Search Results (199)

Ag-doped ZnO is a promising photocatalyst. However, the combined influence of the Ag doping concentration and furnace temperature has not been adequately explored, hindering the optimization of ZnO/Ag materials for practical applications. In this study, ZnO/Ag materials were synthesized via ultrasonic spray pyrolysis by systematically varying both the furnace calcination temperature and the Ag doping concentration. The synthesized materials were analyzed through a range of spectroscopic methods to investigate their structural, morphological, and surface characteristics. Their photocatalytic activity was assessed by monitoring the degradation of methylene blue (MB) under ultraviolet light exposure. The findings indicate that the ZnO sample that was calcined at 400 °C exhibited the highest degradation efficiency among the undoped samples, which can be attributed to its submicron particle size, moderate crystallinity, and high surface hydroxylation. The sample with 5-wt% Ag doping achieved enhanced performance, demonstrating the best photocatalytic activity (65% MB degradation). This improvement was attributed to the synergistic effects of surface plasmon resonance and optimized interaction between the Ag nanoparticles and surface hydroxyl groups. Excessive Ag loading (10 wt%) led to reduced activity owing to potential agglomeration and recombination centers. These results highlight the critical role of both the thermal and chemical parameters in tailoring ZnO-based photocatalysts for wastewater treatment applications. Full article

Implant-associated infections, particularly those linked to Staphylococcus aureus (S. aureus), continue to compromise the clinical success of β-tricalcium phosphate (β-TCP) implants despite their excellent biocompatibility and osteoconductivity. This investigation aims to tackle these challenges by integrating femtosecond (fs)-laser surface processing with two complementary strategies: ion doping and functionalization with green-synthesized silver nanoparticles (AgNPs). AgNPs were produced via fs-laser photoreduction using green tea leaf extract (GTLE), noted for its anti-inflammatory and antioxidant properties. Fs-laser processing was applied to modify β-TCP scaffolds by systematically varying scanning velocities, fluences, and patterns. Lower scanning velocities generated organized nanostructures with enhanced roughness and wettability, as confirmed by scanning electron microscopy (SEM), optical profilometry, and contact angle measurements, whereas higher laser energies induced significant phase transitions between hydroxyapatite (HA) and α-tricalcium phosphate (α-TCP), as revealed by X-ray diffraction (XRD). AgNP-functionalized scaffolds demonstrated markedly superior antibacterial activity against S. aureus compared to the ion-doped variants, attributed to the synergistic interplay of nanostructure-mediated surface disruption and AgNP-induced bactericidal mechanisms. Although ion-doped scaffolds exhibited limited direct antibacterial effects, they showed concentration-dependent activity in indirect assays, likely due to controlled ion release. Both strategies promoted osteogenic differentiation of human bone marrow mesenchymal stem cells (hBM-MSCs) under defined conditions, albeit with transient cytotoxicity at higher fluences and excessive ion doping. Overall, this approach holds promise for markedly improving antibacterial efficacy and osteogenic compatibility, potentially transforming bone regeneration therapies. Full article

In this study, the voltammetric behavior of apocynin on a boron-doped diamond electrode in a phosphate buffer (pH 7.3) has been reported for the first time. The oxidation process is quasi-reversible, diffusion-controlled, and involves one electron and one proton. The product of the electrode reaction is an unstable radical that undergoes successive chemical transformations near the working electrode. The proposed mechanism of this process can be described as E_qC_i and served as the basis for the development of a new voltammetric method for determining apocynin in natural samples. The analytical signal was the anodic peak on DPV curves at a potential of 0.605 V vs. Ag/AgCl. A linear response was observed in the concentration range of 0.213–27.08 mg L⁻¹. The estimated LOD and LOQ values were 0.071 and 0.213 mg L⁻¹, respectively. The effectiveness of the method was demonstrated both in control determinations and in the analysis of the dietary supplement. This procedure is simple, fast, sensitive, selective, and requires no complicated sample preparation, which is limited only to a simple extraction with ethanol. The low consumption of non-toxic reagents makes it environmentally friendly. To the best of our knowledge, this is the first presentation of a voltammetric procedure to determine this analyte studied in a phosphate buffer solution on a boron-doped diamond electrode. It can also be easily adapted to determine other phenolic compounds with antioxidant properties in various matrices. Full article

Here, we report the hydrothermal synthesis of BFO (bismuth ferrite) and Bi_1−xAg_xFeO₃ (x = 0.01, 0.02) ultrafine nanopowders. The diffraction patterns show that all obtained particles belong to the R3c space group. On top of that, crystal structure prediction has been accomplished using bond valence calculations (BVCs). Several promising perovskite structures have been proposed together with experimentally observed modifications of BFO as a function of silver doping. Magnetization measurements were performed on BFO, both pure and substituted with 1% and 2% of Ag. The addition of Ag in BFO did not affect the Neel temperature, T_N = 630 K for all samples; instead, the influence of Ag was observed in the increase in the value and irreversibility of magnetization, which are usual characteristics of weak ferromagnetism. Our calculations based on density functional theory (DFT) are in agreement with the experimental finding of enhanced magnetization upon Ag doping of antiferromagnetic BFO, which is assigned to the perturbation of magnetic-type interactions between Fe atoms by Ag substitutional doping. Additionally, electronic and magnetic properties were studied for all phases predicted by the BVCs study. DFT predicted half-metallicity in the γ phase of BFO, which may be of great interest for further study and potential applications. Full article

Silver (Ag) is a precious and valuable metal, and it has many carrier minerals. Through LA-ICP-MS analysis, it was found that jamesonite not only contains lead (Pb) and antimony (Sb) as precious metals but also trace amounts of Ag. In practice, the flotation method is generally used to recover these metals. This paper employs density functional theory calculations to demonstrate that after Ag doping in jamesonite, the Ag atoms exist in the lattice channels of jamesonite, and they form strong covalent bonds with the S atoms, resulting in strong interactions. When Ag is doped in the channels, the adsorption of sodium diethyldithiocarbamate (DDTC) as a collector on the Ag-doped jamesonite surface is the strongest, while that of butyl xanthate is the weakest. The adsorption interactions on the Ag-doped jamesonite surface are also stronger than on pure jamesonite. Coordination chemistry studies reveal that Ag⁺ undergoes a transition from a d¹⁰ to a d⁹s¹ electronic configuration when incorporated into jamesonite, which increases its reactivity by generating unpaired electrons available for π-backbonding with collector molecules. Furthermore, owing to the high polarizability of Ag, the presence of Ag atoms alters the electronic environment of the surrounding Pb atoms, which enhances the π-backbonding interactions between the adsorbate reagent molecules and the Ag active sites. The research results are of great significance for the efficient recovery of Ag-containing jamesonite and provide a reference for the study of the properties of Ag-doped minerals. Full article

Thin-film solar cells (TFSCs) represent a promising frontier in renewable energy technologies due to their potential for cost reduction, material efficiency, and adaptability. This literature review examines the key materials and advancements that make up TFSC technologies, with a focus on Cu(In,Ga)Se₂ (CIGS), cadmium telluride (CdTe), and Cu₂ZnSnS₄ (CZTS) and its sulfo-selenide counterpart Cu₂ZnSn(S,Se)₄ (CZTSSe). Each material’s unique properties—including tuneable bandgaps, high absorption coefficients, and low-cost scalability—make them viable candidates for a wide range of applications, from building-integrated photovoltaics (BIPV) to portable energy solutions. This review explores recent progress in the enhancement of power conversion efficiency (PCE), particularly through bandgap engineering, alkali metal doping, and interface optimization. Key innovations such as silver (Ag) alloying in CIGS, selenium (Se) alloying in CdTe, and sulfur (S) to Se ratio optimization in CZTSSe have driven PCE improvements and expanded the range of practical uses. Additionally, the adaptability of TFSCs for roll-to-roll manufacturing on flexible substrates has further cemented their role in advancing renewable energy adoption. Challenges remain, including environmental concerns, but ongoing research addresses these limitations, paving the way for TFSCs to become a crucial technology for transitioning to sustainable energy systems. Full article

The utilization of heat-shielding glazing technologies can efficiently promote carbon emission reductions and energy savings by decreasing solar irradiation into buildings. Although a variety of glazing technologies have been created for solar glazing, either the heat-shielding performance is low, the thermal stability is poor, or the cost is high. Here, we report a thermally stable heat-shielding coated glass for solar glazing in a simple way via direct calcination of Ce and Sb co-doped SnO₂ nanoparticles with polysilazane (PSZ) coatings in air. The resulting coated glass has transmittances of 4.7% at 250–380 nm, 59.3% at 380–780 nm, and 9.7% at 780–2500 nm; excellent environment stability under accelerated aging conditions over 350 h; and also a ca. 50-fold lower fixed cost than commercial low-E glass. Moreover, a coated glass with a high pencil hardness of 9H was also fabricated via further spraying and calcinating of a PSZ coating as the cover layer, which is also the hardest coated solar glaze to our knowledge. The high solar-shielding performance and unprecedented low cost of the Ce and Sb co-doped SnO₂-coated glass, as well as the simplicity of its fabrication, exhibit great potential in energy-saving buildings and cars. Full article

Indium tin oxide (ITO) is a commonly used material for transparent conductive electrodes (TCE) in optoelectronic applications. On the other hand, graphene has superior electrical conductivity and exceptional mechanical flexibility, which makes it a promising candidate as a TCE material. This work proposes a CVD graphene/ITO hybrid electrode enhanced by doping with silver nanowires (Ag-NWs). The study aims to improve the performance of the electrode by optimizing two key parameters during the fabrication process: the thermal annealing time after the transfer of graphene on ITO and the Ag-NWs doping conditions. The annealing treatment is fundamental to reducing the residues on the surface of graphene and increasing the interface contact between graphene and ITO. The correct coverage and distribution of the dopant on graphene is obtained by controlling the concentration of the Ag-NWs and the spin coating speeds. The results indicate a substantial improvement in the optical and electrical performance of the Ag-NWs/graphene/ITO hybrid electrode. A remarkably low sheet resistance of 42.4 Ω/sq (±2 Ω/sq) has been achieved while maintaining a high optical transmittance of 87.3% (±0.5%). Full article

TiO₂ films and N-doped TiO₂ films modified with silver (Ag/N-TiO₂) were synthesized using DC magnetron sputtering. By varying the N₂ flow rate and the Ag sputtering power, respectively, the degree of doping and modification was managed. The microstructure, morphology, and properties of the thin film were studied using X-ray diffraction, field emission scanning electron microscopy, UV visible diffuse reflectance spectroscopy, and atomic force microscopy. The results show that TiO₂ in Ag/N-TiO₂ composite has an anatase structure, and the absorption spectrum of (Ag/N-TiO₂) thin film shows a red shift. The best photocatalytic degradation effect regarding the N-TiO₂ films was observed with an N₂ flow rate of 16 sccm (standard cubic per minute). The degradation rate in MO (Methyl orange) pure solution (C₀ = 10 mg/L) can reach 100% in 85 min, and in the MO-Na₂SO₄ mixed solution (C₀ = 10 mg/L, C C_Na2SO4 = 12.5 g/L), it only takes 40 min. Ag/N-TiO₂ films exhibited the highest degradation efficiency at a 5 W sputtering power and 50 s of sputtering time, reaching a 100% degradation rate in MO pure solution that can reach 100% in 50 min, and in the MO-Na₂SO₄ mixed solution, it only takes 36 min. The photocatalytic decomposition of MO was greatly accelerated by the addition of Na₂SO₄, which worked best with a 12.5 g/L concentration. However, when the concentration of Na₂SO₄ is above or below 12.5 g/L, Na₂SO₄ exhibits significant inhibition of photocatalytic degradation. Photocatalytic cycling experiments showed that the photocatalyst still maintained an effective degradation performance after four cycles. The degradation mechanism was analyzed using first-order kinetics and energy band theory. Compared to powder particles, the photocatalyst on the films has high stability and can be recovered 100%. So, photocatalysts on films have great potential for industrial applications. Full article

WS₂ films exhibit excellent tribological properties in a vacuum, but they are prone to failure due to oxidation in air, which severely limits their application. Cu has great potential to improve the tribological properties of WS₂, similar to that of Au and Ag. Thus, to clarify the contribution of Cu to the tribological properties of WS₂ films and provide new insight for the development of new multi-environmentally adaptable films, this study deposited WS₂-Cu composite films under different sputtering powers of the Cu target by magnetron sputtering systems, and the Cu target was supplied by DC power. Then, the structure of films was analyzed by FESEM, EDS and XPS. The results show that Cu is difficult to uniformly dope on the WS₂ film at a high sputtering power of Cu target, showing possibly low solubility of Cu in WS₂ film. However, a uniform and dense WS₂-Cu composite film was deposited under the lower sputtering power of Cu target. Furthermore, the results of the nanoindentation test demonstrated that the WS₂-Cu composite films exhibited high hardness (6.6 GPa). Finally, the tribological properties of the WS₂-Cu films were examined, and their friction interface was characterized by SEM, EDS and TEM. The WS₂-Cu film demonstrated superior tribological behavior in air (the average friction coefficient is 0.09), based on a special sliding interface, low oxidation levels of WS₂ and Cu-rich transfer film. This study provides a new insight and a new method for improving the environmental adaptation ability of WS₂ film. Full article

Piezoelectric materials (PZTs) enjoy extensive applications in the field of electromechanical sensors due to their sensitive response to external electric fields. The limited piezoelectric response for single-layer piezoceramic pellets drives the use of multilayered technology to increase the electric displacement of a single piezo device. As is well known, Ag is commonly used as a metal for electrodes in devices based on traditional PZTs, which always densify at a high temperature above 1100 °C, resulting in Ag migration. Here, a high-performance samarium-ion-doped Sm_0.01Pb_0.99(Zr_0.54Ti_0.46)O₃ ceramic was selected as parent materials to develop a new Ag-cofired ceramic matrix with a sintering temperature of 920 °C by glass flux. The ceramic composition with 2.0 wt% glass addition exhibits the excellent performance of piezoelectric d₃₃~492 pC/N, planar electromechanical coupling coefficient k_p~50.1%, mechanical quality factor Q_m~68.71, and Curie temperature T_c~356 °C, respectively. The cyclic stability of d₃₃ was measured below 6.6% at 30 kV/cm, which indicates that the piezoceramic has good temperature stability and fatigue resistance. Therefore, this study provides a novel high-performance piezoelectric system to meet the cofired requirement for multilayered piezoelectric devices. Full article

Autogenous grafts remain the “gold standard” in bone tissue grafting procedures; however, limitations such as donor site morbidity, invasiveness, and limited availability have spurred research into alternative materials. Hydroxyapatite (HA), a widely used bioceramic, is known for its bioactivity and biocompatibility. Nonetheless, its inherent brittleness and porosity necessitate modifications to enhance its mechanical and functional properties. Ionic doping has emerged as a transformative strategy to improve the properties of HA by integrating ions such as strontium (Sr²⁺), magnesium (Mg²⁺), and zinc (Zn²⁺). These dopants influence HA’s crystal structure, morphology, and solubility, resulting in enhanced bioactivity, accelerated bone mineralization, and improved mechanical properties, such as increased fracture resistance and wear durability. Additionally, antimicrobial properties can be achieved through the inclusion of silver ions (Ag⁺), reducing the risk of peri-implant infections. This review focuses on the effects of ionic doping on the structure and functionality of hydroxyapatite, emphasizing advancements in tailoring its properties to clinical needs. By consolidating two decades of research, this study highlights how ionic doping bridges the gap between synthetic biomaterials and native bone, unlocking new potential in regenerative medicine and orthopedic applications. Full article

In the present study, for the first time, aluminum-doped zinc oxide (AZO) thin films with nanoinclusions of amorphous carbon have been synthesized via spin coating, and the thermoelectric performances were investigated varying the aging period of the solution, the procedure of carbon nanoparticles’ addition, and the annealing atmosphere. The addition of nanoparticles has been pursued to introduce phonon scattering centers to reduce thermal conductivity. All the samples showed a strong orientation along the [002] crystallographic direction, even though the substrate is amorphous silica, with an intensity of the diffraction peaks reaching its maximum in samples annealed in the presence of hydrogen, and generally decreasing by the addition of carbon nanoparticles. Absolute values of the Seebeck coefficient improve when nanoparticles are added. At the same time, electric conductivity is higher for the sample with 1 wt.% of carbon and annealed in Ar with 1% of H₂, both increasing in absolute value with the temperature rise. Among all the samples, the lowest thermal conductivity value of 1.25 W/(m∙K) was found at room temperature, and the highest power factor was 111 μW/(m∙K²) at 325 °C. Thus, the introduction of carbon effectively reduced thermal conductivity, while also increasing the power factor, giving promising results for the further development of AZO-based materials for thermoelectric applications. Full article

As reported during the last five years, SnSe is one of the leading thermoelectric (TE) materials with a very low lattice thermal conductivity. However, its elements are not as heavy as those of classical thermoelectric materials like PbTe or Bi₂Te₃. Its outstanding TE properties were revealed after repeated purification steps to minimize the amount of oxygen contamination, followed by spark plasma sintering. Recently, we showed that hot-pressing—once optimized—can yield comparable or even better TE performance using the examples of Na- and Cu- as well as Na- and Ag-co-doped SnSe. However, long-term stability remains a challenge during cycling between low and high temperatures. Here, we investigated whether the cooling procedure has a significant impact on the thermoelectric properties of SnSe. We compared cooling of the melt with a 1:1 ratio of Sn:Se from 1273 K down to room temperature in air with quenching in water. As typical for undoped SnSe, both materials were extrinsic p-type semiconductors due to Sn defects. The air-quenched sample exhibited higher thermal conductivity, lower electrical conductivity, and higher Seebeck coefficient, all consistent with a smaller number of defects and thus a smaller number of charge carriers due to the slower cooling procedure. This resulted in a comparatively low peak figure-of-merit value zT of 0.61 at 823 K for the air-quenched sample, compared to the substantially higher peak zT of 1.58 at 813 K for the water-quenched sample. Full article

Herein, this study reports the development of a multifunctional conductive antibacterial cotton fabric through the utilization of the natural polyphenol-mediated silver mirror reaction. The experimental results demonstrate that polyphenols can effectively facilitate the deposition of silver nanoparticles (AgNPs), resulting in a uniform and durable hybrid nanocoating on the cotton fabric. The effects of polyphenol’s molecular weights on the coating structures and stabilities have been revealed via two distinct approaches: washing resistance and electrochemical testing systems. It has been concluded that lower-molecular-weight phenols induce a compact and dense coating structure, whereas polyphenols such as tannic acid exhibit relatively high stability, achieving an excellent conductivity of 0.2 S/cm and a good washing resistance of 67% over five cycles. The underlying mechanism has been further confirmed by the cyclic voltammetry measurements, suggesting that polyphenols play a significant role in stabilizing AgNPs and preventing their dissolution. Furthermore, the Ag-doped polyphenol-coated fabrics exhibit notable antibacterial properties. By coupling natural polyphenols with typical silver mirror reactions, this study not only offers a sustainable alternative to synthetic chemicals but also presents a promising method to endow cotton textiles with the dual properties of conductivity and antibacterial activity. Full article