A review of carbon-based and non-carbon-based catalyst supports for the selective catalytic reduction of nitric oxide

• Shahreen Binti Izwan Anthonysamy,
• Syahidah Binti Afandi,
• Mehrnoush Khavarian and
• Abdul Rahman Bin Mohamed

Beilstein J. Nanotechnol. 2018, 9, 740–761, doi:10.3762/bjnano.9.68

• gasoline engines. In the SCR of NO, a reducing agent must be introduced into the system in order to successfully convert NO into nitrogen (N2), inert gases such as ammonia (NH3), and urea [5]. The reaction system reduces the Gibbs free energy values initiated by the reducing agent; the introduction of

Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields

• Emil Petrescu,
• Cristina Cirtoaje and
• Octavian Danila

Beilstein J. Nanotechnol. 2018, 9, 399–406, doi:10.3762/bjnano.9.39

• , the phase difference becomes: and the intensity of the laser beam crossing through the sample is: The equation of the maximum deviation angle as a function of time is obtained from the total free energy of the system by applying the Euler–Lagrange equation. Elastic continuum theory states that a

• liquid crystal is acting like a continuous fluid and the interaction forces between its molecules are elastic. Taking into account a strong anchoring on the glass support, the free energy density of such a system with added quantum dots is: where fN is the liquid crystal free energy density, fE is a term

• threshold, the deviation angle is very small and the free energy caused by the elastic forces is: where K1 and K3 are the splay and bent elastic constants and θz = ∂θ/∂z. Due to the presence of the QDs, the electric properties of the mixture change. Hence, instead of perpendicular dielectric permittivity

Dynamic behavior of a nematic liquid crystal with added carbon nanotubes in an electric field

• Emil Petrescu and
• Cristina Cirtoaje

Beilstein J. Nanotechnol. 2018, 9, 233–241, doi:10.3762/bjnano.9.25

• the carbon nanotube surfaces, with the glass support and with the applied field. By applying the elastic continuum theory we can write the free energy of a system consisting of a liquid crystal and SWCNTs in electric field as: Here is the elastic free energy of liquid crystal, is the interaction

• free energy of liquid crystals with the applied electric field, is the interaction free energy between LC and SWCNTs and is the interaction free energy of the carbon nanotubes with the applied field. When a planar aligned cell is considered and the electric field is perpendicular to the support (i.e

• ., parallel to the z-axis), the molecular orientation is characterized by the distortion angle θ between the director and the x-axis (Figure 1). Thus, the free energy of the liquid crystal is: where θz = ∂θ/∂z, d is the cell thickness and K1, K3 are elastic constants. The interaction free energy of a liquid

Nematic topological defects positionally controlled by geometry and external fields

• Pavlo Kurioz,
• Marko Kralj,
• Bryce S. Murray,
• Charles Rosenblatt and
• Samo Kralj

Beilstein J. Nanotechnol. 2018, 9, 109–118, doi:10.3762/bjnano.9.13

• parameterize the nematic order parameter as where {q1,q2,q3} are the variational parameters. A convenient metric for the degree of biaxiality is the biaxiality parameter [14][15]: A uniaxial state and configurations with maximum biaxiality are denominated by β2 = 0 and β2 = 1, respectively. Free energy and

• scaling We write the free energy as the sum of volume and surface integrals: The condensation (fc), elastic (fe) and external electric field (ff) free energy densities are expressed as [5][15]: respectively. The quantities A0, B, C are material constants, T* is the supercooling temperature, L is the

• ≈ 0.18. For temperatures close below TIN it follows ξb ≈ 20 nm, ξE(E ≈ 106 V/m) ≈ 1 μm, de(w ≈ 10−4 J/m2) ≈ 1 μm. We obtained nematic structures for the given boundary conditions by minimizing the total free energy of the system. The resulting Euler–Lagrange equilibrium equations for the variational

Growth model and structure evolution of Ag layers deposited on Ge films

• Arkadiusz Ciesielski,
• Lukasz Skowronski,
• Ewa Górecka,
• Jakub Kierdaszuk and
• Tomasz Szoplik

Beilstein J. Nanotechnol. 2018, 9, 66–76, doi:10.3762/bjnano.9.9

• ) and X-ray diffraction (XRD) measurements proved that segregation of germanium into the surface of the silver film is a result of the gradient growth of silver crystals. The free energy of Ge atoms is reduced by their migration from boundaries of larger grains at the Ag/SiO2 interface to boundaries of

Review on optofluidic microreactors for artificial photosynthesis

• Xiaowen Huang,
• Jianchun Wang,
• Tenghao Li,
• Jianmei Wang,
• Min Xu,
• Weixing Yu,
• Abdel El Abed and
• Xuming Zhang

Beilstein J. Nanotechnol. 2018, 9, 30–41, doi:10.3762/bjnano.9.5

• area. Finally, we conclude with a discussion of the technical barriers that hinder their practical application. Basic mechanisms of artificial photosynthesis The APS reaction is not a spontaneous reaction, for example, the Gibbs free energy in water splitting increases by 237 kJ·mol−1, and the required

Magnetic field induced orientational transitions in liquid crystals doped with carbon nanotubes

• Danil A. Petrov,
• Pavel K. Skokov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2807–2817, doi:10.3762/bjnano.8.280

• to the minimum of free energy Here, K11, K22 and K33 are the Frank elastic moduli; χa and are the diamagnetic susceptibility anisotropies of LC and CNTs, respectively; μ0 is the permeability of vacuum; f is the volume fraction of CNTs in the suspension; Wp is the surface density of the coupling

• ). This allows us to neglect the interaction between the CNTs. The term F1 in Equation 1 is the free energy density of elastic deformations of the LC [36]. The contributions F2 and F3 take into account the interaction energies of the LC matrix and CNTs with the magnetic field. The term F4 describes the

• CNTs in LCs [14][18][38]. The last term F5 is the contribution of the entropy of mixing of an ideal solution of CNTs in the LC matrix. As it is known, the state of thermodynamic equilibrium corresponds to the minimum of the free energy (Equation 1), which is a functional of the two vectors n and m, and

The rational design of a Au(I) precursor for focused electron beam induced deposition

• Ali Marashdeh,
• Thiadrik Tiesma,
• Niels J. C. van Velzen,
• Sjoerd Harder,
• Remco W. A. Havenith,
• Jeff T. M. De Hosson and
• Willem F. van Dorp

Beilstein J. Nanotechnol. 2017, 8, 2753–2765, doi:10.3762/bjnano.8.274

• much, we have calculated the changes in Gibbs free energy (ΔG) for particular reactions for isolated molecules at 298 K and a pressure of 1 × 10−4 Pa (1 × 10−6 mbar). Table 2 shows the reaction energies, including those for ClAuPF3 (which is as unstable as ClAuCO [50]) and CF3AuCO. Please note that the

Ferrocholesteric–ferronematic transitions induced by shear flow and magnetic field

• Dmitriy V. Makarov,
• Alexander A. Novikov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2552–2561, doi:10.3762/bjnano.8.255

• tensor. The Ericksen stress tensor , included in the stress tensor σki, is determined by the expression where P is the pressure, δki is the Kronecker symbol and FV is the bulk density of free energy of a ferrocholesteric [10][26]: Here K11, K22, K33 are the Frank constants, q0 is the wave number of the

• temperature. The contribution of F1 to the free energy density (Equation 6) determines the energy of orientational elastic deformations of the director field. F2 is the bulk density of the interaction energy of the magnetic field H with an LC matrix (quadrupole mechanism of the magnetic field effect on an FC

• ). F3 is the bulk density of the interaction energy of the magnetic field H with the magnetic moment μ = MSvpn of the particles (the dipole mechanism of the magnetic field effect on an FC). F4 is the contribution of the entropy of mixing of an ideal solution of magnetic particles to the free energy of a

Dynamic behavior of a nematic liquid crystal mixed with CoFe₂O₄ ferromagnetic nanoparticles in a magnetic field

• Emil Petrescu,
• Cristina Cirtoaje and
• Cristina Stan

Beilstein J. Nanotechnol. 2017, 8, 2467–2473, doi:10.3762/bjnano.8.246

• angle approximation and obtain: A theoretical characterization of distortion angle as a function of the time was made considering the model of a ferronematic liquid crystal in a magnetic field similar to the one proposed in [33]. By applying the elastic continuum theory, the free energy density of the

Au nanostructure fabrication by pulsed laser deposition in open air: Influence of the deposition geometry

• Rumen G. Nikov,
• Anna Og. Dikovska,
• Nikolay N. Nedyalkov,
• Georgi V. Avdeev and
• Petar A. Atanasov

Beilstein J. Nanotechnol. 2017, 8, 2438–2445, doi:10.3762/bjnano.8.242

• are arranged along the (111) reflection plane of Au, which possesses the lowest surface-free energy. This crystallite alignment leads to the chain-like nanostructure formation on the substrate, as shown in Figure 1b. The XPS analysis of the as-deposited Au nanostructure is presented in Figure 3. The

Identifying the nature of surface chemical modification for directed self-assembly of block copolymers

• Laura Evangelio,
• Federico Gramazio,
• Matteo Lorenzoni,
• Michaela Gorgoi,
• Francisco Miguel Espinosa,
• Ricardo García,
• Francesc Pérez-Murano and
• Jordi Fraxedas

Beilstein J. Nanotechnol. 2017, 8, 1972–1981, doi:10.3762/bjnano.8.198

• enthalpic interactions [4]. The global parameters that govern the phase behavior of BCPs are given by the χ·N product, where χ stands for the Flory Huggins parameter and N the number of statistical segments in a BCP chain, which is related to the free energy of the system and the composition of the blocks

• becomes evident that when the brush cooling is performed in nitrogen rather than in air, the polymer has the proper surface free energy to induce the alignment of the BCP after the lithography and BCP spin-coating. In order to understand the origin of the influence of the DSA process, we have performed

Stick–slip boundary friction mode as a second-order phase transition with an inhomogeneous distribution of elastic stress in the contact area

• Iakov A. Lyashenko,
• Vadym N. Borysiuk and
• Valentin L. Popov

Beilstein J. Nanotechnol. 2017, 8, 1889–1896, doi:10.3762/bjnano.8.189

• transition (which follows from the computer simulations [14][15] and experimental investigations [5]), the free-energy density can be written in the form [10]: where T is the temperature of the lubricant; Tc is the critical temperature; εel is the shear component of the elastic stress; α, a and b are

Two-dimensional carbon-based nanocomposites for photocatalytic energy generation and environmental remediation applications

• Suneel Kumar,
• Ashish Kumar,
• Ashish Bahuguna,
• Vipul Sharma and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2017, 8, 1571–1600, doi:10.3762/bjnano.8.159

Spin-chemistry concepts for spintronics scientists

• Konstantin L. Ivanov,
• Alexander Wagenpfahl,
• Carsten Deibel and
• Jörg Matysik

Beilstein J. Nanotechnol. 2017, 8, 1427–1445, doi:10.3762/bjnano.8.143

• Introduction In general, chemical reactions are discussed in terms of thermodynamics: reaction enthalpy, reaction entropy and free energy. It is also recognized that steric and charge effects can lead to kinetic control of the reaction dynamics by introduction of activation energies. In some cases, chemical

Investigation of growth dynamics of carbon nanotubes

• Marianna V. Kharlamova

Beilstein J. Nanotechnol. 2017, 8, 826–856, doi:10.3762/bjnano.8.85

• nanotubes. Figure 4a–d shows the changes in Gibbs free energy for the reaction between Ni and different carbon precursors (CO, CH4, C2H4 and C2H2). According to these data, nickel carbide forms under a broad range of temperatures for the reaction with C2H4 and C2H2 (Figure 4a,b), while temperatures higher

• than 800 K are needed for the reaction with CO and CH4 (Figure 4c,d). The negative changes in Gibbs free energy increase in the line with CO, CH4, C2H4 and C2H2. This explains why C2H2 is one of the most reactive carbon precursors for the nanotube synthesis. The changes in Gibbs free energy for the

• reaction between C2H2 and different metallic catalysts (Ni, Co, Fe, W and Mo) are presented in Figure 4e–i. The formation of metal carbides is predicted at the elevated temperatures during nanotube growth for all these metals. The largest increases in Gibbs free energy are predicted for the reactions with

Calculating free energies of organic molecules on insulating substrates

• Julian Gaberle,
• David Z. Gao and
• Alexander L. Shluger

Beilstein J. Nanotechnol. 2017, 8, 667–674, doi:10.3762/bjnano.8.71

• molecular dynamics. Both molecules contain the same anchoring groups and benzene ring structures, yet differ in their flexibility. Therefore, the entropic contributions to their free energy differ, which affects surface processes. Using potential of mean force and thermodynamic integration techniques, free

• understanding dynamic processes of organic molecules on insulating substrates. Keywords: entropy; free energy; molecular dynamics; organic molecules; potential of mean force; thermodynamic integration surface step; Introduction In recent years molecular films and self-assembled monolayers have attracted a lot

• ]. Previous theoretical studies focussed on modelling adsorption [21][25][26], diffusion [27][28] and simple processes such as the flipping of a molecule [29]. The probability assigned to each of these processes is governed by the change in free energy ΔG, which can be derived from statistical mechanics [30

Diffusion and surface alloying of gradient nanostructured metals

• Zhenbo Wang and
• Ke Lu

Beilstein J. Nanotechnol. 2017, 8, 547–560, doi:10.3762/bjnano.8.59

• channels from conventional GBs, the term “nonequilibrium” GBs was used. In this case, GBs might gather a large number of irregular (extrinsic) dislocation structures, so that extra free energy might be introduced in the interfaces, while misorientations across them remain stable [22][23]. The existence of

• the issues accelerating diffusion in the GNS layers, because no system (see Table 1) contains components which are inclined to form GB complexions connected with GB prewetting or pseudo-partial wetting [46][50]. Diffusion kinetics and free energy of different interfaces As illustrated in Figure 3a

• situations of GBs (referring to the section “Diffusion behavior in nanostructured surface layers”), the significantly enhanced diffusivity along TBs in the GNS Cu is also expected be induced by a higher stored energy and/or with a higher density of defects. The free energy of GBs varies with the

Formation and shape-control of hierarchical cobalt nanostructures using quaternary ammonium salts in aqueous media

• Ruchi Deshmukh,
• Anurag Mehra and
• Rochish Thaokar

Beilstein J. Nanotechnol. 2017, 8, 494–505, doi:10.3762/bjnano.8.53

• lattice arrangement that simultaneously satisfies the thermodynamic energy criteria of minimum free energy configuration [36]. In the transition regime, from 15 to 30 min (Figure 3h), we observe that the small nanoparticles almost disappear and intermediate clusters form by the assembly of nanoparticles

Fiber optic sensors based on hybrid phenyl-silica xerogel films to detect n-hexane: determination of the isosteric enthalpy of adsorption

• Jesús C. Echeverría,
• Ignacio Calleja,
• Paula Moriones and
• Julián J. Garrido

Beilstein J. Nanotechnol. 2017, 8, 475–484, doi:10.3762/bjnano.8.51

• sensitivity to VOCs has received scarce attention. Adsorption is a spontaneous and exothermic process involving a decrease in the total free energy of the system [15][16]. When a vapor molecule is adsorbed on a surface, this molecule changes from three to two degrees of translational freedom and, as a result

Flexible photonic crystal membranes with nanoparticle high refractive index layers

• Torben Karrock,
• Moritz Paulsen and
• Martina Gerken

Beilstein J. Nanotechnol. 2017, 8, 203–209, doi:10.3762/bjnano.8.22

• reorientation of the PEO to the surface–water interface the interfacial free energy is reduced. The modified PDMS surface exhibits a time-dependent water contact angle. It drops rapidly in the first 30 s and is stable after ≈200 s. The contact angle is reduced to 20° at a concentration of about 2% of PEO in the

Influence of hydrofluoric acid treatment on electroless deposition of Au clusters

• Rachela G. Milazzo,
• Antonio M. Mio,
• Giuseppe D’Arrigo,
• Emanuele Smecca,
• Alessandra Alberti,
• Gabriele Fisichella,
• Filippo Giannazzo,
• Corrado Spinella and
• Emanuele Rimini

Beilstein J. Nanotechnol. 2017, 8, 183–189, doi:10.3762/bjnano.8.19

• , in the first case the layer-by-layer growth prevails while a 3D arrangement is promoted by the DHF pretreatment of 240 s. It is well known that HF strongly modifies the silicon surface roughness [26][27][28][29] and wetting properties [30]. The surface-free energy of gold is 1410 × 10−3 J/m−2, while

• , and the obtained root mean square (RMS) was 3 nm, which is about one order of magnitude higher than a typical Si wafer (Figure 2c). Consequently, the surface-free energy increases [33] for a rougher surface and promotes 3D cluster formation by offering preferential sites for nucleation as apex or

• they thicken and rearrange their own crystalline structure. HF is known to etch SiO2, changing the surface chemical composition and also the free energy of Si. As a result, the layered gold is freed and the outlying atoms move toward inner regions to reduce their surface free energy. The process is

Sensitive detection of hydrocarbon gases using electrochemically Pd-modified ZnO chemiresistors

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Gennaro Cassano,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2017, 8, 82–90, doi:10.3762/bjnano.8.9

• consumption, and poor stability over the time [38]. These limits can be overcome by functionalization of ZnO nanostructures with noble metal nanoparticles. Specifically, Pt and Pd are widely applied for monitoring explosive and toxic gases. The catalytic metals do not change the free energy of the reactions

A new approach to grain boundary engineering for nanocrystalline materials

• Shigeaki Kobayashi,
• Sadahiro Tsurekawa and
• Tadao Watanabe

Beilstein J. Nanotechnol. 2016, 7, 1829–1849, doi:10.3762/bjnano.7.176

• ] have suggested that the stability of the nanocrystalline structure is improved by preferential segregation of solute atoms to grain boundaries because their excess free energy can be reduced. Therefore, it is very likely that the grain boundary microstructure characterized by appropriate

• sharp texture is introduced in thin films with help of orientation-dependent surface free energy (namely by applying the surface energy-driven grain growth during annealing), specific low-Σ CSL boundaries can be preferentially introduced, depending on the type and the sharpness of texture [52][128][129

Surface roughness rather than surface chemistry essentially affects insect adhesion

• Matt W. England,
• Tomoya Sato,
• Makoto Yagihashi,
• Atsushi Hozumi,
• Stanislav N. Gorb and
• Elena V. Gorb

Beilstein J. Nanotechnol. 2016, 7, 1471–1479, doi:10.3762/bjnano.7.139

• influence, despite both of these affecting the magnitude of water contact angles (CAs). Additionally, the attachment of the leaf beetle Gastrophysa viridula did not strongly depend on the free energy of the surface of the substrate [34]. More recently, the attachment strength of the beetle Galerucella