Se Nanoparticles Research Articles

Simultaneous removal of lead and selenium through biomineralization as lead selenide by anaerobic granular sludge

This study demonstrated the simultaneous removal of lead (Pb) and selenium (Se) as lead selenide biomineralization using anaerobic granular sludge. The microbial community of the granular sludge was first enriched for 140 days in the presence of Pb(II) only, selenate and selenite only, Pb(II)+selenate, and Pb(II)+selenite. In the absence of Se, removal of Pb(II) mainly occurred via biosorption and deposited on the biomass as lead oxide and lead carbonate. The Pb removal efficiency (94% of initial 50 mg L-1) was reduced to 90% and 86% in the presence of selenate and selenite, respectively, due to biosorption. Addition of Pb(II) didn’t exert any toxic effect on the Se-reducing microbial community, on the contrary: Pb(II) addition improved the Se removal efficiency for selenate from 85% to 90%, but did not affect selenite removal after 14 d of incubation. The bioreduction of the Se-oxyanions produced elemental Se (Se(0)) and selenide, which later interacted with Pb(II) to produce lead selenide (PbSe). Adsorption of Pb(II) onto the Se(0) nanoparticles and precipitation as the Se(0)-Pb complex might also have contributed to the simultaneous removal of Pb and Se. XPS and XRD analysis further confirmed the immobilization of Pb as PbSe, PbO and PbCO3 in the biomass.

Nanoselenium versus bulk selenium as a dietary supplement: Effects on growth, feed efficiency, intestinal histology, haemato‐biochemical and oxidative stress biomarkers in Nile tilapia ( Oreochromis niloticus Linnaeus, 1758) fingerlings

Five isonitrogenous (30% crude protein) diets were formulated to contain two forms of selenium (Se): convention Se named Bulk-Se or Se nanoparticles (Nano-Se), both forms of Se supplemented at two levels 0.4 and 0.8 mg kg−1 diet compared to the control diet without addition for a period of 84 days. Nile tilapia, Oreochromis niloticus, fingerlings (5.0 ± 0.2 g) fed tested diets in triplicates at a rate of 5% of their total biomass three times a day for 84 days. The results showed that the best growth performance and amylase and lipase enzymes activity (p ≤ 0.05) were observed in fish fed 0.4 or 0.8 mg kg−1 Nano-Se diet. In anterior intestine, fish fed 0.8 mg kg−1 Nano-Se recorded the highest level (p ≤ 0.05) of villi height and width and goblet cell number. The highest values mucosal-to-serosal amplification ratio (MSR) and absorption area of villous were recorded in fish fed 0.4 mg kg−1 Nano-Se. Fish fed 0.8 mg kg−1 Nano-Se recorded the highest value (p ≤ 0.05) of villi height, villi width, MSR and crypt thickness, while fish fed the control diet recorded the lowest level one in posterior intestine. In addition, fish fed 0.8 mg kg−1 Nano-Se noted the best values of haemoglobin, haematocrit, red blood cells and white blood cell count. Alanine and aspartate aminotransferases were lower, while total serum protein, albumin and globulin contents were significantly higher in fish fed diet contained 0.4 or 0.8 mg kg−1 Nano-Se compared to Bulk-Se and control diet. The highest significant values of superoxide dismutase, catalase, glutathione peroxidase, glutathione, glutathione-S-transferase and glutathione reductase activity accompanied with the lowest MDA value recorded of fish fed diet supplemented with 0.8 mg kg−1 Nano-Se. The results indicated that the inclusion of Nano-Se at 0.8 mg kg−1 was the recommended source and level of Se to improve performance, efficiency of nutrient, digestive enzyme activity and absorption surface of intestine, haemato-biochemical parameters and oxidative stress responses of Nile tilapia compared with other treatments.

Salt Stress Mitigation via the Foliar Application of Chitosan-Functionalized Selenium and Anatase Titanium Dioxide Nanoparticles in Stevia (Stevia rebaudiana Bertoni).

High salt levels are one of the significant and major limiting factors on crop yield and productivity. Out of the available attempts made against high salt levels, engineered nanoparticles (NPs) have been widely employed and considered as effective strategies in this regard. Of these NPs, titanium dioxide nanoparticles (TiO2 NPs) and selenium functionalized using chitosan nanoparticles (Cs–Se NPs) were applied for a quite number of plants, but their potential roles for alleviating the adverse effects of salinity on stevia remains unclear. Stevia (Stevia rebaudiana Bertoni) is one of the reputed medicinal plants due to their diterpenoid steviol glycosides (stevioside and rebaudioside A). For this reason, the current study was designed to investigate the potential of TiO2 NPs (0, 100 and 200 mg L−1) and Cs–Se NPs (0, 10 and 20 mg L−1) to alleviate salt stress (0, 50 and 100 mM NaCl) in stevia. The findings of the study revealed that salinity decreased the growth and photosynthetic traits but resulted in substantial cell damage through increasing H2O2 and MDA content, as well as electrolyte leakage (EL). However, the application of TiO2 NPs (100 mg L−1) and Cs–Se NPs (20 mg L−1) increased the growth, photosynthetic performance and activity of antioxidant enzymes, and decreased the contents of H2O2, MDA and EL under the saline conditions. In addition to the enhanced growth and physiological performance of the plant, the essential oil content was also increased with the treatments of TiO2 (100 mg L−1) and Cs–Se NPs (20 mg L−1). In addition, the tested NPs treatments increased the concentration of stevioside (in the non-saline condition and under salinity stress) and rebaudioside A (under the salinity conditions) in stevia plants. Overall, the current findings suggest that especially 100 mg L−1 TiO2 NPs and 20 mg L−1 Cs–Se could be considered as promising agents in combating high levels of salinity in the case of stevia.

Rich Se nanoparticles modified cobalt carbonate hydroxide as an efficient electrocatalyst for boosted hydrogen evolution in alkaline conditions

Nonprecious metal hydroxides are promising electrocatalyst candidates for oxygen evolution reaction. However, their hydrogen evolution reaction (HER) performance is not satisfactory, which limits their application for water splitting. Herein, a facile electrodeposition reduction strategy was applied to fabricate rich Se nanoparticles modified cobalt carbonate hydroxide nanoarrays on carbon cloth (Se NPs/CoCH NAs/CC) with η10 of 84.3 mV for HER, which is much smaller than that of original CoCH NAs/CC (η10 = 347.7 mV). The superior performance of Se NPs/CoCH NAs/CC was due to its large active surface area, rich active sites, and synergistic effect between Co-Se. DFT simulations also revealed that free energy for atomic hydrogen adsorption is much lower on Se NPs/CoCH (0.75 eV) than on CoCH (1.36 eV). Moreover, this work offered a simple and efficient strategy for developing hierarchical selenium/hydroxides with outstanding HER performance, which contributed to the cost and energy savings for mass hydrogen production.

Biological Removal of Se and Cd from Acidic Selenite- and Cadmium-containing Wastewater with Limited Carbon Availability.

This study presents a successful treatment of biological acidic Se(IV)- and Cd(II)-containing wastewater via the SBR with limited carbon source (100 mg/L COD). Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), high solution transmission electron microscopy (HRTEM) and X-ray photoelectron spectrometer (XPS) results verified the formation of elemental Se and CdSe nanoparticles in the sludge. The abundance of genera in the microbial community gradually changed over the treatment phases depending on the Se(IV) and Cd(II) exposure with different influent COD concentrations. The taxa of Proteiniclasticum, Clostridium_sensu_stricto_12, Longilinea and Mycobacterium were dominant. Redundancy analysis (RDA) indicates that COD concentrations had the greatest impact on Zoogloea and Pseudomonas by promoting an increased abundance and decreased abundance, respectively. Overall, the results extended our understanding of the mechanisms and microbial community responding for the Se(IV) and Cd(II) removal under limited carbon availability in acidic wastewater.

Citrullus colocynthis extract and synthesized Selenium nanoparticles enhance non‐specific response and resistance against Aeromonas sobria in Nile tilapia ( Oreochromis niloticus )

The effects of Citrullus colocynthis extract (CCE) and synthesized Se nanoparticles (Nano-Se) on non-specific immune response and resistance to Aeromonas sobria in Nile tilapia (Oreochromis niloticus) were investigated. Treatments included three levels of Nano-Se (0.5, 1 and 2 mg/kg of feed), three levels of CCE (0.1%, 0.3% and 0.5%) and control group (no additives). The diets were fed for 4 weeks, and biochemical indices, serum lysozyme, respiratory burst activities and antioxidant enzymes were measured on weeks 1, 2 and 4. After 4 weeks of feeding, fish were infected with A. sobria and mortalities were recorded for 14 days. Results of this study showed that feeding tilapia with CCE and Nano-Se supplements significantly enhanced biochemical indices, serum lysozymes and respiratory burst. CCE treatments had a moderate effect on superoxide dismutase and no effect on the other antioxidant enzymes. Nano-Se treatments had significantly positive effects on antioxidant enzymes. Both CCE and Nano-Se supplements reduced mortality following A. sobria infection. The lowest mortality (13%) was observed in the group fed with 2 mg/kg Nano-Se, and the highest mortality of 90% was observed in the control group. It can be concluded that C. colocynthis extract and synthesized Nano-Se supplementation added to fish feed can act as immunostimulants and enhance the immune functionality, antioxidant status and disease resistance in cultured Nile tilapia (O. niloticus).

Synthesis of C:Se nanoparticles via laser ablated with magnetic field on porous silicon for gas sensor applications

The presented study synthesized C:Se NPs via a combination of the laser along with magnetic field at various laser pulse energies 200, 600 and 1000mJ with 100 shots, have been deposited on the porous silicon (PS) through the use of drop-casting method. The pattern of the X-ray diffraction (XRD) had indicated the nanocrystaline of specimens. In Atomic force microscopy (AFM), which shows agglomeration of C:Se NPs increased, the distribution of the granularity showed that the distribution of part was almost Gaussian, also the transmission electron microscope (TEM) indicated that the synthesized C:Se particles have an average particle size of 35 nm. Bright-field TEM images show complementary contrast, confirming the formation of core/shell structures. The optical measurements in wavelength range ultraviolet-visible near infrared (UV–vis–NIR) as well as a transition of indirect type with 4 eV band gap is specified. Also, the electrical characteristics like barrier height (ΦB), ideal factor (n) for Al/C:Se NPs/PS/Si/Al heterojunction were concluded with measurements of current-voltage (I-V). Lastly, the operation temperature variations associated with NO2 and NH3 gas sensors are subjected to fabrication from the prepared samples on response time, sensor sensitivity and recover time was examined. The maximum sensitivity of C:Se/PS at 1000 mJ gas sensor to 60 ppm of NO2 about 202.5% at around 100 °C,also the maximum sensitivity of C:Se/PS at 1000mJgas sensor to 200 ppm of NH3 can reach 17.9%, and the optimum sensing temperature of C: Se/PS sensor is at around 150 °C.

Co0.85Se nanoparticles armored by N-doped carbon layer with electronic structure regulation functions: An efficient oxygen evolution electrocatalyst

In this work, with the assistance of polymeric nonionic surfactant Pluronic F127, 2D nanosheets glycerol cobalt self-assembled into the ball-flower structure composites (CoG@F127). Then, CoG@F127 is coated by polydopamine (PDA) to form CoG@F127@PDA. After the calcination with Se powder, CoG@F127@PDA is transformed into the ball-flower hierarchical structure Co0.85Se-NC/C, in which Co0.85Se nanoparticles are coated with nitrogen doped carbon (NC). The Co0.85Se nanoparticles anchored on the NC can avoid the aggregation, maintain structure stability and expose more electrocatalytic active sites for oxygen evolution reaction (OER). Specially, Co0.85Se-NC/C-750 shows a small Tafel slope of 47.2 mV dec-1 in 1.0 M KOH that is even lower than IrO2 and most of the reported Co-based catalysts. Besides, the theoretical calculations by density functional theory (DFT) suggest that NC could tailor the electronic structure of Co0.85Se, leading to optimized free energy change (ΔG) of the speed-controlled step and density of states (DOS).

Improvement of responsivity of C:Se nanoparticles ablated on porous silicon

The effectiveness of applying an external magnetic field in the C:Se/PS was studied nanoparticle (NPs) synthesized in a laser wavelength generated by a Q-switched- laser via pulsed Laser Ablation in 1064 nm. The pattern of the X-ray diffraction (XRD) had indicated the nano-crystaline of specimens. Results of the Atomic force microscope (AFM) analysis for C:Se/PS showed have decreased the average roughness after magnetic field application. UV–vis result displayed that the gap of the optical energy of nano-particles increase from 3.6 to 4.2 eV following the application of magnetic field throughout ablation. The electrical characteristics like the ideal factor (n) and barrier height (ΦB) for Al/C:SeNPs/PS/Si/Al heterojunction have been determined with measurements of current-voltage (I-V). In addition, the effectiveness of C:Se/PS photodetectors was improved across a wide range of wavelengths, the quantum efficiency (Q.E) of C:Se/PS photodetectors decreased from 85% to 23% at 600 nm following the application of magnetic field throughout ablation.

Conditions adjustment of polycaprolactone nanofibers scaffolds encapsulated with core shells of Au@Se via laser ablation for wound healing applications

Au@Se core–shell nanoparticles were obtained via laser ablation technique to be incorporated into polycaprolactone (PCL) nanofibrous scaffolds for wound healing applications at different contributions of Se nanoparticles (SeNPs). The synthesized layers were inspected via X-ray diffraction (XRD) and Fourier transformed infrared (FTIR). Additionally, microstructural and surface morphology were followed with different SeNPs contributions before and after fibroblast culturing. Moreover, Selenium dopant is affected Maximum roughness valley depth while it starts from 0.31 µm at Au@0.0Se@PCL reaching 0.457 µm at Au@12Se@PCL; however, after culturing starts from 0.3833 µm reaching 0.41 µm. Besides, the antibacterial activity was screened, showing the absence of inhibition zones in free selenium composition; however, it grows up reaching 8.3 ± 0.8, and 8.0 ± 0.8 for E. coli and S. aureus, respectively at the maximum contribution of selenium. SeNPs contributed composites show higher cell viability than Selenium free composite that it reaches its max in Au@8.0Se@PCL, recording 95.3 ± 2.3%. Composites show an excellent Wound dressing capability that its performance is directly proportional to selenium content. This significant enrichment of antibacterial activity and cell viability could recommend these composites for additional research in medical applications.

Biogenic Selenium Nanoparticles: A Fine Characterization to Unveil Their Thermodynamic Stability.

Among the plethora of available metal(loid) nanomaterials (NMs), those containing selenium are interesting from an applicative perspective, due to their high biocompatibility. Microorganisms capable of coping with toxic Se-oxyanions generate mostly Se nanoparticles (SeNPs), representing an ideal and green alternative over the chemogenic synthesis to obtain thermodynamically stable NMs. However, their structural characterization, in terms of biomolecules and interactions stabilizing the biogenic colloidal solution, is still a black hole that impairs the exploitation of biogenic SeNP full potential. Here, spherical and thermodynamically stable SeNPs were produced by a metal(loid) tolerant Micrococcus sp. Structural characterization obtained by Scanning Electron Microscopy (SEM) revealed that these SeNPs were surrounded by an organic material that contributed the most to their electrosteric stabilization, as indicated by Zeta (ζ) potential measurements. Proteins were strongly adsorbed on the SeNP surface, while lipids, polysaccharides, and nucleic acids more loosely interacted with SeNMs as highlighted by Fourier Transform Infrared Spectroscopy (FTIR) and overall supported by multivariate statistical analysis. Nevertheless, all these contributors were fundamental to maintain SeNPs stable, as, upon washing, the NM-containing extract showed the arising of aggregated SeNPs alongside Se nanorods (SeNRs). Besides, Density Functional Theory (DFT) calculation unveiled how thiol-containing molecules appeared to play a role in SeO32− bioreduction, stress oxidative response, and SeNP stabilization.

Synthesis of C:Se nanoparticles ablated on porous silicon for sensing NO2 and NH3 gases

In this work, synthesis and characterizing of carbon: selenium nanoparticles (C:Se NPs) are synthesized by laser ablation Q-switched Nd:YAG laser with wavelength of 1064 nm at different laser pulses energy 200, 600 and 800 mJ with 100 shots and porous silicon (PS) was presented. X-ray diffraction (XRD) was utilized for examining the structural properties. In addition, the results of the Atomic force microscope (AFM) analysis an 39.76 nm as average diameter which is coordinated in rod-like shape appearing for C:Se NPs, also the transmission electron microscope (TEM) indicated that the synthesized C:Se particles have been spherical with average particle size in range of (25 and 75) nm. Lastly, the variations of operation temperature related toNH3 and NO2 gas sensors that are fabricated from prepared samples on the sensor sensitivity, recover time and response time were examined, the maximum sensitivity is approximately 205% with regard to (C:Se NPs) ablated via laser energy 800mJ on PS of gas NO2, also the maximum sensitivity is approximately 43% in terms of(C:Se NPs) ablated via laser energy 200mJ on PS of gas NH3.

Novel nanoformulated combination of Se and CeO2 particles loaded polylactic‐co‐glycolic acid vesicle to improved anti‐inflammation and auto‐regenerative for the treatment and care of spinal cord injury

Polymer functionalized nanoparticles (NPs) have a great attention in biomedical applications owing to their unique properties like regenerative antioxidant, anti‐inflammatory, auto‐catalytic properties, and biocompatibility. In this current work, we demonstrated a facile synthesis of Se‐CeO2 via chemical method followed by precipitation method. The prepared Se NPs were characterized by ultraviolet–visible (UV‐vis) spectroscopy, and the size and morphology of the NPs were analysed using transmission electron microscopy (TEM). Meanwhile, Se‐CeO2 NPs loaded on polylactic‐co‐glycolic acid (PLGA) nanocarrier were characterised by Fourier transform infrared (FT‐IR), scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), TEM, and energy dispersive X‐ray analysis (EDAX) mapping techniques. The morphological and spectroscopic investigations of prepared nanomaterials have exhibited favourable morphological structure and chemical interactions with respective polymeric molecules, which established that nanovesicle suitability for the SCI functional recovery. We first investigated Se nanoformulated CeO2 material for the potential healing of in vitro spinal cord study. Our results demonstrated that preparation of NPs loaded PLGA nanocarrier has provide effective spinal cord regeneration and imply that it was explored that promising nanocarrier in the SCI treatment. Se‐NPs encapsulated CeO2 nanostructures administrations for SCI therapies have greatly suppressed oxidative stress and induced anti‐inflammatory action, which leads to prospective therapeutic benefits of spinal cord regeneration. These investigative results demonstrate that Se‐CeO2 NPs with PLGA carrier could have great attention for effecient functional recovery treatment and care for spinal cord injury.

Thermal-assisted photocatalytic H2 production over sulfur vacancy-rich Co0.85Se/Mn0.3Cd0.7S nanorods under visible light

Defect engineering, heterojunction construction and photo–thermal synergy are efficient means to improve photocatalytic performance. Herein, we present Co0.85Se nanoparticles in-situ grown on sulfur vacancy-rich MnxCd1−xS nanorods. The as-obtained Co0.85Se/Mn0.3Cd0.7S heterojunctions achieved H2-production rate of 46.7 mmol/h/g at 5 ℃, which is 14 times higher than sulfur vacancy-poor Mn0.3Cd0.7S and better than 1 wt% Pt/Mn0.3Cd0.7S. Sulfur vacancies, nonstoichiometric Co0.85Se and Co0.85Se/MnxCd1−xS heterojunctions provide more active sites, harvest light and speed up charge carriers transfer for photocatalytic process. Moreover, elevating reaction temperature can decrease charge-transfer resistance, promote the kinetics for reducing H2O to H2, and thus accelerate H2-generation rate (up to 79.7 mmol/h/g at 25 ℃). The apparent quantum yield increases from 29.3% to 37.0% when the reaction temperature rises from 5 to 25 ℃. This work proposes a promising strategy for the application of sulfur vacancy and nonstoichiometric metal-selenide cocatalyst in thermo-assisted photocatalysis.

Preparation and characterization of C:Se nano-rods ablated on porous silicon

In this work, Carbon:Selenium (C:Se) nanoparticles (NPs) are preparation by laser ablation at diverse laser energy 200, 400, 600,800 and 1000 mJ with 100 shots and laser wavelength 1064 nm then deposited on porous silicon (PS). PS are fabricated using electrochemical etching (ECE) method for p-type crystalline silicon (c-Si) wafers of (100) orientation.The pattern of X-ray diffraction (XRD) showed the sample's nanocrystaline.Results of the Atomic force microscope (AFM) analysis an average diameter of 39.76 nm coordinated in a rod-like shape appears for C:Se NPs. UV–vis result displayed that the optical energy gap of the nanoparticles increases. The electrical properties such as barrier height (ΦB) and ideality factor (n) of the Al/C:SeNPs/PS/Si/Al heterojunction were determined from the current density-voltage (J-V) measurements.

Metal-organic-framework-derived multi-heteroatom doped Cu1.8Se/C composites for high-performance Na-ion hybrid capacitor

A series of smulti-heteroatom doped Cu1.8Se/C composites are synthesized through a one-step direct selenization of Cu-based MOF containing hexa(4-carboxyl-phenoxy)-cyclotriphosphazene (HCTP-COOH) ligand. The MOF-derived Cu1.8Se/C composites with nanosheet structures are characterized to be Cu1.8Se nanoparticles embedded in carbon matrix doped with N, P and O atoms. The superior sodium-storage performance of Cu1.8Se/C-450 composite is proven to be resulted from the high specific surface area, the unique structure and the multi-heteroatom doping. The Na-ion half-cells from Cu1.8Se/C-450 electrodes exhibit a maximum capacity of 372.9 mA h g−1 at 50 mA g−1, an satisfactory rate capacity (133.3 mA h g−1 at 5 A g−1) and modest cycling stability. A sodium-ion hybrid capacitor (SHIC) device Cu1.8Se/C-450//AC assembled with Cu1.8Se/C-450 and AC shows desirable energy-storage properties. It delivers a maximum energy density of 65.8 W h kg−1 at 81.4 kW kg−1, and a capacity retention of 75.3% with 3000 testing cycles at 2 A g−1 with the operation voltage window of 0–4.0 V. The prospects of stated materials synthesis strategy and application of the as-prepared material Cu1.8Se/C-450 in SHIC device are presented.

Biological selenite removal and recovery of selenium nanoparticles by haloalkaliphilic bacteria isolated from the Nakdong River.

Microbial selenite reduction has increasingly attracted attention from the scientific community because it allows the separation of toxic Se from waste sources with the concurrent recovery of Se nanoparticles, a multifunctional material in nanotechnology industries. In this study, four selenite-reducing bacteria, isolated from a river water sample, were found to reduce selenite by > 85% within 3d of incubation, at ambient temperature. Among them, strain NDSe-7, belonging to genus Lysinibacillus, can reduce selenite and produce Se nanospheres in alkaline conditions, up to pH 10.0, and in salinity of up to 7.0%. This strain can reduce 80mg/L of selenite to elemental Se within 24hat pH 6.0-8.0, at a temperature of 30-40°C, and salinity of 0.1-3.5%. Strain NDSe-7 exhibited potential for use in Se removal and recovery from industrial saline wastewater with high alkalinity. This study indicates that extremophilic microorganisms for environmental remediation can be found in a conventional environment.

In Vivo Bioavailability of Selenium in Selenium-Enriched Streptococcus thermophilus and Enterococcus faecium in CD IGS Rats

The selenium (Se) enrichment of yeasts and lactic acid bacteria (LAB) has recently emerged as a novel concept; the individual health effects of these beneficial microorganisms are combined by supplying the essential micronutrient Se in a more bioavailable and less toxic form. This study investigated the bioavailability of Se in the strains Enterococcus faecium CCDM 922A (EF) and Streptococcus thermophilus CCDM 144 (ST) and their respective Se-enriched forms, SeEF and SeST, in a CD (SD-Sprague Dawley) IGS rat model. Se-enriched LAB administration resulted in higher Se concentrations in the liver and kidneys of rats, where selenocystine was the prevalent Se species. The administration of both Se-enriched strains improved the antioxidant status of the animals. The effect of the diet was more pronounced in the heart tissue, where a lower glutathione reductase content was observed, irrespective of the Se fortification in LAB. Interestingly, rats fed diets with EF and SeEF had higher glutathione reductase activity. Reduced concentrations of serum malondialdehyde were noted following Se supplementation. Diets containing Se-enriched strains showed no macroscopic effects on the liver, kidneys, heart, and brain and had no apparent influence on the basic parameters of the lipid metabolism. Both the strains tested herein showed potential for further applications as promising sources of organically bound Se and Se nanoparticles.

Ni0.85Se/MoSe2 Interfacial Structure: An Efficient Electrocatalyst for Alkaline Hydrogen Evolution Reaction

Catalyzing hydrogen evolution reaction in alkali media is challenging owing to the sluggish kinetics, originated from the water dissociation process. In this context, synergistic coupling between Ni/Co-based materials with transition metal dichalcogenides (TMDs) often accelerates the alkaline hydrogen evolution reaction (HER). Significant interaction between the two components and active-site density are the keys for achieving a promising catalytic activity. This report emphasizes a two-step selenization approach to prepare a Ni0.85Se/MoSe2 interfacial structure with abundant active sites. Initially, Ni0.75Se nanoparticles were prepared using the solvothermal method and subsequently employed them as a support for the growth of MoSe2 under hydrothermal conditions. This resulted in the formation of a Ni0.85Se/MoSe2 interfacial structure. The results of physical characterization techniques confirm the significant interaction between Ni0.85Se and MoSe2. The interfacial structures showed a superior HER activity in alkali media compared to the individual components; especially, Ni0.85Se/MoSe2 (20) delivers a current density of 10 mA cm–2 at an overpotential of 108 mV. The improved HER activity of the interfacial structure is attributed to the (i) efficient water dissociation process over the Ni0.85Se promoter and (ii) exposure of more catalytic active sites (edges) of MoSe2. In addition, as-prepared Ni0.75Se exhibits a better oxygen evolution reaction (OER) activity by delivering a current density of 10 mA cm–2 at an overpotential of 340 mV. Furthermore, overall water splitting has been demonstrated by constructing an electrolyzer using Ni0.85Se/MoSe2 (20) and Ni0.75Se as a cathode and anode, respectively. The electrolyzer delivers a current density of 10 mA cm–2 at a cell potential of 1.7 V. The long-term stability experiment and the post catalytic characterization reveals the high robustness of the Ni0.85Se/MoSe2 interfacial structure.

The cellular immunotherapy of integrated photothermal anti-oxidation Pd–Se nanoparticles in inhibition of the macrophage inflammatory response in rheumatoid arthritis

Reducing the inflammatory response is a major goal in the therapy of rheumatoid arthritis (RA). Herein, we integrated palladium nanoparticles (Pd NPs) with selenium nanoparticles (Se NPs) and obtained a multiple nanosystem (Pd@Se-HA NPs) that could simultaneously scavenge hydroxyl radicals (⋅OH) and provide a photothermal effect. The Pd@Se-HA NPs were constructed by a simple self-assembly method in which Se NPs were electrostatically bonded to Pd NPs; hyaluronic acid (HA) was linked to the NPs by ester bonding to provide macrophage targeting ability. The experiments show that the combined therapy of eliminating ⋅OH with Se NPs and utilizing PTT with Pd NPs could effectively reduce the inflammatory response in macrophages more effectively than either individual NP treatment. In addition, the outer layer of HA could specifically target the CD44 receptor to enhance the accumulation of Pd@Se NPs at the lesion, further enhancing the therapeutic effect. After treatment for 15 days, the Pd@Se-HA NPs nearly eliminated the inflammatory response in the joints of mice in an induced RA model, and prevented joint damage and degradation.