Effect of nanostructured MoS2 morphology on the glucose sensing of electrochemical biosensors

In this study, the effects of the morphological characteristics of MoS₂ nanomaterials on the glucose sensing of electrochemical biosensors were explored. Nanostructured MoS₂ materials, including nanoparticles (NPs), nanoflowers (NFs), and nanoplatelets (NPLs), were prepared via a simple hydrothermal method. The structure and morphological characteristics of MoS₂ nanomaterials were examined through X-ray diffraction, field emission scanning electron microscopy, and Raman spectroscopy. Electrochemical properties were analyzed through cyclic voltammetry. Results showed that the obtained sensitivity was 64, 68.7, and 77.6 μAmM⁻¹ cm⁻² for MoS₂ NP-, MoS₂ NF-, and MoS₂ NPL-based biosensors, respectively. The limit of detection (LOD) of all MoS₂-based glucose biosensors was 0.081 mM. In addition, the pH, temperature, glucose oxidase (GOx) concentration, reproducibility, specificity, and stability of glucose biosensors with different MoS₂ morphologies were also investigated and indicated the oxidation current response of the MoS₂ NPL-based glucose biosensor was higher than that of MoS₂ NF- and NP-based biosensors.     

Growth of monolayer and bilayer MoS2 through the solution precursor for high-performance photodetectors

Various studies suggest that the performances of TMDs are largely thickness dependent. In this paper, we develop a chemical vapor deposition method to synthesis monolayer and bilayer MoS₂ flakes with a solution precursor. The MoS₂ phototransistors were prepared to investigate their optoelectronic performance. The MoS₂ photodetectors exhibit high detectivity of 2.44 × 10¹¹ and a fast response/recovery time of 97 ms/291 ms. The photoresponsivity of bilayer MoS₂ flakes was found up to 7160 A W⁻¹. Our research will pave a pathway to control the layer numbers of other TMDs nanostructures, expand the application of high performance 2D materials.     

Microwave-assisted rapid synthesis of Ag nanoparticles/graphene nanosheet composites and their application for hydrogen peroxide detection

Abstract  

Ag nanoparticles/graphene nanosheet (AgNPs/GN) composites have been rapidly prepared by a one-pot microwave-assisted reduction method, carried out by microwave irradiation of a N,N-dimethylformamide (DMF) solution of graphene oxide (GO) and AgNO₃. Several analytical techniques including UV–vis spectroscopy, FT-IR spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) have been used to characterize the resulting AgNPs/GN composites. It suggests that such composites exhibit good catalytic activity toward reduction of hydrogen peroxide (H₂O₂), leading to a H₂O₂ sensor with a fast amperometric response time of less than 2 s. The linear detection range is estimated to be from 0.1 to 100 mM (r = 0.999), and the detection limit is estimated to be 0.5 μM at a signal-to-noise ratio of 3.     

Performance enhancement of multilayer MoS2 phototransistors via photoresist encapsulation

We propose the encapsulation of bottom-gate multilayer MoS₂ phototransistors with an AZ®5214E photoresist as an effective device design to enhance the optoelectronic properties of the phototransistors. The photoresist-encapsulated MoS₂ phototransistors, based on mechanically exfoliated MoS₂ crystals, exhibited an improved device performance. After the photoresist encapsulation, the responsivity and detectivity of the device increased by seven-fold to 3.2 × 10³ A W⁻¹ and by five-fold to 2.3 × 10¹² Jones, respectively, under a 650-nm laser with an incident power density of 2.1 mW cm⁻². We attribute the observed enhancement in the phototransistor performance to the enhanced electrical properties owing to the n-type doping via photoresist encapsulation. These results demonstrate that MoS₂ phototransistors can achieve high performance without complicated device architecture and process, and thus, photoresist encapsulation presents an effective method for developing high-performance two-dimensional optoelectronic devices.     

Novel molybdenum disulfide nanosheets–decorated polyaniline: Preparation,characterization and enhanced electrocatalytic activity for hydrogen evolution reaction

Novel molybdenum disulfide nanosheets–decorated polyaniline (MoS₂/PANI) was synthesized and investigated as an efficient catalyst for hydrogen evolution reaction (HER). Compared with MoS₂, MoS₂/PANI nanocomposites exhibited higher catalytic activity and lower Tafel slope for HER in H₂SO₄ solution. The amount of 19 wt% PANI for coupling with MoS₂ resulted in a high current density of 80 mA cm⁻² at 400 mV (vs. RHE). In addition, the optimal MoS₂/PANI nanocomposite showed impressive long-term stability even after 500 cycles. The enhanced catalytic activity of MoS₂/PANI nanocomposites was primarily ascribed to the effective electron transport channels of PANI and the increase of electrochemically accessible surface area in composite materials, which was advantageous to facilitate the charge transfer at catalyst/electrolyte interface.     

Au@SiO2 core/shell nanoparticle assemblage used for highly sensitive SERS‐based determination of glucose and uric acid

The use of Au@SiO₂ core/shell nanoparticle (NP) assemblage with highly sensitive surface‐enhanced Raman scattering (SERS) was investigated for the determination of glucose and uric acid in this study. Rhodamine 6G dye molecules were used to evaluate the SERS enhancement factor for the synthesized Au@SiO₂ core/shell NPs with various silica shell thicknesses. The enhancement of SERS signal from Rhodamine 6G was found to increase with a decrease in the shell thickness. The core/shell assemblage with silica layer of 1–2 nm over a Au NP of ~36 nm showed the highest SERS signal. Our results show that the SERS technique is able to detect glucose and uric acid within wide concentration ranges, i.e. 20 ng/dL to 20 mg/dL (10⁻¹²–10⁻³ M) and 16.8 ng/dL to 2.9 mg/dL (10⁻¹¹–1.72 × 10⁻⁴ M), respectively, with associated lower detection limits of ~20 ng/dL (~1.0 × 10⁻¹² M) and ~16.8 ng/dL (~1.0 × 10⁻¹¹ M). Our work offers a low‐cost route to the fabrication of agile sensing devices applicable to the monitoring of disease progression. Copyright © 2013 John Wiley & Sons, Ltd.     

Ultrasonically assisted synthesis of barium stannate incorporated graphitic carbon nitride nanocomposite and its analytical performance in electrochemical sensing of 4-nitrophenol

We describe the ultrasonic assisted preparation of barium stannate-graphitic carbon nitride nanocomposite (BSO-gCN) by a simple method and its application in electrochemical detection of 4-nitrophenol via electro-oxidation. A bath type ultrasonic cleaner with ultrasonic power and ultrasonic frequency of 100 W and 50 Hz, respectively, was used for the synthesis of BSO-gCN nanocomposite material. The prepared BSO-gCN nanocomposite was characterized by employing several spectroscopic and microscopic techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, fourier transform infra-red, field emission scanning electron microscopy, and high resolution transmission electron microscopy, to unravel the structural and electronic features of the prepared nanocomposite. The BSO-gCN was drop-casted on a pre-treated glassy carbon electrode (GCE), and their sensor electrode was utilized for electrochemical sensing of 4-nitrophenol (4-NP). The BSO-gCN modified GCE exhibited better electrochemical sensing behavior than the bare GCE and other investigated electrodes. The electroanalytical parameters such as charge transfer coefficient (α = 0.5), the rate constant for electron transfer (k_s = 1.16 s⁻¹) and number of electron transferred were calculated. Linear sweep voltammetry (LSV) exhibited increase in peak current linearly with 4-NP concentration in the range between 1.6 and 50 μM. The lowest detection limit (LoD) was calculated to be 1 μM and sensitivity of 0.81 μA μM⁻¹ cm⁻²_. A 100-fold excess of various ions, such as Ca²⁺, Na⁺, K⁺, Cl⁻, I⁻, CO₃²⁻, NO₃, NH₄⁺ and SO₄²⁻ did not able to interfere with the determination of 4-NP and high sensitivity for detecting 4-NP in real samples was achieved. This newly developed BSO-gCN could be a potential candidate for electrochemical sensor applications.     

Ultrasonication-assisted liquid-phase exfoliation enhances photoelectrochemical performance in α-Fe2O3/MoS2 photoanode

This study successfully manufactured a p-n heterojunction hematite (α-Fe₂O₃) structure with molybdenum disulfide (MoS₂) to address the electron–hole transfer problems of conventional hematite to enhance photoelectrochemical (PEC) performance. The two-dimensional MoS₂ nanosheets were prepared through ultrasonication-assisted liquid-phase exfoliation, after which the concentration, number of layers, and thickness parameters of the MoS₂ nanosheets were respectively estimated by UV–vis, HRTEM and AFM analysis to be 0.37 mg/ml, 10–12 layers and around 6 nm. The effect of heterojunction α-Fe₂O₃/MoS₂ and the role of the ultrasonication process were investigated by the optimized concentration of MoS₂ in the forms of bulk and nanosheet on the surface of the α-Fe₂O₃ electrode while measuring the PEC performance. The best photocurrent density of the α-Fe₂O₃/MoS₂ photoanode was obtained at 1.52 and 0.86 mA.cm⁻² with good stability at 0.6 V vs. Ag/AgCl under 100 mW/cm² (AM 1.5) illumination from the back- and front-sides of α-Fe₂O₃/MoS₂; these values are 13.82 and 7.85-times higher than those of pure α-Fe₂O₃, respectively. The results of electrochemical impedance spectroscopy (EIS) and Mott-Schottky analysis showed increased donor concentration (2.6-fold) and decreased flat band potential (by 20%). Moreover, the results of IPCE, ABPE, and OCP analyses also supported the enhanced PEC performance of α-Fe₂O₃/MoS₂ through the formation of a p–n heterojunction, leading to a facile electron–hole transfer.     

Boosting the electrochemiluminescence of luminol by high-intensity focused ultrasound pretreatment combined with 1T/2H MoS2 catalysis to construct a sensitive sensing platform

In the luminol-O₂ ECL system, O₂ as an endogenous coreactant has the advantages of non-toxicity and stability. Improving the efficiency to generate radicals of O₂ is a challenge currently. In this work, a strategy combining physical method - ultrasound and nanomaterial with unique physicochemical properties was designed to enhance the ECL signal of luminol-O₂ system. Specifically, high-intensity focused ultrasound (HIFU) pretreatment as a non-invasive method could generate ROS (H₂O₂, O₂^•−, OH•, ¹O₂) in situ, triggering and boosting the ECL signal of luminol. In addition, 1T/2H MoS₂ with excellent catalytic activity could catalyze the H₂O₂ produced in situ, accelerate the oxidation of luminol and further enhance the ECL response. At the same time, combined with the catalytic hairpin assembly (CHA) reaction, the constructed ECL biosensing platform showed excellent performance for the detection of miRNA-155. The concentration range of 0.1 fM ∼ 1 nM with the detection limit as low as 0.057 fM were obtained. Furthermore, the ECL biosensor was also successfully applied to the determination of miRNA-155 in human serum samples. The established ECL sensing platform opens up a promising method for the detection of clinical biomarkers.     

Synthesis of silver nanoparticles by sonogalvanic replacement on aluminium powder in sodium polyacrylate solutions

The process of the formation of silver nanoparticles (AgNPs) via the method of galvanic replacement (GR) of Ag⁺ with aluminum powder in sodium polyacrylate (NaPA) solutions in the ultrasonic (US) field has been studied. It was observed, that the yellow colloidal solutions of stabilized AgNPs with the absorption maximum at ∼ 410 nm were obtained under the application of US power by 20 W and frequency by 20 kHz in the wide range of AgNO₃ and NaPA concentrations (0.1 – 0.5 mM and 0.5 – 5.0 g/L respectively) at 25 ⁰C. It was shown, that the GR process under US field occurs without of the significant induction period. Using the UV–vis spectroscopy the kinetics of AgNPs formation has been studied and it was observed the first order kinetics with respect to Ag⁺ ions both for the nucleation and growth processes. It was found that observable rate constants of nucleation are close for the all experimental conditions but the observable rate constants of growth decreased with increasing of initial concentration of AgNO₃. Based on the obtained kinetic data it was proposed a mechanism of the formation of AgNPs consisted of the following two main stages: 1) the nucleation with the formation of primary nanoclusters (AgNCs) on aluminum surface followed by their ablation from the surface of the sacrificial metal by ultrasound into bulk of solution; 2) the transformation of AgNCs in AgNPs via growth from the Al surface and / or agglomeration of AgNCs. Using TEM it was found that the size of obtained AgNPs does not exceed of 25 nm and slightly depends on the initial concentrations of precursors. High antimicrobial activity of obtained colloidal solutions against gram-negative and gram-positive bacteria as well as against fungi was observed.     

Ultrasonic assisted-Fenton-like degradation of nitrobenzene at neutral pH using nanosized oxides of Fe and Cu

Ultrasonic-assisted heterogeneous Fenton reaction was used for degradation of nitrobenzene (NB) at neutral pH conditions. Nano-sized oxides of α-Fe₂O₃ and CuO were prepared, characterized and tested in degradation of NB (10 mg L⁻¹) under sonication of 20 kHz at 25 °C. Complete degradation of NB was effected at pH 7 in presence of 10 mM H₂O₂ after 10 min of sonication in presence of α-Fe₂O₃ (1.0 g L⁻¹), (k = 0.58 min⁻¹) and after 25 min in case of CuO (k = 0.126 min⁻¹). α-Fe₂O₃ showed also effective degradation under the conditions of 0.1 g L⁻¹ oxide and 5.0 mM of H₂O₂, even though with a lower rate constant (0.346 min⁻¹). Sonication plays a major role in enhancing the production of hydroxyl radicals in presence of solid oxides. Hydroxyl radicals-degradation pathway is suggested and adopted to explain the differences noted in rate constants recorded on using different oxides.     

One-step chemically vapor deposited hybrid 1T-MoS2/2H-MoS2 heterostructures towards methylene blue photodegradation

The photocatalytic degradation of methylene blue is a straightforward and cost-effective solution for water decontamination. Although many materials have been reported so far for this purpose, the proposed solutions inflicted high fabrication costs and low efficiencies. Here, we report on the synthesis of tetragonal (1T) and hexagonal (2H) mixed molybdenum disulfide (MoS₂) heterostructures for an improved photocatalytic degradation efficiency by means of a single-step chemical vapor deposition (CVD) technique. We demonstrate that the 1T-MoS₂/2H-MoS₂ heterostructures exhibited a narrow bandgap ∼ 1.7 eV, and a very low reflectance (<5%) under visible-light, owing to their particular vertical micro-flower-like structure. We exfoliated the CVD-synthesised 1T-MoS₂/2H-MoS₂ films to assess their photodegradation properties towards the standard methylene blue dye. Our results showed that the photo-degradation rate-constant of the 1T-MoS₂/2H-MoS₂ heterostructures is much greater under UV excitation (i.e., 12.5 × 10⁻³ min⁻¹) than under visible light illumination (i.e., 9.2 × 10⁻³ min⁻¹). Our findings suggested that the intermixing of the conductive 1T-MoS₂ with the semi-conducting 2H-MoS₂ phases favors the photogeneration of electron-hole pairs. More importantly, it promotes a higher efficient charge transfer, which accelerates the methylene blue photodegradation process.     

Hydrothermal synthesis of ultra-highly concentrated,well-stable Ag nanoparticles and their application for enzymeless hydrogen peroxide detection

In this article, we have reported on the synthesis of ultra-highly concentrated (5.88 M), well-stable Ag nanoparticles (AgNPs). The AgNPs were formed by hydrothermal heat treatment of an aqueous solution of poly [(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)] (PQ11), a kind of cationic polyeletrolyte, in the presence of AgNO₃ powder at 170 °C, without the additional step of introducing other reducing agents and protective agents. Transmission electron microscopy (TEM) observations reveal that the as-formed AgNPs mainly consist of small nanoparticles about 10 nm in diameter. Most importantly, it was found that such dispersion can form stable films on bare electrode surfaces and the AgNPs contained therein still exhibit notable catalytic performance for reduction of hydrogen peroxide (H₂O₂). This H₂O₂ sensor has a fast amperometric response time of less than 3 s. Its linear range is estimated to be from 0.1 to 60 mM (r = 0.993), and the detection limit is estimated to be 1.6 μM at a signal-to-noise ratio of 3.     

Green sonochemical synthesis and fabrication of cubic MnFe2O4 electrocatalyst decorated carbon nitride nanohybrid for neurotransmitter detection in serum samples

The binary nanomaterials and graphitic carbon based hybrid has been developed as an important porous nanomaterial for fabricating electrode with applications in non-enzymatic (bio) sensors. We report a fast synthesis of bimetal oxide particles of nano-sized manganese ferrite (MnFe₂O₄) decorated on graphitic carbon nitride (GCN) via a high-intensity ultrasonic irradiation method for C (30 kHz and 70 W/cm²). The nanocomposites were analyzed by powder X-ray diffraction, XPS, EDS, TEM to ascertain the effects of synthesis parameters on structure, and morphology. The MnFe₂O₄/GCN modified electrode demonstrated superior electrocatalytic activity toward the neurotransmitter (5-hydroxytryptamine) detection with a high peak intensity at +0.21 V. The appealing application of the MnFe₂O₄/GCN/GCE as neurotransmitter sensors is presented and a possible sensing mechanism is analyzed. The constructed electrochemical sensor for the detection of 5-hydroxytryptamine (STN) showed a wide working range (0.1–522.6 μM), high sensitivity (19.377 μA μM⁻¹ cm⁻²), and nano-molar detection limit (3.1 nM). Moreover, it is worth noting that the MnFe₂O₄/GCN not only enhanced activity and also promoted the electron transfer rate towards STN detection. The proposed sensor was analyzed for its real-time applications to the detection of STN in rat brain serum, and human blood serum in good satisfactory results was obtained. The results showed promising reproducibility, repeatability, and high stability for neurotransmitter detection in biological samples.     

Development of sulphurized SnS thin film solar cells

Thin films of tin sulphide (SnS) have been grown by sulphurization of sputtered tin precursor layers in a closed chamber. The effect of sulphurization temperature (T_s) that varied in the range of 150–450 °C for a fixed sulphurization time of 120 min on SnS film was studied through various characterization techniques. X-ray photoelectron spectroscopy analysis demonstrated the transformation of metallic tin layers into SnS single phase for T_s between 300 °C and 350 °C. The X-ray diffraction measurements indicated that all the grown films had the (111) crystal plane as the preferred orientation and exhibited orthorhombic crystal structure. Raman analysis showed modes at 95 cm⁻¹, 189 cm⁻¹ and 218 cm⁻¹ are related to the A_g mode of SnS. AFM images revealed a granular change in the grain growth with the increase of T_s. The optical energy band gap values were estimated using the transmittance spectra and found to be varied from 1.2 eV to 1.6 eV with T_s. The Hall effect measurements showed that all the films were p-type conducting nature and the layers grown at 350 °C showed a low electrical resistivity of 64 Ω-cm, a net carrier concentration of 2 × 10¹⁶ cm⁻³ and mobility of 41 cm² V⁻¹ s⁻¹. With the use of sprayed Zn_0.76Mg_0.24O as a buffer layer and the sputtered ZnO:Al as window layer, the SnS based thin film solar cell was developed that showed a conversion efficiency of 2.02%.     

Characteristics of a type-II n-MoS2/p-Ge van der Waals heterojunction

A few-atomic-layer molybdenum disulfide (MoS₂) film on Si/SiO₂ substrates grown by metal-organic chemical vapor deposition was investigated. The few-atomic-layer MoS₂ film was subsequently transferred onto a (100) p-Ge substrate to build a van der Waals n-p heterojunction. The as-grown few-atomic-layer MoS₂ film and the MoS₂/Ge heterostructure were characterized atomic force microscopy, spectroscopic ellipsometry, high-resolution scanning transmission electron microscopy, Raman spectroscopy analyses, photoluminescence (PL) measurements at room temperature (RT, 300 K), and type-II band alignment of the heterostructure determined by ultraviolet photoelectron spectroscopy. The RT-PL measurements showed dominant peaks at 1.96 and 1.8 eV for the as-grown MoS₂ and red-shifted PL peaks for that transferred onto Ge. We examined the electrical characteristics of the few-atomic-layer MoS₂ by forming a type-II band alignment van der Waals heterojunction with a highly doped p-Ge. The heterojunction solar cell exhibited an open-circuit voltage of 0.15 V and a short-circuit current density of 45.26 μA/cm². The external quantum efficiency measurements showed a spectral response up to approximately 500 nm owing to the absorption by the few-atomic-layer MoS₂ film.     

Highly Efficient and Flexible Scintillation Screen Based on Organic Mn(II) Halide Hybrids toward Planar and Nonplanar X-Ray Imaging

The urgency for cost-effective, high-resolution, flexible X-ray imaging detectors is generating great demand for scintillators with low-temperature processability, high scintillation yield, and negligible afterglow. X-ray imaging materials are currently dominated by inorganic scintillators in the form of rigid films and bulk crystals, which have inherent limitations including high-temperature, complex synthesis, and considerable challenges toward advanced nonplanar imaging. Here, high-performance and flexible X-ray scintillators based on novel zero-dimensional (0D) (BTPP)₂MnX₄ (BTPP = benzyltriphenylphosphonium; X = Cl, Br) halides are reported. They emit bright green light originating from the ⁴T₁-⁶A₁ transition of Mn²⁺ under X-ray excitation. In particular, (BTPP)₂MnBr₄ single crystals exhibit excellent air- and radiation-stability, a high scintillation yield of 53 000 photons MeV⁻¹, a low detection limit of 89.9 nGy_air s⁻¹, and an ultralow afterglow comparable to commercial Bi₄Ge₃O₁₂ (BGO) single crystals. Moreover, the (BTPP)₂MnCl₄@polydimethylsiloxane (PDMS) flexible scintillation screens achieve a high spatial resolution of 14.1 lp mm⁻¹ and realize high-quality imaging results of nonplanar objects. This study demonstrates that the flexible scintillation screens based on low-dimensional Mn(II) hybrid halides have significant potential for low-dose and high-resolution X-ray imaging applications.     

Molecularly imprinted polymer based potentiometric sensor for the determination of 1-hexyl-3-methylimidazolium cation in aqueous solution

The molecular imprinting technique is powerful to prepare functional materials with molecular recognition properties. In this work, a potentiometric sensor was fabricated by dispersing molecularly imprinted polymers (MIPs) into plasticized PVC matrix and used for the determination of 1-hexyl-3-methylimidazolium cation ([C₆mim]⁺) in aqueous solution. The MIPs were synthesized by precipitation polymerization using 1-hexyl-3-methylimidazolium chloride ([C₆mim]Cl) as the template molecule, methacrylic acid (MAA) and ethylene glycol dimethacrylat (EGDMA) as the functional monomers, and EGDMA also as the cross-linking agent. The as-prepared electrode exhibited a Nernstian response (58.87 ± 0.3 mV per decade) to [C₆mim]⁺ in a concentration range from 1.0 × 10⁻⁶ to 0.1 mol kg⁻¹ with a low detection limit of 2.8 × 10⁻⁷ mol kg⁻¹, high selectivity, and little pH influence. The as-prepared electrode was used for the detection of the [C₆mim]⁺ in distilled water, tap water, and river water with a good recovery. It was also successfully applied in the determination of mean activity coefficients of [C₆mim]Br in fructose + water systems based on the potentiometric method at 298.15 K.

     

Optical Nonlinearity of Emerging ZrS2 and HfS2 Semiconductors

Compatible with existing processing technology, chemical vapor deposition method is used to synthesize ZrS₂ and HfS₂ films a a large scale. The nonlinear optical properties are characterized by Z-scan measurement with femtosecond pulses at 800 nm. The results show that saturable absorption happens in ZrS₂ owing to the larger ground state absorption than the excited state absorption, while reverse saturable absorption appears in HfS₂ due to the two-photon absorption. The figure of merit values of ZrS₂ (≈4.30 ± 0.12 × 10⁻¹⁵ esu cm) and HfS₂ (≈6.0 ± 1.4 × 10⁻¹⁵ esu cm) are much larger than those of MoS₂ and graphene in ultrafast nonlinear optical performance at the wavelength of 800 nm.     

UV-induced synthesis,characterization and formation mechanism of silver nanoparticles in alkalic carboxymethylated chitosan solution

The silver nanoparticles (AgNPs) were synthesized in an alkalic aqueous solution of silver nitrate (AgNO₃)/carboxymethylated chitosan (CMCTS) with ultraviolet (UV) light irradiation. CMCTS, a water-soluble and biocompatible chitosan derivative, served simultaneously as a reducing agent for silver cation and a stabilizing agent for AgNPs in this method. UV–vis spectra and transmission electron microscopy (TEM) images analyses showed that the pH of AgNO₃/CMCTS aqueous solutions, the concentrations of AgNO₃ and CMCTS can affect on the size, amount of synthesized AgNPs. Further by polarized optical microscopy it was found that the CMCTS with a high molecular weight leads to a branch-like AgNPs/CMCTS composite morphology. The diameter range of the AgNPs was 2–8 nm and they can be dispersed stably in the alkalic CMCTS solution for more than 6 months. XRD pattern indicated that the AgNPs has cubic crystal structure. The spectra of laser photolysis of AgNO₃/CMCTS aqueous solutions identified the early reduction processes of silver cations (Ag⁺) by hydrated electron formed by photoionization of CMCTS. The rate constant of corresponding reduction reaction was 5.0 × 10⁹ M⁻¹ s⁻¹.