A novel method of synthesis of small band gap SnS nanorods and its efficient photocatalytic dye degradation

Formulation of silver phosphate/graphene/silica nanocomposite for enhancing the photocatalytic degradation of trypan blue dye in aqueous solution

Photocatalytic degradation of several harmful organic compounds has been presented as a potential approach to detoxify water in recent decades. Trypan Blue (TB) is an acidic azo dye used to distinguish live cells from dead ones and it's classified as a carcinogenic dye. In this study, silver phosphate (Ag3PO4) nanoparticles and novel Ag3PO4/graphene/SiO2 nanocomposite have been successfully prepared via simple precipitation method. Afterward, their physical properties, chemical composition, and morphology have been characterized using SEM, EDS, TEM, SAED, BET, XRD, FTIR and UV-VIS spectroscopy. The specific surface area of Ag3PO4 and Ag3PO4/G/SiO2 nanocomposite were reported to be 1.53 and 84.97 m2/g, respectively. The band gap energy of Ag3PO4 and Ag3PO4/G/SiO2 nanocomposite was measured to be 2.4 and 2.307 eV, respectively. Photocatalytic degradation of Trypan blue (TB) was studied at different parameters such as pH, catalyst dosage, initial concentration, and contact time. The results showed that, at initial dye concentration of 20 ppm, pH = 2, and using 0.03 g of Ag3PO4/G/SiO2 as a photocatalyst, the degradation percent of TB dye in the aqueous solution was 98.7% within 10 min of light exposure. Several adsorption isotherms such as Langmuir, Freundlich, and Temkin adsorption isotherms have been tested in addition to the photocatalytic degradation kinetics. Both catalysts were found to follow the Langmuir isotherm model and pseudo-second-order kinetic model. Finally, the possible photocatalytic performance mechanism of Ag3PO4/G/SiO2 was proposed.

Synthesis of Cu and Zr-based coordination polymers with N/O donors and investigation of their photocatalytic activity against dye

The coordination polymers (CPs) of Cu and Zr were synthesized by the hydrothermal method. The orotic acid potassium salt (H3KL) was used as a linker, which coordinates via O-O. Whereas, 4,4'-trimethylenedipyridine (4,4'-TMDP) was used as a bifunctional monomer, which coordinates via N-N. The synthesized CPs were characterized by FTIR, P-XRD, TGA, DSC and SEM. The photocatalytic activity was investigated against methylene blue (MB) under sunlight irradiation. Both Cu-CP and Zr-CP exhibited potential activity for the degradation of MB, which was 72 % for Cu-CP and 93 % for Zr-CP. The band gap of the CPs was also investigated, and the observed value was 2.2 eV. The band gap indicates that these compounds could bring breakthroughs as photocatalysts instead of semiconductors. These kinds of CPs could be used for multiple purposes in industry and in a green environment.

Nanosensitizer-mediated augmentation of sonodynamic therapy efficacy and antitumor immunity

The dense stroma of desmoplastic tumor limits nanotherapeutic penetration and hampers the antitumor immune response. Here, we report a denaturation-and-penetration strategy and the use of tin monosulfide nanoparticles (SnSNPs) as nano-sonosensitizers that can overcome the stromal barrier for the management of desmoplastic triple-negative breast cancer (TNBC). SnSNPs possess a narrow bandgap (1.18 eV), allowing for efficient electron (e-)-hole (h+) pair separation to generate reactive oxygen species under US activation. More importantly, SnSNPs display mild photothermal properties that can in situ denature tumor collagen and facilitate deep penetration into the tumor mass upon near-infrared irradiation. This approach significantly enhances sonodynamic therapy (SDT) by SnSNPs and boosts antitumor immunity. In mouse models of malignant TNBC and hepatocellular carcinoma (HCC), the combination of robust SDT and enhanced cytotoxic T lymphocyte infiltration achieves remarkable anti-tumor efficacy. This study presents an innovative approach to enhance SDT and antitumor immunity using the denaturation-and-penetration strategy, offering a potential combined sono-immunotherapy approach for the cancer nanomedicine field.

Enhanced activation of H2O2 by bimetallic Cu2SnS3: A new insight for Cu (II)/Cu (I) redox cycle promotion

HYPOTHESIS

Despite that the development of Cu₂SnS₃ (CTS) catalyst has attracted increasing interests, few study has reported to investigate its heterogeneous catalytic degradation of organic pollutants in a Fenton-like process. Furthermore, the influence of Sn components towards Cu (II)/Cu (I) redox cycling in CTS catalytic systems remains a fascinating research.

EXPERIMENTS

In this work, a series of CTS catalysts with controlled crystalline phases were prepared via a microwave-assisted pathway and applied in the H₂O₂ activation for phenol degradation. The efficiency of phenol degradation in CTS-1/H₂O₂ system (CTS-1: the molar ratio of Sn (copper acetate) and Cu (tin dichloride) is determined to be Sn:Cu = 1:1) was systematically investigated by controlling various reaction parameters including H₂O₂ dosage, initial pH and reaction temperature. We discovered that Cu₂SnS₃ exhibited superior catalytic activity to the contrast monometallic Cu or Sn sulfides and Cu (I) acted as the dominant active sites. The higher Cu (I) proportions conduce to the higher catalytic activities of CTS catalysts. Quenching experiments and electron paramagnetic resonance (EPR) further proved that the activation of H₂O₂ by CTS catalyst produces reactive oxygen species (ROS) and subsequently leads to degradation of the contaminants. A reasonable mechanism of enhanced H₂O₂ activation in Fenton-like reaction of CTS/H₂O₂ system was proposed for phenol degradation by investigating the roles of copper, tin and sulfur species.

FINDINGS

The developed CTS acted as a promising catalyst in Fenton-like oxidation progress for phenol degradation. Importantly, the copper and tin species contribute to a synergetic effect for the promotion of Cu (II)/Cu (I) redox cycle, which thus enhanced the activation of H₂O₂. Our work may offer new insight on the facilitation of Cu (II)/Cu (I) redox cycle in Cu-based Fenton-like catalytic systems.

Sunlight-induced enhanced photocatalytic reduction of chromium (VI) and photocatalytic degradation of methylene blue dye and ciprofloxacin antibiotic by Sn3O4/SnS2 nanocomposite

Detection of residual organic and inorganic species in water bodies, including drinking water, has led to developing strategies for their removal. Here, we report a very efficient method of removing Cr(VI), organic dye, and antibiotic from water using a type-II heterojunction based on Sn₃O₄/SnS₂ solar photocatalyst. The toxic Cr(VI) species are reduced by photocatalytic methodology, while methylene blue (MB) dye and ciprofloxacin (CIP) antibiotics are removed by photocatalytic degradation. The structural, compositional, morphological, and optical properties of the hydrothermally synthesized photocatalyst have been studied. Under sunlight exposure, more than 99.9% of Cr(VI) is reduced within 60 min at a reaction rate of 0.066 min^-1. While 99.6% of MB and 90% of CIP degradation are achieved in 90 min and 120 min, corresponding to photocatalytic degradation rates of 0.043 min^-1 and 0.019 min^-1, respectively. The total organic carbon after degradation corresponded to 85.1% for MB and 72.4% for CIP mineralization. The observed photocatalytic degradation is attributed to in situ generation of reactive oxygen species (ROS), e.g., superoxide radicals and hydroxyl radicals. The role of ROS towards photocatalytic degradation of MB and CIP, respectively, was confirmed from ROS scavenging studies. The MB and CIP degradation mechanism has been discussed by analyzing their degradation products.

Novel N,C,S-TiO2/WO3/rGO Z-scheme heterojunction with enhanced visible-light driven photocatalytic performance

Novel N,C,S-TiO₂/WO₃/rGO Z scheme photocatalyst was successfully synthesized from graphite, TIOT, and ammonium metatungstate precursors. Material characteristics such as crystal structure, surface morphology, functional groups, specific surface area, elemental composition, band gap energy, and electron-hole recombination were characterized by XRD, TEM, BET, SEM/EDX, FT-IR, UV-VIS, and PL methods. The as-synthesized novel N,C,S-TiO₂/WO₃/rGO Z-scheme heterojunction photocatalyst exhibited visible light-driven photocatalytic activity (the band gap energy = 2.24 eV), could generate both effective electrons and holes, and presented the lowest electron-hole recombination rate compared to all individual components. Different factors impacting the photocatalytic decomposition of Direct Blue 71 (DB 71) by the N,C,S-TiO₂/WO₃/rGO system were studied. The results showed that pH of the solution, catalyst load, DB 71 initial concentration, and reaction time affected the DB 71 photocatalytic degradation efficiency. The DB 71 degradation completed after 100 min with a typical efficiency of over 91%, which was much better than other photocatalytic systems. The DB 71 degradation process followed the pseudo-first-order kinetics model with coefficients of determination > 0.95 for all conditions. The photocatalyst was easily regenerated, and exhibited a very good stability, with a photocatalytic degradation efficiency of over 83.0% after 3 cycles.

SnS Nanosheets for Rapid and Effective Bacteria Sterilization Under Near-infrared Irradiation

Today, the threat of pathogenic bacterial infection worldwide that leads to the increase of mortality rate strongly demands the development of new antibacterial agents that can kill bacteria quickly and effectively. Although there are a lot of antibacterial agents that have been developed so far, few studies on the antibacterial performance of SnS have been investigated at 808 nm laser. Here, we synthesized SnS nanosheets with strong near-infrared absorption performance and excellent antibacterial performance via a simple solvothermal synthesis route. The as-prepared SnS nanosheets showed excellent photothermal conversion efficiency (38.7 %), photodynamic performance, and photostability, and at the same time 99.98 % and 99.7 % sterilization effect against Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis (B. subtilis) under near-infrared irradiation (808 nm, 1.5 W/cm² ). This study suggests that SnS nanosheets could be a promising candidate for antibacterial therapy owing to the synergetic effects of photothermal and photodynamic performance.

Thioglycolic acid assisted hydrothermal growth of SnS 2D nanosheets as catalysts for photodegradation of industrial dyes

We present our work on the rapid hydrothermal synthesis of highly crystalline 2D SnS nanostructures. An innovative idea is used in which thioglycolic acid is the sulfur precursor source. Structural studies indicate the material has grown in a single-phase orthorhombic structure. The single-phase formation of the material is also confirmed from the rietveld refinement of the experimental XRD data and by raman spectroscopic analysis. Morphological studies show the formation of 2D sheets having thickness in the nanoscale (100-150 nm) dimensions. Optical absorbance studies show the material is visible-light active exhibiting an indirect bandgap of 1.1 eV and direct band gap ∼1.7 eV. Density functional theory calculations support the experimental bandgap results. Photocatalytic activity of the nanosheets was investigated against methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) dyes employing a solar simulator as the source of photons (light source). The nanosheets were found to photodegrade 80% of MB, 77% of RhB and 60% of MO in 120 min of light illumination. Reusability and post catalytic properties affirm the durability and stability of the nanosheets, which is very important in the context of waste water treatment considering the toxic nature of the effluents from dye industries.

Recognition of M2 type tumor-associated macrophages with ultrasensitive and biocompatible photoelectrochemical cytosensor based on Ce doped SnO2/SnS2 nano heterostructure

Tumor-associated macrophages (TAMs) play central roles in the regulation of tumor growth. TAMs can be differentiated into M1 and M2 types, which are responsible for the inhibition and growth of tumor tissues, respectively. Recognition of M2-TAMs is significant for the diagnosis and therapy of cancer, which is however severely limited due to the deficiency of selective and sensitive photoelectrochemical sensors. In this work, using Ce doped SnO₂/SnS₂ nano heterostructure as the highly sensitive platform, a photoelectrochemical sensor enabling the recognition of M2-TAMs was fabricated for the first time. By the decoration of CD163 antibody on the platform, the ultrasensitive photoelectrochemical sensor can selectively detect the CD163 protein on the surface of M2-TAMs. To our best knowledge, this is the first demonstration for recognition of M2-TAMs using photoelectrochemical method. The fabricated cytosensor has ultra-sensitive photocurrent response, applicable biological compatibility, high selectivity and relatively wide linear sensing range (5 × 10¹ to 1 × 10⁵ cells/ml) with a low detection limit (50 cells/ml) for the detection of M2-TAMS. This kind of PEC cytosensor would provide a novel analysis and detection strategy for M2-TAMs.

Synthesis, local structure and optical property studies of α-SnS microrods by synchrotron X-ray pair distribution function and micro-Raman shift

The PDF refinement shows layer structure of SnS-A with two distinct bond lengths, one nearly parallel to the ‘a’ axis and another perpendicular to the ‘a’ axis, it corresponds to bond lengths of 2.62528 (38) Å and 2.66204 (03) Å.

The Frontiers of Nanomaterials (SnS, PbS and CuS) for Dye-Sensitized Solar Cell Applications: An Exciting New Infrared Material

To date, extensive studies have been done on solar cells on how to harness the unpleasant climatic condition for the binary benefits of renewable energy sources and potential energy solutions. Photovoltaic (PV) is considered as, not only as the future of humanity's source of green energy, but also as a reliable solution to the energy crisis due to its sustainability, abundance, easy fabrication, cost-friendly and environmentally hazard-free nature. PV is grouped into first, second and third-generation cells. Dye-sensitized solar cells (DSSCs), classified as third-generation PV, have gained more ground in recent times. This is linked to their transparency, high efficiency, shape, being cost-friendly and flexibility of colour. However, further improvement of DSSCs by quantum dot sensitized solar cells (QDSSCs) has increased their efficiency through the use of semiconducting materials, such as quantum dots (QDs), as sensitizers. This has paved way for the fabrication of semiconducting QDs to replace the ideal DSSCs with quantum dot sensitized solar cells (QDSSCs). Moreover, there are no absolute photosensitizers that can cover all the infrared spectrum, the infusion of QD metal sulphides with better absorption could serve as a breakthrough. Metal sulphides, such as PbS, SnS and CuS QDs could be used as photosensitizers due to their strong near infrared (NIR) absorption properties. A few great dependable and reproducible routes to synthesize better QD size have attained much ground in the past and of late. The injection of these QD materials, which display (NIR) absorption with localized surface plasmon resonances (SPR), due to self-doped p-type carriers and photocatalytic activity could enhance the performance of the solar cell. This review will be focused on QDs in solar cell applications, the recent advances in the synthesis method, their stability, and long term prospects of QDSSCs efficiency.

Construction of a solar spectrum active SnS/ZnO p–n heterojunction as a highly efficient photocatalyst: the effect of the sensitization process on its performance

Comparison of photocatalytic activity of ex situ and in situ sensitized 1D SnS/ZnO in the photodegradation of multiple organic dyes under sunlight.

Preparation and characterization of electrodeposited SnS:In thin films: Effect of In dopant

SnS:In thin films were grown on fluorine doped tin oxide (FTO) substrate by cathodic electrodeposition technique. The solution was containing 2mM SnCl₂ and 16mM Na₂S₂O₃ and different amounts of 1mM InCl₃ as In-dopant. The pH, bath temperature, deposition time, and deposition potential (E) were fixed at 2.1, 60°C, 30min, and -1V, respectively. The XRD results showed that the synthesized films were polycrystalline orthorhombic SnS. The XPS results demonstrated that the films were composed of Sn, S and In. According to the FESEM images, an increase in In-dopant concentration leads to a change in morphology from grain-like to sheet-like having a nanoscale thickness of 20-80nm and fiber-like. The PL spectra of undoped SnS exhibited four emission peaks including a UV peak, two blue emission peaks, and an IR emission peak. According to the UV-Vis spectra, the direct band gap of SnS:In thin films was estimated to be 1.40-1.66eV.

Two-dimensional bismuth oxybromide coupled with molybdenum disulphide for enhanced dye degradation using low power energy-saving light bulb

In the present work, two-dimensional bismuth oxybromide (BiOBr) was synthesized and coupled with co-catalyst molybdenum disulphide (MoS₂) via a simple hydrothermal process. The photoactivity of the resulting hybrid photocatalyst (MoS₂/BiOBr) was evaluated under the irradiation of 15 W energy-saving light bulb at ambient condition using Reactive Black 5 (RB5) as model dye solution. The photo-degradation of RB5 by BiOBr loaded with 0.2 wt% MoS₂ (MoBi-2) exhibited more than 1.4 and 5.0 folds of enhancement over pristine BiOBr and titanium dioxide (Degussa, P25), respectively. The increased photocatalytic performance was a result of an efficient migration of excited electrons from BiOBr to MoS₂, prolonging the electron-hole pairs recombination rate. A possible charge transfer diagram of this hybrid composite photocatalyst, and the reaction mechanism for the photodegradation of RB5 were proposed.

Growth of single-crystalline cubic structured tin(ii) sulfide (SnS) nanowires by chemical vapor deposition

SnS nanowires with high aspect-ratio were developed by chemical vapor deposition and their physical and chemical properties were explored, along with their field effect transistor characteristics.

3D porous ZnO–SnS p–n heterojunction for visible light driven photocatalysis

3D porous ZnO–SnS is prepared as a highly efficient, low cost, and low toxicity visible light driven photocatalyst.

Non-stoichiometric SnS microspheres with highly enhanced photoreduction efficiency for Cr(vi) ions

Sn²⁺ self-doped SnS microparticles were synthesized via a simple template-free hydrothermal route. The ability to tune the band structure while minimizing defect generation makes self-doped SnS an efficient photocatalyst for treating waste water.

The design of new magnetic-photocatalyst nanocomposites (CoFe2O4–TiO2) as smart nanomaterials for recyclable-photocatalysis applications

Magnetically recyclable 3D CoFe₂O₄–TiO₂photocatalyst nanocomposite.

A mechanistic approach for superoxide radicals and singlet oxygen mediated enhanced photocatalytic dye degradation by selenium doped ZnS nanoparticles

Superoxide and singlet oxygen mediated photocatalytic dye degradation by Se-doped ZnS NPs.

Ethylene glycol mediated synthesis of SnS quantum dots and their application towards degradation of eosin yellow and brilliant green dyes under solar irradiation

SnS (tin sulfide) quantum dots (QDs) were synthesized by a chemical coprecipitation method using ethylene glycol as a solvent and capping agent and thiourea as a sulfur source at a temperature of 160 °C, 4 h.