Solvothermal Treatment Research Articles

A “performance-inheritance” strategy for achieving hydrophilic/hydrophobic fluorescent biomass-derived carbon dots through simple solvothermal treatments

It remains a challenge to obtain hydrophilic/hydrophobic materials with promising biocompatibility and environmental compatibility by simple methods. Herein, we designed a “performance-inheritance” strategy and for the first time constructed hydrophilic/hydrophobic fluorescent spirulina-derived carbon dots (CDs) through simple solvothermal treatments. The contact angle of hydrophobic CDs with near-infrared (NIR) fluorescence is 110°, while hydrophilic CDs with blue fluorescence is 19°. We further revealed that the NIR luminescence is derived from the chlorophyll structure, while blue fluorescence is from the surface states. Based on the hydrophilicity/hydrophobicity of CDs, a ratiometric sensor was constructed to detect water content in organic solutions. In addition, CDs with NIR emission have low toxicity and good biocompatibility, making them efficient probes for bioimaging. This strategy provides a simple method for the high value-added conversion of algae and a new perspective for the “design-preparation-application” of biomass-derived CDs with specific properties.

Carbon dot aggregates: a new strategy to promote corrosion inhibition performance of carbon dots

The corrosion of metal not only produces serious economic losses and environmental pollution but also threatens equipment safety. Carbon dots (CDs) exhibit outstanding inhibition properties to availably retard the corrosion of metal. However, the present CDs-based corrosion inhibitors still fail to fully exert the environmentally friendly and low-cost merits of CDs. To address this issue, CD aggregates (CDAs) prepared by low-cost and eco-friendly CDs are developed as novel corrosion inhibitors for the first time, and their corrosion inhibition mechanism is disclosed. Specifically, CDAs with excellent long-term dispersion stability are synthesized by solvothermal treatment of CDs formed by citric acid and urea. CDAs at only 200 mg/L provide a corrosion inhibition effect of 90.38% for Q235 carbon steel in 1 mol/L HCl solution, approximately 1.53 times higher than that of CDs (59.21%). Moreover, the corrosion inhibition mechanism of CDAs is proposed through the analysis of adsorption isotherm, examination of corrosion morphologies, and theoretical calculations. That is, CDAs physically and chemically adsorb on the carbon steel surface, mainly hindering its anodic reaction, thus retarding the corrosion of carbon steel. This research firstly verifies the corrosion inhibition potential of green and low-cost CDAs and provides a novel strategy to promote the corrosion inhibition performance of CDs, promoting the progress of aggregate-based corrosion inhibitors.

Construction of α-Fe2O3 Nanorods/UiO-66-NH2 by in-situ Growth with Photocatalytic Reduction of Cr (VI)

Abstract Cr (VI) is widely used in industry but its high toxicity causes environmental pollution that needs addressing. The growth of photosensitive materials on semiconductor surfaces can successfully stop photogenerated electron-hole pair recombination, increasing photocatalytic efficiency. Herein, α-Fe2O3 nanorods/UiO-66-NH2 compounds were successfully obtained through the in-situ solvothermal approach. By using 2-aminoterephthalic acid in the solvothermal treatment of Zr4+ adsorbed α-Fe2O3 nanorods, the UiO-66-NH2 nanocrystals were evenly distributed on the nanorods. In addition, the reduction efficiency of wastewater reached 93% after 150 min of light exposure, much higher than uncompounded materials. Moreover, the α-Fe2O3/UiO-66-NH2 crystals had good regeneration ability, retaining 73% of Cr (VI) removal capacity after four cycles. In this process, α-Fe2O3 and UiO-66-NH2 effectively complexed to form a heterojunction, which effectively suppressed the complexation of electrons (e-) and holes (h+). This efficient complex facilitates the photocatalytic degradation of highly noxious Cr (VI) to Cr (III) under visible light. The efficient Cr (VI) elimination ability comes from the photocatalytic reduction mechanism where they form a special interface to promote the movement of electrons and holes for efficient removal. This work provides both a new approach for in-situ synthesis and a reference for efficient Cr (VI) elimination.

Yolk@shell layered NiCo hydroxide: Controllable synthesis, sulfuration and electrochemical applications for hybrid supercapacitors

Developing electrode materials with rational structures is an important strategy for constructing high-performance hybrid supercapacitors (HSCs). Herein, designing a yolk@shell structure composed of layered nickel-cobalt hydroxide with a Ni/Co feed ratio of 4:1 (denoted as layered Ni4Co1 hydroxide) and nickel-cobalt sulfide with a sulfuration duration of 2 h (labeled as Ni4Co1S-2h) to enhance the capacity and stabilize the cyclic performances of HSCs was conducted. The yolk@shell structured microspheres of layered Ni4Co1 hydroxide were synthesized using a cetyltriethylammonium bromide (CTAB) template-assisted solvothermal treatment. Subsequently, nickel-cobalt sulfide microspheres with the unique yolk@shell structure were prepared from layered Ni4Co1 hydroxide precursor. Notably, yolk@shell Ni4Co1S-2h microspheres feature a large specific surface area and an interspace between the yolk and shell, facilitating charge transfer but also effectively alleviating volume expansion during ion transport and electron transfer. The resultant Ni4Co1S-2h material demonstrates a superior capacity of 902.2 C·g−1 at 3·A g−1, while the assembled Ni4Co1S-2h//porous carbon (PC) HSC shows a relatively higher energy density (83.1 Wh·kg−1) and power density (15000 W·kg−1). The design of yolk@shell structured layered Ni4Co1 hydroxide and Ni4Co1S-2h electrode materials holds significant implications for the advancement of high-performance HSCs.

Photocatalytic degradation of propranolol hydrochloride in aqueous medium employing bentonite-TiO2 nanocomposites

Propranolol hydrochloride, a widely used medication, contaminates water bodies as it’s not fully metabolized by humans. Conventional water treatment methods are ineffective against it, necessitating more advanced approaches like heterogeneous photocatalysis. TiO2, often used as a photocatalyst, is typically combined with other materials to form nanocomposites, enhancing its activity. This study evaluated TiO2 synthesized via sol–gel method with organophilized bentonite for propranolol removal. Composites were prepared through solvothermal treatment, and an experimental design assessed the TiO2/bentonite ratio, time, and temperature of the solvothermal treatment effects on photocatalytic activity. Increasing these parameters led to a nanocomposite capable of removing over 99 % of propranolol in water after 60 min of adsorption followed by 150 min of photocatalysis. The nanocomposite remained active after four treatment cycles. Characterization revealed TiO2 (anatase) nanoparticles with a size range of 6–13 nm dispersed in bentonite’s fine tubular structures. This research underscores the potential of TiO2-based nanocomposites in addressing pharmaceutical contamination in water bodies efficiently.

Urea solvothermal regeneration of spent LiNi0.5Co0.2Mn0.3O2: Performance and environmental benefits

With the large-scale application of power batteries, a large number of spent lithium-ion batteries (LIBs) will be formed in recent years. The improper disposal of spent LIBs will pose significant environmental pollution. LiNi0.5Co0.2Mn0.3O2 (NCM), as a typical type of LIBs cathodes material, are widely used and can be highly recycled. However, the existing hydrometallurgical and pyrometallurgical recycling processes consume large amounts of energy and introduce serious secondary pollution. This work presents a simple straightforward direct regeneration process that uses urea solvothermal treatment followed by calcination to obtain urea-regenerated spent NCM (UR-S-NCM). Surprisingly, the specific capacity of the regenerated NCM of UR-S-NCM recovers completely and reaches 166 mAh/g, higher than that of fresh NCM (F-NCM) at 156 mAh/g. After 100 charge/discharge cycles, the specific capacity of UR-S-NCM is 37 % higher than that of F-NCM at the same condition. Additionally, the CO2 emissions per kilogram of the regenerated UR-S-NCM are only 1.79 kg, about 31 % of pyrometallurgy and 48 % of hydrometallurgy, respectively. The surface smoothness, grain boundaries and layered structure of UR-S-NCM are recovered from S-NCM to the same situation of F-NCM. Smooth surface facilitates Li+ migration into and out of UR-S-NCM, grain boundaries reduction diminishes electrolyte corrosion, and the layered structure accommodates more Li+ compared to the spinel structure of S-NCM. This work provides an eco-friendly direct regeneration process and offers a new insight for LIBs regeneration.

Electrochemical detection of human papillomavirus DNA based on an ultrasensitive electrochemical sensing platform using N-graphene paper

Human papillomavirus (HPV) is the primary cause of cervical cancer, a major global health concern affecting women worldwide. Early detection of high-risk HPV genotypes is crucial for timely intervention and reducing disease burden. However, current detection methods often lack sensitivity, speed, or cost-effectiveness, especially in resource-limited settings. This work addresses this critical need by developing an ultrasensitive electrochemical biosensing platform based on nitrogen-doped graphene paper electrodes for quantifying high-risk HPV16 DNA sequences. The N-graphene nanohybrid, fabricated via simple solvothermal treatment of biomass-derived graphene oxide, demonstrated significantly enhanced electrical and electrocatalytic properties compared to undoped graphene. DNA detection was achieved through characteristic oxidation signals of guanine bases, which displayed a wide linear dynamic range (0.5–100 μg/mL), low detection limit (75 pg/mL), and excellent reproducibility (relative standard deviation <3.5 %). Detailed spectroscopic and electrochemical analyses revealed the key roles of pyridinic nitrogen defects in improving interfacial charge transfer kinetics and mitigating biofouling issues. This synergistic combination of high electrical conductivity and versatile surface functionality paves the way for equipment-free, point-of-care genosensor devices tailored for quantitative biomarker screening in resource-constrained environments.

Incorporation of SnSe2/SnO2 heterostructures in carbon nanotubes for excellent lithium storage performance

As a new type of negative electrode material, tin-based material exhibits a high theoretical capacity. However, tin-based anode materials always undergo severe volume change upon alloying reaction during lithium insertion and extraction, which leads to the pulverization of the active materials and poor electrochemical performance, seriously hampering its practical application. In this work, oxygen-containing group functionalized carbon nanotubes (FCNTs) were facilely obtained, and the three-dimensional crosslinked SnSe2-SnO2@FCNTs multiphase materials were prepared by solvothermal and high-temperature heat treatment. The formation of Sn-O-C bonds from oxygen-containing functional groups of FCNTs combined with Sn can promote the electric connection and integrity of the composites. The implanted defects in FCNTs can not only be beneficial to anchoring SnO2 and SnSe2 nanoparticles, but also helpful to the penetration of Li+ ions into the electrodes from electrolyte. In addition, the large Fermi energy difference between SnSe2 and SnO2 nanoparticles results in the formation of a built-in electric field at the interface of the multiphase materials, accelerating the diffusion of ions. The smaller size of the multiphase materials leads to significant pseudocapacitive behavior, which facilitates the highly reversible surface/interface adsorption. Under the multiple effects of FCNTs, SnSe2, and SnO2, the SnSe2-SnO2@FCNTs multiphase materials exhibited excellent electrochemical performance. At a current density of 0.1A·g-1, a discharge specific capacity of 898.0mAh·g-1 was achieved. When the current density was increased to 2A·g-1, it still exhibited a discharge specific capacity of 443.9mAh·g-1. After a long charge/discharge cycling at 1A·g-1 over 450 cycles, it still showed a specific capacity of ~ 400mAh·g-1. This work significantly demonstrated the enhanced Li-storage performance of SnSe2-SnO2 heterostructures incorporated in the functionalized multi-walled CNTs. This opens a new way to synthesize advanced tin-based materials as high-performance anodes for high-energy density lithium-ion batteries.

Metal Organic Frameworks‐Derived NiO/NiCo2O4 Heterostructures for Effective Methanol Oxidation Reaction

AbstractThe electrochemical process of methanol oxidation reaction (MOR), which is closely associated with electrochemical production of formate and hydrogen, is considered a highly viable avenue for advancing renewable energy technologies. Nevertheless, the development and creation of affordable, effective, and durable electrocatalysts for MOR continue to present significant obstacles. In this study, a hierarchical porous NiO/NiCo2O4/NF electrode is fabricated through the integration of solvothermal and thermal oxidation treatments of Ni‐MOF‐74 and NiCo‐Asp. After thoroughly assessing the electrochemical performance for MOR, NiO/NiCo2O4/NF demonstrates a significant current density of 140 mA cm−2 at 1.6 V (vs. RHE) and a tafel slop of 45.0 mV·dec−1 in 1 M KOH and 0.5 M methanol. The excellent performance of MOR can be ascribed to the hierarchical porous nature that enhances mass and electron transport while offering numerous active sites for electrocatalytic reactions. Additionally, the hetero interface between NiO and NiCo2O4 could further enhance electron transfer rate and reaction kinetics for the MOR. The developed NiO/NiCo2O4/NF electrode shows potential as a viable and economical alternative to Pt‐based electrocatalysts for MOR‐based applications.

Pseudocapacitive Na ion storage in binder-less, carbon additive-free Nb2O5-x electrode synthesised via solvothermal-assisted electro-coating with enhanced areal capacitance and lowered impedance parameters

Negatrodes with wide negative operating voltage, high electrochemical storage capacity, and intrinsic metal ion intercalation abilities are vital to the continuous development of storage devices with simultaneous energy and power density improvement. Herein, we report binder-less coating of non-stoichiometric vacancy-implanted Nb2O5-x as carbon additive-free negatrode on FTO substrate for asymmetric supercapacitor and sodium ion capacitor applications. The negatrode was fabricated through vacuum-less and low-temperature solvothermal-assisted electro-coating technique and yielded several orders of enhancement in its areal capacitance and retained ca. 90 % of its capacity after 5000 cycles of charge-discharge in aqueous Na+ electrolyte. The solvothermal treated electro-coated electrode (STT_Nb2O5-x) achieved an areal capacitance of 22.58 mF/cm2, which was far higher than those of hydrothermal-treated electro-coated HTT_Nb2O5 and Nb2O5 electrodes. The solvothermal treatment simultaneously enhanced the electro-coated samples' impedance properties and mass load through oxygen vacancy implantation and re-crystallization of the electro-coated Nb2O5 layer, respectively. This study presented a facile and energy-efficient technique of direct coating of defect-enhanced pseudocapacitive nanomaterials for the fabrication of electrochemical storage devices.

Carbon dots-based dual-mode sensor for highly selective detection of nitrite in food substrates through diazo coupling reaction

As an antioxidant and preservative agent, nitrite (NO2−) plays an essential role in the food industry to maintain freshness or inhibit microbial growth. However, excessive addition of NO2− is detrimental to health, so accurate and portable detection of NO2− is critical for food quality control. Notably, the selectivity of most carbon dots (CDs)-based fluorescence sensors was not enough due to the nonspecific interaction mechanism of hydrogen bond, electrostatic interaction and inner filter effect etc. Herein, a novel fluorescence/UV–vis absorption (FL/UV–vis) dual-mode sensor was developed on basis of mC-CDs, which were prepared by simple solvothermal treatment of m-Phenylenediamine (m-PDA) and cyanidin cation (CC). The fluorescence of these mC-CDs could be selectively responded by NO2− through the specific diazo coupling reaction between NO2− and amino groups on the surface of mC-CDs, thus effectively improving the selectivity of NO2− detection. The CDs-based fluorescence sensor possessed a low detection limit of 0.091 μM and 0.143 μM for FL and UV–vis methods and the excellent linear range of 0.0–60.0 μM. Furthermore, the mC-CDs sensor was employed to detect NO2− in real samples with a recovery rate of 97.11 %–104.15 % for quantitative addition. Moreover, the smartphone-assisted fluorescence sensing platform developed could identify the subtle color changes that could not be distinguished by the naked eye, and had the advantages of fast detection speed and intelligence. More importantly, the portable solid phase sensor based on mC-CDs had been successfully applied to the specific fluorescence identification and concentration monitoring of NO2−. Accordingly, the designed sensor provided a new strategy for the highly selective and convenient sensing of NO2− in food substrates, and paved the way for the wide application of CDs-based nanomaterials in the detection of food safety.

Renewable synthesis of MoO3 nanosheets via low temperature phase transition for supercapacitor application

2D transition metal oxides have created revolution in the field of supercapacitors due to their fabulous electrochemical performance and stability. Molybdenum trioxides (MoO3) are one of the most prominent solid-state materials employed in energy storage applications. In this present work, we report a non-laborious physical vapor deposition (PVD) and ultrasonic extraction (USE) followed by vacuum assisted solvothermal treatment (VST) route (DEST), to produce 2D MoO3 nanosheets, without any complex equipment requirements. Phase transition in MoO3 is often achieved at very high temperatures by other reported works. But our well-thought-out, robust approach led to a phase transition from one phase to another phase, for e.g., hexagonal (h-MoO3) to orthorhombic (α-MoO3) structure at very low temperature (90 °C), using a green solvent (H2O) and renewable energy. This was achieved by implementing the concept of oxygen vacancy defects and solvolysis. The synthesized 2D nanomaterials were investigated for electrochemical performance as supercapacitor electrode materials. The α-MoO3 electrode material has shown supreme capacitance (256 Fg−1) than its counterpart h-MoO3 and mixed phases (h and α) of MoO3 (< 50 Fg−1). Thus, this work opens up a new possibility to synthesize electrocapacitive 2D MoO3 nanosheets in an eco-friendly and energy efficient way; hence can contribute in renewable circular economy.

Ratiometric Fluorescent pH Sensing with Carbon Dots: Fluorescence Mapping across pH Levels for Potential Underwater Applications.

Ocean acidification has become a major climate change concern requiring continuous observation. Additionally, in the industry, pH surveillance is of great importance. Consequently, there is a pressing demand to develop robust and inexpensive pH sensors. Ratiometric fluorescence pH sensing stands out as a promising concept. The application of carbon dots in fluorescent sensing presents a compelling avenue for the advancement of pH-sensing solutions. This potential is underpinned by the affordability of carbon dots, their straightforward manufacturing process, low toxicity, and minimal susceptibility to photobleaching. Thus, investigating novel carbon dots is essential to identify optimal pH-sensitive candidates. In this study, five carbon dots were synthesized through a simple solvothermal treatment, and their fluorescence was examined as a function of pH within the range of 5-9, across an excitation range of 200-550 nm and an emission range of 250-750 nm. The resulting optical features showed that all five carbon dots exhibited pH sensitivity in both the UV and visible regions. One type of carbon dot, synthesized from m-phenylenediamine, displayed ratiometric properties at four excitation wavelengths, with the best results observed when excited in the visible spectrum at 475 nm. Indeed, these carbon dots exhibited good linearity over pH values of 6-9 in aqueous Carmody buffer solution by calculating the ratio of the green emission band at 525 nm to the orange one at 630 nm (I525nm/I630nm), demonstrating highly suitable properties for ratiometric sensing.

Aqueous glass-coated CsPbI3 quantum dots implanted in g-C3N4 nanosheets for efficient photocatalytic water splitting and H2O2 generation

Increasing visible light harvesting and improving charge carrier separation and transfer efficiency are crucial for photocatalytic H2O2 generation using graphitic carbon nitrides (g-C3N4) based catalysts. In this paper, a high temperature solid synthesis was developed to create water stable SiO2 glass coated CsPbI3 (CsPbI3@SiO2) quantum dots (QDs) with high brightness and extraordinary stability. These CsPbI3@SiO2 QDs were implanted in superior thin g-C3N4 nanosheets via a solvothermal synthesis. The red-emission of CsPbI3 QDs and the blue emission of g-C3N4 nanosheets were quenched after incorporation to confirm that photogenerated electron transition occurred. The further polymerization of g-C3N4 during solvothermal treatment resulted in CsPbI3@SiO2/g-C3N4 with well-developed interface to improve the charge transfer efficiency. A type II heterostructure formed after CsPbI3@SiO2 QDs incorporated with g-C3N4 nanosheets. The heterostructure revealed enhanced photocatalytic H2 and H2O2 generation, in which the evolution rate of H2O2 was 2454.4 μmol·g−1·h−1 while the photocatalytic H2 generation rate was 2463.1 μmol·g−1·h−1. The mechanism test indicated that the photocatalytic production of H2O2 was carried through a two-step single-electron redox process. Superoxide radicals were important intermediates for the generation of H2O2. This study provides a new scheme for the preparation of g-C3N4 based heterojunction photocatalyst for efficient photocatalytic production of H2O2 and H2.

Enhanced Photocatalytic Degradation of Methyl Orange by Metal‐Tio2 Nanoparticles

AbstractIn this study, a series of transition metal‐doped TiO2 was prepared by a simple sol‐solvothermal method. Mix an ethanol solution of tetrabutyl titanate and metal nitrate solution to obtain a homogeneous sol, which is then subjected to solvothermal treatment. After calcination, the metal‐TiO2 naoncomposite was obtained. Selected transition metal precursors, including Cu, Fe, Ag, Cr, Co and Zn, were doped into TiO2 nanocatalysts to assess photocatalytic degradation activities. The results show that 1 mol % Ag−TiO2 photocatalyst has a larger specific surface area, a stable anatase phase and the narrowest forbidden band energy (3.00 eV). In photocatalytic degradation of methyl orange (MO) tests, 1 mol % Ag−TiO2 could reach 100 % decolourisation after 70 min and 75.43 % mineralisation after 90 min. ESR analysis confirmed that Ag doping significantly increased the content of ⋅O2− and ⋅OH for the TiO2 catalyst, which are responsible for the oxidation reactions and consequently degradation of pollutants. The photocatalytic degradation mechanism of MO was also proposed. The TOC analyses confirmed the mineralization of MO. The excellent thermal and chemical stability of 1 mol % Ag−TiO2 has also been demonstrated by thermogravimetric analysis and cycling experiments. Electrochemical tests have also demonstrated the excellent electrochemical properties of 1 mol % Ag−TiO2.

An anionic two dimensional covalent organic framework from tetratopic borate centres pillared by lithium ions

Non-covalent interactions play an important role for the framework formation of two-dimensional covalent organic frameworks. Until now, π–π interactions and hydrogen bonding are the main reported forces facilitating the stacking of framework layers. Here, we present a two-dimensional anionic covalent organic framework based on tetratopic borate linkages, where layers are connected by ionic interactions between the linkage site and counter cations. The crystalline covalent organic framework is accessed through the formation of an amorphous borate-based polymer and subsequent solvothermal treatment. The progress of crystallization is investigated, revealing the crystallite growth and morphological change from agglomerated dense particles to hollow crystallite spheres. Due to the pillared nature, the crystallites can be exfoliated into nanosheets by sonication of the material in the presence of methanol. The crystallization and ordered arrangement of the lithium ions in the interlayer space is shown to benefit the conductivity tenfold compared to the amorphous material.

Carbon quantum dots from carbohydrate-rich residue of birch obtained following lignin-first strategy

Carbon quantum dots (CQDs) were successfully synthesized from carbohydrate-rich residue of birch obtained following the lignin-first strategy. The optical and physicochemical properties of the CQDs were studied, along with their potential for photocatalytic pollutant degradation. By combining solvothermal and chemical oxidation methods, the product yield of CQDs from carbohydrate-rich residue reached 8.1 wt%. Doping nitrogen enhances the graphitization of CQDs and introduces abundant amino groups to the surface, thereby boosted the quantum yield significantly from 8.9 % to 18.7 %-19.3 %. Nitrogen-doped CQDs exhibited efficient photocatalytic degradation of methylene blue, reaching 37 % within 60 min, with a kinetic degradation rate of 0.00725 min−1. This study demonstrates that carbohydrate-rich residue obtained from lignin-first strategy are ideal precursors for synthesizing CQD with high mass yield and quantum yield by combining solvothermal treatment and chemical oxidation methods, offering a novel approach for the utilization of whole biomass components following the lignin-first strategy.

Recycling of Nd−Fe−B sintered magnets into a single phase by solvothermal treatment and CaH2 reduction-diffusion

Recycling computer hard disk drives from Waste Electrical and Electronic Equipment (WEEE) has been achieved according to a two-step approach that combines solvothermal treatment and CaH2 reduction-diffusion, resulting in the production of a single-phase material. The magnets underwent solvothermal treatment, followed by CaH2 reduction at varying temperatures (200°C, 250°C and 300°C). We examined the impact of CaH2 as a reducing agent on the final product, using X-ray diffraction, Mössbauer spectrometry and SQUID magnetometry. After the solvothermal treatment, the powder contains both Nd2Fe14BHx and Nd(OH)3 phases. At 200°C, Nd(OH)3 was reduced without degradation of the magnetic Nd2Fe14BHx phase, as confirmed by Mössbauer spectrometry. Furthermore, an analysis of the magnetic properties indicates an increase in magnetization after CaO removal, confirming its successful elimination.

Synergistic effect of carbon nanotube and encapsulated carbon layer enabling high-performance SnS2-based anode for lithium storage

Tin disulfide (SnS2), due to large interlayer spacing and high theoretical capacity, is regarded as a prospective anode material for lithium-ion batteries. Nevertheless, the poor electron conductivity of SnS2 and huge volumetric change during the lithiation/delithiation process lead to a rapid capacity decay of the battery, hindering its commercialization. To address these issues, herein, SnS2 is in-situ grown on the surface of carbon nanotubes (CNT) and then encapsulated with a layer of porous amorphous carbon (CNT/SnS2@C) by simple solvothermal and further carbonization treatment. The synergistic effect of CNT and porous carbon layer not only enhances the electrical conductivity of SnS2 but also limits the huge volumetric change to avoid the pulverization and detachment of SnS2. Density functional theory calculations show that CNT/SnS2@C has high Li+ adsorption and lithium storage capacity achieving high reaction kinetics. Consequently, cells with the CNT/SnS2@C anode exhibit a high lithium storage capacity of 837 mAh/g after 100 cycles at 0.1 A/g and retaining a capacity of 529.8 mAh/g under 1.0 A/g after 1000 cycles. This study provides a fundamental understanding of the electrochemical processes and beneficial guidance to design high-performance SnS2-based anodes for LIBs.

Irinotecan-loaded magnetite-silica core-shell systems for colorectal cancer treatment

Colorectal cancer represents a worldwide spread type of cancer and it is regarded as one of the leading death causes, along with lung, breast, and prostate cancers. Since conventional surgical resection and chemotherapy proved limited efficiency, the use of alternative drug delivery systems that ensure the controlled release of cytostatic agents possess immense potential for treatment. In this regard, the present study aimed to develop and evaluate the efficiency of a series of irinotecan-loaded magnetite-silica core–shell systems. The magnetite particles were obtained through a solvothermal treatment, while the silica shell was obtained through the Stöber method directly onto the surface of magnetite particles. Subsequently, the core–shell systems were physico-chemically and morpho-structurally evaluated trough X-ray diffraction (XRD) and (high-resolution) transmission electron microscopy ((HR-)TEM) equipped with a High Annular Angular Dark Field Detector (HAADF) for elemental mapping. After the irinotecan loading, the drug delivery systems were evaluated through Fourier-transform infrared spectroscopy (FT-IR), thermogravimetry and differential scanning calorimetry (TG-DSC), and UV–Vis spectrophotometry. Additionally, the Brunauer–Emmett-Teller (BET) method was employed for determining the surface area and pore volume of the systems. The biological functionality of the core-shells was investigated through the MTT assay performed on both normal and cancer cells. The results of the study confirmed the formation of highly crystalline magnetite particles comprising the core and mesoporous silica layers of sizes varying between 2 and 7 nm as the shell. Additionally, the drug loading and release was dependent on the type of the silica synthesis procedure, since the lack of hexadecyltrimethylammonium bromide (CTAB) resulted in higher drug loading but lower cumulative release. Moreover, the nanostructured systems demonstrated a targeted efficiency towards HT-29 colorectal adenocarcinoma cells, as in the case of normal L929 fibroblast cells, the cell viability was higher than for the pristine drug. In this manner, this study provides the means and procedures for developing drug delivery systems with applicability in the treatment of cancer.