, and other environmental conditions. Here, we report the magnetic properties of (C12H25NH3)2Cu(Br1 – xClx)4 and (C6H9C2H4NH3)2Cu(Br1 – xClx)4 systems that are self-assembled layered structures formed by solution processing. The systems exhibit paramagnetic to ferromagnetic transition with the Curie temperature and amount of magnetization both controllable by halogen content in the stoichiometric composition. Magnetocaloric properties have been investigated to find out the suitability of highly stable (C12H25NH3)2CuCl4 in environment friendly low-temperature magnetic refrigeration technology. A large magnetic entropy change varying from ∼0.6 J kg−1 K−1 to larger than 2.0 J kg−1 K−1 is measured from isothermal magnetization data around the Curie temperature at field variations 0–10 kOe and 0–60 kOe, respectively. Characteristic critical exponents from the field-dependent magnetic entropy changes have been determined, which show excellent agreement with the three-dimensional Heisenberg model.

Study of Structure and Electronic Properties of Heterointerfaces for Photovoltaic Applications

The linkage between the atomic structure and the electronic property is complex for heterointerfaces involving multicomponent organic–inorganic systems because of large configurations and chemical ...

Upconversion luminescence in cellulose composites (fibres and paper) modified with lanthanide-doped SrF2 nanoparticles

The use of functional nanomaterials and their combination with organic polymers leads to the formation of advanced composites and hybrid inorganic–organic systems having unique properties.

Pengaruh Perbedaan Aplikasi Pestisida pada Struktur Komunitas Mikroarthropoda Tanah dalam Skala Lapangan dan Laboratorium

The choice of using pesticides with natural ingredients or synthetic chemicals is a differentiator between organic farming systems and inorganic farming systems. Pesticides are additives in agriculture to control pests or weeds. Abamectin is one of the active ingredients that can be found in pesticides. Ground microarthropods are members of the soil mesofauna, which are soil animals that have a body size ranging from 0.2-2 mm. The purpose of this study was to determine the effect of differences in the application of pesticides on a field or laboratory scale on the structure of soil microarthropod communities. Soil samples were taken from three agricultural lands, namely Bandungan inorganic agricultural land, Kopeng inorganic agricultural land and Kopeng organic agricultural land. The study was conducted in August to December 2018 in the Ecology and Biosystematic Laboratory of the Department of Biology, FSM Undip. Found a total of 60 species species richness originating from 13 orders. The application of pesticides which include the concentration and frequency of pesticide spraying has a negative influence on the structure of soil microarthopod communities. Application of abamectin pesticides on a laboratory scale proves that the administration of abamectin pesticides that exceeds the recommended concentration will adversely affect the structure of the soil microathropod community. Based on statistical tests of soil microarthropod species diversity from the results of the application of pesticides on a field and laboratory scale is significantly different.

Aerosol Optical Tweezers Constrain the Morphology Evolution of Liquid-Liquid Phase-Separated Atmospheric Particles

Summary Chemical models of atmospheric particles are vital in understanding the role of aerosol particles in atmospheric chemistry, air pollution, human health, and climate change. Advancing these models requires new frameworks that can realistically predict how critical particle properties evolve. We present such a framework for predicting particle phase separation and which morphology will prevail; this controls how each particle interacts with and affects the atmosphere. We studied the mixing behavior of α-pinene secondary organic aerosol (SOA) with different organic phases, as relative humidity was varied to determine the interplay between polarity, miscibility, interfacial tension, and the resulting morphology. Using measurements from aerosol optical tweezers experiments and literature data, a general trend in morphology with increasing atmospheric oxidation was observed, from biphasic partially engulfed (where both phases are immediately accessible to the gas phase) to biphasic core shell (where the organic shell conceals the core) and finally to a single-phase, homogeneous morphology.

PW12/CN@Bi2WO6 composite photocatalyst prepared based on organic-inorganic hybrid system for removing pollutants in water

In the drive toward green and sustainable chemistry in wastewater treatment, it is necessary to explore more efficient and stable photocatalysts to achieve the degradation of antibiotic and reduction of heavy metal ions. To this end, an organic-inorganic hybrid PW12/CN@Bi2WO6 composite photocatalyst was prepared: PW12/CN composite was prepared by heating H3PW12O40, melamine and phytic acid; PW12/CN@Bi2WO6 was synthesized via PW12/CN and Bi2WO6 by hydrothermal method. The photocatalytic activity of as-prepared photocatalyst was evaluated by degrading tetracycline hydrochloride (TC) and reducing hexavalent chromium (Cr(VI)) under the simulated xenon light source. The results show the PW12/CN@Bi2WO6 composite always maintains high catalytic performance for TC and Cr6+ and has well cycle stability. After irradiation for 90 and 100 min, the most effective 10%-PW12/CN@Bi2WO6 achieved a removal rate of 98.7% for Cr(VI) and 97.5% for TC. Photoluminescence spectroscopy and photoelectrochemical results demonstrate that the charge separation is enhanced for the PW12/CN@Bi2WO6, attributed to the introduction of the organic-inorganic systems to enhance the absorbance of light energy, promote charge transfer and inhibit e− and h+ pair recombination. In addition, the free radical scavenging test and electron spin resonance analysis (ESR) test indicate that the main species of action are h+ and O2− in the photocatalytic oxidation reaction. Further, the mechanism of photocatalysis was proposed by Mott-Schottky. The strategy improving catalytic performance through organic-inorganic hybrid systems provides a new route for the development of photocatalysts.

Calculation of Electron Ionization Mass Spectra with Semiempirical GFNn-xTB Methods.

In this work, we have tested two different extended tight-binding methods in the framework of the quantum chemistry electron ionization mass spectrometry (QCEIMS) program to calculate electron ionization mass spectra. The QCEIMS approach provides reasonable, first-principles computed spectra, which can be directly compared to experiment. Furthermore, it provides detailed insight into the reaction mechanisms of mass spectrometry experiments. It sheds light upon the complicated fragmentation procedures of bond breakage and structural rearrangements that are difficult to derive otherwise. The required accuracy and computational demands for successful reproduction of a mass spectrum in relation to the underlying quantum chemical method are discussed. To validate the new GFN2-xTB approach, we conduct simulations for 15 organic, transition-metal, and main-group inorganic systems. Major fragmentation patterns are analyzed, and the entire calculated spectra are directly compared to experimental data taken from the literature. We discuss the computational costs and the robustness (outliers) of several calculation protocols presented. Overall, the new, theoretically more sophisticated semiempirical method GFN2-xTB performs well and robustly for a wide range of organic, inorganic, and organometallic systems.

Fracture and wrinkle patterns of metal/elastomer bilayers on glass slides induced by high temperature annealing

Inorganic-organic multilayer systems are ubiquitous in many important technological applications and have received considerable attention recently. Although the mechanics, structures, materials and performances of multilayer devices under room temperature have been extensively investigated, the effect of heat on the inorganic-organic composite systems remains unclear. Here we report on the fracture and wrinkle behaviors of metal/elastomer (silver/polydimethylsiloxane(PDMS)) bilayers resting on glass slides induced by high temperature annealing. It is found that as the annealing temperature is beyond a critical value, the PDMS layer is fractured and detaches from the glass slide due to the thermal contraction during cooling. The fractured PDMS layer bends upward and places the silver film under a compressive stress, which is relieved by formation of multiple wrinkle patterns. The morphological characteristics, evolutional behaviors and potential mechanisms of both fracture and wrinkle patterns are discussed in detail. The report in this work could promote better understanding of the effect of heat on the mechanical durability of metal/elastomer/solid multilayer systems.