Recent advances and perspectives on intercalation layered compounds part 1: design and applications in the field of energy.

Herein, initially, we present a general overview of the global financial support for chemistry devoted to materials science, specifically intercalation layered compounds (ILCs). Subsequently, the strategies to synthesise these host structures and the corresponding guest-host hybrid assemblies are exemplified on the basis of some families of materials, including pillared clays (PILCs), porous clay heterostructures (PCHs), zirconium phosphate (ZrP), layered double hydroxides (LDHs), graphite intercalation compounds (GICs), graphene-based materials, and MXenes. Additionally, a non-exhaustive survey on their possible application in the field of energy through electrochemical storage, mostly as electrode materials but also as electrolyte additives, is presented, including lithium technologies based on lithium ion batteries (LIBs), and beyond LiBs with a focus on possible alternatives such XIBs (X = Na (NIB), K (KIB), Al (AIB), Zn (ZIB), and Cl (CIB)), reversible Mg batteries (RMBs), dual-ion batteries (DIBs), Zn-air and Zn-sulphur batteries and supercapacitors as well as their relevance in other fields related to (opto)electronics. This selective panorama should help readers better understand the reason why ILCs are expected to meet the challenge of tomorrow as electrode materials.

Recent advances and perspectives for intercalation layered compounds. Part 2: applications in the field of catalysis, environment and health.

Intercalation compounds represent a unique class of materials that can be anisotropic (1D and 2D-based topology) or isotropic (3D) through their guest/host superlattice repetitive organisation. Intercalation refers to the reversible introduction of guest species with variable natures into a crystalline host lattice. Different host lattice structures have been used for the preparation of intercalation compounds, and many examples are produced by exploiting the flexibility and the ability of 2D-based hosts to accommodate different guest species, ranging from ions to complex molecules. This reaction is then carried out to allow systematic control and fine tuning of the final properties of the derived compounds, thus allowing them to be used for various applications. This review mainly focuses on the recent applications of intercalation layered compounds (ILCs) based on layered clays, zirconium phosphates, layered double hydroxides and graphene as heterogeneous catalysts, for environmental and health purposes, aiming at collecting and discussing how intercalation processes can be exploited for the selected applications.

Fenton-like Degradation of Methylene Blue on Attapulgite Clay Composite by Loading of Iron-Oxide: Eco-Friendly Preparation and Its Catalytic Activity.

The continuous discharge of organic dyes into freshwater resources poses a long-term hazard to aquatic life. The advanced oxidation Fenton process is a combo of adsorption and degradation of pollutants to detoxify toxic effluents, such as anti-bacterial drugs, antibiotics, and organic dyes. In this work, an activated attapulgite clay-loaded iron-oxide (A-ATP@Fe3O4) was produced using a two-step reaction, in which attapulgite serves as an enrichment matrix and Fe3O4 functions as the active degrading component. The maximum adsorption capacity (qt) was determined by assessing the effect of temperature, pH H2O2, and adsorbent. The results showed that the A-ATP@Fe3O4 achieves the highest removal rate of 99.6% under optimum conditions: 40 °C, pH = 3, H2O2 25 mM, and 0.1 g dosage of the composite. The dye removal procedure achieved adsorption and degradation equilibrium in 120 and 30 min, respectively, by following the same processes as the advanced oxidation approach. Catalytic activity, kinetics, and specified surface characteristics suggest that A-ATP@Fe3O4 is one of the most promising candidates for advanced oxidation-enrooted removal of organic dyes.

Enhanced dispersion of prussian blue via intercalation into layered double hydroxides for efficient solar seawater evaporation.

Prussian blue (PB) is favored for its photothermal absorption capability in solar vapor generation applications. However, the photothermal conversion efficiency of current PB-based devices is limited by the material's poor dispersion. Herein, we report a method of incorporating PB in the interlayers of layered double hydroxides (LDHs) to prevent its aggregation. The dispersion is further enhanced and stabilized by the addition of sodium dodecyl sulfate (SDS). The thermal and water stability of PB is improved due to the rigid structure of LDHs and interactions between layers and anions. Elemental analysis confirms that with the increase of molar ratio of Mg/Al and the introduction of SDS, concentrations of PB are decreased accordingly. As a result, the rate of solar vapor generation is increased by 35.9% for powders containing 50 mg of equivalent PB. Of note, converting this material into a three-dimensional structure of high rebound foam further enhances solar water evaporation rate, from 0.79 kg m-2 h-1 to 0.98 kg m-2 h-1, with only 20 mg of equivalent PB, increasing the corresponding photothermal conversion efficiency from 53.8% to 66.3%.

A α-L-rhamnosidase from Echinacea purpurea endophyte Simplicillium sinense EFF1 and its application in production of Calceorioside B.

Calceorioside B, a multifunctional phenylethanol glycosides (PhGs) derivative, exhibits a variety of notable properties, such as antithrombotic, anti-tumorigenic, anti-neocoronavirus, anti-inflammatory, and neuroprotective effects. However, the large-scale production of calceorioside B is routinely restricted by its existence as an intermediary compound derived from plants, and still unachieved through excellent and activity chemical synthesis. Here, a total of 51 fungal endophytes were isolated from four PhGs-producing plants, and endophyte Simplicillium sinense EFF1 from Echinacea purpurea was identified with the ability to de-rhamnosing isoacteoside to generate calceorioside B. According to the RNA-transcription of EFF1 under the various substrates, a key gene CL1206.Contig2 that undertakes the hydrolysis function was screened out and charactered by heterologous expression. The sequence alignment, phylogenetic tree construction and substrate specificity analysis revealed that CL1206 was a novel α-L-rhamnosidase that belongs to the glycosyl hydrolase family 78 (GH78). The optimum catalytic conditions for CL1206 were at pH 6.5 and 55 °C. Finally, the enzyme-catalyzed approach to produce calceorioside B from 50 % crude isoacteoside extract was explored and optimized, with the maximum conversion rate reaching 69.42 % and the average producing rate reaching 0.37 g-1.L-1.h-1, which offered a great biocatalyst for potential industrial calceorioside B production. This is the first case for microorganism and rhamnosidase to show the hydrolysis ability to caffeic acid-modified PhGs.

Adsorption of Co2+ and Cr3+ in Industrial Wastewater by Magnesium Silicate Nanomaterials.

In this paper, two flower-like magnesium silicate nanomaterials were prepared. These and another two commercial magnesium silicate materials were characterized using a scanning electron microscope, the N2 adsorption-desorption method, and other methods. The structure-activity relationship between the adsorption performance of these four magnesium silicate materials and their specific surface area, pore size distribution, and pore structure was compared. The results showed that the 3-FMS modified by sodium dodecyl sulfonate (SDS) had the largest specific surface area and pore size, the best adsorption performance, and the largest experimental equilibrium adsorption capacity (qe,exp) for Co2+, reaching 190.01 mg/g, and Cr3+, reaching 208.89 mg/g. The adsorption behavior of the four materials for Co2+ and Cr3+ both fitted the pseudo-second-order kinetic model and Langmuir adsorption model, indicating that chemical monolayer uniform adsorption was the dominant adsorption process. Among them, the theoretical adsorption capacity (qm) of 3-FMS was the highest, reaching 207.62 mg/g for Co2+ and 230.85 mg/g for Cr3+. Through further research, it was found that the four materials mainly removed Co2+ and Cr3+ through electrostatic adsorption, surface metal ions (Mg2+), and acidic groups (-OH and -SO3H) exchanging with ions in solution. The adsorption performance of two self-made flower-like magnesium silicate materials for Co2+ and Cr3+ was superior to that of two commercial magnesium silicates.

Colloid Mill-Assisted Ultrasonic-Fractional Centrifugal Purification of Low-Grade Attapulgite and Its Modification for Adsorption of Congo Red.

Attapulgite (APT) is widely used in wastewater treatment due to its exceptional adsorption and colloidal properties, as well as its cost-effectiveness and eco-friendliness. However, low-grade APT generally limits its performance. Here, a colloid mill-assisted ultrasonic-fractional centrifugal purification method was developed to refine low-grade APT. This process successfully separated and removed impurity minerals such as quartz and dolomite from the raw ore, resulting in a refined APT purity increase from 16.9% to 60% with a specific surface area of 135.5 m2∙g-1. Further modifying of the refined APT was carried out through the hydrothermal method using varying dosages of cetyltrimethylammonium chloride (CTAC), resulting in the production of four different APT adsorbents denoted as QAPT-n (n = CTAC mole number) ranging from 0.5 to 5 mmol. Using Congo red (CR) as the target pollutant, the QAPT-5 sample exhibited the best adsorption capacity with the maximum quantity of 1652.2 mg∙g-1 in a neutral solution at 30 °C due to the highest surface charge (zeta potential = 8.25 mV). Moreover, the QAPT-5 pellets (~2.0 g adsorbent) shaped by the alginate-assisted molding method removed more than 96% of 200 mL aqueous solution containing 200 mg∙L-1 CR and maintained this efficiency in 10 adsorption-elution cycles, which exhibited the promising practical application.

Characterization of three novel stem rot pathogens and their antagonistic endophytic bacteria associated with Cistanche deserticola.

Cistanche deserticola is a precious Chinese medicinal material with extremely high health care and medicinal value. In recent years, the frequent occurrence of stem rot has led to reduced or even no harvests of C. deserticola. The unstandardized use of farm chemicals in the prevention and control processes has resulted in excessive chemical residues, threatening the fragile desert ecological environment. Therefore, it is urgent to explore safe and efficient prevention and control technologies. Biocontrol agents, with the advantages of safety and environment-friendliness, would be an important idea. The isolation, screening and identification of pathogens and antagonistic endophytic bacteria are always the primary basis. In this study, three novel pathogens causing C. deserticola stem rot were isolated, identified and pathogenicity tested, namely Fusarium solani CPF1, F. proliferatum CPF2, and F. oxysporum CPF3. For the first time, the endophytic bacteria in C. deserticola were isolated and identified, of which 37 strains were obtained. Through dual culture assay, evaluation experiment and tissue culture verification, a biocontrol candidate strain Bacillus atrophaeus CE6 with outstanding control effect on the stem rot was screened out. In the tissue culture system, CE6 showed excellent control effect against F. solani and F. oxysporum, with the control efficacies reaching 97.2% and 95.8%, respectively, indicating its great potential for application in the production. This study is of great significance for the biocontrol of plant stem rot and improvement of the yield and quality of C. deserticola.

Fe(OH)x modified ultra-small Ru nanoparticles for highly efficient hydrogen evolution reaction and its application in water splitting.

Developing highly active electrocatalysts for overall water splitting is of remarkable significance for industrial production of H2. Herein, exceptionally active Fe(OH)x modified ultra-small Ru nanoparticles on Ni(OH)2 nanosheets array (Fe(OH)x-Ru/Ni(OH)2) for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are reported. The Fe(OH)x-Ru/Ni(OH)2 nanosheets array prepared with Fe/Ru molar ratio of 5 only requires extremely low overpotentials of 61, 127 and 170 mV to reach current densities of 100, 500 and 800 mA cm-2 in 1 M KOH, respectively, exceeding Pt/C catalyst (75, 160 and 177 mV). Meanwhile, the Fe(OH)x/Ni(OH)2 nanosheets array derived from Fe(OH)x-Ru/Ni(OH)2 exhibits excellent OER activity. It gains current densities of 100, 500 and 800 mA cm-2 at considerably low overpotentials of 265, 285 and 296 mV, respectively, much lower than those of RuO2 and most reported electrocatalysts. The introduction of Fe(OH)x significantly improves the HER activity of Ru nanoparticles by tunning the electronic structure and forming interfaces between Ru and Fe(OH)x. Dramatically, the integrated alkaline electrolyzer based on Fe(OH)x-Ru/Ni(OH)2 and Fe(OH)x/Ni(OH)2 nanosheets array pair just needs 1.649 V to yield a current density up to 500 mA cm-2, exceeding most reported water-splitting electrocatalysts. The strategy reported in this work can be facilely extended to prepare other similar Ru based materials and their derivatives with outstanding catalytic performance for water splitting.

Indole inhibited the expression of csrA gene in Escherichia coli.

Indole is a very important signal molecule which plays multiple regulatory roles in many physiological and biochemical processes of bacteria, but up to now, the reasons for its wide range of functions have not been revealed. In this study, we found that indole inhibits the motility, promotes glycogen accumulation and enhances starvation resistance of Escherichia coli. However, the regulatory effects of indole became insignificant while the global csrA gene was mutated. To reveal the regulatory relationship between indole and csrA, we studied the effects of indole on the transcription level of csrA, flhDC, glgCAP and cstA, and also the sensing of the promoters of the genes on indole. It was found that indole inhibited the transcription of csrA, and only the promoter of the csrA gene can sense indole. Namely, indole indirectly regulated the translation level of FlhDC, GlgCAP and CstA. These data indicates that indole regulation is related with the regulation of CsrA, which may throw light on the regulation mechanism research of indole.

Facile preparation of Au-loaded mesoporous In2O3 nanoparticles with improved ethanol sensing performance.

The in situ monitoring of toxic volatile organic compound gases using metal oxide-based gas sensors is still challenging. Herein, mesoporous In2O3 nanoparticles, assembled using smaller nanoparticles, were synthesized via a facile solvothermal method and used to load Au nanoparticles to prepare mesoporous Au/In2O3 for ethanol detection. The obtained In2O3 and Au/In2O3 were meticulously analysed by XRD, SEM, BET, TEM and XPS techniques. It was revealed that Au nanoparticles were uniformly distributed on mesoporous In2O3 nanoparticles. Notably, the obtained mesoporous 1% Au/In2O3 is highly sensitive to ethanol gas at an optimal working temperature of 180 °C, showing a response of 55 to 50 ppm of ethanol, which is considerably higher compared to that of In2O3 nanoparticles. The significantly enhanced sensitivity results from the electronic and chemical sensitization effects of Au nanoparticles. Moreover, the mesoporous Au/In2O3 nanoparticles also showed eminent selectivity, short response/recovery time, low detection limit, good linear relationship, superb repeatability, and wonderful long-term stability, suggesting that Au/In2O3 nanoparticles have great potential application for in situ monitoring of ethanol gas.

NiFe-LDH-Decorated Ti-Doped Hematite Photoanode for Enhancing Solar Water-Splitting Efficiency.

Ti-doped α-Fe2O3 nanorods were prepared by a facile hydrothermal method, followed by a NiFe-LDH catalyst that was electrodeposited on the doped α-Fe2O3 nanorods to structure an integrating photoanode Ti:Fe2O3/NiFe-LDH for improving solar PEC water-splitting efficiency. The structure and properties of electrode materials were characterized and the PEC properties of photoanodes were measured. The results show that the photocurrent density of the photoanode enhances 11.25 times at 1.23 V (vs RHE) and the IPCE value enhances 4.10 times at 420 nm compared with pristine α-Fe2O3. The enhancement is attributed to the separating of photogenerated electron-hole, the increase of carrier density, and the acceleration of the carrier transfer rate due to the dual action of doping and catalysis.

Modified approaches to prepare nano-magnesium silicates with hierarchical pore structure and their performance towards adsorption of Cd2.

A series of flower-like magnesium silicate samples with hierarchical pore were prepared by the solvothermal method under template-free conditions using sodium dodecyl sulfate as the modifier and ethanol-water as the solvent. These samples were characterized by various methods and were evaluated for the adsorption of heavy metal Cd2+. The results showed that the adding modifier did not change the crystal structure of the magnesium silicate samples. In the range of 2~80 nm, they still showed hierarchical pore distribution mainly composed of mesopores and macropores, which facilitates the rapid transport of adsorbent within the pore channel. Therefore, the adsorption of Cd2+ was greatly accelerated. Meanwhile, the larger specific surface area (as high as 553 m2/g) of these samples significantly increased the theoretical maximum adsorption amount of Cd2+ up to 295.3 mg/g due to more available adsorption sites. The adsorption dynamic behavior of the samples on Cd2+ was in accordance with the pseudo-second-order adsorption model, and their thermodynamic behavior follows the Langmuir adsorption model. The adsorption mechanism of the sample was proposed as electrostatic adsorption and exchange of metal ions and acidic groups on its surface with ions in solution. The obtained magnesium silicate materials are expected to remove heavy metals from wastewater.

A new l-serine binding orphan SerBP affects indole synthesis in Pantoea ananatis.

Indole is traditionally known as a metabolite of l-tryptophan and now as an important signaling molecule in bacteria, however, the understanding of its upstream synthesis regulation is very limited. Pantoea ananatis YJ76, a predominant diazotrophic endophyte isolated from rice (Oryza sativa), can produce indole to regulate various physiological and biochemical behaviors. We constructed a mutant library of YJ76 using the mTn5 transposon insertion mutation method, from which an indole-deficient mutant was screened out. Via high-efficiency thermal asymmetric interlaced PCR (hiTAIL-PCR), the transposon was determined to be inserted in a gene (RefSeq: WP014605468.1) of unknown function that is highly conserved at the intraspecific level. Bioinformatics analysis implied that the protein (Protein ID: WP089517194.1) encoded by the mutant gene is most likely to be a new orphan substrate-binding protein (SBP) for amino acid ABC transporters. Amino acid supplement cultivation experiments and surface plasmon resonance revealed that the protein could bind to l-serine (KD = 6.149 × 10-5 M). Therefore, the SBP was named as SerBP. This is the first case that a SBP responds to l-serine ABC transports. As a precursor of indole synthesis, the transmembrane transported l-serine was directly correlated with indole signal production and the mutation of serBP gene weakened the resistance of YJ76 to antibiotics, alkali, heavy metals, and starvation. This study provided a new paradigm for exploring the upstream regulatory pathway for indole synthesis of bacteria.

Bi nanoparticles modified the WO3/ZnWO4 heterojunction for photoelectrochemical water splitting.

The novel ternary photoanode was successfully prepared by Bi nanoparticles (Bi NPs) modified on type II heterojunction of WO3-ZnWO4 using the simple and effective drop casting and chemical impregnation methods. The photoelectrochemical (PEC) experimental tests revealed that the photocurrent density of the ternary photoanode of WO3/ZnWO4(2)/Bi NPs reaches 3.0 mA/cm2 at 1.23 V (vs. RHE), which is 6 times of the WO3 photoanode. The incident photon-to-electron conversion efficiency (IPCE) at 380 nm wave length reaches 68%, which increases 2.8 times compared to WO3 photoanode. The observed enhancement can be attributed to the formation of type II heterojunction and modification of Bi NPs. The former broadens the absorption range for visible light and improves the carrier separation efficiency, while the latter enhances the light capture ability through the local surface plasmon resonance (LSPR) effect of Bi NPs and the generation of hot electrons.

Construction of tea tree oil/salicylic acid/palygorskite hybrids for advanced antibacterial and anti-inflammatory performance.

This study describes the construction of a tailor-made clay-based hybrid with advanced dermocompatibility, antibacterial and anti-inflammatory performance by incorporating tunable ratios of tea tree oil (TTO) and salicylic acid (SA) into the naturally occurring porous structure of palygorskite (Pal). Among the three TTO/SA/Pal (TSP) systems constructed, TSP-1 with a TTO : SA ratio of 1 : 3 demonstrated the lowest 3T3 NRU predicted acute oral toxicity and dermal HaCaT cytotoxicity as well as the most pronounced antibacterial activity with a selective inhibitory action against the pathogens (E. coli, P. acnes and S. aureus) over the beneficial (S. epdermidis) species inhabiting on the human skin. Also noticeable is that exposure of these skin commensal bacteria to TSP-1 prevented the antimicrobial resistance evolution compared to the conventional antibiotic ciprofloxacin. Mechanistic investigation of its antibacterial modes of action revealed a synergy between the TTO and SA loadings on the Pal supports in reactive oxygen production, causing oxidative damage to bacterial cell membranes and increased leakage of intracellular compounds. Additionally, TSP-1 significantly decreased the proinflammatory cytokines of IL-1ß, IL-6, IL-8, and TNF-α in a bacterial lipopolysaccharide-stimulated differentiated THP-1 macrophage model, showing the potential to inhibit inflammatory responses in bacterial infections. Overall, this is the first report exploring the potential of constructing clay-based organic-inorganic hybrids as alternatives to antibiotics to combat bacterial resistance with advanced compatibility and anti-inflammatory benefits that are desired for the development of topically applied biopharmaceuticals.

NiFePB-modified ZnO/BiVO4 photoanode for PEC water oxidation.

Photoelectrochemical (PEC) water splitting has been recognized as the most promising approach for directly converting solar energy into chemical energy, and substantial efforts have been made to develop a highly efficient and low-cost photoanode for enhancement of PEC water splitting efficiency due to sluggish water oxidation reaction kinetics. A ternary NiFePB-modified ZnO/BiVO4 heterojunction photoanode was simply assembled by low-temperature hydrothermal, metal-organic decomposition and electrodeposition methods to improve the water splitting efficiency; its photocurrent density for water oxidation reached 1.66 mA cm-2 at 1.23 V (vs. RHE); in comparison, that of ZnO is only 0.4 mA cm-2. The onset potential manifests a cathodic shift of ∼283 mV compared to ZnO. The IPCE and the ABPE respectively are 3.1 and 6.4 times those of ZnO, respectively. This improvement is ascribed to the efficient separation of photogenerated electrons and holes by the formation of a heterojunction between ZnO and BiVO4 and the enhancement in the oxygen evolution reaction kinetics by the decoration of the co-catalyst NiFePB as a hole acceptor.

Synthesis of unconventional Pd-Se nanoparticles for phase-dependent ethanol electrooxidation.

By tuning the amount of the Se precursors during the synthesis, orthorhombic PdSe2, cubic Pd17Se15, and monoclinic Pd7Se2 nanoparticles are synthesized, which show phase-dependent electrocatalysis for the ethanol oxidation reaction. This work advances the controllable synthesis of transition metal selenides and inspires their applications in electrocatalysis.

Introducing High-Valence Iridium Single Atoms into Bimetal Phosphides toward High-Efficiency Oxygen Evolution and Overall Water Splitting.

Single atoms are superior electrocatalysts having high atomic utilization and amazing activity for water oxidation and splitting. Herein, this work reports a thermal reduction method to introduce high-valence iridium (Ir) single atoms into bimetal phosphide (FeNiP) nanoparticles toward high-efficiency oxygen evolution reaction (OER) and overall water splitting. The presence of high-valence single Ir atoms (Ir4+ ) and their synergistic interaction with Ni3+ species as well as the disproportionation of Ni3+ assisted by Fe collectively contribute to the exceptional OER performance. In specific, at appropriate Ir/Ni and Fe/Ni ratios, the as-prepared Ir-doped FeNiP (Ir25 -Fe16 Ni100 P64 ) nanoparticles at a mass loading of only 35 µg cm-2 show the overpotential as low as 232 mV at 10 mA cm-2 and activity as high as 1.86 A mg-1 at 1.5 V versus RHE for OER in 1.0 m KOH. Computational simulations confirm the vital role of high-valence Ir to weaken the adsorption of OER intermediates, favorable for accelerating OER kinetics. Impressively, a Pt/C||Ir25 -Fe16 Ni100 P64 two-electrode alkaline electrolyzer affords a current density of 10 mA cm-2 at a low cell voltage of 1.42 V, along with satisfied stability. An AA battery with a nominal voltage of 1.5 V can drive overall water splitting with obvious bubbles released.

Fibrous Clays in Dermopharmaceutical and Cosmetic Applications: Traditional and Emerging Perspectives.

Functionalization of natural clay minerals for high value-added pharmaceutical and cosmetic applications receives significant research attention worldwide attributable to a rising demand and ongoing search for green, efficient, economically sustainable and ecofriendly geomaterials. Fibrous clays, i.e. palygorskite and sepiolite, are naturally-occurring hydrated magnesium aluminum silicate clay minerals with 2:1 layer-chain microstructure and one-dimensional nanofibrous morphology. Due to their unique structural, textural and compatibility features, over the past decade, fibrous clays and their organic modified derivatives are increasingly used in the dermopharmaceutical and cosmetic fields as excipients, active agents or nanocarriers to develop novel skin delivery systems or to modify drug release profile for enhanced health effects. This comprehensive review presents the up-to-date information on fibrous clays used in topically-applied products for therapeutic and cosmetic purposes with the focus on their performance-related structural characteristics and the underlying mechanisms. The recent advancement of fibrous clay-based skin delivery systems was summarized in wide range of applications including pelotherapy, wound healing, antimicrobial action, coloration and UV protection. An overview of the commonly used topically-applied dosage forms (powders, hydrogels, films, peloids and Pickering emulsion) as well as the toxicological aspects was also included, which might provide guidance to the design and development of fibrous clay-based skin delivery systems.