The current work demonstrates the controlled synthesis of graphitic carbon nitride grafted silver (g-C
3
N
4
-g-Ag) doped tin oxide (SnO
2
) quantum dots (QDs) using the co-precipitation method. This ...research aimed to decrease the charge recombination rate of SnO
2
and enhance their multifunctional effectiveness as catalysts and antibacterial agents with molecular docking analysis. The doping of g-C
3
N
4
-g-Ag increased the charge separation efficacy and number of active sites, resulting in the enhancement of catalytic and antibacterial activities. 6 mL of g-C
3
N
4
-g-Ag doped SnO
2
QDs indicated remarkable dye removal activity of over 97.7%, which signifies its potential application in various environmental settings. Furthermore, the doped QDs demonstrated the 4.05 ± 0.08 mm inhibition area contrary to multiple drug resistant (MDR)
Staphylococcus aureus
(
S. aureus
). The inhibitory effect of g-C
3
N
4
-g-Ag doped SnO
2
QDs on DNA gyrase
S. aureus
and tyrosyl-tRNA synthetase
S. aureus
was elucidated using molecular docking analysis, supporting their bactericidal activity.
Crystallographically preferred oriented porous Ta3N5 nanotubes (NTs) were synthesized by thermal nitridation of vertically oriented, thick-walled Ta2O5 NTs, strongly adhered to the substrate. The ...adherence on the substrate and the wall thickness of the Ta2O5 NTs were fine-tuned by anodization, thereby helping to preserve their tubular morphology for nitridation at higher temperatures. Samples were studied by scanning electron microscopy, high-resolution electron microscopy, X-ray diffraction, Rietveld refinements, ultraviolet–visible spectrophotometry, X-ray photoelectron spectroscopy, photoluminescence spectra, and electrochemical techniques. Oxygen content in the structure of porous Ta3N5 NTs strongly influenced their photoelectrochemical activity. Structural analyses revealed that the nitridation temperature has crystallographically controlled the preferential orientation along the (110) direction, reduced the oxygen content in the crystalline structure and the tubular matrix, and increased the grain size. The preferred oriented porous Ta3N5 NTs optimized by the nitridation temperature presented an enhanced photocurrent of 7.4 mA cm–2 at 1.23 V vs RHE under AM 1.5 (1 Sun) illumination. Hydrogen production was evaluated by gas chromatography, resulting in 32.8 μmol of H2 in 1 h from the pristine porous Ta3N5 NTs. Electrochemical impedance spectroscopy has shown an effect of nitridation temperature on the interfacial charge transport resistance at the semiconductor–liquid interface; however, the flat band of Ta3N5 NTs remained unchanged.
Monoclinic Ta3N5 thin films were synthesized by thermal nitridation of amorphous Ta2O5 films directly sputtered by radio frequency magnetron sputtering. The samples were studied by high resolution ...transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis-NIR spectrophotometry, rietveld refinements, spectroscopic ellipsometry and electrochemical techniques. The surface composition of Ta3N5 thin film was found to be different than the underlying film, affecting the optical properties of the material. Rietveld refinement has confirmed that the nitridation process results in Schottky and oxygen substitutional defects within the crystalline structure of monoclinic Ta3N5 thin film. The optical constants of the film were obtained by spectroscopic ellipsometry within a spectral range of 4.60-0.54 eV, i.e. 270-2300 nm. The suitable parameterization was found to consist of three Tauc-Lorentz and one Lorentz oscillators. The conduction band, valence band and the flat band positions were determined by photoelectrochemical techniques, presenting a strong dependence on pH of the eletrolyte. Improved photocurrent was obtained in alkaline conditions and attributed to the shorter depletion region width measured by Mott-Schottky and the lower recombination life time measured by open circuit potential decay analyses.
Zn–Fe layered double hydroxide (LDH) was synthesized through the low-temperature-based coprecipitation method. Various concentrations of Ag (1, 3, and 5 wt %) with a fixed amount (5 wt %) of ...polyvinylpyrrolidone (PVP) were doped into LDH nanocomposites. This research aims to improve the bactericidal properties and catalytic activities of doping-dependent nanocomposites. Adding Ag and PVP to LDH enhanced oxygen vacancies, which increased the amount of hydroxide adsorption sites and the number of active sites. The doped LDH was employed to degrade rhodamine-B dye in the presence of a reducing agent (NaBH4), and the obtained results showed maximum dye degradation in a basic medium compared to acidic and neutral. The bactericidal efficacy of doped Zn–Fe (5 wt %) showed a considerably greater inhibition zone of 3.65 mm against Gram-negative (G–ve) or Escherichia coli (E. coli). Furthermore, molecular docking was used to decipher the mystery behind the microbicidal action of Ag-doped PVP/Zn–Fe LDH and to propose an inhibition mechanism of β-ketoacyl-acyl carrier protein synthase II E. coli (FabH) and deoxyribonucleic acid gyrase E. coli behind in vitro results.
Ta3N5 is a promising photoelectrode for solar hydrogen production; however, to date pristine Ta3N5 electrodes without loading co‐catalysts have presented limited photoelectrochemical (PEC) ...performance. In particular, large external biasing has been required to run water oxidation, the origin of which is investigated herein. Ta3N5 nanotubes (NTs) prepared by nitridation were characterized by a wide range of techniques. The bandgap was confirmed by a novel PEC technique. Nondestructive synchrotron‐excited XPS has shown the presence of reduced Ta species deeper in the Ta3N5 surface. Lower photocurrent and transient spikes that were intense at lower applied biasing were observed under water oxidation; however, spikes were inhibited in the presence of a sacrificial agent and photocurrent was improved even at low biasing. It was observed for the first time that the lower PEC performance under water oxidation can be attributed to the presence of interband trapping states associated with pristine Ta3N5 NTs/electrolyte junction. These states correspond to the structural defects in Ta3N5, devastate PEC performance, and present the necessity to apply higher biasing. The key to circumvent them is to use a sacrificial agent in the electrolyte or to load a suitable co‐catalyst to avoid hole accumulation under water oxidation, thereby improving the phootocurrent. The findings on the interband states could also provide guidance for the investigation of PEC properties of new types of semiconducting devices.
Semiconductor–liquid interfaces: Under water‐oxidation conditions, the photogenerated holes are trapped in the interband states related to the crystalline defects in Ta3N5. However, in the case of a sacrificial reagent, these holes are efficiently scavenged. A key factor to improve water oxidation at lower biasing is the hole scavenging from the surface of pristine Ta3N5 nanotubes achieved by adding a suitable co‐catalyst on its surface (see figure).
This research lays the groundwork for preparing graphene oxide (GO)-doped CaO nanocomposites for efficient antibacterial potential and dye degradation. The study aimed to reduce the recombination ...rate of the electron hole (e
−
/h
+
) of CaO and improve charge transfer. This issue can be minimized by doping high-surface area GO into CaO quantum dots (QDs). Herein, the one-pot co-precipitation technique has prepared various concentrations (1, 3, and 5 wt%) of GO-doped CaO. Characterization techniques were used to investigate optical, elemental analysis, microstructural, functional, and morphological properties. The addition of GO into QDs showed excellent catalytic activity (CA) to control sample CaO against methylene blue (MB) in basic and acidic media compared to the neutral media. The synergistic effect of morphological alternation attributed to an increase in the mechanism of CA upon doping. Various concentrations of GO to QDs promised remarkable bactericidal potency against
Escherichia coli
.
Mitigating the global warming caused by CO2 emissions from anthropogenic sources is a hot research topic in the current era. The high cost and difficulty in handling liquid solvent absorbents for CO2 ...capture are the main barriers to their industrial application. Earth-abundant solid sorbents are favorable candidates for CO2 separation, offering a low energy penalty for CO2 desorption. Here, Polysulfone (PSF) nanocomposites were prepared by simple solution blending. The carbon-based fillers, namely carbon nanotubes (CNT), and activated carbon (CA) in the range of 5–20 wt%, containing iron nanoparticles, were used as fillers. Their morphological, thermal, CO2 capture capacity and magnetic properties were comprehensively studied. Transmission electron microscopy (TEM) evidenced uniform filler distribution in the polymer matrix with sizes of 47–54 nm. Thermal analysis revealed an approximately 4 °C improvement in both the initial (Tonset) and maximum (Tmax) degradation temperatures by adding 5 wt% of nanoparticles compared to the pristine polymer. The glass transition temperature (Tg) of the pristine PSF and produced nanocomposites showed identical values as estimated by differential scanning calorimetry (DSC). The increase in filler amount gradually decreased the water contact angle values, indicating a hydrophilic classification of the PSF nanocomposites. The obtained PSF nanocomposites exhibited an efficient CO2 capture capacity of about 40–61 mgCO2/g at 45 °C, higher than pristine PSF. This remarkable achievement sets a new benchmark compared to previously developed systems. The introduction of the filler transforms the diamagnetic polymer matrix into a ferromagnet, presenting a coercivity of about 480 Oe, enhancing the material's potential for applications in microelectronics.
•Exception carbon dioxide capture capacity demonstrated by the material.•Innovative magnetic polymer nanocomposites.•Novel synthesis method for metal-activated carbon and carbon nanotubes.•Enhanced thermal stability is achieved by incorporating carbon-based filler.
In this work, we address a knowledge gap regarding how cation and anion doping affect the stability and optoelectronic properties of Cs3Sb2I9 perovskites. We have employed Density Functional Theory ...(DFT) to investigate structures doped with Ag, In, Mo, Nb, Sc, Bi, Br and Cl in both 0D hexagonal P63/mmc and 2D trigonal P 3‾ m1 Cs3Sb2I9 polymorphs. Our results show that doping with either Sc, Bi, or In leads to negative decomposition energy and doping with Ag or In results in a reduced band gap while enhancing absorption, offering beneficial enhancements for LED and photovoltaic applications. Mo and Nb doping facilitate d-d transitions at lower energies, which is also significant for light emission applications. Conversely, halogen doping allows for fine-tuning the band gap with minimal changes in effective mass, accompanied by lattice parameter contraction, yielding more stable Sb-X bonds. Additionally, our analysis demonstrates that the 0D polymorph allows for easier dopant incorporation, leading to improved stability compared to the 2D structure. The results from this study offer important directions for experimentalists to explore in the development of efficient energy conversion materials.
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In this work, we show the effect of the thermal treatment temperature on the photoelectrochemical (PEC) activity of CdSe/TiO
2
nanocomposites. TiO
2
nanotubes (NTs) were synthesized by anodization ...and the nanocomposites were obtained by depositing CdSe clusters
via
magnetron sputtering. A two-step thermal treatment was performed: heating the TiO
2
NTs at different temperatures prior to CdSe deposition and further heating the CdSe/TiO
2
nanocomposites. The nanocomposites were characterized by Rutherford backscattering spectroscopy (RBS), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV-Vis spectrophotometry, and electrochemical impedance spectroscopy (EIS). To compare the PEC performance of the CdSe/TiO
2
nanocomposites and pristine TiO
2
NTs, linear sweep voltammetry (LSV) curves were obtained under visible light and under 1 sun illumination. It was observed that CdSe incorporation into the TiO
2
template enhances the visible light absorbance thereby improving the PEC performance of the nanocomposites. We have found that the optical, structural and PEC properties of the CdSe/TiO
2
nanocomposites are dependent on the thermal treatment temperature of the TiO
2
nanotubular substrate, prior to CdSe deposition. Moreover, a three-fold improvement in photocurrent was observed upon further thermal treatment of the obtained nanocomposite.
Effect of the thermal treatment temperature on the photoelectrochemical (PEC) activity of CdSe/TiO
2
nanocomposites.
In the present work, an activated biocarbon (aBC) was studied as a support in Pd electrocatalyst for ethanol oxidation reaction (EOR) in alkaline medium. Pd/aBC sample was compared with a commercial ...Vulcan carbon supported Pd electrocatalyst. The Pd particles morphology were influenced by the high content of oxygenated surface functional groups of aBC support, which can be relevant for the synthesis of Pd based electrocatalysts, because the Pd particles formation mechanism involves the adsorption of Pd
2+
on negative charged sites of aBC support. This adsorption occurs preferentially on electron donor sites such as oxygenated functional groups. Therefore, the higher concentration of these groups in aBC surface can determine a higher concentration of initial nuclei sites for Pd particles formation contributing to the particles agglomeration on aBC support, compromising the Pd/aBC electrocatalytic performance. For both prepared electrocatalysts, the spectroelectrochemical analysis demonstrates that the acetate ion is the main product of the EOR in the alkaline medium.
