ÁñÁ«³ÉÈËappÏÂÔØ

Porous carbons are ideal contenders for supercapacitor electrodes; however, challenges in creating a high surface area in conjunction with controlled surface functionalization still exist. Herein, a low cost and green route for the synthesis of nitrogen and sulfur codoped nanoporous biocarbons using casein and dithiooxamide with high specific surface areas is reported. The textural properties are tuned by varying the synthesis temperature, wherein the nitrogen-doped porous carbon (N-PC) shows a high surface area (2132 m2 g-1) and ample microporosity (>90%). The N and S codoped porous carbons shows considerable surface areas (2068¿1944 m2 g-1). N-PC displays a specific capacitance of 149 F g-1 at a current density of 0.5 A g-1 in a three-electrode system. Interestingly, N and S codoped material N,S-PC500 shows an uplift of ¿20% (178 F g-1) in the specific capacitance. The synergetic effect of S and N heteroatoms enhances the specific capacitance due to the provision of additional electrochemical active sites and enhances conductivity. N,S-PC500 also reveals a capacity retention of 93.2% after 3000 cycles at a current density of 5 A g-1. Overall, N and S codoping in porous carbon prove to be a facile ploy to enhance the specific capacitance of materials.

Transition metal carbides, known as MXenes, particularly Ti3C2Tx, have been extensively explored as promising materials for electrochemical reactions. However, transition metal carbonitride MXenes with high nitrogen content for electrochemical reactions are rarely reported. In this work, transition metal carbonitride MXenes incorporated with Pt-based electrocatalysts, ranging from single atoms to sub-nanometer dimensions, are explored for hydrogen evolution reaction (HER). The fabricated Pt clusters/MXene catalyst exhibits superior HER performance compared to the single-atom-incorporated MXene and commercial Pt/C catalyst in both acidic and alkaline electrolytes. The optimized sample shows low overpotentials of 28, 65, and 154¿mV at a current densities of 10, 100, and 500¿mA¿cm-2, a small Tafel slope of 29¿mV dec-1, a high mass activity of 1203¿mA mgPt-1 and an excellent turnover frequency of 6.1¿s-1 in the acidic electrolyte. Density functional theory calculations indicate that this high performance can be attributed to the enhanced active sites, increased surface functional groups, faster charge transfer dynamics, and stronger electronic interaction between Pt and MXene, resulting in optimized hydrogen absorption/desorption toward better HER. This work demonstrates that MXenes with a high content of nitrogen may be promising candidates for various catalytic reactions by incorporating single atoms or clusters. (Figure presented.).

Single-atom metal catalysts (SACs) hold immense promise for catalytic applications, yet their potential as volatile organic compound (VOC) sensing materials remains largely untapped. Here, we report a facile approach to produce Cu single-atom (Cu-SA) embedded mesoporous carbon nitride (mCN) hybrid material for precise and selective detection of VOCs. The study highlights the exceptional sensing capabilities of Cu-SA-mCN, focusing on its remarkable selectivity for aliphatic esters, acids, and water molecules. Explicitly, the material demonstrates an exciting adsorption capacity of 109.4¿mmol¿g-1 for acetic acid, showcasing its superior performance, which is three times higher than mesoporous carbon nitride without Cu single atoms. The high selectivity and sensitivity of Cu-SA-mCN are attributed to the mesoporous nature, abundant nitrogen moieties, and Cu-SAs present within the material. Density functional theory (DFT) calculation results demonstrate a strong charge transfer between Cu-SA-mCN and adsorbate molecules, contributing to the material's excellent sensing properties. This work opens new avenues in the development of mCN materials embedded with single metal atoms, enriching the field of VOC sensors with stable, accurate, and cost-effective solutions with potential applications in environmental monitoring and industrial safety. Graphical Abstract: (Figure presented.)

Metal-free nitrides (MFNs) including carbon nitride (CN), boron nitride (BN), and borocarbonitride (BCN), have shown immense potential as single metal atom catalysts (SACs). They can act as excellent host support for anchoring and stabilizing single metal atoms. However, critical challenges related to the precise loading of single metal atoms and their accurate characterization are still being pursued. The current review explores the various aspects of MFNs-SACs. Synthesis methods including carbonization, self-assembly, microwave, ball milling and atomic layer deposition are discussed. Characterisation using X-ray absorption, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), Wavelet transform extended X-ray absorption fine structure (WT-EXAFS), and scanning transmission electron microscopy (STEM) which are useful to explore atomic-level structure and coordination of the MFNs-SACs are discussed in depth. The theoretical understanding of the structural framework of the MFNs-SACs using the packages including Vienna ab initio simulation (VASP), projector-augmented wave (PAW), Perdew-Burke Ernzerhof (PBE) and spin-polarized DFT is discussed in detail. A comprehensive discussion of electrocatalytic and photocatalytic applications of MFNs-SACs is evaluated. In the end, conclusions and future outlooks are provided with a focus on what is already achieved and what further can be achieved in the field by utilizing advanced scientific research and knowledge.

In this work, the synthesis of core-shell ordered mesoporous silica nanoparticles (CSMS) with tunable particle size and shape through a dual surfactant-assisted approach is demonstrated. By varying the synthesis conditions, including the type of the solvent and the concentration of the surfactant, monodispersed and ordered mesoporous silica nanoparticles with tunable particle size (140¿600¿nm) and morphologies (hexagonal prism (HP), oblong, spherical, and hollow-core) can be realized. Comparative studies of the Cabazitaxel (CBZ)-loaded HP and spherical-shaped CSMS are conducted to evaluate their drug delivery efficiency to PC3 (prostate cancer) cell lines. These nanoparticles showed good biocompatibility and displayed a faster drug release at acidic pH than at basic pH. The cellular uptake of CSMS measured using confocal microscopy, flow cytometry, microplate reader, and ICP-MS (inductively coupled plasma mass spectrometry) techniques in PC3 cell lines revealed a better uptake of CSMS with HP morphology than its spherical counterparts. Cytotoxicity study showed that the anticancer activity of CBZ is improved with a higher free radical production when loaded onto CSMS. These unique materials with tunable morphology can serve as an excellent drug delivery system and will have potential applications for treating various cancers.

The demands of the information era, driven by cloud computing and big data, necessitate high-density storage systems. In magnetic recording media, reducing bit size is crucial for significantly increasing areal density. Consequently, using single atoms as recording bits offers the potential to achieve unprecedented areal densities. However, achieving ferromagnetism in single atoms typically requires very low temperatures, and synthesizing large areas of single atoms for recording media remains a significant challenge. In this study, a straightforward mixing and stirring method was employed to intercalate a large number of Ni single-atoms into MoS2 nanosheets. Remarkably, room-temperature ferromagnetism was observed in all samples. Specifically, the 2% Ni-doped MoS2 exhibited a magnetic moment of 0.53 µB, which is close to the theoretical value. The magnetization depends on the bonding between nickel and sulfur atoms. In 2% Ni-doped MoS2, nickel prefers to form Ni-S bonds, while at higher doping concentrations, S-Ni-S bonding is more prevalent, leading to antiferromagnetic coupling. The observed ferromagnetism in these higher-concentration-doped samples may be attributed to strain in the nanosheets induced by nickel intercalation or nanostructured NiS particles.

Beudantite, an As-Pb containing Fe(III) sulfate secondary mineral, is formed via the oxidation of sulfide-rich tailings in mining-impacted regions. The geochemical stability of beudantite plays a key role in controlling the cycling and transport of As and Pb in mine sites. However, the fate of beudantite under dynamic pH conditions and its effect on As and Pb mobility remain elusive. We investigated the mobility dynamics of As and Pb during the dissolution of beudantite under variable pH conditions (2-8) relevant to mine sites by using a complementary suite of analytical methods. Results demonstrate that under acidic pH conditions, aqueous As and Pb content increased slightly, with just 0.7 % and 6.7 % of As and Pb partitioned from the beudantite crystal structure over 56 days. Notably, the rate at which the dissolution of beudantite led to solubilization of elements followed the order Fe > As > Pb within the first 2 h of dissolution. In contrast, the order shifted to Pb > Fe > As after 2 h. Arsenic K-edge X-ray absorption spectroscopy analyses revealed no shifts in As speciation or secondary mineralogical transformation. Here, we show for the first time that beudantite could be considered a relatively stable mineral host for As and Pb over a broad spectrum of environmental conditions. Beudantite can be expected to immobilise metals liberated by the primary weathering of sulfide-rich mine wastes, thereby lowering the risk to the environment and human health resulting from their discharge into the surrounding environment and aquifer.

Hybrid ion capacitors (HICs) have aroused extreme interest due to their combined characteristics of energy and power densities. The performance of HICs lies hidden in the electrode materials used for the construction of battery and supercapacitor components. The hunt is always on to locate the best material in terms of cost-effectiveness and overall optimized performance characteristics. Functionalized biomass-derived porous carbons (FBPCs) possess exquisite features including easy synthesis, wide availability, high surface area, large pore volume, tunable pore size, surface functional groups, a wide range of morphologies, and high thermal and chemical stability. FBPCs have found immense use as cathode, anode and dual electrode materials for HICs in the recent literature. The current review is designed around two main concepts which include the synthesis and properties of FBPCs followed by their utilization in various types of HICs. Among monovalent HICs, lithium, sodium, and potassium, are given comprehensive attention, whereas zinc is the only multivalent HIC that is focused upon due to corresponding literature availability. Special attention is also provided to the critical factors that govern the performance of HICs. The review concludes by providing feasible directions for future research in various aspects of FBPCs and their utilization in HICs.

Copper iodide (CuI) is a promising p-type transparent thermoelectric material for near-room temperature energy harvesting. We report a high-power factor for selenium (Se)-doped CuI films. Ion beam-sputtered CuI films were doped using 30 keV 80Se+ implantation with Se concentration varying between 0.50% and 6.50%. Hall effect measurements showed a ~34% increase in electrical conductivity (s ¿ 36.1 O-1cm-1) due to a ~54% increase in carrier density (pH ¿ 5.4 × 1019 cm-3) in the p-type ¿-CuI film implanted with 5.0 × 1014 Se.cm-2. A high Seebeck coefficient, a ¿ 388.9 µVK-1-1, and moderate electrical conductivity, s ¿ 29.1 O-1cm-1, yield a nearly 85% increase in the power factor, a2s ¿ 439.7 µWm-1K-2, for a 1.0 × 1015 Se.cm-2 implanted film compared to the unimplanted film (a2s ¿ 236.4 µWm-1K-2). Monte Carlo simulation and ab initio density functional theory calculations revealed that the increased displacement per atom values and the {SeI-VCu} defect complex-induced shallow acceptor could be attributed to the observed increase in hole density. Our results highlight that native defects and defect complexes are beneficial for enhancing the power factor in transparent CuI for thermoelectric applications.

The careful selection of carbon precursors for chemical activation is critical in obtaining cost-effective and efficient porous activated biocarbons with multifunctional properties. Herein, we report on utilising almond skin to synthesize porous activated biocarbons via solid-state KOH activation. Through precise manipulation of the impregnation ratio of KOH to the non-porous carbon, a range of materials with intriguing properties including high surface area, large pore volume, tunable micro and mesopores, and surface functionalization with oxygen were synthesized. The optimized material ASPC5-4 displayed an extremely high surface area (3535 m2 g-1), a large pore volume (1.9 cm3 g-1), a high proportion of mesopores (96.5 %) and a notable surface oxygen content (6.93 wt %). These excellent features allowed ASPC5-4 to adsorb a record amount of CO2 at 0 °C/30 bar (39.81 mmol g-1). Another material ASPC5-2 exhibited a high content of micropores and adsorbed 5.92 mmol g-1 of CO2 at 0 °C/1 bar. ASPC5-4 also exhibited great potential as a supercapacitor electrode, displaying a high specific capacitance in both a three-electrode (354 F g-1/0.5 A g-1) and two-electrode (203 F g-1/0.5 A g-1) systems. It also demonstrated high power and energy densities of 638 W kg-1 and 47 W h kg-1, respectively.

Magnetic 2D-layered materials are promising for the applications of spintronic devices and compact magnetic devices. There are only a few reported intrinsic 2D-based magnetic materials. Therefore, introducing magnetic element into 2D-layered materials is an effective strategy to synthesize 2D-layered magnetic materials. Recently, ferromagnetism has been realized by doping single transition-metal or rare-earth element, whereas, there is no report by codoping of both transition-metal and rare-earth elements. Herein, Co and Nd are codoped into MoS2-layered crystals by ion implantation. An extremely high magnetization of 6916.3 emu cm-3 at 10 K and 80.3 emu cm-3 at 300 K is achieved. The high magnetization is attributed to the contribution from both transition-metal and rare-earth elements as well as defects, such as vacancy of cation ions, anions, or interstitials. Hence, herein, a useful strategy may be opened to develop high-performance magnetic materials based on 2D-layered materials.

Thin film epitaxy is essential for state-of-the-art semiconductor applications. The combination of different substrates and deposition methods leads to various crystallographic orientation relationships between thin films and substrates, which have a decisive impact on thin film performance. By utilizing pulsed laser deposition, we discovered a very high-index (7 1 ¯ 4) ¿oriented NiO thin film when deposited on r-plane (10 1 ¯ 2) sapphire substrates. The in-plane epitaxial relations are [13 1 ¯] NiO||[1 2 ¯ 10] Sapphire and [1 ¯ 12] NiO||[10 11 ¯] Sapphire , and the lattice mismatch is 3.2% and 0.4% along two directions, respectively. Exchange bias studies by the deposition of Co on NiO (111) and NiO (7 1 ¯ 4) show different behaviors, which may be associated with the spin density and alignment on the surface. Graphical abstract: [Figure not available: see fulltext.].

Catalytic hydrogen combustion (CHC) is a promising technology for clean, efficient, and safe energy generation in hydrogen-fueled systems such as fuel cells and passive autocatalytic recombination. This study investigates catalytic hydrogen combustion over the Pd-Cu/Al2O3 catalysts at low temperatures (<125 °C) to determine the rate law using a differential fixed-bed reactor. The particle size distribution and reducibility of the catalysts were studied to investigate the influence of the catalyst composition on its reactivity. Higher reduction temperatures promoted the formation of metallic Pd, leading to improved catalytic reactivity at the optimized composition of Pd0.75Cu0.25/Al2O3. Furthermore, the rate law of CHC over the optimized catalyst was determined by non-linear regression based on the experimental reaction rates obtained under different partial pressures of H2 and O2. The Langmuir-Hinshelwood single-site mechanism was found to provide the best description of the catalytic combustion of hydrogen at low temperatures.

We report on the catalytic activity of ordered mesoporous aluminosilicate, AlSBA-1 with 3D cage type porous structure, in the isopropylation of naphthalene (NP). The higher isopropylates: triisopropylnaphthalene (TriIPN) and tetraisopropylnaphthalene (TetIPN) isomers were formed over AlSBA-1 in addition to isopropylnaphthalene (IPN) and diisoprpylnaphthalene (DIPN) isomers. The higher isopropylates were started to form at 225 °C as primary products, which were produced by multi-step isopropylation from NP occurred during one stay on the catalytic site cooperated with the propene adsorbed neighbor acid sites. TriIPN isomers were composed of four isomers (1,3,7-. 1,3,5-, 1,3,6-, and 1,4,6-) formed from DIPN isomers. These formations of TriIPN isomers are controlled by the distribution of DIPN isomers. ß,ß-DIPN isomers lead to a,ß,ß-TriIPN isomers, and a,a-DIPN to a,a,ß-TriIPN, respectively. However, a,ß-DIPN isomers give both of a,a,ß- and a,ß,ß-TriIPN isomers depending on the reaction conditions. The distribution of TriIPN isomers is operated by their kinetic and thermodynamic properties. Bulky and unstable a,a,ß-TriIPN isomers (1,3,5- and 1,4,6-) were predominant at low temperatures, 175¿250 °C, and at low NP/Cat ratio at 250 °C, where the catalysis mainly proceeded under kinetic control. However, the formation of slim and stable a,ß,ß-TriIPN isomers (1,3,7- and 1,3,6-) increased with raising the temperatures, and was primary at 300 °C, where the catalysis occurred under thermodynamic control. From these results, it is concluded that the isopropylation of NP over AlSBA-1 occurs under kinetic and/or thermodynamically controls based on the reactivity of the reactants and the stability of the products, and no steric control concerns by mesopores.

Biomass-derived nanoporous carbons (BNCs) are attractive materials for CO2 capture and energy storage due to their unique surface properties and the availability of low-cost and abundant supply of carbon sources. However, the order of the carbon atoms, the nature of the porosity and surface functional groups are critical in dictating the performance of BNCs for such applications. Herein, a solid-phase activation strategy is introduced to prepare O-functionalized BNCs with embedded graphene-like structures using D(+)-glucose as a precursor. The optimised material shows a high surface area (3572 m2 g-1), and surface oxygenated functional groups, which lead to a high CO2 adsorption of 5.28 mmol g-1 at 1 bar and 31.5 mmol g-1 at 30 bar at 0 °C. Moreover, as an electrode material, the optimised sample exhibits an impressive specific capacitance (Cs) of 305 F g-1 at 0.5 A g-1 and 207 F g-1 at 10 A g-1 in a three-electrode supercapacitor. It also shows high specific capacitance (250 F g-1 at 0.5 A g-1), a high energy density (58 Wh/kg), and stable cyclic performance in a two-symmetric electrode system. The presented materials and their application performance results are promising and could pave the way for the development of more sophisticated materials for CO2 capture, energy storage and beyond.

Starting from sterically encumbered 2,6-di-tert-butylphenyl phosphate (dtbppH2) and co-ligand 3,5-dimethyl pyrazole (dmpz), it is possible to isolate either mono-, di- or tetranuclear copper phosphates by varying the copper source and making attendant changes in the reaction conditions. For example, reaction of copper nitrate with dtbppH2 and dmpz at 60 °C leads to the isolation of the mononuclear copper phosphate [Cu(dtbppH)2(dmpz)(MeOH)2] (1) as the only product. However, the use of copper acetate in place of copper nitrate and conducting the reaction at the room temperature leads to the formation of both dinuclear [Cu(dtbpp)(dmpz)2]2 (2) and tetranuclear [Cu2(dtbpp)(dmpz)2(OAc)(MeO)]2 (3) from the same reaction mixture. Compounds 2 and 3 could be isolated in pure form through fractional crystallization. Copper phosphates 1¿3 have been characterized by both analytical and spectroscopic methods including EPR and magnetic measurements. The molecular structures of all three compounds were established through single crystal diffraction studies. Dc magnetic measurements indicate antiferromagnetic interactions between the metal centres in all the compounds.

We report an integrated approach by combining in-situ activation, doping and natural nanotemplating to design low-cost and highly efficient N-doped nanoporous carbons for energy storage and carbon capture applications. N-doped nanoporous carbons are prepared by impregnating sucrose, 3-amino 1,2,4-triazole and the ZnCl2 into the nanochannels of the mixed kaolin-halloysite nanotube nanoclay, followed by carbonization and clay template removal. The prepared materials exhibit micro and mesoporosity, high specific surface areas (1360¿1695 m2 g-1), and nitrogen content (7.73¿12.34 wt%). The optimized material offers the specific capacitance of 299 F g-1 (0.3 A g-1) and 134 F g-1 (10 A g-1) with excellent cycling stability (91% capacity retention after 4000 cycles/5 A g-1). N-doping together with the interconnected micro and mesoporous structure, offers a more ion accessible surface and further provides enhanced charge transfer, hydrophilicity, and the interaction of the electrode-electrolyte ions. The optimized material adsorbs 24.4 mmol g-1 of CO2 at 30 bar pressure and 0 °C. The synthesized materials performed better as supercapacitor and CO2 adsorbent than halloysite clay, kaolin clay, activated carbon, nanoporous carbons, and mesoporous silica. The method presented here will provide a unique platform for synthesizing a series of advanced nanostructures for electrochemical and carbon capture applications.

In this paper, biocomposites were prepared with carrageenan/fish scale/allopurinol collagen by solution method. Carrageenan fish scale collagen and allopurinol were used at different ratio and the effect of varying the component ratio was investigated by studying the shape, morphology, thermal behavior, and drug release ability of the biocomposites. By varying the carrageenan/collagen ratio, the shape of the biocomposites can be modified. When high amount of carrageenan was used, biocomposites were obtained in film whereas higher content of collagen produced powder form of biocomposites. The characteristics of the biocomposites were studied by Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction Analysis (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Thermal Gravimetric Analysis (TGA), and Differential Scanning Calorimetric (DSC) techniques. The drug (allopurinol) release ability of the biocomposites was evaluated with Ultraviolet¿Visible Spectroscopy (UV¿Vis). Biocomposites in the powder form are different from the biocomposites in the film form by having different shape, morphology, thermal behavior, and drug release ability. However, both are sensitive to pH of solution in drug release process. In addition, the cell toxicity of allopurinol and these biocomposites was evaluated with Vero cells by MTT method. The obtained results confirmed that the biocomposite materials in film shape are promising for the application in biomedicine.

How particular bonds form in quantum materials has been a long-standing puzzle. Two key concepts dealing with charge degrees of freedom are dimerization (forming metal-metal bonds) and charge ordering. Since the 1930s, these two concepts have been frequently invoked to explain numerous exciting quantum materials, typically insulators. Here we report dimerization and charge ordering within the dimers coexisting in metallic NaRu2O4. By combining high-resolution x-ray diffraction studies and theoretical calculations, we demonstrate that this unique phenomenon occurs through a new type of bonding, which we call Z-type ordering. The low-temperature superstructure has strong dimerization in legs of zigzag ladders, with short dimers in legs connected by short zigzag bonds, forming Z-shape clusters: simultaneously, site-centered charge ordering also appears. Our results demonstrate the yet unknown flexibility of quantum materials with the intricate interplay among orbital, charge, and lattice degrees of freedom.

We demonstrate a synthesis of copper nanoparticles decorated over nitrogen-doped mesoporous carbon with different N and Cu contents which exhibit conducting, redox, basic, adsorption, and excellent textural properties. These materials are prepared through a nanotemplating approach by simultaneously encapsulating sucrose, guanidine hydrochloride, and Cu(NO3)2 into the porous channels of mesoporous SBA-15 at a low carbonization temperature of 600 °C. The prepared materials exhibit an ordered mesoporous carbon framework with bimodal pores, decorated with nitrogen and Cu functionalities on the surface of the pores and in the wall structure. The presence of nitrogen functionalities in the porous carbon matrix not only helps to reduce the Cu ions but also stabilizes the nanoparticles and offers redox sites, which are beneficial for adsorption and electrochemical applications. The optimized sample exhibits the highest adsorption capacity of different gases such as CO2 ¿ 22.5 mmol/g at 273 K, H2 -13.5 mmol/g at 77 K at 30 bar and CH4 - 5 mmol/g at 298 K and 50 bar. We also demonstrate that the prepared material shows a high selectivity of adsorption towards CO2 in a mixture of CO2/H2 and CO2/CH4 and it also registers a high supercapacitance of 209 F g-1 at a current density of 1 A g-1 with excellent cyclic stability.

In order to overcome the current energy and environment crisis caused by fossil fuels depletion and greenhouse gas emission, it is indispensable to introduce new, eco-friendly, high-performance materials into energy conversion and storage applications. 2D transition metal oxides (TMOs) are regarded as the promising candidates due to their excellent electrochemical properties. However, their innate poor electronic conductivity greatly restricts their applications in energy conversion and storage. This review discusses and summarizes the developed strategies to overcome the limitation through surface modification including defect engineering, heteroatom incorporation and interlayer doping, as well as hybridization with conductive materials. In addition, a detailed summary of their synthesis and applications in supercapacitors, lithium ion batteries and electrocatalysis is included. Finally, future prospective such as opportunities and challenges is discussed for the successful implementation of 2D TMOs in the field of energy applications.

The isopropylation of naphthalene (NP) was carried out over a BEA zeolite (BEA38; SiO2/Al2O3 = 38) focused on the selectivities for diisopropylnaphthalene (DIPN) and triisopropylnaphthalene (TriIPN) isomers. The isopropylation gave possible eight DIPN isomers including ß,ß- (2,6- and 2,7-), a,ß- (1,3-, 1,6-, and 1,7-), and a,a- (1,4- and 1,5-). The catalysis over BEA works two types of controls: kinetic control operates to form predominantly bulky and unstable a,a-DIPN at low temperatures, and thermodynamic controls work for the predominant formation of the slim and stable ß,ß-DIPN at high temperatures, although the intermediately bulky and stable a,ß-DIPN are the major products through both controls. The enhanced selectivities for ß,ß-DIPN were observed at the early stages of the catalysis in the range of 200-300 °C, which operate under new type of thermodynamic control over fresh catalyst through thermodynamically preferred transition states; however, they decreased with the increase in the selectivities for a,a- and a,ß-DIPN, and converged after prolonged reaction period. The isopropylation of DIPN isomers gives TriIPN isomers: unstable and bulky 1,3,5- and 1,4,6-TriIPN with a,a,ß-substitution, and stable and slim 1,3,7- and 1,3,6-TriIPN with a,ß,ß-substitution. The low temperatures favor the former isomers, whereas the selectivity for the latter isomers increases with increasing reaction temperature. These results indicate that TriIPN isomers principally form under kinetic control at low temperatures, and thermodynamic controls participate in the catalysis at high temperatures. The selectivities for TriIPN isomers kept constant during the reaction at all temperatures: 200, 250, and 300 °C. The catalysis occurs inside the BEA channels and allow even the formation of bulky 1,3,5- and 1,4,6-TriIPN; however, all isomers cannot be isomerized to the others in the channels and on the external surfaces. Severe coke-deposition occurred during the catalysis, particularly in the early stages; however, the catalyst is recovered by the calcination with a small change in catalytic activity.

We investigated the CO2 adsorption and electrochemical conversion behavior of triazole-based C3N5 nanorods as a single matrix for consecutive CO2 capture and conversion. The pore size, basicity, and binding energy were tailored to identify critical factors for consecutive CO2 capture and conversion over carbon nitrides. Temperature-programmed desorption (TPD) analysis of CO2 demonstrates that triazole-based C3N5 shows higher basicity and stronger CO2 binding energy than g-C3N4. Triazole-based C3N5 nanorods with 6.1 nm mesopore channels exhibit better CO2 adsorption than nanorods with 3.5 and 5.4 nm mesopore channels. C3N5 nanorods with wider mesopore channels are effective in increasing the current density as an electrocatalyst during the CO2 reduction reaction. Triazole-based C3N5 nanorods with tailored pore sizes exhibit CO2 adsorption abilities of 5.6¿9.1 mmol/g at 0 °C and 30 bar. Their Faraday efficiencies for reducing CO2 to CO are 14¿38% at a potential of -0.8 V vs. RHE.

The isopropylation of naphthalene (NP) over USY zeolite (FAU06, SiO2/Al2O3 = 6) gave all eight possible diisopropylnaphthalene (DIPN) isomers: ß,ß- (2,6- and 2,7-), a,ß- (1,3-, 1,6-, and 1,7-), and a,a- (1,4- and 1,5-). The catalyses were operated under kinetic and/or thermodynamic controls depending on the reaction temperatures since the cavities of FAU topology are wide enough to form all DIPN isomers. Enhanced selectivities for ß,ß-DIPN were observed at the early stages at 200°C, 250°C, and 300°C although the selectivities decreased with the increasing periods, accompanying the increase in a,a- and a,ß-DIPN. The enhancement occurred under new types of thermodynamic controls through thermodynamically preferred transition states to ß,ß-DIPN. Triisopropylnaphthalene (TriIPN) isomers were also formed in the isopropylation. Unstable a,a,ß-TriIPN (1,4,6- and 1,3,5-) was predominantly formed at lower temperatures, however, decreased with the increased of stable a,ß,ß-TriIPN (1,3,6- and 1,3,7-) at higher temperatures. The predominant formation of 1,4,6-TriIPN was also observed in the initial stages in the range of 200°C, 250°C, and 300°C, as reaction period was increased, while the selectivity for the isomer was decreased with concomitant increase in the selectivities for the other isomers. These changes of the selectivities operated under kinetic and/or thermodynamic controls. Large cavities of the zeolite allowed the formation of all TriIPN isomers without steric restriction.

Current and potential beneficial applications of engineered nanomaterials (ENM) are outweighed by the potential concern of their environmental implications. Understanding the impact of ENM release in the aquatic systems is complicated by the transport of the nanoparticles (NPs) especially in presence of various biotic and abiotic factors. Several attempts have been made to understand the aggregation and sedimentation of ENM in presence of individual factors such as natural organic matter and clay and in presence of salts to address their transportation and fate. The objective of the current study is to compare the effect of abiotic factors on the pH dependent stability and aggregation of TiO2 and CuO NP in a relevant fish embryo (E3) medium as a function of time. The aggregation and the sedimentation are compared in presence of humic acid (HA) alone, montmorillonite clay alone, and their combination. It is observed that in presence of HA, the aggregation of TiO2 NP and CuO NP decreases at pH 6, 8, and 10 and heteroagglomeration of TiO2 NP and CuO NP occurs with clay minerals at pH 2 and 4. It is also found that CuO NP are more stable than TiO2 NP in E3 medium and are perturbed to a lesser extent by the abiotic factors as compared to TiO2. Clay and HA are interesting naturally occurring matter in the aqueous environment that can affect the size, charge, and sedimentation behavior of ENM and thus affect their bioavailability and eventual toxicological fate.

We report on the preparation of ordered mesoporous carbon nitrides (MCN) with a 3D porous structure, tuneable nitrogen contents and basicity and their basic catalytic activities on the Knoevenagel condensation of benzaldehyde with malononitrile. The chemical structure and the nitrogen contents of the materials are finely tuned with the simple adjustment of the calcination temperature from 350 to 550 °C. The samples prepared at 350 and 400 °C exhibit C3N5 structures with 1-amino/imino-1,2,4-triazole moieties, whereas the samples synthesised at 450, 500, and 550 °C possess C3N4 structures with 2-amino/imino-1,3,5-triazine moieties. The materials prepared at the temperature lower than 400 °C show much higher activity than those of the samples prepared at 450, 500 and 550 °C. The change in the catalytic activities of these materials is linked with the change of the structure, nitrogen contents and the functional groups on the surface of the materials prepared at different temperatures. CO2 temperature programme desorption study reveals that 1-amino/imino-1,2,4-triazole moieties in C3N5 samples provide high basicity due to the strain in 5-membered 1,2,4-triazole rings; however, the samples with 1,3,5-triazine moieties have limited basicity which significantly affects the catalytic activity of the material. The optimised C3N5 catalyst shows an enhanced catalytic activity when compared to other mesoporous basic catalysts and C3N4. It is also found that the optimised catalysts are highly stable and can be recycled several times and no major change in the activity is observed.

In this article, boundary element method simulations are used to optimise the geometry of silver and gold nanocone probes to maximise the localised electric field enhancement and tune the near-field resonance wavelength. These objectives are expected to maximise the sensitivity of tip-enhanced Raman microscopes. Similar studies have used limited parameter sets or used a performance metric other than localised electric field enhancement. In this article, the optical responses for a range of nanocone geometries are simulated for excitation wavelengths ranging from 400 to 1000 nm. Performance is evaluated by measuring the electric field enhancement at the sample surface with a resonant illumination wavelength. These results are then used to determine empirical models and derive optimal nanocone geometries for a particular illumination wavelength and tip material. This article concludes that gold nanocones are expected to provide similar performance to silver nanocones at red and near-infrared wavelengths, which is consistent with other results in the literature. In this article, 633 nm is determined to be the shortest usable illumination wavelength for gold nanocones. Below this limit, silver nanocones will provide superior enhancement. The use of gold nanocone probes is expected to dramatically improve probe lifetime, which is currently measured in hours for silver coated probes. Furthermore, the elimination of passivation coatings is expected to enable smaller probe radii and improved topographical resolution.

We present measurements of resistivity, x-ray absorption (XAS) and emission (XES) spectroscopy together with ab initio band structure calculations for quasi two dimensional ruthenate Na2RuO3. Density function calculations (DFT) and XAS and XES spectra both show that Na2RuO3 is a semiconductor with an activation energy of ~80 meV. Our DFT calculations reveal large magneto-elastic coupling in Na2RuO3 and predict that the ground state of Na2RuO3 should be antiferromagnetic zig-zag.