Search

The co-extraction of pertechnetate (TcO 4 - ) is a problematic issue that complicates the Plutonium Uranium Reduction EXtraction (PUREX) process for reprocessing spent nuclear fuel. Unfortunately, research on the interactions of TcO 2 2+ is very scarce. This work quantitatively investigated the interactions of TcO 4 - with UO 2 2+ is very scarce. This work quantitatively investigated the interactions of TcO 4 - form complexes of 1 : 1 to 1 : 3 molar ratios, in which the stability constants of the UO 4 - complexes are slightly higher than those of the UO 2 2+ complexes. The structures of the complexes of UO 2 2+ and TcO 4 - /ReO 4 - . The UV-Vis and Raman spectra of the complexes are simulated, and it is found that the second solvation shell needs to be explicitly taken into account in the DFT calculations in order to obtain Raman spectra comparable to the experiments. The results in this work help understand the co-extraction behavior of TcO 2 2+ -TcO 4 - complexes are slightly higher than those of the UO 2 2+ -ReO 4 - complexes. The structures of the complexes of UO 2 2+ with TcO 4 - /ReO 4 - are modeled by DFT calculations. The DFT calculations indicate that the TcO 4 - /ReO 4 - anions are monodentate coordinated with UO 2 2+ . The UV-Vis and Raman spectra of the complexes are simulated, and it is found that the second solvation shell needs to be explicitly taken into account in the DFT calculations in order to obtain Raman spectra comparable to the experiments. The results in this work help understand the co-extraction behavior of TcO 4 - with UO 2 2+ in spent nuclear fuel reprocessing.

A relatively unexplored approach in heterometallic chemistry of transition metals and lanthanides has been developed toward the controlled synthesis of a new family of linear heterotrinuclear Ln(III)-Pd(II)-Ln(III) complexes with the general formula [Ln 2 Pd(pao) 2 (NO 3 ) 6 (MeOH) 2 (H 2 O) 2 ]·[Pd(pao) 2 ] 4 , where Ln III = Dy III (2), Gd III (3), Er III (4) and Yb III (5). This strategy was based on the diamagnetic 'metalloligand' [Pd(pao) 2 ] (1), where pao - is the anion of 2-pyridinealdoxime, containing two dangling oximate O-atoms which were trans to each other and available for binding with oxophilic lanthanide ions. Because of their trans -configuration, the [Pd(pao) 2 ] 'metalloligand' was able to direct the binding of two {Ln(NO 3 ) 3 (MeOH)(H 2 O)} units on opposite sites, thus yielding the reported trinuclear {Ln-Pd-Ln} clusters. Complexes 2-5 constitute a new family of trinuclear heterometallic {Ln 2 Pd} species, and they represent the first examples of a directional assembly approach towards the coordination of 4f-metal ions. Compounds 2 and 5 exhibit out-of-phase signals under applied dc fields of 300 and 2000 Oe, respectively, characteristics of the slow magnetization relaxation, albeit with very small energy barriers for the magnetization reversal. This was due to the combined onset of fast quantum tunneling and the weak crystal field effects induced by the coordinated ligands. The combined results highlight the potential of using the 'metal complexes as ligands' method to deliberately prepare heterometallic Pd II -Ln III complexes with unique structural and interesting physicochemical (magnetic, optical, catalytic) properties.

The removal of emerging contaminants (ECs) from drinking water is a current challenge of global concern. Graphene-based sorbents are attracting increasing interest in this field owing to the chemical versatility of graphene-based materials, their commercial availability and processability in various 3D structures. Herein, for the first time, graphene aerogels (GAs) are reported based on the synergy of graphene oxide (GO) and graphene nanoplatelets (GNPs) derived from waste tire and their use as a sorbent for a mixture of ECs in tap water. Reduction of GO up to 52.1% (O/C = 0.092) was demonstrated through X-ray photoelectron spectroscopy, whereas no changes in the GNP structure during aerogel synthesis were demonstrated with comprehensive spectroscopic and microscopic characterisation. Adsorption of a selection of ECs in a mixture from tap water was tested under flow conditions by inserting the aerogels into filtration cartridges and filtering tap water spiked with the mixture of ECs. Remarkably, the GO + GNP aerogel showed an increase in adsorption capacity of about 2.3 times that of the rGO aerogel owing to the higher obtained surface area, 27 instead of 16 m 2 g -1 , and the resultant more-reduced structure., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Modified nanofibers with a more aligned and very thin structure are a potential approach owing to their promising properties and enhanced fuel cell performance compared to conventional randomly oriented nanofibers. The strategy to fabricate randomly oriented nanofibers has been widely explored. However, the key factors of oriented fibres, such as the degree of alignment, diameter, bead generation, and precision, have not been investigated in detail. In this work, four specific profiles of nanofibres related to the parameters of the electrospinning system were analysed in more detail for the first time: collector speed, distance, voltage, and nozzle movement. The concentration was set at a constant value of 10% (w/w) of polyvinyl alcohol (PVA), which is suitable for the potential application of fabricating membrane electrode assemblies (MEAs) for fuel cells. The results indicated that the applied electrical voltage is the most important factor among all the features. Taguchi methods implemented in this work revealed the correlation factors for each specific parameter., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Herein, zeolitic imidazole framework (ZIF)-8/red phosphorus photocatalysts were prepared via a solvothermal method for simultaneous organic dye degradation and hydrogen (H 2 ) generation. The 5 wt% ZIF-8/RP photocatalyst achieved the highest H 2 generation rate of 822.5 μmol h -1 g -1 and 92% rhodamine dye degradation under natural sunlight irradiation. This approach offers an effective strategy to replace costly and toxic traditional electron donors with organic dye pollutants for H 2 generation.

TiO 2 remains one of the most popular materials used in catalysts, photovoltaics, coatings, and electronics due to its abundance, chemical stability, and excellent catalytic properties. The tailoring of the TiO 2 structure into two-dimensional nanosheets prompted the successful isolation of graphene and MXenes. In this review, facet-controlled TiO 2 and monolayer titanate are outlined, covering their synthesis route and formation mechanism. The reactive facet of TiO 2 is usually controlled by a capping agent. In contrast, the monolayer titanate is achieved by ion-exchange and delamination of layered titanates. Each route leads to 2D structures with unique physical and chemical properties, which expands its utilisation into several niche applications. We elaborate the detailed outlook for the future use and research studies of facet-controlled TiO 2 and monolayer titanates. Advantages and disadvantages of both structures are provided, along with suggested applications for each type of 2D TiO 2 nanosheets., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Organic compounds constitute a substantial part of atmospheric particulate matter not only in terms of mass concentration but also in terms of distinct functional groups. The glass transition temperature provides an indirect way to investigate the phase state of the organic compounds, playing a crucial role in understanding their behavior and influence on aerosol processes. Molecular dynamics (MD) simulations were implemented here to predict the glass transition temperature ( T ) of atmospherically relevant organic compounds as well as the influence of their functional groups and length of their carbon chain. The cooling step used in the simulations was chosen to be neither too low (to supress crystallization) nor too high (to avoid g ) of atmospherically relevant organic compounds as well as the influence of their functional groups and length of their carbon chain. The cooling step used in the simulations was chosen to be neither too low (to supress crystallization) nor too high (to avoid T is sensitive to the functional groups as follows: carboxylic acid (-COOH) > hydroxyl (-OH) and (-COOH) > carbonyls (-CO). Increasing the number of carbon atoms leads to higher g overprediction). According to the MD simulations, the predicted T g was observed. The architecture of the carbon chain (linear, or branched, or ring) was also found to impact the glass transition temperature. Compounds containing a non-aromatic carbon ring are characterized by a higher T compared to linear and branched ones with the same number of carbon atoms.g for the linearly structured compounds. Linear compounds with lower molecular weight were found to exhibit a lower T g . No clear correlation between O : C and T g was observed. The architecture of the carbon chain (linear, or branched, or ring) was also found to impact the glass transition temperature. Compounds containing a non-aromatic carbon ring are characterized by a higher T g compared to linear and branched ones with the same number of carbon atoms.

The escalating demand for energy storage underscores the significance of supercapacitors as devices with extended lifespans, high energy densities, and rapid charge-discharge capabilities. Ceria (CeO 2 ), known for its exceptional properties and dual oxidation states, emerges as a potent material for supercapacitor electrodes. This study enhances its capacitance by integrating it with Metal-Organic Frameworks (MOFs), carbon-rich compounds noted for their good conductivity. In our research, hollow ceria (h-ceria) is synthesized via hydrothermal methods and amalgamated with Ce-MOF, employing 2,6-dinaphthalene dicarboxylic acid as a ligand, to fabricate Ce-MOF@h-CeO 2 composites. The structural and morphological characteristics of the composite are methodically examined using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), and Fourier-Transform Infrared (FT-IR) spectroscopy. The band gap of the materials is ascertained through UV-Diffuse Reflectance Spectroscopy (UV-DRS). Electrochemical behavior and redox properties of the Ce-MOF composites are explored using Cyclic Voltammetry (CV), Galvanostatic Charge and Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS), providing insights into the material's stability. Electrochemical characterization of the composite reveals maximum specific capacitance, energy density and power density are 2643.78 F g -1 at a scan rate of 10 mV s -1 , 249.22 W h kg -1 , and 7.9 kW kg -1 , respectively. Additionally, the specific capacitance of Ce-MOF synthesized with a 2,6-dinaphthalene dicarboxylic acid (NDC) ligand reaches 995.59 F g -1 , surpassing that of Ce-MOF synthesized using a 1,3,5-tricarboxylic acid (H 3 BTC) ligand. These findings highlight the promising economic potential of high-performance, environmentally sustainable, and cost-effective energy storage devices. The innovative Ce-MOF@h-CeO 2 composite materials at the core of this research pave the way for advancing the field of energy storage solutions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The surge in interest surrounding energy storage solutions, driven by the demand for electric vehicles and the global energy crisis, has spotlighted the effectiveness of carbon-based supercapacitors in meeting high-power requirements. Concurrently, metal-organic frameworks (MOFs) have gained attention as a template for their integration with graphene oxide (GO) in composite materials which have emerged as a promising avenue for developing high-power supercapacitors, elevating smart supercapacitor efficiency, cyclic stability, and durability, providing crucial insights for overcoming contemporary energy storage obstacles. The identified combination leverages the strengths of both materials, showcasing significant potential for advancing energy storage technologies in a sustainable and efficient manner. In this research, an in-depth review has been presented, in which properties, rationale and integration of MOF/GO composites have been critically examined. Various fabrication techniques have been thoroughly analyzed, emphasizing the specific attributes of MOFs, such as high surface area and modifiable porosity, in tandem with the conductive and stabilizing features of graphene oxide. Electrochemical characterizations and physicochemical mechanisms underlying MOF/GO composites have been examined, emphasizing their synergistic interaction, leading to superior electrical conductivity, mechanical robustness, and energy storage capacity. The article concludes by identifying future research directions, emphasizing sustainable production, material optimization, and integration strategies to address the persistent challenges in the field of energy storage. In essence, this research article aims to offer a concise and insightful resource for researchers engaged in overcoming the pressing energy storage issues of our time through the exploration of MOF/GO composites in smart supercapacitors., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

High silica contents rubber composites are favored in the green tire industry for their ability to reduce rolling resistance. However, achieving effective silica dispersion in natural rubber, particularly at high silica content, poses a challenge. In addition, the choice of impeller configuration significantly influences mixing performance, especially in commercial production, which requires large mixing tanks. Therefore, understanding the scaling-up process for this mixing system is essential. This research aims to investigate the mixing of silica dispersion in natural latex, specifically focusing on a high silica content regime. The flow characteristics of each liquid phase were simulated by employing the Computational Fluid Dynamics (CFD) approach, with a two-fluid model serving as the model based. Analyses were conducted on two variants of stirred tank reactors including four baffles and flat bottoms. Four configurations of Rushton turbine impellers were considered: four 90° blades (RT4-90), four 45° blades (RT4-45), six 90° blades (RT6-90), and six 45° blades (RT6-45). The simulations revealed that the 90° blade promoted the radial flow, while the 45° blades enhanced axial flow, through the process of diverting a significant proportion of the fluid above impeller, this regime effectively increases the liquid's velocity. Increasing the number of blades led to a more homogeneous velocity profile within the impeller region. Additionally, higher fluid velocity was observed in a larger mixing tank. In a smaller tank, the impact of impeller design (number and angle of the impeller) on mixing time was less pronounced. However, the mixing time decreased with the increasing blade number in a larger tank. In addition, the 45° blade angle tends to decrease the mixing time. The optimum design is the Ruston turbine with six blades set at a 45° angle. Furthermore, the upscaling criteria that were proposed by Norwood and Metzner were used into this inquiry. The suggested scaling criterion was consistently applied to the mixing of high silica natural latex, with no deviation exceeding 10%., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

In this work, we employ a fast and less toxic modified Hummers' method to develop graphene oxide (GO) with varying degrees of oxidation and investigate the effect of the latter on the structure and the thermal properties of the synthesized materials. Two different key parameters, the time of the oxidation reaction and the mass of the oxidation agent, were systematically altered in order to fine tune the oxidation degree. All graphene oxides were characterized by a plethora of experimental techniques, like X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) as well as infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) for their structural, thermal and chemical identification. The results revealed that for a certain amount of oxidant, the time does not affect the final degree of oxidation of the materials, at least for the examined reaction times, because very similar structural patterns and thermal properties were obtained. At the same time, the oxygen-containing functional groups were found very similar. On the other hand, the degree of oxidation was found highly dependent on the mass of the oxidizing agent. XRD analysis showed a systematic increase of the interlayer distance of the synthesized GOs with the increase of the oxidant mass, whereas both the enthalpy of reduction and the % weight loss were increased. Moreover, XPS measurements provided a quantitative evaluation of the amount of carbon and oxygen in the materials; the increase of the oxidant mass led to a decrease of the total carbon content with the concurrent increase of the total oxygen amount.

Covalent organic frameworks (COFs) are a new class of functional solids featuring several fantastic structural characteristics, including a great diversity of building units and cross-linking patterns, precise integration of building blocks, and adjustable topology of porous architecture. In addition to the above features, some COF samples are constructed with high-density conjugated fragments, which have unique potential advantages in fluorescence imaging, and thus may have great potential applications in bioimaging. Herein, this article summarizes the recent progress in the design and preparation of fluorescent covalent organic frameworks. We investigate the systemic correlation between the structural qualities of COF networks and biological sensors. Finally, the significant advantages, major challenges, and future opportunities of fluorescent covalent organic frameworks are discussed for the development of next-generation porous materials for sensing applications.

In situ Raman and FTIR spectra complemented by in situ Raman/ 18 O isotope labelling are exploited for deciphering the structural properties and configurations of the (ReO x ) n phase dispersed on monoclinic ZrO 2 at temperatures of 120-400 °C under oxidative dehydration conditions and coverages in the range of 0.71-3.7 Re nm -2 . The dispersed (ReO x ) n phase is heterogeneous, consisting of three distinct structural units: (a) Species-I with mono-oxo termination ORe(-O-Zr) m (ReO mode at 993-1005 cm -1 ); (b) Species-IIa with di-oxo termination (O) 2 Re(-O-Zr) m -1 (symmetric stretching mode at 987-998 cm -1 ); and (c) Species-IIb with di-oxo termination (O) 2 Re(-O-Zr) u (symmetric stretching mode at 982-991 cm -1 ); all terminal stretching modes undergo blue shifts with increasing coverage. With increasing temperature, a reversible temperature-dependent Species-IIa ↔ Species-I transformation is evidenced. At low coverages, below 1 Re nm -2 , isolated species prevail; at 400 °C the mono-oxo ORe(-O-Zr) m Species-I is the majority species, the di-oxo Species-IIa occurs in significant proportion and di-oxo Species-IIb is in the minority. At coverage ≥1.3 Re nm -2 , at 400 °C the di-oxo Species-IIa prevails clearly over mono-oxo Species-I. Below 80 °C and at a low coverage of 0.71 Re nm -2 , the occurrence of a fourth structural unit, Species-III taking on a tri-oxo configuration (symmetric stretching mode at 974 cm -1 ) is evidenced. All temperature-dependent structural and configurational transformations are fully reversible and interpreted by mechanisms at the molecular level.

The sustainable production of catechol derivatives is a challenging task. Catechyl (C) and guaiacyl (G) lignins coexisting in waste tung nutshells are promising feedstocks to form valuable catechol derivatives, but the depolymerization of C/G lignin typically involves a catalytic reductive process that cannot produce these oxidized aromatic chemicals. Herein, we demonstrated that the sustainable production of catechol derivative aldehydes and acids from C/G lignin could be achieved through a heterogeneous copper-catalyzed oxidative process. Under optimized conditions, the Cu-NC-800 catalyst affords a 43.5 mg g -1 yield (8.9 wt%, based on Klason lignin) of aromatic aldehydes (protocatechuic aldehyde, vanillin) and acids (protocatechuic acid, vanillic acid). XRD and XPS analyses showed that CuO and Cu 2 O may be the active species during the heterogeneous oxidation of the Cu-NC-800 catalyst. This study opens new opportunities for the sustainable production of catechol derivatives from C/G-type lignin., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Heterogeneous ice nucleation is a ubiquitous process in the natural and built environment. Deposition ice nucleation, i.e. heterogeneous ice nucleation that - according to the traditional view - occurs in a subsaturated water vapor environment and in the absence of supercooled water on the solid, ice-forming surface, is among the most important ice formation processes in high-altitude cirrus and mixed-phase clouds. Despite its importance, very little is known about the mechanism of deposition ice nucleation at the microscopic level. This study puts forward an adsorption-based mechanism for deposition ice nucleation through results from a combination of atomistic simulations, experiments and theoretical modelling. One of the most potent laboratory surrogates of ice nucleating particles, silver iodide, is used as a substrate for the simulations. We find that water initially adsorbs in clusters which merge and grow over time to form layers of supercooled water. Ice nucleation on silver iodide requires at minimum the adsorption of 4 molecular layers of water. Guided by the simulations we propose the following fundamental freezing steps: (1) Water molecules adsorb on the surface, forming nanodroplets. (2) The supercooled water nanodroplets merge into a continuous multilayer when they grow to about 3 molecular layers thick. (3) The layer continues to grow until the critical thickness for freezing is reached. (4) The critical ice cluster continues to grow., Competing Interests: The authors declare that they have no knowledge of competing financial interests or personal relationships that could have influenced the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

The first use of the organic chelate N -hydroxy-1,8-naphthalimide (hynadH) in Dy III chemistry has unveiled access to a synthetic 'playground' composed of four new dinuclear complexes, all of which possess the same planar {Dy 2 (μ-OR) 2 } 4+ diamond-shaped core, resulting from the bridging and chelating capacity of the hynad - groups. The structural stability of the central {Dy 2 } core has allowed for the modulation of the peripheral coordination sites of the metal ions, and specifically the NO 3 - ratio of capping groups, thus affording the compounds [Dy - ratio of capping groups, thus affording the compounds [Dy 2 (hynad) 2 (NO 3 ) 4 (DMF) 2 ] (1), (Me 4 N) 2 [Dy 2 (hynad) 2 (NO 3 ) 6 ] (2), [Dy 2 (hynad) 4 (NO 3 ) 2 (H 2 O) 2 ] (3), and [Dy 2 (hynad) 6 (H 2 ] (4). Because of the chemical and structural modifications in the series 1-4, the Dy 2 coordination polyhedra are also dissimilar, comprising the muffin (1 and 3), tetradecahedral (2), and spherical tricapped trigonal prismatic (4) geometries. Complexes 1, 2, and 4 exhibit a ferromagnetic response at low temperatures, while 3 is antiferromagnetically coupled. All compounds exhibit out-of-phase ( III coordination polyhedra are also dissimilar, comprising the muffin (1 and 3), tetradecahedral (2), and spherical tricapped trigonal prismatic (4) geometries. Complexes 1, 2, and 4 exhibit a ferromagnetic response at low temperatures, while 3 is antiferromagnetically coupled. All compounds exhibit out-of-phase ( χ ) ac signals as a function of ac frequency and temperature, thus behaving as single-molecule magnets (SMMs), in the absence or presence of applied dc fields. Interestingly, the hynad M ) ac signals as a function of ac frequency and temperature, thus behaving as single-molecule magnets (SMMs), in the absence or presence of applied dc fields. Interestingly, the hynad - = 69.62(1) K) for the magnetization reversal which is attributed to the presence of the two axial triangular faces of the spherical tricapped trigonal prism by the negatively charged O-atoms of the hynad U eff = 69.62(1) K) for the magnetization reversal which is attributed to the presence of the two axial triangular faces of the spherical tricapped trigonal prism by the negatively charged O-atoms of the hynad - ligands.

Pellet combustion in residential heating stoves has increased globally during the last decade. Despite their high combustion efficiency, the widespread use of pellet stoves is expected to adversely impact air quality. The atmospheric aging of pellet emissions has received even less attention, focusing mainly on daytime conditions, while the degree to which pellet emissions undergo night-time aging as well as the role of relative humidity remain poorly understood. In this study, environmental simulation chamber experiments were performed to characterize the fresh and aged organic aerosol (OA) emitted by a pellet stove. The fresh pellet stove PM 1 (particulate matter with an aerodynamic diameter less than 1 μm) emissions consisted mainly of OA (93 ± 4%, mean ± standard deviation) and black carbon (5 ± 3%). The primary OA (POA) oxygen-to-carbon ratio (O : C) was 0.58 ± 0.04, higher than that of fresh logwood emissions. The fresh OA at a concentration of 70 μg m -3 (after dilution and equilibration in the chamber) consisted of semi-volatile (68%), low and extremely low volatility (16%) and intermediate-volatility (16%) compounds. The oxidation of pellet emissions under dark conditions was investigated by injecting nitrogen dioxide (NO 2 ) and ozone (O 3 ) into the chamber, at different (10-80%) relative humidity (RH) levels. In all dark aging experiments secondary organic aerosol (SOA) formation was observed, increasing the OA levels after a few hours of exposure to NO 3 radicals. The change in the aerosol composition and the extent of oxidation depended on RH. For low RH, the SOA mass formed was up to 30% of the initial OA, accompanied by a moderate change in both O : C levels (7-8% increase) and the OA spectrum. Aging under higher RH conditions (60-80%) led to a more oxygenated aerosol (increase in O : C of 11-18%), but only a minor (1-10%) increase in OA mass. The increase in O : C at high RH indicates the importance of heterogeneous aqueous reactions in this system, that oxidize the original OA with a relatively small net change in the OA mass. These results show that the OA in pellet emissions can chemically evolve under low photochemical activity ( e.g. the wintertime period) with important enhancement in SOA mass under certain conditions., Competing Interests: The authors declare that are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Commercial TS-1 zeolite was functionalized as a stable catalyst for the one-pot transformation of fructose to methyl lactate (MLA) by the reaction solvent (methanol) to generate increased catalytic activity. As a result, TS-1 was recycled for 14 cycles without a regeneration process by calcination and accompanied by a surprising increased catalytic activity. This work is expected to provide a new option for the industrial production of biomass-based MLA by heterogeneous chemocatalysis.

The third-order nonlinear optical (NLO) properties of a series of platinum diimine-dithiolate complexes [Pt(N^N)(S^S)] were investigated by means of Z -scan measurements, revealing second hyperpolarizability values up to 10 -29 esu, saturable absorption properties, and nonlinear refractive behaviour, which were rationalized also by means of DFT calculations.

The initial use of a tetradentate Schiff base (LH 2 ) derived from the 2 : 1 condensation between 2-hydroxyacetophenone and cyclohexane-1,2-diamine in 4f-metal chemistry is described. The 1 : 2 reaction of Ln(NO 3 ) 3 · x H 2 O (Ln = lanthanoid or yttrium) and LH 2 in MeOH/CH 2 Cl 2 has provided access to isostructural complexes [Ln(NO 3 ) 3 (L'H 2 )(MeOH)] in moderate to good yields. Surprisingly, the products contain the corresponding Schiff base ligand L'H 2 possessing six aliphatic -CH 2 - groups instead of the -CH-(CH 2 ) 4 -CH- unit of the cyclohexane ring, i.e. an unusual ring-opening of the latter has occurred. A mechanism for this Ln III -assisted/promoted LH 2 → L'H 2 transformation has been proposed assuming transient Ln II species and a second LH 2 molecule as the H 2 source for the reduction of the cyclohexane moiety. DFT calculations provide strong evidence for the great thermodynamic stability of the products in comparison with analogous complexes containing the original intact ligand. The structures of the Pr III , Sm III , Gd III , Tb III , and Ho III complexes have been determined by single-crystal X-ray crystallography. The 9-coordinate Ln III centre in the molecules is bound to six oxygen atoms from the three bidentate chelating nitrato groups, two oxygen atoms that belong to the bidentate chelating organic ligand, and one oxygen atom from the coordinated MeOH group. In the overall neutral bis(zwitterionic) L'H 2 ligand, the acidic H atoms are clearly located on the imino nitrogen atoms and this results in the formation of an unusual 16-membered chelating ring. The coordination polyhedra defined by the nine donor atoms around the 4f-metal-ion centres can be best described as distorted, spherical capped square antiprisms. The Eu III , Tb III , and Dy III complexes exhibit Ln III -based luminescence in the visible region, with the coordinated L'H 2 molecule acting as the antenna. Ac magnetometry experiments show that the Dy III member of the family behaves as an SIM at zero field and under external dc fields of 0.1 and 0.2 T without the enhancement of the peaks' maxima, suggesting that QTM is not the relaxation path. The Gd III complex behaves, rather unexpectedly, as a SIM with two different magnetic relaxation paths occurring at very close temperatures; this behaviour is tentatively attributed to a very small axial zero-field splitting ( D ∼ 0.1 cm -1 ), which cannot be detected by magnetization or susceptibility experiments. The prospects of the present, first results in the lanthanoid(III)-LH 2 chemistry are discussed.

The structural and configurational characteristics of the species comprising the (VO x ) n phase dispersed on TiO 2 (P25) are studied under oxidative dehydration conditions by in situ molecular vibrational spectroscopy (Raman, FTIR) complemented by in situ Raman/ 18 O isotope exchange and Raman spectroscopy under static equilibrium at temperatures of 175-430 °C and coverages in the 0.40-5.5 V nm -2 range. It is found that the dispersed (VO x ) n phase consists of distinct species with different configurations. At low coverages of 0.40 and 0.74 V nm -2 , isolated (monomeric) species prevail. Two distinct mono-oxo species are found: (i) a majority Species-I, presumably of distorted tetrahedral OV(-O-) 3 configuration with VO mode at 1022-1024 cm -1 and (ii) a minority Species-II, presumably of distorted octahedral-like OV(-O-) 4 configuration with VO mode at 1013-1014 cm -1 . Cycling the catalysts in the 430 → 250 → 175 → 430 °C sequence results in temperature-dependent structural transformations. With decreasing temperature, a Species-II → Species-I transformation with concomitant surface hydroxylation takes place by means of a hydrolysis mechanism mediated by water molecules retained by the surface. A third species (Species-III, presumably of di-oxo configuration with ν s / ν as at ∼995/985 cm -1 , an association of VO 4 ) shows the highest reactivity to water. For coverages above 1 V nm -2 , an association of VO x units takes place leading to gradually larger polymeric domains when the coverage is increased in the 1.1-5.5 V nm -2 domains comprise building units that maintain the structural characteristics (termination configuration and V coordination number) of Species-I, Species-II, and Species-III. The terminal VO stretching modes are blue-shifted with increasing (VO x ) n domain size. A lower extent of hydroxylation is evidenced under static equilibrium forced dehydrated conditions, thereby limiting the temperature dependent structural transformations and excluding the possibility of incoming water vapors as the cause for the temperature dependent effects observed in the x Raman/FTIR spectra. The results address open issues and offer new insight in the structural studies of VO n domain size. A lower extent of hydroxylation is evidenced under static equilibrium forced dehydrated conditions, thereby limiting the temperature dependent structural transformations and excluding the possibility of incoming water vapors as the cause for the temperature dependent effects observed in the in situ Raman/FTIR spectra. The results address open issues and offer new insight in the structural studies of VO x /TiO 2 catalysts.

A synthetically controllable two-step spin transition was observed in iron(II) spin crossover nanoparticles of the dehydrated one-dimensional coordination polymer [Fe(NH 2 trz) 3 ]Br 2 (NH 2 trz = 4-amino-1,2,4-triazole) using the reverse micellar method. The change from two-step to one-step hysteretic characteristics succeeded by changing the reaction time.

Biomass-activated carbon has made a great contribution as an adsorbent in the field of dye wastewater treatment. In this study, the response surface method (RSM) based on the Box-Behnken design was used to optimize the preparation process. Bamboo fiber activated carbon (BAC) with a specific surface area of 2892 m 2 g -1 and a pore volume of 1.80 cm 3 g -1 was prepared. Various characterization methods (SEM, XPS, XRD, and Raman spectroscopy) were used to analyze the micro-structure of BAC. In the microscopic state, the BAC is fibrous and maintains the originally connected pores of the bamboo fiber. After high-temperature activation, the microcrystallinity of BAC decreases, and the degree of graphitization is low, indicating the presence of amorphous carbon. The adsorption capacity of BAC to crystal violet in simulated wastewater was evaluated via an adsorption experiment. Under the following conditions: the dosage of BAC was 0.04 g, the concentration was 600 mg L -1 , the adsorption temperature and time were 25 °C and 30 min, respectively, and the as-prepared BAC had a 99.96% removal rate. The adsorption process conformed to the pseudo-second-order kinetic model and Langmuir adsorption isotherm model, indicating that the adsorption process of CV on BAC belonged to monomolecular layer adsorption. The adsorption process occurs spontaneously and is accompanied by heat release, and the maximum adsorption capacity of BAC within a given concentration range could reach 1353.09 mg g -1 . SEM-EDS characterization before and after adsorption showed that ion exchange and the presence of oxygen-containing functional groups played an important role in promoting the adsorption process. The results show that BAC considerably affects CV removal, which has great application prospects., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (This journal is © The Royal Society of Chemistry.)

Determining the optimum layer thickness, for the anode and cathode, is of utmost importance for minimizing the costs of the alkaline direct ethanol fuel cell (DEFC) without lowering the electrochemical performance. In this study, the influence of layer thickness on the performance of the ethanol oxidation reaction (EOR) and oxygen reduction reaction (ORR) in an alkaline medium and resistance was investigated. The prepared gas diffusion electrodes (GDEs) were fully characterized, with scanning electron microscopy to determine the layer thickness and electrochemically in half-cell configuration. Cyclic voltammetry and polarization curve measurements were used to determine the oxidation and reduction processes of the metals, the electrochemical active surface area, and the activity towards the ORR and EOR. It was demonstrated that realistic reaction conditions can be achieved with simple and fast half-cell GDE measurements. Single cell measurements were conducted to evaluate the influence of factors, such as membrane or ethanol crossover. In addition, electrochemical impedance spectra investigation was performed to identify the effect of layer thickness on resistance. This successfully demonstrated that the optimal layer thicknesses and high maximum power density values (120 mW cm -2 ) were achieved with the Pt-free catalysts and membranes used., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Electrocatalyst development for alkaline direct ethanol fuel cells is of great importance. In this context we have designed and synthesized cerium-modified cobalt manganese oxide (Ce-CMO) spinels on Vulcan XC72R (VC) and on its mixture with reduced graphene oxide (rGO). The influence of Ce modification on the activity and stability of the oxygen reduction reaction (ORR) in absence and presence of ethanol was investigated. The physicochemical characterization of Ce-CMO/VC and Ce-CMO/rGO-VC reveals CeO 2 deposition and Ce doping of the CMO for both samples and a dissimilar morphology with respect to the nature of the carbon material. The electrochemical results display an enhanced ORR performance caused by Ce modification of CMO resulting in highly stable active sites. The Ce-CMO composites outperformed the CMO/VC catalyst with an onset potential of 0.89 V vs. RHE, a limiting current density of approx. -3 mA cm -2 and a remaining current density of 91% after 3600 s at 0.4 V vs. RHE. In addition, remarkable ethanol tolerance and stability in ethanol containing electrolyte compared to the commercial Pt/C catalyst was evaluated. These outstanding properties highlight Ce-CMO/VC and Ce-CMO/rGO-VC as promising, selective and ethanol tolerant ORR catalysts in alkaline media., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The systematic investigation of the general reaction scheme Dy III /X - /LH 2 , where X - = Cl - , CF 3 SO 3 - , ClO 4 - is the pocket-type ligand 2,6-diacetylpyridine bis(picolinoylhydrazone), resulting from the condensation of 2,6-diacetylpyridine with picolinic acid hydrazide, has led to a new family of mono-, di-, and tetranuclear metal complexes of the formulae [DyCl 2 - , and LH 2 is the pocket-type ligand 2,6-diacetylpyridine bis(picolinoylhydrazone), resulting from the condensation of 2,6-diacetylpyridine with picolinic acid hydrazide, has led to a new family of mono-, di-, and tetranuclear metal complexes of the formulae [DyCl 2 (LH 2 )(MeOH)]Cl (1), [Dy 2 (O 3 SCF 3 ) 2 (LH) 2 (MeOH) 1.42 (H 2 O) 0.58 ](O 3 SCF 3 ) 2 (2), [Dy 2 (LH) 2 (MeOH) 2 (H 2 O) 2 ](ClO 4 ) 4 (3), and [Dy 4 (OH) 2 ] (4), respectively. The organic chelate undergoes metal-assisted amide-iminol tautomerism and adopts the neutral zwitterionic, and single- and double-deprotonated forms, respectively, upon coordination with the metal center(s). Interestingly, the different forms of the ligand LH 2 CMe) 6 (L) 2 ] (4), respectively. The organic chelate undergoes metal-assisted amide-iminol tautomerism and adopts the neutral zwitterionic, and single- and double-deprotonated forms, respectively, upon coordination with the metal center(s). Interestingly, the different forms of the ligand LH 2 compounds of various nuclearities and different magnetic properties. All complexes 1-4 exhibit frequency-dependent, out-of-phase ( - /L 2- ) tails of signals in zero external dc field, characteristic of the onset of quantum tunnelling of magnetization. Attempts to suppress the tunnelling through the application of an external dc field were mostly successful in the case of complex 1, where entirely visible peaks of III compounds of various nuclearities and different magnetic properties. All complexes 1-4 exhibit frequency-dependent, out-of-phase ( χ have been observed and rendered possible the fit of the data to the Arrhenius equation, thus yielding the parameters: M ) tails of signals in zero external dc field, characteristic of the onset of quantum tunnelling of magnetization. Attempts to suppress the tunnelling through the application of an external dc field were mostly successful in the case of complex 1, where entirely visible peaks of χ '' M have been observed and rendered possible the fit of the data to the Arrhenius equation, thus yielding the parameters: U eff is the pre-exponential factor. The combined results demonstrate the ability of pyridyl-bis(acylhydrazone) ligands to yield chemically, structurally, and magnetically interesting compounds through their rich interconversion between various amide-iminol resonance forms.τ 0 = 1.9(1) × 10 -6 s, where U eff is the effective energy barrier for the magnetization reversal and τ 0 is the pre-exponential factor. The combined results demonstrate the ability of pyridyl-bis(acylhydrazone) ligands to yield chemically, structurally, and magnetically interesting compounds through their rich interconversion between various amide-iminol resonance forms.

Reactions of 2-benzoylpyridine, (py)(ph)CO, with InX 3 (X = Cl, Br) in EtOH at room temperature have been studied. The InCl 3 /(py)(ph)CO system has provided access to complex [InCl 3 {(py)(ph)CO}(EtOH)]·{(py)(ph)CO} (1) and the byproduct {(pyH)(ph)CO}Cl (2). The reaction of InBr 3 with (py)(ph)CO has led to a mixture of (L)[InBr 4 {(py)(ph)CO}] (3) and [In 2 Br 4 {(py)(ph)CH(O)} 2 (EtOH) 2 ] (4), where L + is the 9-oxo-indolo[1,2- a ]pyridinium cation and (py)(ph)CH(O) - is the anion of (pyridin-2-yl)methanol. Based on solubility and crystallisation time differences between the two components of the mixture, complex 4 was isolated in pure form, i.e. free from 3. The formations of the counterion L + and the coordinated (py)(ph)CH(O) - anion represent clearly InBr 3 -promoted/assisted transformations. Reaction mechanisms have been proposed for the formation of 2, 3 and 4. Complex 4 could also be isolated by the reaction of InBr 3 and pre-formed (py)(ph)CH(OH) in EtOH. The solid-state structures of 1, 3 and 4 were determined by single-crystal X-ray crystallography, while the identity of the salt 2 was confirmed by microanalyses and a variety of spectroscopic techniques, including ESI-MS spectra. In the indium(III) complexes, the metal ions are 6-coordinate with a distorted octahedral geometry. The halogeno groups (Cl - , Br - ) in the three complexes are terminal. The (py)(ph)CO molecule behaves as a N,O-bidentate (1.11) ligand in 1 and 3. A terminal EtOH ligand completes the coordination sphere of In III in 1. The alkoxo oxygen atoms of the two 2.21 (py)(ph)CH(O) - ligands doubly bridge the In III centers in 4 creating a {InIII2(μ-OR) 2 } 4+ core; a nitrogen atom of one reduced organic ligand, two bromo ions and one terminal EtOH molecule complete the 6-coordination at each metal centre. Complexes 1, 3 and 4 were characterised by IR and Raman spectroscopies, and the data were discussed in terms of their known solid-state structures. Molar conductivity data and 1 H NMR spectra were used in an attempt to probe the behaviour of the complexes in DMSO. The to-date observed metal ion-assisted/promoted transformations of (py)(ph)CO are also discussed.

Fe 2 O 3 reduction to Fe with carbon requires a high temperature of 1200 °C in a blast furnace process. We have discovered a novel low-temperature reduction route from γ-phase Fe 2 O 3 to Fe with carbon. The reduction temperature was 430 °C, which is the lowest recorded up to now.

In this study, we studied the feasibility of preparing high-quality needle coke from coal liquefaction pitch. Nine types of blending pitch (coal liquefaction pitch and anthracene oil mixed with different ratios) were used as raw materials to generate needle coke via the co-carbonization method. Optical microscopy, X-ray diffraction, Raman spectroscopy and scanning electron microscopy were employed to determine the properties (microstructure, distribution of carbon microcrystals, true density and micro-strength) of the needle coke derived by the co-carbonization method. Actually, the co-carbonization of coal liquefaction pitch and anthracene oil was an essential method to control the micro-structure and property of the derived needle coke. Briefly, the needle coke derived by the co-carbonization of coal liquefaction pitch and anthracene oil had a lower content of mosaic structure of 14.17%, ideal carbon crystal content of 82.67%, and true density of 2.296 g cm -3 . Briefly, the addition of anthracene oil is a suitable method to adjust the property of coal liquefaction pitch, which is also a good method to produce high-quality needle coke via the co-carbonization of coal liquefaction pitch and anthracene oil. Thus, the use of coal liquefaction pitch and anthracene oil as raw materials to generate high-quality needle coke is a considerable method to realize the clean and high value-added utilization of coal liquefaction pitch., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (This journal is © The Royal Society of Chemistry.)

The development of photocatalysts with high activity and low cost is still a major challenge. Since its synthesis in 2019, C 3 N 5 has become an emerging photocatalytic material and has been widely studied. In this work, we report on the preparation of LaCoO 3 /C 3 N 5 nanosheets and the use of LaCoO 3 instead of precious metals to improve photocatalytic hydrogen production activity. First, LaCoO 3 was successfully prepared by the sol-gel method and then a series of high-efficiency Z-type LaCoO 3 /C 3 N 5 heterojunction photocatalysts were synthesized by the solvothermal method. Various characterization techniques (XRD, FT-IR, SEM, TEM, EDS, XPS, UV-Vis DRS, BET, ESR) confirmed the formation between LaCoO 3 nanoparticles and C 3 N 5 nanosheet heterostructures and interface interactions. In the photocatalytic water split test, 50 wt% LaCoO 3 /C 3 N 5 showed the highest photocatalytic activity of 956.11 μmol h -1 g -1 , which was 3.21 and 1.59 times that of LaCoO 3 and C 3 N 5 , respectively. This work not only designs an inexpensive and efficient LaCoO 3 /C 3 N 5 photocatalytic system for water splitting or other photocatalytic applications, but also provides ideas for constructing new material photocatalytic systems., Competing Interests: The authors listed in the manuscript have declared that they have no competing interests., (This journal is © The Royal Society of Chemistry.)

Particulate matter from biomass burning emissions affects air quality, ecosystems and climate; however, quantifying these effects requires that the connection between primary emissions and secondary aerosol production is firmly established. We performed atmospheric simulation chamber experiments on the chemical oxidation of residential biomass burning emissions under dark conditions. Biomass burning organic aerosol was found to age under dark conditions, with its oxygen-to-carbon ratio increasing by 7-34% and producing 1-38 μg m -3 of secondary organic aerosol (5-80% increase over the fresh organic aerosol) after 30 min of exposure to NO 3 radicals in the chamber (corresponding to 1-3 h of exposure to typical nighttime NO 3 radical concentrations in an urban environment). The average mass concentration of SOA formed under dark-oxidation conditions was comparable to the mass concentration formed after 3 h (equivalent to 7-10 h of ambient exposure) under ultraviolet lights (6 μg m -3 or a 47% increase over the emitted organic aerosol concentration). The dark-aging experiments showed a substantial increase in secondary nitrate aerosol (0.12-3.8 μg m -3 ), 46-100% of which is in the form of organic nitrates. The biomass burning aerosol pH remained practically constant at 2.8 throughout the experiment. This value promotes inorganic nitrate partitioning to the particulate phase, potentially contributing to the buildup of nitrate aerosol in the boundary layer and enhancing long-range transport. These results suggest that oxidation through reactions with the NO 3 radical is an additional secondary aerosol formation pathway in biomass burning emission plumes that should be accounted for in atmospheric chemical-transport models., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Besides the adjustment of the active centres, the precisely designed microstructures of the carbon hosts also play a significant role in improving the battery performance. Herein, MOF-derived Fe 3 O 4 @NCs were prepared through a molten salt-assisted calcination method at different carbonization temperatures. Compared with the materials obtained at 700 °C, LK450 calcined at a lower temperature of 450 °C maintains suitable pore sizes and more N-doping and exhibits excellent Li-ion transport performance. Thus, the S/LK450 cathode can achieve an outstanding rate performance of up to 5 C (∼528 mA h g -1 ) and an extremely low capacity decay of 0.037% per cycle after 500 cycles at 1C. Notably, even with a high sulfur loading (4.0 mg cm -2 ), the S/LK450 cathode can still deliver a high capacity of 673 mA h g -1 at 0.2C after 100 cycles. Briefly, this work demonstrates the superiorities to prepare the samples at relatively low carbonization temperatures, which guarantee a better ion path structure and sufficient N-doping in the carbon skeleton.

The practical realization of the scaling up of gas-solid multiphase flow reactors with chemical reactions is hindered by chaotic flow behaviors and complex heat and mass transfers in the reactor. In addition, a law to scale up complex reaction mechanisms in multiphase flow systems has been rarely proposed in the existing literature. Thus, this study aims to investigate the scaling up of the catalytic cracking fluidized bed downer reactor based on the similitude method of chemical reaction performance. Three downer reactor scales with a height of 5, 15, and 30 m, were investigated. To anticipate the behavior of reactive flow, a Eulerian-Eulerian CFD model, two-fluid model, was constructed, which was combined with the kinetic theory of granular flow. A four-lump kinetic model was chosen to represent the mechanism of the catalytic cracking reaction of heavy oil from the pyrolysis of waste plastic. The CFD model accurately predicted the species composition distribution. The scaling law based on the geometric similarity, kinematic similarity, and chemical reaction similarity, was proposed. The catalytic cracking performance similarity of the downer reactor was obtained. With variances in the range of 10% and mean relative absolute error less than 5%, the axial and lateral distributions of chemical performance (heavy oil conversion, gasoline mass fraction, and gasoline selectivity) were found to be extremely similar., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

In this study, porous electrospinning polyacrylonitrile nanofiber (PPAN) surface functionalization with amine groups is studied for methyl orange (MO) dye removal from aqueous solution. A series of adsorption experiments were carried out to investigate the influence of initial solution pH value, contact time, initial solution concentration, and adsorption temperature on the adsorption performance. The experimental results showed that the removal of MO on these PPAN-PEI and PPAN-TEPA nanofibrous mats was a pH-dependent process with the maximum adsorption capacity at the initial solution pH of 3, and that the PPAN-PEI and PPAN-TEPA nanofibrous mats could be regenerated successfully after 4 recycling processes. The adsorption equilibrium data were all fitted well to the Langmuir isotherm equation, with maximum adsorption capacity of 1414.52 mg g -1 and 1221.09 mg g -1 for PPAN-PEI and PPAN-TEPA, respectively. The kinetic study indicated that the adsorption of MO could be well fitted by the pseudo-second-order equation and Weber-Morris model. Thermodynamic parameters such as free energy, enthalpy, and entropy of adsorption of the MO were also evaluated, and the results showed that the adsorption was a spontaneous exothermic adsorption process., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The structural properties of the (WO x ) n phase dispersed on TiO 2 (P25, anatase) at surface densities of 0.5-4.5 W nm -2 ( i.e. up to approximately a monolayer) were explored by using in situ Raman and FTIR spectroscopy, in situ Raman/ 18 O exchange and Raman spectroscopy in static equilibrium at temperatures of 175-430 °C. Deciphering the temperature and coverage dependence of the spectral features under oxidative dehydration conditions showed that (i) the (WO x ) n dispersed phase is heterogeneous at 430 °C consisting of two distinct mono-oxo species: Species-I with C 3v -like OW(-O-) 3 configuration (WO mode at 1009-1014 cm -1 ) and Species-II with C 4v -like OW(-O-) 4 site is formed with first order of priority and its formation ceases after the complete consumption of the most basic hydroxyls that are titrated first, hence is abundant at low coverage (<1.5 W nm -1 ); (ii) the OW(-O-) 3 site is formed with first order of priority and its formation ceases after the complete consumption of the most basic hydroxyls that are titrated first, hence is abundant at low coverage (<1.5 W nm -2 ); (iii) the OW(-O-) 4 site prevails over the OW(-O-) 3 ; (iv) lowering the temperature in the 430 → 250 → 175 °C sequence does not affect the structural and vibrational properties of OW(-O-) -2 but leads to the gradual transformation of the OW(-O-) -2 ; (iv) lowering the temperature in the 430 → 250 → 175 °C sequence does not affect the structural and vibrational properties of OW(-O-) 3 but leads to the gradual transformation of the OW(-O-) 4 site to a di-oxo (O) 2 ) and the partial association of adjacent OW(-O-) 3 site (with a symmetric stretching mode at ∼985 cm -1 ) and the partial association of adjacent OW(-O-) 4 units. All temperature-dependent structural/configurational transformations are fully reversible in the 430-175 °C range and are interpreted at the molecular level by a mechanism involving water molecules retained at the surface that act in a reversible temperature-dependent mediative manner resulting in hydroxylation (upon cooling, e.g. 430 → 250 → 430 °C). One can tune the speciation of the dispersed (WO e.g. to 430 °C). The Raman spectra obtained for the hydroxyl region confirm the successive hydroxylation/dehydroxylation steps during temperature cycles ( e.g. phase under dehydrated conditions by appropriate control of temperature and coverage. x ) n phase under dehydrated conditions by appropriate control of temperature and coverage.

Severe fog events during winter months in India are a serious concern due to the higher incidence of road accidents, flight delays and increased occurrence of respiratory diseases. The present paper is an attempt to study the twenty fog samples collected from the rooftop of an academic building of Guru Nanak Dev University, Amritsar, India from November 2017 to January 2018. Fog samples were analysed for various parameters viz. pH, electrical conductivity (EC), chloride (Cl - ), nitrate (NO 3 - ) and sulphate (SO 4 2- ) levels. The pH, EC, and Cl - , NO 3 - and SO 4 2- levels in the fog samples were estimated as 6.3-7.9, 240-790 μS cm -1 , 108-2025 μeq L -1 molar ratio in the fog was estimated as 7.6 which suggests the burning of fossil fuel as the major pollutant from vehicular exhausts. Multiple regression analysis was performed to evaluate the effect of PM -1 and 822-5642 μeq L -1 ratio and relative humidity (RH) on visibility. A box-cox plot of power transformation produced better model fitting, employing a square root transformation of the visibility which indicated that the PM 4 2- to NO 3 - molar ratio in the fog was estimated as 7.6 which suggests the burning of fossil fuel as the major pollutant from vehicular exhausts. Multiple regression analysis was performed to evaluate the effect of PM 2.5 /PM 10 ratio and relative humidity (RH) on visibility. A box-cox plot of power transformation produced better model fitting, employing a square root transformation of the visibility which indicated that the PM 2.5 /PM 10 and RH have an exponential effect on visibility., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Designs and developments of proton conductors are highly important in chemistry and energy fields. In this study, a novel metal-organic framework H 2 DAB-MgNi(ox) 3 was synthesized. X-ray powder diffraction, scanning transmission electron microscopy, and scanning transmission electron microscopy-energy-dispersive X-ray mapping measurements demonstrated that the H 2 DAB-MgNi(ox) 3 had a solid-solution structure, with the homogeneous distribution of Mg and Ni elements. The proton conductivity of H 2 DAB-MgNi(ox) 3 was enhanced from that of H 2 DAB-Ni 2 (ox) 3 at 95% relative humidity by Mg substitution.

In this study, a simple, fast, one-pot approach for the isolation of nanowires (NWs) in coordination chemistry is reported. Nanowires (NWs) of spin-crossover (SCO) materials are extremely rare. Here, an innovative and easy synthetic process was developed to prepare NWs of a switchable polymorph of the known complex trans -[Fe(NCS) 2 (abpt) 2 ] using a wet-chemistry approach for the first time; abpt is the bidentate chelating ligand 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole. The remarkable smoothness of the high-spin to low-spin transition, monitored through variable-temperature (300-80 K) Raman microscopy, compared with the sharp transition exhibited by the polycrystalline material, demonstrates the effect of the topological properties on the physical phenomena of the system.

Biocompatible polymer coatings for magnetic nanoparticles have shown to drastically increase their usability towards biomedical applications. The coatings imprint characteristics such as stability, resistance to non-specific adsorption and tolerance in complex media for biomedicine. Herein, a thorough investigation towards the anionic ring-opening polymerization of glycidol on the surface of carbon-coated cobalt nanoparticle was performed. Reaction parameters that influence polymer growth have been investigated. Thereafter, a maximal achievable hyperbranched polyglycidol M of up to 1148 g mol w under optimal reaction conditions was obtained. With this coating, the dispersion stability of the particles could be substantially increased, the non-specific adsorption of proteins could be decreased to 10% while retaining an efficient magnetic separation.-1 under optimal reaction conditions was obtained. With this coating, the dispersion stability of the particles could be substantially increased, the non-specific adsorption of proteins could be decreased to 10% while retaining an efficient magnetic separation., Competing Interests: W. J. S. declares a financial interest as he is a shareholder of Turbobeads LLC, a company producing magnetic nanoparticles., (This journal is © The Royal Society of Chemistry.)

Nitrogen-doped reduced graphene oxide-supported palladium-cobalt nanoparticles (PdCo NPs/NrGO NSs) are synthesized and used as a high-performance and low-cost anodic catalyst for direct hydrazine-hydrogen peroxide fuel cells. The SEM and TEM images of PdCo NPs/NrGO NSs show the uniform metal nanoparticle distribution on the NrGO NSs. The reduction of the oxygen functional groups and the doping of the nitrogen atoms in the GO framework are confirmed by FT-IR and XRD spectroscopic studies. The Pd catalysts modified by Co exhibit a higher catalytic activity, lower onset potential, better durability, and lower impedance values than unmodified Pd catalysts for the electro-oxidation of hydrazine. The kinetic studies show a first-order reaction with an activation energy of 12.51 kJ mol -1 . A direct hydrazine-hydrogen peroxide fuel cell with PdCo NPs/NrGO NSs as anode and Pt/C as cathode provides an open circuit voltage of 1.76 V and a maximum power density of 148.58 mW cm -2 at 60 °C, indicating that the PdCo NPs/NrGO NSs are an economical, high performance and reliable anode catalyst for the direct hydrazine-hydrogen peroxide fuel cell., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

Copper selenide is widely considered to be a promising candidate for high-performance flexible thermoelectrics; however, most of the reported ZT values of copper selenides are unsatisfactory at a relatively low temperature range. Herein, we utilized some wet chemical methods to synthesize a series of copper selenides. XRD, SEM and TEM characterizations revealed that CuSe, Cu 3 Se 2 and Cu 2- x Se were prepared successfully and possessed different morphologies and sizes. Based on the analysis of their thermoelectric properties, Cu 2- x Se exhibited the highest Seebeck coefficient and lowest thermal conductivity among the three samples owing to its unique crystal structure. After being sintered at 400 °C under N 2 atmosphere, the electrical conductivity of Cu 2- x Se enhanced considerable, resulting in a significant improvement of its ZT values from 0.096 to 0.458 at 30 to 150 °C. This result is remarkable for copper selenide-based thermoelectric materials at a relatively low temperature range, indicating its brilliant potential in the field of flexible thermoelectric devices., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

The mechanical microenvironment of cells has been associated with phenotypic changes that cells undergo in three-dimensional spheroid culture formats. Radial asymmetry in mechanical stress - with compression in the core and tension at the periphery - has been analyzed by representing tissue spheroids as homogeneous visco-elastic droplets under surface tension. However, the influence of the granular microstructure of tissue spheroids in the distribution of mechanical stress in tissue spheroids has not been accounted for in a generic manner. Here, we quantify the distribution and propagation of mechanical forces in structurally heterogeneous multicellular assemblies. For this, we perform numerical simulations of a deformable cell model, which represents cells as elastic, contractile shells surrounding a liquid incompressible cytoplasm, interacting by means of non-specific adhesion. Using this model, we show how cell-scale properties such as cortical stiffness, active tension and cell-cell adhesive tension influence the distribution of mechanical stress in simulated tissue spheroids. Next, we characterize the transition at the tissue-scale from a homogeneous liquid droplet to a heterogeneous packed granular assembly.

Organometal halide perovskite (CH 3 NH 3 PbI 3 ) semiconductors have been promising candidates as a photoactive layer for photovoltaics. Especially for high performance devices, the crystal structure and morphology of this perovskite layer should be optimized. In this experiment, by employing solvent-antisolvent vapor techniques during a modified sequential deposition of PbI 2 -CH 3 NH 3 I layers, the morphology engineering was carried out as a function of antisolvent species such as: chloroform, chlorobenzene, dichlorobenzene, toluene, and diethyl ether. Then, the optical, morphological, structural, and surface properties were characterized. When dimethyl sulfoxide (DMSO, solvent) and diethyl ether (antisolvent) vapors were employed, the CH 3 NH 3 PbI 3 layer exhibited relatively desirable crystal structures and morphologies, resulting in an optical bandgap ( E ) of 1.61 eV, crystallite size ( g ) of 89.5 nm, and high photoluminescence (PL) intensity. Finally, the stability of perovskite films toward water was found to be dependent on the morphologies with defects such as grain boundaries, which was evaluated through contact angle measurement.t ) of 89.5 nm, and high photoluminescence (PL) intensity. Finally, the stability of perovskite films toward water was found to be dependent on the morphologies with defects such as grain boundaries, which was evaluated through contact angle measurement., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

A highly efficient pretreatment strategy using ethylene glycol with dilute sulfuric acid was developed for the fractionation of lignocellulose. The pretreatment behaviors were related to the composition analysis and structure of the samples analyzed by SEM, XRD, FTIR and 2D HSQC NMR, resulting in 80.3% delignification and 84.7% retention of cellulose under the selected conditions (120 °C, 60 min, and 0.6 wt% H 2 SO 4 (w/w)). The enzymatic hydrolysis sugar yield significantly increased from 24.1 to 70.6% (3 FPU g -1 ), which displayed immense improvement compared with untreated corn stover (24.1%), nearly 3-fold higher than its untreated counterparts. Besides, the regenerated lignin could be fitted to valorize renewable aromatic chemicals and alkane fuels. The present study shows that the pretreatment is a simple, efficient and promising process for corn stover biorefinery., Competing Interests: The authors declare that there are no conflicts interest., (This journal is © The Royal Society of Chemistry.)

Using solely highly hydrophilic particles to stabilize emulsions, especially high internal phase emulsions, has always been an important challenge. Here pH-responsive Pickering emulsions stabilized by a low concentration of bare highly hydrophilic Ludox CL nanoparticles without surface modification or addition of surfactants are developed at neutral pH. The dispersed nanoparticles can be transformed into an aggregate state with a network-like structure near the isoelectric point, which contributes to the stabilization of the emulsions. Moreover, the vdW attraction between particles and droplets also plays a key role in the formation of emulsions, which can make the aggregated nanoparticles adsorb tightly around the droplets rather than penetrate the oil-water interface. The formed protective armor and network-like aggregates separate droplets from each other to prevent coalescence. At a low nanoparticle concentration (0.5 wt%), a high internal phase emulsion can be formed and can last up to half a year. This system can emulsify not only the hydrocarbon oil but also the fluoroalkane oil phase. Finally, organic-inorganic composite particles are fabricated using the template action of the Pickering emulsions. The method of preparing composite particles is more convenient than the traditional Pickering emulsion polymerization which often requires the modification of the surface of the hydrophilic particles or the addition of auxiliary monomers. This study provides a simple green strategy for the preparation of a more stable Pickering emulsion stabilized by surface-inactive nanoparticles and will broaden the scope of applications.

In addition to previously studied {CuGd 6 }, {CuGd 4 }, {CuLn 7 } and {CuLn 8 } coordination clusters (Ln = trivalent lanthanide) containing pdm 2- or Hpdm - ligands (H 2 pdm = pyridine-2,6-dimethanol) and ancillary carboxylate groups (RCO 2 ), the present work reports the synthesis and study of three new members of a fifth family of such complexes. Compounds [Cu - ), the present work reports the synthesis and study of three new members of a fifth family of such complexes. Compounds [Cu 5 Ln 4 O 2 (OMe) 4 (NO 3 ) 4 (O 2 CCH 2 Bu t ) 2 (pdm) 4 ] (Ln = Dy, 1; Ln = Tb, 2; Ln = Ho, 3) were prepared from the reaction of Ln(NO 2 ] (Ln = Dy, 1; Ln = Tb, 2; Ln = Ho, 3) were prepared from the reaction of Ln(NO 3 ) 3 ·xH 2 O (x = 5, 6), CuX 2 ·yH 2 O (X = ClO 4 , Cl, NO 3 ; y = 6, 2 and 3, respectively), H 2 pdm, Bu t CH 2 CO 2 H and Et 3 N (2 : 2.5 : 2 : 1 : 9) in MeCN/MeOH. Rather surprisingly, the copper(ii)/yttrium(iii) analogue has a slightly different composition, i.e. [Cu 5 Y 4 O 2 (OMe) 4 (NO 3 ) 2 (O 2 CCH 2 Bu t ) 4 (pdm) 4 ] (4). The structures of 1·4MeCN·1.5MeOH and 4·2MeOH were solved by single-crystal X-ray crystallography. The five Cu 2 ] (4). The structures of 1·4MeCN·1.5MeOH and 4·2MeOH were solved by single-crystal X-ray crystallography. The five Cu II and four Dy III centres in 1 are held together by two μ 5 -O 2- , four μ-MeO - , two syn,synη 1 :η 1 :μ Bu t CH 2 CO 2 - , four η 2 :η 1 :η 2 (each of these groups chelates a Cu 3 pdm 2- (each of these groups chelates a Cu II atom and simultaneously bridges two Dy III atoms through its two -CH 2 O - arms) and two μ-MeOH ligands. The four terminal nitrato groups each chelate (η 1 :η 1 ) a Dy III atoms form a rectangle with edges of 3.061(1) and 6.076(1) Å. The four Dy II centres also form a rectangle that lies above and below the plane of the Cu II centres, with edges of 3.739(1) and 5.328(1) Å. The two strictly planar rectangles are almost perpendicular. Two trigonal bipyramidal μ III centres also form a rectangle that lies above and below the plane of the Cu II centres, with edges of 3.739(1) and 5.328(1) Å. The two strictly planar rectangles are almost perpendicular. Two trigonal bipyramidal μ 5 -O 2- frameworks together. The molecule 4 has a very similar structure to that of 1, differences being the replacement of the two chelating nitrato groups of 1 by two chelating Bu 5 and Dy 4 frameworks together. The molecule 4 has a very similar structure to that of 1, differences being the replacement of the two chelating nitrato groups of 1 by two chelating Bu t ligands in 4 and the coordination polyhedra of the Ln 2 CO 2 - ) on analytically pure samples of 1-3, collected in the 300-2 K range, indicate that ferromagnetic exchange interactions dominate leading to large spin ground states. The χ III and Y III atoms (Snub diphenoids in 1 and biaugmented trigonal prisms in 4). Dc magnetic susceptibility data (χ M exchange interactions. Studies of the dynamic magnetic properties of the {Cu M T vs. T data for 4 suggest moderately strong antiferromagnetic Cu II Cu II exchange interactions. Studies of the dynamic magnetic properties of the {Cu 5 Ln 4 } clusters show that 1 behaves as a SMM at zero field and 2 is a very weak field-induced SMM, while 3 exhibits only weak tails in the χ'' M vs. T plots at various ac frequencies at zero dc field.

The objective of this study is to analyze the effects of zirconium (Zr) and silver (Ag) doping on the photoactivity of titania (TiO 2 ). Zr-Ag (ZA) co-doped TiO 2 products were fabricated via sol-gel technique and their properties (structural and chemical) were characterized. The weight ratio of TiO 2 was fixed, while weight ratios of Zr and Ag were varied from 2 to 4, 6 and 8 wt% while synthesized samples were calcined at 400 °C for 3 h. The XRD results demonstrated that the incorporation of metal doping agents failed to alter the host material's lattice structure, however, its crystallite size was reduced from 13.54 to 5.05 nm with increasing Zr 4+ and Ag + concentrations. FTIR spectroscopy was used to examine various functional groups. In the attained spectra, an ample absorption peak between 500 and 1000 cm -1 was recorded, which was ascribed to Ti-O-Ti linkage vibration mode present within TiO 2 . Surface morphology, microstructure, SAED patterns and elemental composition were examined with FE-SEM, HR-TEM and EDX, which served to confirm the ZA-doped TiO 2 product. Band gap energy of the co-doped material was significantly reduced as indicated by a higher wavelength redshift in the spectra. The photoactivity and kinetics of photo-products were investigated by observing photo-decolorization of methylene blue (MB) under a radiation source. Photodecomposition of MB was dramatically enhanced when titania co-doped with Zr and Ag was employed compared to un-doped or mono-doped TiO 2 . The ZA (8 wt%) co-doped TiO 2 photocatalyst depicted the maximum MB removal efficiency (∼93%) within 90 min under a light source., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

Sustainable agroindustry has presented many challenges related to waste management. Most of its residues are lignocellulosic biomass materials with great application potential due to their chemical composition, hence the use of biomass-derived carbon materials in energy storage has received growing interest in recent years. In this work, highly micro-porous carbonaceous materials using the endocarp of the coffee fruit or coffee husk (CH) as precursor are obtained. Specifically, three different activating agents (KOH, K 2 CO 3 , and steam) to derive activated carbons (ACs) with good capacitive properties are tested. The properties of ACs such as surface chemistry, texture, crystal graphite size, and order in the carbonaceous structure are assessed and compared. The capacitive behavior inherent to the activation routes is also characterized by means of Cyclic Voltammetry (CV), Galvanostatic Charge/Discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS). The obtained specific capacitance values range from 106 to 138 F g -1 for a discharge current of 0.5 A g -1 . These results nominate coffee husk as a good precursor of carbonaceous materials suitable for energy storage., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Peptide-based molecules hold great potential as targeted inhibitors of intracellular protein-protein interactions (PPIs). Indeed, the vast diversity of chemical space conferred through their primary, secondary and tertiary structures allows these molecules to be applied to targets that are typically deemed intractable via small molecules. However, the development of peptide therapeutics has been hindered by their limited conformational stability, proteolytic sensitivity and cell permeability. Several contemporary peptide design strategies are aimed at addressing these issues. Strategic macrocyclization through optimally placed chemical braces such as olefinic hydrocarbon crosslinks, commonly referred to as staples, may improve peptide properties by (i) restricting conformational freedom to improve target affinities, (ii) improving proteolytic resistance, and (iii) enhancing cell permeability. As a second strategy, molecules constructed entirely from d-amino acids are hyper-resistant to proteolytic cleavage, but generally lack conformational stability and membrane permeability. Since neither approach is a complete solution, we have combined these strategies to identify the first examples of all-d α-helical stapled and stitched peptides. As a template, we used a recently reported all d-linear peptide that is a potent inhibitor of the p53-Mdm2 interaction, but is devoid of cellular activity. To design both stapled and stitched all-d-peptide analogues, we used computational modelling to predict optimal staple placement. The resultant novel macrocyclic all d-peptide was determined to exhibit increased α-helicity, improved target binding, complete proteolytic stability and, most notably, cellular activity., (This journal is © The Royal Society of Chemistry 2020.)