The preparation temperature influences the physicochemical nature and activity of nanoceria

• Robert A. Yokel,
• Wendel Wohlleben,
• Johannes Georg Keller,
• Matthew L. Hancock,
• Jason M. Unrine,
• D. Allan Butterfield and
• Eric A. Grulke

Beilstein J. Nanotechnol. 2021, 12, 525–540, doi:10.3762/bjnano.12.43

• fewer oxygen vacancies and exhibits, therefore, a predominance of surface Ce+4, compared to a solvothermally synthesized nanoceria material with more oxygen vacancies, which produce a preponderance of surface Ce+3, it was hypothesized the NM-212 would have less catalytic activity. Another nanoscale

• +. Increased Ce3+ is accompanied by an increase in oxygen vacancies that weaken the crystal lattice [14]. According to the dissolution framework by Gray and co-workers, Ce3+ can follow more dissolution pathways (including oxidative dissolution) than Ce4+ [59]. The much greater percentage of Ce3+ on the surface

Interface interaction of transition metal phthalocyanines with strontium titanate (100)

• Reimer Karstens,
• Thomas Chassé and
• Heiko Peisert

Beilstein J. Nanotechnol. 2021, 12, 485–496, doi:10.3762/bjnano.12.39

• increased by introducing oxygen vacancies into the crystal structure or by doping (e.g., n-type doping with niobium, Nb5+). Generally, two different terminations of STO(100) are known, that is, the surface can be either TiO2- or SrO-terminated. The TiO2 termination can be achieved by (ex situ) acid

Exploring the fabrication and transfer mechanism of metallic nanostructures on carbon nanomembranes via focused electron beam induced processing

• Christian Preischl,
• Linh Hoang Le,
• Elif Bilgilisoy,
• Armin Gölzhäuser and
• Hubertus Marbach

Beilstein J. Nanotechnol. 2021, 12, 319–329, doi:10.3762/bjnano.12.26

• ) [13], thin layers of porphyrin molecules [14][15], and surface-anchored metal-organic frameworks (SURMOFs) [16][17]. For oxide surfaces it is known that the activation mechanism is based on reactive oxygen vacancies, which are locally created by electron-stimulated oxygen desorption [18][19]. Whereas

ZnO and MXenes as electrode materials for supercapacitor devices

• Ameen Uddin Ammar,
• Ipek Deniz Yildirim,
• Feray Bakan and
• Emre Erdem

Beilstein J. Nanotechnol. 2021, 12, 49–57, doi:10.3762/bjnano.12.4

• point defects. PL yields defect-related emission from all possible defects whereas EPR reveals only signals from paramagnetic defects [7]. Therefore, using EPR one obtains signals from the vacancies or interstitials that are ionized and become paramagnetic. In ZnO, singly ionized oxygen vacancies are

• ionized oxygen vacancies located either in volume or at the surface of the material. (b) PL spectra showing all possible defect centers, including non-paramagnetic ones. The defects emit visible light yielding a broad emission band [4]. (c) Tauc plot obtained from UV–vis reflectance measurements

Unravelling the interfacial interaction in mesoporous SiO₂@nickel phyllosilicate/TiO₂ core–shell nanostructures for photocatalytic activity

• Bridget K. Mutuma,
• Xiluva Mathebula,
• Isaac Nongwe,
• Bonakele P. Mtolo,
• Boitumelo J. Matsoso,
• Rudolph Erasmus,
• Zikhona Tetana and
• Neil J. Coville

Beilstein J. Nanotechnol. 2020, 11, 1834–1846, doi:10.3762/bjnano.11.165

• that facilitates easy adsorption of organic molecules and their transfer onto the active sites of TiO2 [22][23]. Additionally, the interaction between SiO2 and TiO2 could result in the creation of oxygen vacancies that promote charge-transfer processes and, hence, enhance the photocatalytic activity

• electronegativity and ionic radius between the metal ions and titania can alter the concentration of oxygen vacancies in the TiO2 lattice. Hence, the higher electronegativity of Ni2+ in NiPS [43] can induce defect sites within the structure and, consequently, alter light absorption and charge-transfer processes [51

• ][67]. These oxygen vacancies easily act as hole traps that lower the charge-carrier recombination rate, resulting in more free electrons that can give rise to more superoxide radicals upon reaction with adsorbed surface oxygen [23]. Furthermore, the flake-like NiPS morphology could act as a suitable

Nanocasting synthesis of BiFeO₃ nanoparticles with enhanced visible-light photocatalytic activity

• Thomas Cadenbach,
• Maria J. Benitez,
• A. Lucia Morales,
• Cesar Costa Vera,
• Luis Lascano,
• Francisco Quiroz,
• Alexis Debut and
• Karla Vizuete

Beilstein J. Nanotechnol. 2020, 11, 1822–1833, doi:10.3762/bjnano.11.164

• to point out that a comparison of bandgap values with different BiFeO3 samples is very difficult as particle shape, size, phase purity, as well as oxygen vacancies have a strong impact on the electronic structure of the resulting material. Photocatalytic activity The photocatalytic activity of all

Structural and electronic properties of SnO₂ doped with non-metal elements

• Jianyuan Yu,
• Yingeng Wang,
• Yan Huang,
• Xiuwen Wang,
• Jing Guo,
• Jingkai Yang and
• Hongli Zhao

Beilstein J. Nanotechnol. 2020, 11, 1321–1328, doi:10.3762/bjnano.11.116

• oxygen vacancies, and thus, increase the charge density of the Sn sites. The replacement of O with N can simultaneously decrease the release of CO2. While there are reports on experiments regarding the doping of SnO2 with non-metal elements, the mechanism of the effect of non-metal element doping on the

Adsorption behavior of tin phthalocyanine onto the (110) face of rutile TiO₂

• Lukasz Bodek,
• Mads Engelund,
• Aleksandra Cebrat and
• Bartosz Such

Beilstein J. Nanotechnol. 2020, 11, 821–828, doi:10.3762/bjnano.11.67

• molecule towards the surface. Also, the electrostatic landscape of a reduced rutile (110) surface prepared in UHV by sputter–anneal cycles is complicated. The cleaning procedure creates oxygen vacancies, which in turn leads to the formation of polarons near the surface [29][30][31]. Additionally, water

• molecules may dissociate at oxygen vacancies and form hydroxy groups on the surface. Both species can be recognized in our STM images and they both lead to the formation of dipole moments pointing away from the surface [32]. Their local arrangement may play a significant role in the interaction between a

Effect of Ag loading position on the photocatalytic performance of TiO₂ nanocolumn arrays

• Jinghan Xu,
• Yanqi Liu and
• Yan Zhao

Beilstein J. Nanotechnol. 2020, 11, 717–728, doi:10.3762/bjnano.11.59

• the catalyst, so the catalyst needs to have a certain adsorption capacity for dye molecules. Due to the presence of oxygen vacancies, the surface of TiO2 is usually negatively charged and has a good adsorption capacity for cationic dye molecules [36]. Commonly used cationic dyes are rhodamine, methyl

Multiwalled carbon nanotube based aromatic volatile organic compound sensor: sensitivity enhancement through 1-hexadecanethiol functionalisation

• Nadra Bohli,
• Meryem Belkilani,
• Juan Casanova-Chafer,
• Eduard Llobet and
• Adnane Abdelghani

Beilstein J. Nanotechnol. 2019, 10, 2364–2373, doi:10.3762/bjnano.10.227

• decoration of MWCNTs Prior to their deposition on the interdigitated electrode surface, the MWCNTs were treated by oxygen plasma to create oxygen vacancies on the walls of the CNTs in order to enhance their surface reactivity [14][15]. The detailed description of the experimental steps undertaken is

Improved adsorption and degradation performance by S-doping of (001)-TiO₂

• Xiao-Yu Sun,
• Xian Zhang,
• Xiao Sun,
• Ni-Xian Qian,
• Min Wang and
• Yong-Qing Ma

Beilstein J. Nanotechnol. 2019, 10, 2116–2127, doi:10.3762/bjnano.10.206

• % to 68.5% due to the synergistic effects of the oxygen vacancies, increased number of surface chemical adsorption centers as a result of SO42− adsorption on the TiO2 surface and the larger pore size. (3) S-doping increases the MB degradation rate from 6.9 × 10−2 min−1 to 18.2 × 10−2 min−1 due to an

• , the XP spectrum of O 1s can be fitted by three peaks and the CSs correspond to TiO2, –OH and oxygen vacancies (Ov) [44]. As the RS/Ti increases, the ratio of Ov increases from 4.3% (2-S0) to 22.9% (2-S3) and then decreases again to 19.9% (2-S5) (Table 3). The XPS signals of the oxygen vacancies were

• the O 2p orbitals. At the same time, the ratio of the Ov increases in the order of 2-S0.5 < 2-S1 < 2-S5 < 2-S3, as given in Table 3; therefore, the decrease of the DOS mainly results from an increase of the ratio of oxygen vacancies. Figure 6 shows the UV–vis DRS of 2-S0, 2-S0.5, 2-S1, 2-S3 and 2-S5

Improvement of the thermoelectric properties of a MoO₃ monolayer through oxygen vacancies

• Wenwen Zheng,
• Wei Cao,
• Ziyu Wang,
• Huixiong Deng,
• Jing Shi and
• Rui Xiong

Beilstein J. Nanotechnol. 2019, 10, 2031–2038, doi:10.3762/bjnano.10.199

• , China 10.3762/bjnano.10.199 Abstract We have investigated the thermoelectric properties of a pristine MoO3 monolayer and its defective structures with different oxygen vacancies using first-principles methods combined with Boltzmann transport theory. Our results show that the thermoelectric properties

• oxygen vacancies leads to a sharp peak near the Fermi level in the density of states. This proves to be an effective way to enhance the ZT values of the MoO3 monolayer. The increased ZT values can reach 0.84 (x-axis) and 0.12 (y-axis) at 300 K. Keywords: Boltzmann transport theory; first-principles

• calculations; molybdenum trioxides; MoO3 monolayer; oxygen vacancies; thermoelectric properties; Introduction Thermoelectric materials that can directly convert temperature gradients to voltage gradients and vice versa provide a valid strategy to mitigate the global energy crisis. Owing to the unique ability

Kelvin probe force microscopy work function characterization of transition metal oxide crystals under ongoing reduction and oxidation

• Dominik Wrana,
• Karol Cieślik,
• Wojciech Belza,
• Christian Rodenbücher,
• Krzysztof Szot and
• Franciszek Krok

Beilstein J. Nanotechnol. 2019, 10, 1596–1607, doi:10.3762/bjnano.10.155

• conductivity. Here, a huge advantage over other materials is the possibility of oxides that self-dope via the introduction of oxygen vacancies [13], which is also a reason why there are not many reliable experimental studies on the work function of transition metal oxides (with one notable exception [14

• beforehand, resulting in the formation of a high concentration of oxygen vacancies. Therefore, the conductivity is much higher than that of a pristine single crystal, which has been estimated via a comparable LC-AFM study to be around 10−16 S [28]. Here the observed changes of conductivity on the surface

• comparable conductivity but notably different work functions. The reason behind this is that although undoped SrTiO3(100) is a band insulator, it could be easily self-doped with oxygen vacancies upon thermal reduction [28][30]. Reduction preferentially occurs at the surface, resulting in the reconstruction

Direct observation of oxygen-vacancy formation and structural changes in Bi₂WO₆ nanoflakes induced by electron irradiation

• Hong-long Shi,
• Bin Zou,
• Zi-an Li,
• Min-ting Luo and
• Wen-zhong Wang

Beilstein J. Nanotechnol. 2019, 10, 1434–1442, doi:10.3762/bjnano.10.141

• prominent role of oxygen vacancies in the photocatalytic performance of bismuth tungsten oxides is well recognized, while the underlying formation mechanisms remain poorly understood. Here, we use the transmission electron microscopy to investigate the formation of oxygen vacancies and the structural

• evolution of Bi2WO6 under in situ electron irradiation. Our experimental results reveal that under 200 keV electron irradiation, the breaking of relatively weak Bi–O bonds leads to the formation of oxygen vacancies in Bi2WO6. With prolonged electron irradiation, the reduced Bi cations tend to form Bi

• . Keywords: bismuth tungsten oxide; electron diffraction; electron irradiation; nanoflakes; oxygen vacancies; Introduction Bi2WO6 has drawn great interest regarding its physical properties such as the piezoelectric effect and ferroelectricity with large spontaneous polarization and high Curie temperature [1

Gas sensing properties of individual SnO₂ nanowires and SnO₂ sol–gel nanocomposites

• Alexey V. Shaposhnik,
• Dmitry A. Shaposhnik,
• Sergey Yu. Turishchev,
• Olga A. Chuvenkova,
• Stanislav V. Ryabtsev,
• Alexey A. Vasiliev,
• Xavier Vilanova,
• Francisco Hernandez-Ramirez and
• Joan R. Morante

Beilstein J. Nanotechnol. 2019, 10, 1380–1390, doi:10.3762/bjnano.10.136

• nanowires, which is usually connected with the presence of oxygen vacancies [35][37][38]. The decrease in the half-widths and the increase in the relative intensity of the peaks for each of the features observed around 490 eV (main absorption edge of the SnO2) provides evidence for a more ordered structure

• structure density of states is typical of native SnO2-x oxide covering the surface of pure metallic tin foils [37][38] and was confirmed for SnO2 powder samples by the presence of noticeable amounts of oxygen vacancies (Figure 7). XANES oxygen lines near K-edge spectra are presented in Figure 8. The fine

• , powder particles may contain noticeable amounts of oxygen vacancies in their volume. This assumption moves the electronic structure of SnO2 powder particles close to the bulk (core) of natural SnO2-x oxides as confirmed by the XANES Sn M4,5 results (see Figure 7). After calcination, followed by

Imaging the surface potential at the steps on the rutile TiO₂(110) surface by Kelvin probe force microscopy

• Masato Miyazaki,
• Huan Fei Wen,
• Quanzhen Zhang,
• Yuuki Adachi,
• Jan Brndiar,
• Ivan Štich,
• Yan Jun Li and
• Yasuhiro Sugawara

Beilstein J. Nanotechnol. 2019, 10, 1228–1236, doi:10.3762/bjnano.10.122

• [1][2][3][4][5][6][7]. The catalytic activity can be enhanced by the presence of defects, such as oxygen vacancies (Ov), Ti interstitials (Tiint) [8], and crystal steps. TiO2 is an n-type semiconductor because of these defects. In addition, reactive oxygen species, such as OH and H2O2 (compounds with

Photoactive nanoarchitectures based on clays incorporating TiO₂ and ZnO nanoparticles

• Eduardo Ruiz-Hitzky,
• Pilar Aranda,
• Marwa Akkari,
• Nithima Khaorapapong and
• Makoto Ogawa

Beilstein J. Nanotechnol. 2019, 10, 1140–1156, doi:10.3762/bjnano.10.114

• visible wavelengths (blue and green emission at around 436–438 nm and 544–548 nm) of ZnO hybridized with CTA-smectites varies depending on the ZnO loading. This was attributed to defects, such as oxygen vacancies in ZnO, and trapped surface charges. The photoluminescence intensity of ZnO in saponite and

Quantitative analysis of annealing-induced instabilities of photo-leakage current and negative-bias-illumination-stress in a-InGaZnO thin-film transistors

• Dapeng Wang and
• Mamoru Furuta

Beilstein J. Nanotechnol. 2019, 10, 1125–1130, doi:10.3762/bjnano.10.112

• higher-energy light irradiation, demonstrating that the generated ionized oxygen vacancies (VO+/VO2+) are neutralized by capturing electrons [8]. However, SS degradation still can be observed in the 300 °C-annealed TFT under the irradiation with short-wavelength light (below 430 nm), indicating that

Rapid, ultraviolet-induced, reversibly switchable wettability of superhydrophobic/superhydrophilic surfaces

• Yunlu Pan,
• Wenting Kong,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2019, 10, 866–873, doi:10.3762/bjnano.10.87

• are generated on the TiO2 surfaces under UV illumination. The holes lead to the production of oxygen vacancies to enhance the adsorption of hydroxy groups, while the hydroxy groups are replaced by oxygen atoms that have a stronger bond on the defect sites during heating process. However, the change in

On the transformation of “zincone”-like into porous ZnO thin films from sub-saturated plasma enhanced atomic layer deposition

• Alberto Perrotta,
• Julian Pilz,
• Stefan Pachmajer,
• Antonella Milella and
• Anna Maria Coclite

Beilstein J. Nanotechnol. 2019, 10, 746–759, doi:10.3762/bjnano.10.74

• spectra confirm the removal of the carbon functionalities and the calcined layers showed an O/Zn ratio of 1.0 ± 0.1 (Table 1). The oxygen peaks were decomposed into two contributions, assigned to the oxygen–zinc bonds in the oxide lattice (O–Zn, 529.8 eV), and zinc hydroxides and/or oxygen vacancies (Zn

• are reported as a function of the plasma exposure time (see also Supporting Information File 1). For short plasma exposure times, the spectrum was fitted with three distinct peaks: one at 532.8 eV, attributed to organic oxygen, another one at 531.3 eV, assigned to Zn hydroxides and/or defective oxygen

• (vacancies). The latter peak is also attributed to the formation of metal carbonates, in line with the FTIR results and the literature values [60]. Finally, the peak at 529.8 eV was attributed to lattice O–Zn bonds [56]. Increasing the plasma time led to the decrease and eventual disappearance of the pure

Ceria/polymer nanocontainers for high-performance encapsulation of fluorophores

• Kartheek Katta,
• Dmitry Busko,
• Yuri Avlasevich,
• Katharina Landfester,
• Stanislav Baluschev and
• Rafael Muñoz-Espí

Beilstein J. Nanotechnol. 2019, 10, 522–530, doi:10.3762/bjnano.10.53

• combine biocompatibility with a high oxygen-scavenging ability. Cerium oxide is a lanthanide metal oxide with a redox potential behavior that can easily switch between cerium(IV) and cerium(III) and has the capability to leave oxygen vacancies in the crystal lattice [39]. Cerium(IV) oxide exhibits

• , which yielded the hybrid sample NC-CeO2. The fluorescence intensity is higher than for nanocapsules synthesized under ambient conditions without CeO2, but also even higher than for the sample NC(Ar) prepared under argon atmosphere. The oxygen vacancies present in the structure of cerium(IV) oxide

Sub-wavelength waveguide properties of 1D and surface-functionalized SnO₂ nanostructures of various morphologies

• Venkataramana Bonu,
• Binaya Kumar Sahu,
• Arindam Das,
• Sankarakumar Amirthapandian,
• Sandip Dhara and
• Harish C. Barshilia

Beilstein J. Nanotechnol. 2019, 10, 379–388, doi:10.3762/bjnano.10.37

• usual yellow-red luminescence (owing to bridging oxygen vacancies; OB) of the SnO2 is significantly suppressed and the luminescence appearing around the blue spectrum (owing to in-plane O vacancies; OP) becomes strong [13]. Interestingly, with surface functionalization, luminescence tuning is

• 2.6 eV are assigned to band edge transitions. Earlier, it was shown from DFT calculations using an all-electron Gaussian approximation that formation of an acceptor state close to 1 eV above the valence band occurs due to the stable oxygen vacancies [31]. Thus, the above mentioned studies point out

• ) indicated that the luminescence transitions around 2 and 2.4 eV belonged to bridging and in-plane oxygen vacancies, respectively [34][35][37][38]. Similarly Liu et al. [37] demonstrated that the in-plane oxygen vacancies were responsible for the creation of shallow donor states while the bridging oxygen

Site-specific growth of oriented ZnO nanocrystal arrays

• Rekha Bai,
• Dinesh K. Pandya,
• Sujeet Chaudhary,
• Veer Dhaka,
• Vladislav Khayrudinov,
• Jori Lemettinen,
• Christoffer Kauppinen and
• Harri Lipsanen

Beilstein J. Nanotechnol. 2019, 10, 274–280, doi:10.3762/bjnano.10.26

• may in turn impact the physical properties on account of the known role of oxygen vacancies and defects on electron transport behavior of ZnO [26][27]. But in our case no such high temperature processing is required at any stage. Cho et al. [17] have used a solution method with tri-potassium citrate

Zn/F-doped tin oxide nanoparticles synthesized by laser pyrolysis: structural and optical properties

• Florian Dumitrache,
• Iuliana P. Morjan,
• Elena Dutu,
• Ion Morjan,
• Claudiu Teodor Fleaca,
• Monica Scarisoreanu,
• Alina Ilie,
• Marius Dumitru,
• Cristian Mihailescu,
• Adriana Smarandache and
• Gabriel Prodan

Beilstein J. Nanotechnol. 2019, 10, 9–21, doi:10.3762/bjnano.10.2

• SnO2 in its undoped form is an n-type semiconductor with a direct bandgap of 3.6 eV at room temperature. Its n-type conductivity is due to oxygen vacancies in its rutile structure. The bandgap, starting from the bulk value, increases as the size of the nanocrystal decreases, due to electron confinement

Nanostructure-induced performance degradation of WO₃·nH₂O for energy conversion and storage devices

• Zhenyin Hai,
• Mohammad Karbalaei Akbari,
• Zihan Wei,
• Danfeng Cui,
• Chenyang Xue,
• Hongyan Xu,
• Philippe M. Heynderickx,
• Francis Verpoort and
• Serge Zhuiykov

Beilstein J. Nanotechnol. 2018, 9, 2845–2854, doi:10.3762/bjnano.9.265

• samples originate from W5+ ions in the lattice, which reveals the formation of a few oxygen vacancies [29][46]. The O 1s spectra for all samples in Figure 5c depict two peaks with one main peak from the lattice oxygen, OL, and another from the oxygen in water molecules, OH2O [47][48]. With increasing