Search results
Search for "catalyst" in Full Text gives 373 result(s) in Beilstein Journal of Nanotechnology. Showing first 200.
Silver nanoparticles loaded on lactose/alginate: in situ synthesis, catalytic degradation, and pH-dependent antibacterial activity
Beilstein J. Nanotechnol. 2023, 14, 781–792, doi:10.3762/bjnano.14.64
- agents [33]. The efficiency of the catalyst can be improved by studying different carrier materials [34][35]. Interface factors, including morphology and capping agents, play a significant role in the catalytic activity of AgNPs. The ionotropic gelation mechanism has been recently employed to create
- toxic dyes, methyl orange (MO) and rhodamine B (RhB), using various doses of the nanocomposite. The degradation of toxic dyes using a nanocomposite catalyst was monitored in situ by measuring UV–vis absorption at ambient temperature, with the concentration changing in a time-dependent manner. The
- effectiveness of the reactions is confirmed by discoloration of the pollutant solution and a reduction in absorbance values in the UV–vis spectra. In a separate study [45], it was shown that the dyes degraded weakly in the absence of a catalyst. As seen in Figure 7 and Figure 8, the reduction of MO and RhB is
Control of morphology and crystallinity of CNTs in flame synthesis with one-dimensional reaction zone
Beilstein J. Nanotechnol. 2023, 14, 741–750, doi:10.3762/bjnano.14.61
- on the growth control in CVD conclude that independent parameters, such as fuel selection, synthesis temperature, vapor pressure, and catalyst, govern CNT growth [6]; all can be manipulated for synthesis control. CVD is preferred because of the high degree of control and the possibility to synthesize
- explored. In flame synthesis, the correct selection of the catalyst is the governing parameter to produce CNTs similar to those made in CVD in an economical production process [7]. Hamzah et al. [8] discussed the control of CNT morphology and growth in flame synthesis taking into account many parameters
- , such as fuel, catalyst, temperature, and diluent. However, the heterogeneous gas properties during combustion lead to a high temperature gradient and a wide distribution of chemical species within the flame. The interrelated processes of heat generation and carbon supply requires an optimum parametric
Titania nanoparticles for photocatalytic degradation of ethanol under simulated solar light
Beilstein J. Nanotechnol. 2023, 14, 616–630, doi:10.3762/bjnano.14.51
- from the interaction with photogenerated hydroxyl radicals. Despite the fact that radical trapping was performed in aqueous solution, it can be indicative for the ability of the catalyst surface to generate hydroxyl radicals in the present investigated system. The main reactions leading to (•OH
- . Probably, a longer irradiation time would be beneficial for ethanol photomineralization over this sample. Also, TO-650-b shows a linear increase of activity after 2 h of irradiation. Figure 11 is illustrative for the different kinds of behavior of the two catalyst series regarding ethanol photodegradation
- and catalytically active defects in the structure of the catalysts. Figure 11 shows also a lower CO2 formation rate for the second catalyst series with a simultaneously increasing H2 formation rate, especially for TO-850-b. From this perspective, it might be interesting to consider these catalysts for
Evaluation of electrosynthesized reduced graphene oxide–Ni/Fe/Co-based (oxy)hydroxide catalysts towards the oxygen evolution reaction
Beilstein J. Nanotechnol. 2023, 14, 420–433, doi:10.3762/bjnano.14.34
- process is primarily the oxygen evolution reaction (OER) due to its sluggish kinetics resulting in a high overpotential and low efficiency [4]. To overcome this problem, robust anode electrode catalyst materials are required. Since the Ru- and Pt-based catalysts used so far for OER are made using limited
- and expensive metals [5], studies on other catalyst materials are being conducted. Recently, transition-metal-based materials including nickel, iron, and/or cobalt have become promising catalysts for OER [6][7][8][9][10]. The materials are characterized by relatively low cost and environmentally
- graphene material with Ni-, Fe- and/or Co-based oxides/hydroxides with high chemical reactivity provides both an effective electron pathway through the catalyst [20] and high specific surface area [21], which is desirable for the OER process [13]. The overall electrocatalytic performance of the hybrid
Bismuth-based nanostructured photocatalysts for the remediation of antibiotics and organic dyes
Beilstein J. Nanotechnol. 2023, 14, 291–321, doi:10.3762/bjnano.14.26
- charges and, hence, increase photocatalytic activity, metallic bismuth can function as a direct plasmonic photocatalyst (similar to Au and Ag) or a co-catalyst [77]. Also, the unique layered crystal structure of Aurivillius-type bismuth oxide-based semiconductors allows for the induction of an internal
- dispersion into the solution. An increase in the concentration of pollutant molecules adsorbed on the catalyst surface while the catalyst dosage is unchanged and the generation of reactive species is constant could be another factor causing the decrease in photocatalytic degradation rate with increasing
Biocatalytic synthesis and ordered self-assembly of silica nanoparticles via a silica-binding peptide
Beilstein J. Nanotechnol. 2023, 14, 280–290, doi:10.3762/bjnano.14.25
- demonstrate that the SiBP acts as a multirole agent when used alone or in combination with a strong base catalyst (NH3). When used alone, SiBP catalyzes the hydrolysis of precursor molecules in a dose-dependent manner and produces 17–20 nm SiO2 particles organized in colloidal gels. When used in combination
- the particles through a capping agent-like effect. (3) The SiBP can increase the efficiency of the self-assembly by modifying the net surface charge of the particle. To test these hypotheses, we have synthesized SiO2 particles with the Stöber method using the SiBP as the only catalyst or in
- scattering (DLS). The efficiency of the self-assembly was evaluated with scanning electron microscopy (SEM), UV–vis spectroscopy, and qualitative visual demonstration. Results and Discussion SiBP alone as catalyst Reaction kinetics were studied via OD measurements of the particles and GC analysis of
A novel approach to pulsed laser deposition of platinum catalyst on carbon particles for use in polymer electrolyte membrane fuel cells
Beilstein J. Nanotechnol. 2023, 14, 190–204, doi:10.3762/bjnano.14.19
- an efficient Pt-based catalyst for polymer electrolyte membrane fuel cells (PEMFCs) by using a cost-effective and efficient physical method to deposit platinum nanoparticles (PtNPs) on carbon supports directly from the platinum target. The method developed avoids the chemical functionalization of the
- carbon substrate and the chemical synthesis of PtNPs during catalyst fabrication. Platinum was deposited on carbon particles at room temperature using a pulsed laser deposition (PLD) system equipped with an ArF excimer laser (λ = 193 nm). The uniform deposition of PtNPs on carbon supports was achieved
- W/cm2 obtained for commercial 20% Pt Vulcan XC-72R. This result was achieved with three times less Pt catalyst on the carbon support compared to the commercial catalyst, which means that a higher catalyst utilization factor was achieved. Keywords: carbon particles; cyclic voltammetry; fuel cells
Non-stoichiometric magnetite as catalyst for the photocatalytic degradation of phenol and 2,6-dibromo-4-methylphenol – a new approach in water treatment
Beilstein J. Nanotechnol. 2022, 13, 1531–1540, doi:10.3762/bjnano.13.126
- solar radiation as an energy source [11]. The photocatalysts are activated by radiation and produce highly reactive photo-induced charge carriers, which can react with the contaminants adsorbed on the surface of the catalyst. Understanding the properties of the photocatalyst material is critical to
- designing an effective photocatalytic process. The factors that influence photocatalytic efficiency include the photocatalyst bandwidth, the recombination rate of photogenerated electron–hole pairs, the use of solar energy, and problems with catalyst degradation. Magnetite is a common auxiliary mineral in
- the facets (220), (311), (400), (422), (511), and (440) of Fe3O4, respectively [21]. The absence of the (210) and (211) peaks confirms that the catalysts were indeed magnetite. The mean size of the catalyst crystallites (D) was calculated from the high-reflection X-ray diffraction profiles by
A TiO2@MWCNTs nanocomposite photoanode for solar-driven water splitting
Beilstein J. Nanotechnol. 2022, 13, 1520–1530, doi:10.3762/bjnano.13.125
- under solar irradiation. Keywords: multi-wall carbon nanotubes (MWCNTs); nanomaterials; photoelectrochemical; TiO2; water splitting; Introduction TiO2 is an excellent photochemical catalyst for environmental and chemical applications due to its good activity regarding numerous reduction and oxidation
- × 3 mm3 of width × height × thickness) as the support for the electrode is immersed in the as-prepared mixture. The catalyst mixture is assembled on the plastic bar under ultrasound for 1 min. Finally, the photoelectrochemical electrode is obtained after drying at 60 °C for 15 min. TiO2@MWCNTs
- surface with a size of 1.5 × 2.0 cm2 is irradiated. A schematic of the experimental apparatus is described in Figure 1. Results and Discussion Characterization of the TiO2@MWCNTs nanocomposite catalyst FE-SEM images of the morphology of the MWCNTs, TiO2 powder, and the TiO2@MWCNTs nanocomposite are shown
Recent trends in Bi-based nanomaterials: challenges, fabrication, enhancement techniques, and environmental applications
Beilstein J. Nanotechnol. 2022, 13, 1316–1336, doi:10.3762/bjnano.13.109
- conduction band (CB) through visible light [39]. The holes in the valence band of the catalyst split water to hydroxyl radicals (•OH). Electrons in the CB of a semiconductor photocatalyst can generate the superoxide anion (•O2−) when they interact with oxygen molecules. During the photocatalytic oxidative
- , the catalyst should have a high CB position and a low VB position, resulting in a large bandgap. These two prerequisites are not compatible. As a direct consequence of this, heterojunctions are produced. To create heterojunction photocatalysts, two semiconductor photocatalysts are combined [44][45
- potential role of Au nanoparticles in the S-scheme heterostructure is noteworthy. They serve as a co-catalyst for improving electron separation and transmission due to the photogenerated potential. By forming heterojunctions, the visible-light absorption as well as the carrier separation efficiency of Bi
Studies of probe tip materials by atomic force microscopy: a review
Beilstein J. Nanotechnol. 2022, 13, 1256–1267, doi:10.3762/bjnano.13.104
- does it generate catalyst patterns in advance. In order to proceed safely and cost-effectively, the method uses mainly ethanol as the carbon source with a 4% flow gravity of hydrogen gas. Notably, using this tip array allows the growth method to be further optimized to produce the highest percentage of
- prominent carbon nanotube tips. This type of process strategy is used to produce CNT tips in wafer-scale AFM. By identifying and manipulating the key growth conditions that control the density and length of carbon nanotube growth; i.e., the amount of Co catalyst and CNT growth time, it is possible to switch
- between ring protruding carbon nanotubes and carbon nanotubes protruding directly from the tip with a high degree of selectivity. However, this growth method does not allow accurate catalyst placement and often produces ring-like tips. Based on the above method, Cheng et al. [11] proposed a simple method
Rapid fabrication of MgO@g-C3N4 heterojunctions for photocatalytic nitric oxide removal
Beilstein J. Nanotechnol. 2022, 13, 1141–1154, doi:10.3762/bjnano.13.96
- are different approaches to mitigate NO pollution, including catalyst/non-catalyst [4], oxidation [5], bioprocesses [6], adsorption [7], absorption [8], and non-thermal plasma technologies [9]. Photocatalytic oxidation is considered a promising approach due to its ability to degrade various air
- absorbs visible light due to its small bandgap below 2.7 eV. Because of this, it has been consistently regarded as a catalyst with excellent optical properties [14][15]. Unfortunately, its narrow bandgap leads to rapid recombination of electron–hole (e−–h+) pairs, and the valence band potential of g-C3N4
Spindle-like MIL101(Fe) decorated with Bi2O3 nanoparticles for enhanced degradation of chlortetracycline under visible-light irradiation
Beilstein J. Nanotechnol. 2022, 13, 1038–1050, doi:10.3762/bjnano.13.91
- separation of electron–hole pairs, thus improving the photocatalytic activity of MIL101(Fe) to a certain extent. Nevertheless, the redox ability of the catalyst is weakened due to the fact that the reduction and oxidation processes on the catalyst surface occur at lower oxidation and reduction potentials
- about the construction of Z-scheme heterojunctions by coupling MIL101(Fe) and Bi2O3. Herein, in order to enhance the photocatalytic efficiency of MIL101(Fe) for degradation of CTC, a novel 0D/3D heterojunction catalyst Bi2O3/MIL101(Fe) was prepared by anchoring Bi2O3 nanoparticles to the surface of
- MIL101(Fe). The experimental results show that the recombination of photogenerated carriers in Bi2O3/MIL101(Fe) is effectively inhibited, and the photocatalytic activity of the composite is significantly improved compared with that of a monomer catalyst. At the same time, the results of the capture
Electrocatalytic oxygen reduction activity of AgCoCu oxides on reduced graphene oxide in alkaline media
Beilstein J. Nanotechnol. 2022, 13, 1020–1029, doi:10.3762/bjnano.13.89
- slow reaction rates of the electrode processes impede the efficiency and, thus, require innovative catalyst designs. The ORR is an irreversible, complex (involving multiple steps and intermediates O, OH−, O2−, HO2− and H2O2) and kinetically slow process (via two- or four-electron transfer) dominating
- limiting current density (JL) of 3.6 mA·cm−2 at 1600 rpm under alkaline conditions. Particle size, composition, and exposure to active sites of the catalyst are important features of ORR electrocatalysis that need to be optimized to obtain the highest mass activity and electron transfer value (n ≈ 4
- ). Oxygen reduction on smaller catalyst particles favours the two-electron pathway, dominated via active edge and corner sites, while the four-electron pathway is catalysed by larger particles [18][30]. The kinetics of oxygen reduction on the surface of the ACC-2 sample was studied via the Koutecky–Levich
Design of a biomimetic, small-scale artificial leaf surface for the study of environmental interactions
Beilstein J. Nanotechnol. 2022, 13, 944–957, doi:10.3762/bjnano.13.83
- ) for 45 min at 70 °C. 20 µL of pyrimidine (Merck KGaA, Darmstadt, Germany) was used as catalyst. The waxes were analyzed quantitatively with a gas chromatograph coupled with a flame ionization detector (GC–FID, 6890N, Agilent Technologies Sales & Services, column: DB-1; 30 m × 0.32 mm, 0.1 μm; J&W
Solar-light-driven LaFexNi1−xO3 perovskite oxides for photocatalytic Fenton-like reaction to degrade organic pollutants
Beilstein J. Nanotechnol. 2022, 13, 882–895, doi:10.3762/bjnano.13.79
- , such as pH value, catalyst dosage, and the additional amount of H2O2. LaFe0.7Ni0.3O3 perovskite oxides could operate efficiently under pH 3.5, catalyst dosage of 50 mg/150 mL, and H2O2 concentration of 133 ppm to decompose the MB dye in the 1st order kinetic rate constant of 0.0506 s−1. Keywords
- transmittance and suitable surface area for degrading methylparaben. Although Ti-doped catalyst was expected as a semiconductor to enhance the photocatalytic efficiency, pure LaFeO3 still revealed the better performance of methylparaben photodegradation than LaTi0.15Fe0.85O3 [28]. On the contrary, Garcia-Muñoz
- , methylene blue, and rhodamine B under visible light irradiation. Their optimal sample was LaFe0.85Cu0.15O3, which could remove dyes much more efficiently due to more generation of hydroxyl radicals than pure LaFeO3 [31]. Ni-doped LaFeO3 was ubiquitously employed as a photo/thermal catalyst or a catalyst
Optimizing PMMA solutions to suppress contamination in the transfer of CVD graphene for batch production
Beilstein J. Nanotechnol. 2022, 13, 796–806, doi:10.3762/bjnano.13.70
- ) and 1860 Ω (FWHM = 567 Ω), respectively, proving that the optimized PMMA mixture enables the production of reproducible arrays of electronic devices with consistent properties. Experimental Graphene growth Single-crystal and large-area graphene were obtained on Cu foil via catalyst-assisted growth in
- a low-pressure CVD system (CVD First Nano, EasyTube 3000). A 25 µm thick annealed Cu foil (Alfa Aesar, purity 99.8%), serving as a metal catalyst, was placed in a graphite enclosed cavity during the whole process. The temperature for annealing and growth was kept stable at 1040 °C by PID thermal
Sodium doping in brookite TiO2 enhances its photocatalytic activity
Beilstein J. Nanotechnol. 2022, 13, 599–609, doi:10.3762/bjnano.13.52
- methylene blue (MB) solution at room temperature under UV light generated by a PLS-SXE300 Xenon lamp with a 365 nm band filter. Following the method reported by Wang et al. [22], 15 mg of the catalyst was dispersed into 75 mL of the MB solution (10 mg/L). Before UV light irradiation, the suspension was
Design and characterization of polymeric microneedles containing extracts of Brazilian green propolis
Beilstein J. Nanotechnol. 2022, 13, 503–516, doi:10.3762/bjnano.13.42
- northeast regions of the states of Paraná, São Paulo, and Minas Gerais [31][32][33]. The PRP used had all suitable characteristics to be used in the following experiments. Preparation of mold When using polydimethylsiloxane (PDMS), the combination of base and catalyst resulted in a translucent mixture
- replicas of this master structure. For the preparation of the PDMS mold, suitable amounts of the catalyst agent and the silicone base were mixed, in a proportion of 1:6, using a beaker and taken to ultrasound for 5 min. Afterwards, the mixture was poured into 12-well plates and taken to ultrasound for
Tubular glassy carbon microneedles with fullerene-like tips for biomedical applications
Beilstein J. Nanotechnol. 2022, 13, 455–461, doi:10.3762/bjnano.13.38
- pyrolysis of methane on a curved alumina surface. The surface provides the catalyst as well as the “strain” required to direct nucleation and growth. Figure 1a is a scanning electron microscopy (SEM) overview image showing a number of glassy carbon microneedles, which grow in the direction of the gas flow
A comprehensive review on electrospun nanohybrid membranes for wastewater treatment
Beilstein J. Nanotechnol. 2022, 13, 137–159, doi:10.3762/bjnano.13.10
- predominant PEMs [13]. Zhang et al. developed nanohybrid PVDF membranes by incorporating zeolite with enhanced thermal and electrochemical performance for lithium-ion batteries [14]. ENHs have also been used as a heterogeneous catalyst in indole synthesis by Savva et al. by incorporating gold nanoparticles
Tin dioxide nanomaterial-based photocatalysts for nitrogen oxide oxidation: a review
Beilstein J. Nanotechnol. 2022, 13, 96–113, doi:10.3762/bjnano.13.7
- −, similarly holes react with water to form hydroxyl radicals). Free radicals and strong oxidizing agents react with NOx to produce NO3−, deposited on the photocatalyst surface. The NO3− product formed on the surface of the catalyst can be easily separated for further treatment by washing with water due [11
- , surface engineering, heterojunction construction, co-catalyst, which will be thoroughly outlined in this review. Structure and bandgap SnO2 has a crystal structure similar to that of rutile TiO2 [41][42]. The unit cell parameters of rutile SnO2 are a = b = 0.47374 nm and c = 0.31864 nm [43]. In one unit
- resulting heterojunction photocatalytically removed 40% NO (initial concentration of 500 ppb) and showed excellent photostability under visible light. The NO2 production from the photocatalytic reaction was also negligible. The good photocatalytic NO degradation of the 2D/0D g-C3N4/SnO2 catalyst is due to
Sputtering onto liquids: a critical review
Beilstein J. Nanotechnol. 2022, 13, 10–53, doi:10.3762/bjnano.13.2
Measurement of polarization effects in dual-phase ceria-based oxygen permeation membranes using Kelvin probe force microscopy
Beilstein J. Nanotechnol. 2021, 12, 1380–1391, doi:10.3762/bjnano.12.102
- permeation membrane, as oxygen sensor material, or for the use in solid oxide fuel cell components [1][5][6]. Apart from this, ceria is also widely employed as a catalyst in the middle- to low-temperature regime (20–400 °C) [7][8][9], making ceria-based dual-phase materials with a second electron-conductive
Morphology-driven gas sensing by fabricated fractals: A review
Beilstein J. Nanotechnol. 2021, 12, 1187–1208, doi:10.3762/bjnano.12.88
- of ZnO dendrites and single-crystal ZnO dendrites up to the macroscale [77]. These were synthesized via a vapor-phase transport method at 930 °C using a copper catalyst. Figure 16a and Figure 16b show, respectively, a schematic and a SEM image of the ZnO dendrite gas sensor device. The ZnO dendrites
Other Beilstein-Institut Open Science Activities
