Incorporation Of Ag Research Articles

Crystallization and Optical Behaviour of Nanocomposite Sol-Gel TiO2:Ag Films

Sol-gel spin coating method was employed for depositing TiO2 and Ag-doped TiO2 films. The effects of Ag doping and the annealing temperatures (300–600 °C) were studied with respect to their structural, morphological, vibrational, and optical properties. Field Emission Scanning Electron microscopy (FESEM) investigation exhibited the grained, compact structures of TiO2-based films. Ag incorporation resulted in a rougher film surface. X-ray diffraction (XRD) results confirmed the formation of Ag nanoparticles and AgO phase, along with anatase and rutile TiO2, strongly depending on Ag concentration and technological conditions. AgO fraction diminished after high temperature annealing above 500 °C. The vibrational properties were characterized by Fourier Transform Infrared (FTIR) spectroscopy. It was found that silver presence induced changes in IR bands of TiO2 films. UV–VIS spectroscopy revealed that the embedment of Ag NPs in titania matrix resulted in higher absorbance across the visible spectral range due to local surface plasmon resonance (LSPR). Ag doping reduced the optical band gap of sol-gel TiO2 films. The optical and plasmonic modifications of TiO2:Ag thin films by the number of layers and different technological conditions (thermal and UV treatment) are discussed.

Assessment of surface hardness and impact strength of denture base resins reinforced with silver–titanium dioxide and silver–zirconium dioxide nanoparticles: In vitro study

Abstract Polymethyl methacrylate (PMMA) is frequently utilised for fabricating denture bases due to its perfect qualities. However, a significant issue with this resin is the occurrence of frequent fractures caused by heavy chewing power, resulting in early cracks and fractures during clinical use. This study investigates the influence of silver, titanium dioxide, and silver zirconia nanoparticles on the surface hardness and impact strength of self-cured denture base. The samples were categorised into four categories according to the incorporation of different nanoparticles. The samples were divided into three subgroups based on the nanoparticle content: 0.1, 0.3, and 0.5% of TiO2 and ZrO2. Each group had a set ratio of 0.3% Ag as an antibacterial agent. Except for the fourth group (Group D), a combination of 0.05, 0.15, and 0.25% of TiO2 and ZrO2, along with 0.3% Ag, was utilised to investigate their collective impact. The Shore D hardness and Charpy test were employed to quantify the surface hardness and impact strength, respectively. The samples were subjected to X-ray diffraction analysis and field emission-scanning electron microscopy to characterise nanoparticles and ascertain the structure of acrylic samples. All nanoparticle-modified samples showed a substantial improvement in surface hardness compared to the control group. The maximum hardness value was seen in the samples containing 0.3% Ag–0.3% TiO2 and 0.3% Ag–0.5% ZrO2. The samples treated with 0.3% Ag and 0.3% TiO2 showed the maximum impact strength. The incorporation of Ag and ZrO2 hinders the ability to withstand impact strength. The samples treated with 0.3% Ag, 0.15% TiO2, and 0.15% ZrO2 exhibited an augmentation in impact strength. Modified samples in all groups showed a colour change, which required colour modifiers.

Unravelling the performance of lead-free perovskite cathodes for rechargeable aqueous zinc-ion batteries

The quest for efficient and sustainable energy storage solutions has led to the emergence of zinc-ion batteries (ZIBs) as a promising candidate, offering numerous advantages in terms of cost-effectiveness, safety, and performance. The key to commercialising ZIBs lies in developing cathode materials that offer high specific capacity and prolonged cycle performance. The present study demonstrates the capability of environmentally friendly, lead-free inorganic perovskites for high-rate rechargeable aqueous zinc-ion batteries with enhanced stability and excellent rate performance. The battery exhibits a high specific capacity of 220 mAh/g at a current density of 1000 mA/g and a quite stable capacity of 50 mAh/g and a good cycling stability of 20000 cycles at a very high rate of 20 A/g. The caesium bismuth iodide perovskite emerges as a promising candidate for cathode material in Zn-ion batteries, exhibiting high specific capacity and superior rate cyclability. Furthermore, incorporation of Ag in CsBi3I10 is found to enhance the specific capacity and exhibits superior cycling stability. This study marks a significant advancement in the utilisation of perovskite materials as new cathodes for high-rate ZIBs.

The effect of co-modification of ultrathin g-C3N4 nanosheets with Ag and S on photocatalytic hydrogen production

The technology of photocatalytic water splitting holds immense potential for hydrogen (H2) generation. However, its development is hindered by a lack of active sites and low efficiency of photogenerated carriers. In this study, Ag-S-CN ultrathin nanosheets were successfully fabricated by co-modification of graphitic carbon nitride (CN) with silver (Ag) and sulfur (S). S doping within the CN layers broadened light absorption and provided additional reaction sites, while the incorporation of Ag into the CN interlayers enhanced the migration rate of photogenerated carriers between adjacent layers via Ag-S bonds. Consequently, the 0.05 Ag-S-CN photocatalyst achieved a high H2 yield of 0.93 mmol g-1 h-1 without requiring any additional cocatalyst, which is approximately 23.25 and 10.33 times higher than that of CN and S-CN, respectively. This work presents an effective strategy for developing highly efficient photocatalysts.

Enhanced Schottky barrier engineering in silver-doped TiO2/p-Si heterojunctions: Insights into electrical behavior and charge carrier dynamics

Heterojunctions were fabricated through the deposition of silver-doped Titanium dioxide (Ag–TiO2) onto p-type crystalline silicon, employing the sol-gel technique. Electrical characterization was conducted with varying Ag concentrations. The investigation revealed that the Schottky barriers at each interface (Ag/TiO2 and Si/Ag), along with the built-in potential at the TiO2/p-Si junction, increase proportionally with the Ag concentration. This observed trend was attributed to the reduction in the TiO2 bandgap due to Ag incorporation, resulting in a concurrent shift in both valence and conduction bands. Consequently, there is a growth of the conduction energy discontinuity and a reduction in the valence one, facilitating hole diffusion while impeding electron transfer across the depletion layer. Furthermore, the introduction of Ag leads to a decrease in both electron and hole concentrations. However, Ag incorporation within the TiO2 matrix manifests as nanoparticles and clusters, resulting in a nonhomogeneous distribution of charge carriers across the sample. Impedance analysis indicates an increase in device resistance and a decrease in effective capacitance.

Influence of Ag doping on structural, morphological, and optical characteristics of sol-gel spin-coated TiO2 thin films

Pure and Ag-doped Titanium dioxide (TiO2) thin films have been synthesized via the sol-gel spin coating method, and their structural, morphological, and optical properties have been investigated. X-ray diffraction analysis verifies that the polycrystalline anatase TiO2 phase is retained up to 2 % Ag doping. However, lattice expansion and grain refinement down to 25.345 nm are observed with increasing Ag content. Scanning electron microscopy (SEM) reveals the formation of large, isolated TiO2 aggregates separated by drying-induced cracks across the film surface. Optical studies show the undoped TiO2 films demonstrate excellent visible transparency (>75 % transmittance) that slightly decreases upon Ag doping, though it remains suitably high for device applications. Meanwhile, optical absorption and defect states improve with more Ag incorporation, narrowing the TiO2 bandgap from 3.83 eV (undoped) to 3.51 eV (2 % Ag-doping) due to the incorporation of Ag-induced electronic states just below the conduction band minimum. The capability to control optical and structural properties through Ag doping highlights the potential of these TiO2 films suitably tailored for photovoltaic devices or self-cleaning coatings.

Investigation of microstructural, hardness, and wear properties of AlCrCuFeNi high entropy alloys produced by hot-pressing with the enhancement of manufacturability through electroless Ag incorporation

This study involves the production of HEA materials using low-temperature and high-pressure principles by mechanical-alloying AlCrCuFeNi high-entropy alloy powders, followed by electroless Ag coating for enhanced interface properties and hot-pressing without additional sintering. The Ag interface significantly improved the bonding of HEA powders. While increasing temperature causes a 10 % weight gain due to oxidation in HEA samples, this rate is only 1.5 % in those produced with Ag-coated HEA. The Ag interface improved the hardness of the HEAs by 50 %. The wear rate was reduced by more than twofold due to the Ag-interfaces. Ag exhibited a self-lubricating effect due to the Ag layers that repeatedly emerge during sliding, resulting in a low friction coefficient of 0.19 and excellent wear resistance.

Enhancing the photovoltaic efficiency of CZTSSe thin-film solar cells via Ag-doping induced defect modulation

Defect modulation is one of the key factors in determining the performance of solar cells, and the presence of defects tends to adversely affect carrier recombination and transport, thus having a direct impact on both cell stability and efficiency. Ag doping can modulate the defects, but in-depth studies on the mechanism of the effect are needed. Therefore, an in-depth study of the effect of Ag incorporation on the defect modulation mechanism of Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells is of great practical significance for understanding the mechanism of action of Ag doping and further optimising the cell performance. In this study, (AgxCu1-x)2ZnSn(S,Se)4 (0 ≤ x ≤ 1) (ACZTSSe) solar cells were successfully prepared by N, N-dimethylformamide (DMF) solution, which have the characteristics of reducing defects and enhancing photovoltaic performance. After the introduction of Ag, the absorber formed a crystal structure with few holes and penetrating top and bottom. And the electrical performance of the solar cell is significantly improved, J0 is reduced from 4.6 × 10−5 A/cm2 to 2.7 × 10−6 A/cm2, and its contribution to the photovoltaic conversion efficiency (PCE) improvement reaches 142%. This indicates that the introduction of Ag helps to optimize the quality of the absorber, thereby reducing the concentration of interfacial and bulk defects. It also reduces carrier recombination and improves carrier lifetime from 0.86 ms to 1.75 ms. Ultimately increasing our cell efficiency from 7.55% to 10.64% when the Ag content reached 5%. These results clearly show that we have successfully achieved the modulation of defects in CZTSSe solar cells by Ag doping.

Incorporation of Ag in Co9S8-Ni3S2 for Predominantly Enhanced Electrocatalytic Activities for Oxygen Evolution Reaction: A Combined Experimental and DFT Study.

Electrodeposition of abundant metals to fabricate efficient and durable electrodes indicate a viable role in advancing renewable electrochemical energy tools. Herein, we deposit Co9S8-Ag-Ni3S2@NF on nickel foam (NF) to produce Co9S8-Ag-Ni3S2@NF as a exceedingly proficient electrode for oxygen evolution reaction (OER). The electrochemical investigation verifies that the Co9S8-Ag-Ni3S2@NF electrode reveals better electrocatalytic activity to OER because of its nanoflowers' open-pore morphology, reduced overpotential (η10=125 mV), smaller charge transfer resistance, long-term stability, and a synergistic effect between various components, which allows the reactants to be more easily absorbed and subsequently converted into gaseous products during the water electrolysis route. Density functional theory (DFT) calculation as well reveals the introduction of Ag (222) surface into the Co9S8 (440)-Ni3S2 (120) structure increases the electronic density of states (DOS) per unit cell of a system and increases the electrocatalytic activity of OER by considerably lowering the energy barriers of its intermediates. This study provides the innovation of employing trimetallic nanomaterials immobilized on a conductive, continuous porous three-dimensional network formed on a nickel foam (NF) substrate as a highly proficient catalyst for OER.

Investigating the role of Ag-doped ZnO thin films in UV photodetectors produced via laser assisted chemical bath growth technique

This study introduces the innovative fabrication of Ag-doped ZnO thin films (AgxZnO(100−x) TFs) with varying silver (Ag) concentrations (x) of 0.5, 1.0, 1.5, and 2.0 at% on glass substrates using a simple and cost-effective method known as laser-assisted chemical bath growth (LACBG). This process aims to create metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors. A continuous wave semiconductor laser with a 444.5 nm wavelength, 5 W power, and 6 min irradiation time was employed to synthesize high-quality Ag-doped ZnO TFs on the glass substrate. Ag electrodes were utilized as Schottky contacts to form MSM UV photodetectors. Structural and morphological analyses conducted using XRD and SEM revealed vertically aligned nanorods and nanoflowers with a high c-axis orientation and hexagonal wurtzite facets, while EDX confirmed Ag incorporation into the ZnO lattice. The UV–Visible absorbance spectra indicated a decrease in bandgap from 3.28 to 2.84 eV with increased Ag content. The current-voltage (I–V) characteristics of the Ag-doped ZnO TFs UV photodetector showed significantly enhanced conductivity at a 2.0 at% concentration level, achieving a responsivity of 10.78 A/W, an external quantum efficiency of 34.67 % at −3 V bias voltage. Finally, the modified device exhibited a sensitivity of 14661.9 %, a gain of 147.62, and a detectivity of 2.25 ×107 Jones, demonstrating its suitability for optoelectronic applications.

(Invited) An Interplay between Electronic and Ionic Processes in Oxide Resistive Switching Devices

Emerging memory devices play a major role in implementing artificial neural networks as basic types of neuromorphic hardware. They provide extra functionality to conventional CMOS technology, such as the ability to implement non-volatile memory within a nanoscale region on the chip. Among 2-terminal devices, the resistive switching random access memory (RRAM) devices are very promising for these applications. However, the mechanisms of resistance changes depend on the oxide and metal electrode material and are still debated. Under an applied stress bias, MIM devices experience changes in their resistance from relatively large, in the high resistance state (HRS), to relatively low, in the low resistance state (LRS). These effects have generally been attributed to defect generation and aggregation in the oxide and depend on the chemical nature of metal electrodes. Using multiscale modelling, we investigate the role of electron injection and hydrogen incorporation inside amorphous (a) oxide films of SiO2, HfO2, Al2O3 and at interfaces with Si and TiN electrodes in creation of new defects, oxide degradation, and resistance change. The initial models of a-SiO2, a-HfO2 and a-Al2O3 structures are created using classical force-fields and the LAMMPS package. The volume and geometry of all structures are fully optimized using density functional theory (DFT) implemented in the CP2K code with the range-separated hybrid PBE0-TC-LRC functional, as described in detail in [1]. The results demonstrate that hole injection into amorphous SiO2, HfO2 and Al2O3 leads to hole localization at low-coordinated O sites in the amorphous network [2]. Injected extra electrons localize in amorphous SiO2 and HfO2 in deep states about 3.0 eV below the mobility edge [2]. Trapping of up to two electrons at intrinsic sites results in weakening of Si-O and Hf-O bonds and emergence of efficient bond breaking pathways for producing neutral O vacancies and interstitial Oi 2- ions with low activation barriers [2]. These barriers as well as barriers for migration of the O2- ion (< 0.5 eV) are further reduced by bias application. Simulations of SiO2/TiN interfaces [3] explain how, as a result of electroforming, the system undergoes very significant structural changes with the oxide being significantly reduced, interface being oxidized, and part of the oxygen leaving the system. Creation of O vacancies facilitates trap-assisted tunnelling through oxide films and is responsible for oxide charging and leakage current. Hydrogen and metal incorporation from metal electrodes leads to creation of additional defects in the oxide. DFT calculations of the incorporation and diffusion of Ag in Ag/SiO2/Me (Me=W or Pt) RRAM devices [4] show how the interplay between Ag+ ion diffusion, electron injection and vacancy creation lead to the formation of Ag clusters and filaments. Atomistic simulations of defect creation in amorphous oxide films are combined with kinetic simulations of trap assisted tunnelling of electrons and ionic diffusion through oxide [5,6]. They provide the mechanisms and time evolution of oxide charging and degradation. These mechanisms are used to simulate the kinetics of dielectric breakdown in devices and explain the mechanisms of set and reset in RRAM devices.[1] A-M. El-Sayed et al., Phys, Rev. B89, 125201 (2014)[2] J. Strand et al., J. Phys.: Condens. Matter30,233001 (2018)[3] J. Cottom et al. ACS Appl. Mater. Interfaces 11, 36232 (2019)[4] K. Patel et al. Microel. Reliab. 98, 144 (2019)[5] A. Padovani et al., J. Appl. Phys. 121, 155101 (2017)[6] J. Strand et al. J. Appl. Phys. 131, 234501 (2022)

Enhanced hydrogen gas sensing performance with Ag-doped WO3 thin film

The paper reports the fabrication of a device, based on the thin film of Ag-doped WO3 nanoparticles, to enhance the hydrogen gas sensing performance. The synthesis of thin films of pristine and Ag-doped WO3 nanoparticles were carried out using the single-step hydrothermal method, followed by the spin coating deposition process. The characterization of the samples was carried out with XRD, FESEM, TEM, FTIR and UV–vis spectroscopy. The consistent pattern observed from the microstructure analysis of data from XRD, UV–vis spectrometer and FTIR validates effective incorporation of Ag into the WO₃ structure. The XRD patterns confirmed the formation of the monoclinic phase of WO3 nanoparticles. The crystallite size and the value of band gap decreased on increasing the Ag doping percentage in WO3. This reduction with Ag-doping could be attributed to the proper substitution of the W with Ag due to their similar sizes. The gas sensing performances of the fabricated sensing devices were analyzed by exposing different concentrations of hydrogen gas ranging from 12.5 ppm to 75 ppm. The device based on the thin film of Ag-doped WO3 performed much better than the device based on the thin film of pristine WO3 nanoparticles. The device with 4% Ag-doped WO3 showed the best sensor response of 98 % for 75 ppm H2 gas concentration with response and recovery time of 76 and 100 s, respectively at 100 °C. The improved response of the device with Ag doping compared to the pristine device could be attributed to the better charge transfer, more defect creation, and the ability of Ag to work as a catalyst to make reaction kinetics faster. The selectivity of the device was tested using the oxidizing and reducing gasses of NO2, H2, and NH3 at 100 °C for 75 ppm gas concentration. The recorded response of the device for NO2, H2, NH3 were 38%, 98%, and 43%, respectively.

Enhancing Ammonia Production by Ag Incorporation in Li-Mediated Nitrogen Reduction Reactions

Enhancing Ammonia Production by Ag Incorporation in Li-Mediated Nitrogen Reduction Reactions

Gas-phase electrochemical CO2 reduction on silver-copper BTC MOF in a zero-gap membrane electrode assembly

Bimetallic AgCu-BTC MOFs, derived from Cu-BTC (HKUST-1), have been synthesized by fast co-precipitation method and evaluated for CO2 reduction reaction (CO2RR) using humidified CO2 gas in a zero-gap configuration. Three compositions with varying Ag content – AgCu-1 (9.4 at.%), AgCu-2 (12.5 at.%), and AgCu-3 (16.5 at.%) – were characterized by SEM-EDS, PXRD, FTIR, and XPS. These structural analyzes confirmed the formation of a low-crystalline AgCu-BTC MOF with Ag+1 ions coordinated to the BTC framework. Electrochemical tests (CV and LSV) revealed that AgCu-3 MOF, with the highest Ag content (16.5 at.%), exhibited a more positive onset potential at -0.65 V vs Ag/AgCl compared to HKUST-1 MOF, indicating enhanced CO2RR activity, owing to Ag incorporation. Constant potential (CP) experiments showed that AgCu-3 MOF predominantly produced CO and H2, achieving faradaic efficiency of approximately 65 % for CO production and 5 % for H2 production. Moreover, lowering the relative humidity (RH%) in the inlet CO2 gas stream from 80% to 20% increased CO production by 2-fold from 6.2 µmol s-1 cm-2 to 13 µmol s-1 cm-2, simultaneously suppressing the hydrogen evolution reaction (HER). This reduction in humidity resulted in an increased local concentration of CO2 at the catalyst site, leading to an enhanced CO2RR rate. However, substantial morphological changes have been observed in the AgCu-3 MOF after the CP experiment under humid CO2 reduction conditions.

Nitric Oxide‐Actuated Titanium Dioxide Janus Nanoparticles for Enhanced Multimodal Disruption of Infectious Biofilms

AbstractSonodynamic therapy (SDT) is promising for combating deep‐seated infectious diseases by generating substantial reactive oxygen species (ROS) through the profound tissue penetration capabilities of ultrasound. However, the compact protective structures of bacterial biofilms present a formidable challenge, impeding ROS efficacy. Given that ROS have a limited diffusion range and current sonosensitizers struggle to infiltrate biofilms, complete eradication of pathogenic bacteria often remains unachieved. In this study, mesoporous titanium dioxide (TiO2) nanoparticles are engineered asymmetrically coated with a thin layer of Ag and loaded with L‐arginine (LA) to construct ultrasound‐propelled nanomotors. These Ag‐TiO2‐LA Janus nanoparticles demonstrate robust self‐propulsion upon ultrasonic activation, allowing for deeper penetration into biofilm matrices and enhancing localized biofilm disruption through improved SDT outcomes. Additionally, the incorporation of Ag not only broadens TiO2’s absorption spectrum but also confers photothermal capabilities upon NIR laser excitation at 808 nm. The Ag‐TiO2‐LA nanomotor amalgamates TiO2’s sonodynamic potential with Ag's photothermal properties, forging a versatile antimicrobial agent capable of efficient biofilm penetration and a synergistic antibacterial effect when subjected to dual NIR and ultrasound stimuli. This innovative, singularly‐structured nanoparticle stands out as an effective combatant against bacterial biofilms and accelerates the healing process of infected wounds, showcasing potential for multifaceted clinical applications.

Systematic investigation and controlled synthesis of Ag/Ti co-doped hydroxyapatite for bone tissue engineering

Hydroxyapatite (HA) is a cornerstone bio ceramic in bone tissue engineering applications, prized for its inherent biocompatibility and structural resemblance to natural bone tissue. However, both porous and dense, conventional HA formulations face notable stability and mechanical robustness constraints, impeding their broader utility. We introduce an innovative biomaterial synthesized via a straightforward and efficient sol-gel method to surmount these challenges and imbue novel scaffolds with multifunctional capabilities. Leveraging a double doping strategy, our approach seeks to enhance mechanical performance and incorporate antibacterial features, maintaining the biocompatibility of HA-based scaffolds for advanced tissue engineering applications. In pursuit of this objective, we synthesized Ag-doped, Ag, Ti-doped, and Ti-doped HA samples to explore the impact of varying dopant types and concentrations on various structural, thermal, crystallographic, chemical, morphological, mechanical, and biocompatibility characteristics. X-ray Diffraction (XRD) analysis confirmed the presence of apatitic phase compositions across all samples, while Fourier-transform Infrared Spectroscopy (FTIR) data corroborated phosphate formation and functional group identification. Scanning Electron Microscopy (SEM) studies revealed a correlation between particle size and dopant concentration, consistent with XRD findings. Nanoindentation results indicated optimal mechanical performance was achieved with balanced incorporation of Ag and Ti ions despite increased Vickers microhardness with higher Ti concentrations. All doped samples exhibited effective antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), except for the Ti-doped HA sample. Moreover, the HA sample co-doped with equal amounts of Ag and Ti demonstrated noncytotoxicity for human lung cancer (A549) cells. In contrast, all doped samples exhibited cytotoxicity towards human prostate cancer cell (PC3) cells. Statistical analysis confirmed a synergistic enhancement of biocompatibility and mechanical performance in HA samples doped with Ag and Ti ions in equal proportions. In conclusion, our study presents a simple and effective approach for enhancing HA's mechanical and antibacterial properties through co-doping with Ag and Ti. This innovative biomaterial holds significant promise for advancing bone tissue engineering applications.

Hydrogen production from low-temperature methanol steam reforming over silver-promoted CuO/ZnO/Ag/Al2O3 Catalyst

Cu-based catalysts featured with high activity at low temperatures and suppressed CO generation are expected to attract significant attention in the methanol steam reforming (MSR) reaction for on-board hydrogen production for proton exchange membrane fuel cells. Herein, we demonstrate that Ag incorporation into a CuO/ZnO/Al2O3 catalyst leads to enhanced hydrogen production activity and suppressed CO selectivity in MSR reactions at low temperatures (200–220 °C). The characterization results revealed that incorporation of a small amount of Ag in the catalyst not only improves the dispersion of the polymetallic components and diversifies the Cu species, but also lowers Cu reduction temperature and brings more oxygen vacancies, thereby leading to improved catalytic performance. The preparation conditions, structure-activity relationship, and stability of the Ag-promoted catalyst were investigated in detail based on time-on-steam tests and characterizations. This finding paves a new possible way for the optimization of the Cu-based catalysts for MSR.

A new design of colorimetric films using bacterial cellulose nanocrystals derived from nata de coco for sensing volatile organic compounds

In this work, bacterial cellulose (BC) derived from Nata de Coco is a polysaccharide material, and it is further processed into bacterial cellulose nanocrystal (BCNC) via acid hydrolysis. Then BCNC is doped with transition metals to enhance its amine/hydrogen sulfide response. Therefore, the aim of this study is to investigate the use of transition metals as indicators to detect amine and hydrogen sulfide gas for efficiently monitoring food spoilage. BCNCs were treated with various concentrations of silver nitrate (AgNO3) and copper sulfate pentahydrate (CuSO4·5H2O). Then the dropwise addition of ascorbic acid was applied to reduce Ag+ and Cu2+ to Ag0 (silver nanoparticle) and Cu0 (copper nanoparticle), which refer to red brown and red wine colors, respectively. The results indicated that BCNC/Ag nanoparticles were spherical, while BCNC/Cu nanoparticles exhibited a rod-like structure. XRD results also presented the incorporation of Ag and Cu nanoparticles, as confirmed by both crystallography structures. Furthermore, UV–Vis spectra showed the adsorption bands at 422–430 nm and 626–629 nm, belonging to Ag and Cu nanoparticles. After H2S and ammonia gas exposure, BH/Ag and BH/Cu films turned black from brown and red. In conclusion, transition metal-doped BCNCs exhibit potential for innovative food spoilage gas sensors.

Tailoring the physical, optical, and structural properties of bismuth oxide to enhance its anionic, cationic, and phenol dye degradation activities

We provide a novel investigation that demonstrates the synthesis of silver-doped bismuth oxide (ABO), holmium-doped bismuth oxide (HBO), nanostructured bismuth oxide (BO), and silver-holmium co-doped bismuth oxide (CDBO) by a cost-effective and straightforward surfactant-assisted co-precipitation technique. In comparison to the BO, ABO, and HBO samples, the optical tests revealed that the CDBO sample exhibited superior photocatalytic characteristics. This is possibly attributed to the physical, optical, and structural properties of the material tailored by the synergistic effect of the adopted strategies, i.e., nanotechnology, oxygen vacancies, and co-doping. The microstructures, physicochemical properties, morphological characteristics, and compositional attributes of the synthesized materials were investigated using sophisticated characterization techniques. The intrinsic conductivity of the bismuth oxide was enhanced with the incorporation of Ag and Ho as co-dopants, as shown by the results obtained from two probe current-voltage experiments. The co-doped sample exhibited the highest efficacy in decomposing rhodamine B dye, with a degradation rate of 91 % during a mere 70-min exposure to W-lamp illumination. The most ideal settings for CDBO photocatalytic activities were identified by comprehensive parameter optimization research. These parameters include a basic pH, a catalyst dosage of 25 mg, a dye concentration of 15 ppm, and an operating temperature of 30 °C. The co-doped and nanostructured photocatalyst also showed an outstanding capability to break down orange II and phenol dye. The trapping experiments' results indicate that the hydroxyl and superoxide radicals play a significant role in the mineralization of the tested dye.

Single atoms and metal nanoclusters anchored to graphene vacancies

Fabricating dispersed single atoms and size-controlled metal nanoclusters remains a difficult challenge due to sintering. Here, we demonstrate that atoms and clusters can be immobilized using atomically clean defect-engineered graphene as the matrix. The graphene is first cleaned of surface contamination with laser heating, after which low-energy Ar irradiation is used to create spatially well-separated vacancies into it. Metal atoms are then evaporated either via thermal or ebeam evaporation onto graphene, where they diffuse until being trapped into a vacancy. The density of embedded structures can be controlled through irradiation dose, and the size of the structures through evaporation time. The resulting structures are confirmed through atomic-resolution scanning transmission electron microscopy and electron energy loss spectroscopy. We demonstrate here incorporation of Al, Ti, Fe, Ag and Au single atoms or nanoclusters, but the method should work equally well for other elements.