Ethosomal (−)-epigallocatechin-3-gallate as a novel approach to enhance antioxidant, anti-collagenase and anti-elastase effects

• Çiğdem Yücel,
• Gökçe Şeker Karatoprak,
• Sena Yalçıntaş and
• Tuğba Eren Böncü

Beilstein J. Nanotechnol. 2022, 13, 491–502, doi:10.3762/bjnano.13.41

• collagenase and elastase enzymes were investigated compared to those of the solution form. Within the scope of antioxidant activity studies, 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+•) radical scavenging and β-carotene/linoleic acid co-oxidation

• values compared to the those of the standard (14.2 µg/mL and 1.54 µg/mL, respectively) [32]. However, the β-carotene/linoleic acid co-oxidation inhibitory effects of our ethosomal formulations were different when compared to those of the synthetic antioxidant butylated hydroxytoluene (BHT) used as the

• -bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+•) radical scavenging effects taken at the end of the cell permeation study were determined based on methods described by Gyamfi et al. and Re et al., respectively [46][47]. In addition, β-carotene/linoleic acid co-oxidation inhibitory effects were

Sputtering onto liquids: a critical review

• Anastasiya Sergievskaya,
• Adrien Chauvin and
• Stephanos Konstantinidis

Beilstein J. Nanotechnol. 2022, 13, 10–53, doi:10.3762/bjnano.13.2

Hierarchically structured 3D carbon nanotube electrodes for electrocatalytic applications

• Pei Wang,
• Katarzyna Kulp and
• Michael Bron

Beilstein J. Nanotechnol. 2019, 10, 1475–1487, doi:10.3762/bjnano.10.146

• from 0.05 to 0.3 V vs RHE, indicating complete coverage of Pt with COad. Pt-CNT/CNT/GC provides a more negative onset potential for CO oxidation at around 0.66 V vs RHE compared to Pt-CNT/GC (≈0.7 V). The negative shift of the onset potential indicates that Pt-CNT/CNT/GC is superior for the electro

• -oxidation of COad compared to Pt-CNT/GC The reason for this improved poisoning tolerance is not known to us at the moment. However, it is known from literature that methanol as well as CO oxidation are very sensitive to Pt surface structure. It might be that a defect-rich structure of our Pt nanoparticles

Mo-doped boron nitride monolayer as a promising single-atom electrocatalyst for CO₂ conversion

• Qianyi Cui,
• Gangqiang Qin,
• Weihua Wang,
• Lixiang Sun,
• Aijun Du and
• Qiao Sun

Beilstein J. Nanotechnol. 2019, 10, 540–548, doi:10.3762/bjnano.10.55

• ][44]. Recent reports show that single-TM-doped BN nanomaterials have been used as efficient catalysts in the reactions of N2 fixation and CO oxidation [45][46]. It is worth noting that Chen and co-workers reported that single Mo supported on defective BN nanosheets presents a highly efficient

Thermal control of the defunctionalization of supported Au₂₅(glutathione)₁₈ catalysts for benzyl alcohol oxidation

• Zahraa Shahin,
• Hyewon Ji,
• Rodica Chiriac,
• Nadine Essayem,
• Franck Rataboul and
• Aude Demessence

Beilstein J. Nanotechnol. 2019, 10, 228–237, doi:10.3762/bjnano.10.21

• nanoparticles (GNPs), GNPs have been of great interest in chemistry, dispersed on metal oxides and in CO oxidation reaction [1]. Today, GNPs of diameter less than 10 nm are known to be a remarkable, heterogeneous catalyst, capable of catalyzing a wide range of reactions including hydrocarbon combustion [2

Fabrication of CeO₂–MO_x (M = Cu, Co, Ni) composite yolk–shell nanospheres with enhanced catalytic properties for CO oxidation

• Ling Liu,
• Jingjing Shi,
• Hongxia Cao,
• Ruiyu Wang and
• Ziwu Liu

Beilstein J. Nanotechnol. 2017, 8, 2425–2437, doi:10.3762/bjnano.8.241

• solvothermal process, highly dispersed MOx species were decorated on the surface of CeO2 yolk–shell nanospheres to form CeO2–MOx composites. As a CO oxidation catalyst, the CeO2–MOx composite yolk–shell nanospheres showed strikingly higher catalytic activity than naked CeO2 due to the strong synergistic

• interaction at the interface sites between MOx and CeO2. Cycling tests demonstrate the good cycle stability of these yolk–shell nanospheres. The initial concentration of M(CH3COO)2·xH2O in the synthesis process played a significant role in catalytic performance for CO oxidation. Impressively, complete CO

• can be expected to create other ceria-based composite oxide systems with various structures for a broad range of technical applications. Keywords: CeO2; CO oxidation; surface decoration; synergistic interaction; yolk–shell structure; Introduction As one of the most important rare-earth oxides, ceria

Low-temperature CO oxidation over Cu/Pt co-doped ZrO₂ nanoparticles synthesized by solution combustion

• Amit Singhania and
• Shipra Mital Gupta

Beilstein J. Nanotechnol. 2017, 8, 1546–1552, doi:10.3762/bjnano.8.156

• .8.156 Abstract Zirconia (ZrO2) nanoparticles co-doped with Cu and Pt were applied as catalysts for carbon monoxide (CO) oxidation. These materials were prepared through solution combustion in order to obtain highly active and stable catalytic nanomaterials. This method allows Pt2+ and Cu2+ ions to

• structure and larger oxygen vacancies. The nanoparticles showed excellent activity for CO oxidation. The temperature T50 (the temperature at which 50% of CO are converted) was lowered by 175 °C in comparison to bare ZrO2. Further, they exhibited very high stability for CO reaction (time-on-stream ≈ 70 h

• ). This is due to combined effect of smaller particle size, large oxygen vacancies, high specific surface area and better thermal stability of the Cu/Pt co-doped ZrO2 nanoparticles. The apparent activation energy for CO oxidation is found to be 45.6 kJ·mol−1. The CO conversion decreases with increase in

Nanocrystalline ZrO₂ and Pt-doped ZrO₂ catalysts for low-temperature CO oxidation

• Amit Singhania and
• Shipra Mital Gupta

Beilstein J. Nanotechnol. 2017, 8, 264–271, doi:10.3762/bjnano.8.29

• doped into ZrO2 and yielded excellent CO oxidation. The working temperature was lowered by 150 °C in comparison to pure ZrO2. Further, it is highly stable for the CO reaction (time-on-stream ≈ 40 h). This is because of a synergic effect between Pt and Zr components, which results in an increase of the

• oxygen mobility and oxygen vacancies and improves the activity and stability of the catalyst. The effects of gas hourly space velocity (GHSV) and initial CO concentration on the CO oxidation over Pt(1%)-ZrO2 were studied. Keywords: CO oxidation; nanomaterials; platinum; solution combustion method

• anthropogenic activities. The catalytic CO oxidation is a very well established and exploited process. So far, noble metals such as Pt, Pd, Rh and Au dominated as catalysts for CO oxidation [10][11][12]. Various supports such as Al2O3, TiO2, SiO2, CeO2, Fe2O3 and carbon nanotubes (CNTs) have also been used for

In situ formation of reduced graphene oxide structures in ceria by combined sol–gel and solvothermal processing

• Jingxia Yang,
• Johannes Ofner,
• Bernhard Lendl and
• Ulrich Schubert

Beilstein J. Nanotechnol. 2016, 7, 1815–1821, doi:10.3762/bjnano.7.174

• solvothermal treatment in ethanol. The appearance of such structures is closely related to cerium tert-butoxide as precursor and ethanol as solvothermal solvent. The rGO-like residues improve the catalytic CO oxidation activity. This was also confirmed by introduction of “external” graphene oxide during sol

• –gel processing, by which the rGO structures and the catalytic activity were enhanced. Keywords: ceria; CO oxidation; graphene oxide; sol–gel processing; Introduction Ceria (CeO2) has been widely studied as catalyst or catalyst support for redox reactions owing to its high oxygen storage and release

• gels proved to be crucial for the specific surface area, the Ce3+ proportion and, as a consequence, the CO oxidation activity of the obtained materials, which were composed of 3.5–5.5 nm ceria nanoparticles. CeO2 solvothermally treated with EtOH had the highest surface area and showed better CO

Electrocatalysis on the nm scale

• R. Jürgen Behm

Beilstein J. Nanotechnol. 2015, 6, 1008–1009, doi:10.3762/bjnano.6.103

• theoretical description of important electrocatalytic reactions, such as hydrogen evolution/water splitting [4][5] or electrocatalytic ammonia synthesis [6]. Additionally, mechanistic studies of electrocatalytic reactions, such as O2 reduction [7], CO oxidation [8] or the electrooxidation of small organic

Synthesis, characterization, and growth simulations of Cu–Pt bimetallic nanoclusters

• Subarna Khanal,
• Ana Spitale,
• Nabraj Bhattarai,
• Daniel Bahena,
• J. Jesus Velazquez-Salazar,
• Sergio Mejía-Rosales,
• Marcelo M. Mariscal and
• Miguel José-Yacaman

Beilstein J. Nanotechnol. 2014, 5, 1371–1379, doi:10.3762/bjnano.5.150

• sizes. Recently, several groups have worked on the synthesis of CuPt core–shell and alloys nanoparticles, obtaining morphologies such as nanotubes, cubes, spheres, hollow structures and others [36][37][38][39]. These particles exhibit excellent catalytic activities for CO oxidation, methanol oxidation

Restructuring of an Ir(210) electrode surface by potential cycling

• Khaled A. Soliman,
• Dieter M. Kolb,
• Ludwig A. Kibler and
• Timo Jacob

Beilstein J. Nanotechnol. 2014, 5, 1349–1356, doi:10.3762/bjnano.5.148

• of extended vicinal Ir single crystal surfaces [5]. There are striking similarities with Ir(320), Ir(310) and Ir(410), for example. CO adlayer oxidation on Ir(210) Studies of CO oxidation on single crystal electrodes are of practical as well as fundamental interest. From the electrocatalytic point of

• view, CO is the most prominent intermediate species responsible for the poisoning of metallic catalysts [38]. Understanding the mechanism of the CO oxidation on single crystal electrodes may lead to a deeper insight into the relation between surface structure and electrocatalytic activity. Therefore

• mechanism [19]. So far, we were not able to identify the type of surface defects, which act as active centers for CO oxidation on H2-cooled Ir(210). However, these sites are absent at the CO-cooled Ir(210) surface, which explains the higher overpotential. After applying oxidation–reduction cycles, the peak

Shape-selected nanocrystals for in situ spectro-electrochemistry studies on structurally well defined surfaces under controlled electrolyte transport: A combined in situ ATR-FTIR/online DEMS investigation of CO electrooxidation on Pt

• Sylvain Brimaud,
• Zenonas Jusys and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2014, 5, 735–746, doi:10.3762/bjnano.5.86

• processes occurring simultaneously, oxidative COad removal and re-adsorption of (bi)sulfate anions, and reveal a distinct structure sensitivity in these processes and also in the structural implications of (bi)sulfate re-adsorption on the CO adlayer. Keywords: CO oxidation; electrocatalysis; in situ

Design criteria for stable Pt/C fuel cell catalysts

• Josef C. Meier,
• Carolina Galeano,
• Ioannis Katsounaros,
• Jonathon Witte,
• Hans J. Bongard,
• Angel A. Topalov,
• Claudio Baldizzone,
• Stefano Mezzavilla,
• Ferdi Schüth and
• Karl J. J. Mayrhofer

Beilstein J. Nanotechnol. 2014, 5, 44–67, doi:10.3762/bjnano.5.5

• VRHE) and the adsorption of hydrogen in the HUPD region (ca. 0.3–0.05 VRHE). The integration of the area under the CO oxidation signal between the CO-stripping voltammogram and the successive voltammogram in CO-free argon atmosphere (background) is a measure of the active surface area. According CO

• degradation cycles, the peak has become sharper, the maximum shifts to a more negative potential (0.85 VRHE), while no significant carbon monoxide oxidation is observed anymore above 0.91 VRHE. Since the peak potential of the CO oxidation is more positive for smaller particles [77][78][79], the described

• changes of shape and the peak potential shift indicate that the CO oxidation before the treatment takes place mainly on small nanoparticles, which are not present anymore after the first 360 degradation cycles. Thus, the initial drastic surface area loss is most likely linked to a loss/rearrangement of

Some reflections on the understanding of the oxygen reduction reaction at Pt(111)

• Ana M. Gómez-Marín,
• Ruben Rizo and
• Juan M. Feliu

Beilstein J. Nanotechnol. 2013, 4, 956–967, doi:10.3762/bjnano.4.108

• proven to be less sensitive to the surface order than other probes, such as CO oxidation [10][16]. Surface order After potential excursions higher than 1.2 V, the CV in the immediate negative potential sweep shows the presence of {110} and {100} defects in the initially featureless hydrogen adsorption

Catalytic activity of nanostructured Au: Scale effects versus bimetallic/bifunctional effects in low-temperature CO oxidation on nanoporous Au

• Lu-Cun Wang,
• Yi Zhong,
• Haijun Jin,
• Daniel Widmann,
• Jörg Weissmüller and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2013, 4, 111–128, doi:10.3762/bjnano.4.13

• are discussed. Keywords: AuAg alloy; AuCu alloy; CO oxidation; dynamic studies; kinetics; nanoporous Au (NPG) catalyst; oxygen storage capacity (OSC); temporal analysis of products (TAP); Introduction Porous metallic materials with well-controlled morphologies and surface properties have attracted

• remarkably high activity for CO oxidation with molecular oxygen at low temperatures, and recent experiments in our laboratory arrived at comparable conclusions [12][13]. In the meantime, high catalytic activities of NPG catalysts were reported also for other reactions, such as oxidative coupling of methanol

• [14], aerobic oxidation of alcohols [15], and oxidation of organosilanols [16]. Until recently, high activities for the CO oxidation over Au catalysts were only reported for gold nanoparticles of a few nanometers in diameter, which are supported on reducible metal oxides such as TiO2, CeO2 and Fe2O3

Plasmonics-based detection of H₂ and CO: discrimination between reducing gases facilitated by material control

• Gnanaprakash Dharmalingam,
• Nicholas A. Joy,
• Benjamin Grisafe and
• Michael A. Carpenter

Beilstein J. Nanotechnol. 2012, 3, 712–721, doi:10.3762/bjnano.3.81

• oxygen on these supports with the activity of the Au nanoparticles produces an active material towards CO oxidation [29]. Thus, it was proposed that the ability of the YSZ support to provide reactive oxygen for CO oxidation increases the critical diameter for CO oxidation enhancement into the 10–30 nm

• the baseline noise. The catalytic reaction of CO to CO2 has been found to have a strong dependence on the Au NP size. Specifically, for inert metal-oxide supports, an enhancement in CO adsorption on the surface occurs only for particles with diameters less than 2 nm [28]. However, activity towards CO

• oxidation also occurs for particle diameters ranging from 12 to 30 nm when the particles are supported on active metal-oxide supports, such as Fe2O3 and YSZ. These supports are able to trap oxygen due to the presence of oxygen vacancies in their lattice. The combined effect of dissociative adsorption of

Template-assisted formation of microsized nanocrystalline CeO₂ tubes and their catalytic performance in the carboxylation of methanol

• Jörg J. Schneider,
• Meike Naumann,
• Christian Schäfer,
• Armin Brandner,
• Heiko J. Hofmann and
• Peter Claus

Beilstein J. Nanotechnol. 2011, 2, 776–784, doi:10.3762/bjnano.2.86

• helpful for fast oxygen transport [23]. Catalytic studies Ceria nanomaterials as supports for precious metals (e.g., Au, Pt) show interesting properties in CO oxidation in the water gas shift reaction as well as in oxygen storage [12][13][14][24][25]. These properties are due to the high occurrence of

Nanostructured, mesoporous Au/TiO₂ model catalysts – structure, stability and catalytic properties

• Matthias Roos,
• Dominique Böcking,
• Kwabena Offeh Gyimah,
• Gabriela Kucerova,
• Joachim Bansmann,
• Johannes Biskupek,
• Ute Kaiser,
• Nicola Hüsing and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2011, 2, 593–606, doi:10.3762/bjnano.2.63

• increase of the catalytic activity with film thickness indicates that transport limitations inside the Au/TiO2 film catalyst are negligible, i.e., below the detection limit. Keywords: Au catalysis; Au/TiO2; CO oxidation; gold nanoparticles; model catalysts; thin-film catalyst; Introduction There is a

• , the Au particles are homogenously distributed in the TiO2 film, with a broad particle-size distribution ranging from 0.25 to 6–8 nm. On the O350 calcined catalyst film, before CO oxidation, the maximum of the particle-size distribution is located close to ~2.0 (mean particle size 2.0 ± 1.6 nm, Figure

•  5, left). As expected from the much higher temperature during the calcination pretreatment, we observed no substantial changes in the gold particle-size distribution after the CO oxidation reaction (see Figure 5 right, mean particle size 2.2 ± 1.3 nm). This result closely resembles previous findings