Formation Of Si-O Bonds Research Articles

Amine-functionalized cellulose-silica composites for the remediation of hexavalent chromium (Cr IV) in contaminated water

Adsorption method for Hexavalent chromium (Cr(VI) removal from domestic and industrial wastewater is widely desirable due to public health concern of the heavy metal. The purpose of this study was to investigate the evaluation of Cr(VI) adsorption using a novel adsorbent: amine-functionalized cellulose-silica composite derived from banana fibers. We employed the in-situ sol–gel method to create cellulose-silica silane functionalized composites, analyzing them through different characterization techniques such as Attenuated total reflectance- Fourier transform infrared spectroscopy (ATR-FTIR), X-ray Diffraction Analysis (XRD), Thermo gravimetric analysis (TGA)/differential thermogravimetric (DTG), Brunauer–Emmett–Teller (BET), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) techniques. ATR-FTIR depicted key organic constituents in raw banana pseudo stem fibers (BF) and the formation of SiO bonds in BCSiO2 composite, and further enhanced by the grafting of N-[3-(trimethoxysilyl)propyl ethylenediamine (DAPTMS) onto the BC-SiO2 surface in BC-SiO2-DAPTMS. XRD and TGA/DTG analyses revealed changes in crystallinity and thermal stability, while BET analysis showcased altered surface area and pore characteristics in BC-SiO2-DAPTMS (2 %). SEM and TEM imaging provided visual evidence of structural modifications and improved dispersion in BC-SiO2-DAPTMS composites. The impact of composite weight, contact time, and pH on Cr(VI) removal rates was examined, revealing optimal performance at slightly acidic pH 4 value (80.7 %) and enhanced efficiency with increased contact time of 65 min (86.66 %), composite weight of 1 g (82.62 %), and initial concentration was for 0.8 mg/l (80 %). The kinetics and isotherms analyzed using pseudo second order (PSO) and pseudo first order (PFO) models, highlight the composite’s efficiency. The Freundlich model was found to better fit the adsorption isotherm data, while the PSO model described the kinetics more accurately. These insights contribute to optimizing the BC-SiO2-DAPTMS (2 %) composite for efficient Cr(VI) ion removal in water treatment applications.

Reinvigorating Photo-Activated R-Alkoxysilanes Containing 2-Nitrobenzyl Protecting Groups as Stable Precursors for Photo-Driven Si-O Bond Formation in Polymerization and Surface Modification.

This study aimed to revitalize silicon-based sol-gel chemistry methodologies utilizing photoprotected R-alkoxysilanes to control the synthesis of unique silicon-based materials. We have investigated the synthesis, characterization, light-induced deprotection, and subsequent polymerization/surface functionalization through the use of 2-nitrobenzyloxy-based photoremovable protecting groups (PPGs) as alkoxy reactive groups on ethyl and phenyl (R x -(alkoxy) y silanes, with x = 0-3 and y = 1-3). The photochemical dynamics, relative efficiencies, and kinetics of the novel alkoxysilane-based PPGs were thoroughly investigated using UV light irradiation by NMR and UV/vis methods. We then explored the tin-catalyzed coupling of photodeprotected products (R x -silanols) to form polymers/oligomers. We have found that photoenabled removal of PPGs and conversion to silanols from all silane systems studied is achieved. Furthermore, these deprotected species are polymerizable into siloxanes and effectively used as light-controlled surface modifiers with masking techniques of which proof-of-concept examples are given, enabling promising application as photolithographic reagents.

First-principles study for orientation dependence of band alignments at the 4H-SiC/SiO2 interface

The orientation dependence of band alignments and the formation of dipoles at the 4H-SiC/SiO2 interface are theoretically investigated on the basis of first-principles calculations. The calculations demonstrate that the offsets of valence and conduction bands depend on the surface orientation and chemical bonds at the 4H-SiC/SiO2 interface. When we exclude the interfaces with C–O bonds which result in CO desorption, the calculated conduction band offset (CBO) on the Si-face with Si-O bonds is larger than those on the C-face with C–Si bonds and m-face with both Si-O and C–Si bonds. Furthermore, it is found the atomic configurations at the 4H-SiC/SiO2 interface result in the formation of dipoles, whose magnitude is large for Si–O and C–O bonds. The formation of large dipoles significantly changes the band structure of 4H-SiC, resulting in large conduction bands offset. Therefore, the formation of a Si-O bond with large dipoles at the interface is of importance in order to obtain a large CBO. The calculated results give insights into improving the reliability of SiC MOSFETs.

Copper-Catalyzed Asymmetric Synthesis of Silicon-Stereogenic Benzoxasiloles.

A Cu-catalyzed asymmetric synthesis of silicon-stereogenic benzoxasiloles has been realized via intramolecular Si-O coupling of [2-(hydroxymethyl)phenyl]silanes. Cu(I)/difluorphos is found to be an efficient catalytic system for enantioselective Si-C bond cleavage and Si-O bond formation. In addition, kinetic resolution of racemic substituted [2-(hydroxymethyl)phenyl]silanes using Cu(I)/ PyrOx (pyridine-oxazoline ligands) as the catalytic system is developed to afford carbon- and silicon-stereogenic benzoxasiloles. Ring-opening reactions of chiral benzoxasiloles with organolithiums and Grignard reagents yield various enantioenriched functionalized tetraorganosilanes.

Streamlining Si-O bond formation through cobalt-catalyzed dehydrocoupling.

Herein we report a strategy for the synthesis of organosilicons, including siloxanes, silyl ethers, and aminosilanes, via Co-catalyzed dehydrogenative coupling between hydrosilanes and nucleophiles. This discovery represents an expansion of the synthetic toolkit for organosilicon synthesis, forging Si-O and Si-N bonds in the presence of cobalt complexes with salen-type ligands.

Deconstructable and Chemically Recyclable High-Density Polyethylene (HDPE)-Like Materials Based on Si-O Bonds.

Polyethylene (PE) is the most widely produced synthetic polymer. By installing chemically cleavable bonds into the backbone of PE, it is possible to produce chemically deconstructable PE derivatives; to date, however, such designs have primarily relied on carbonyl- and olefin-related functional groups. Bifunctional silyl ethers (BSEs; SiR2(OR'2)) could expand the functional scope of PE mimics as they possess strong Si-O bonds, excellent oxidative stabilities, and facile chemical tunability. Here, we report BSE-containing high-density polyethylene (HDPE)-like materials synthesized through a one-pot catalytic ring-opening metathesis polymerization (ROMP) and hydrogenation sequence. The crystallinity of these materials can be adjusted by varying the BSE concentration or the steric bulk of the Si-substituents, providing handles to control thermomechanical properties while maintaining the high thermal stability of HDPE. Two methods for chemical recycling of HDPE mimics are introduced, including a circular approach that leverages acid-catalyzed Si-O bond exchange with 1-propanol. Additionally, despite the fact that the starting HDPE mimics were synthesized by chain-growth polymerization (ROMP), we show that it is possible to recover the molar mass and dispersity of recycled HDPE products using step-growth Si-O bond formation or exchange, generating high molecular weight recycled HDPE products with mechanical properties similar to commercial HDPE.

High-Translucency Zirconia Following Chemical Vapor Deposition with SiH4: Evidence of Surface Modifications and Improved Bonding.

To evaluate the effect of plasma-enhanced chemical vapor deposition (PECVD) with silicon hydride (SiH4) at different times on HT-zirconia surface characteristics and bonding of composite cement before and after thermocycling. Blocks of HT zirconia were obtained, polished, sintered and divided into five groups, according to PECVD time (n = 31): Zr-30 (30 s), Zr-60 (60 s), Zr-120 (120 s) and Zr-300 (300 s). The control group (Zr-0) did not receive PECVD. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS) in conjunction with field-emission scanning electron microscopy (FE-SEM), x-ray photoelectron spectroscopy (XPS), goniometry, and profilometry tests were used for chemical and topographic characterization. Monobond N silane (Ivoclar Vivadent) was applied to the surface, and a cylinder of composite cement (Variolink N) was made (3 x 3 mm). Half of the specimens of each group were stored for 24 h or subjected to thermocycling (6 x 103 cycles). A shear bond strength (SBS) test was performed. Results were subjected to one-way ANOVA and Tukey's tests (α = 0.05). For experimental groups, XPS showed that formation of Si-O bonds contributed to increased surface free energy (SFE). FE-SEM and EDS showed that the longer the deposition time, the greater the amount of silicon on the surface. Zr-60 and Zr-300 presented higher and lower surface roughnesses, respectively. The silicon penetrated the microstructure, causing higher stress concentrations. The bond strength to composite cement was improved after all PECVD deposition times. The PECVD technique with SiH4, associated with chemical treatment with primer based on silane methacrylate, is a solely chemical surface treatment capable of maintaining bonding between composite cement and HT zirconia.

Polymerization during melting of ortho- and meta-silicates: Effects on Q species stability, heats of fusion, and redox state of mid-ocean range basalts (MORBs)

Abstract29Si NMR and Raman spectroscopic studies demonstrate that fusion of crystalline orthosilicates and metasilicates produces melts more polymerized than their precursor crystals. Forsterite, for example, consists of 100% Q0 species, whereas its melt consists of ~50 mol% of Q1 species (Q = a Si tetrahedron and the superscript indicates the number of bridging oxygen atoms in the tetrahedron). Polymerization during melting can be rationalized from an energetics perspective. Si-NBO-M moieties of Q species are more susceptible to librational, rotational, and vibrational modes than are Si-BO-Si moieties (NBO = non-bridging oxygen; BO = bridging oxygen; M = counter cation). Thermal agitation activates these additional modes, thus increasing the CP and free energy of melts. The reaction of Qn to Qn+1 species during melting eliminates Si-NBO-M moieties and produces Si-O-Si moieties that are less susceptible to the additional modes, thereby minimizing the CP of melts. By decreasing the abundances of Q0, Q1, and Q2 species in favor of Q3 and Q4 species, melts become more stable. In the absence of polymerization, melting temperatures of minerals would be appreciably greater than observed.Polymerization involves formation of Si-O bonds, which are strongly endothermic (Si-O bond dissociation is ~798 kJ/mol). The large heats of fusion (ΔHf) of orthosilicates result primarily from polymerization reactions during melting (ΔHf of forsterite, fayalite, and tephroite are ~142, ~92, and ~90 kJ/mol). The fusion of metasilicates and sorosilicates (e.g., pyroxenes and melilites) involves endothermic polymerization and exothermic depolymerization reactions, although the former dominates. These reactions tend to negate each other during melting, yielding less positive ΔHf values than observed for orthosilicate fusion (e.g., ΔHf of enstatite, diopside, pseudowollastonite, and åkermanite are ~73, ~69, ~57, and ~62 kJ/mol). Where polymerization and depolymerization reactions are absent ΔHf is low and is due mostly to disordering during melting (e.g., ΔHf of cristobalite iŝ8.9 kJ/mol).Experimental evidence indicates that ferric iron is present as a negatively charged oxy-anionic complex in melts (e.g., [FeO2]1–) so that oxidation of Fe2+ should proceed according to: 4Femelt2+ + 1O2 + 6Omelt2−→4[FeO2]melt1−.Free oxygen (O2–), a by-product of polymerization reactions, drives the reaction to the right. Midocean ridge basalts (MORBs) consequently should be more oxidized than their source (e.g., lherzolites) or their residues (e.g., harzburgites). Extraction of melt from the upper mantle and deposition in the crust should produce a crust more oxidized than its upper mantle source. Production of O2– during melting and its presence in alkali-rich magmas also explains the alkali-ferric iron effect.

Mechanical property of lignin-modified phenolic foam enhanced by whisker silicon

Fibrous and functional structures based on silicon whiskers were modified with a silane coupling agent. They were further used with a phenolic resin (PR) and lignin to produce three types of phenolic foams (PF) upon stirring with foaming agents. The obtained solid foams (LWSPF) were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results indicated that the formation of Si-O bonds in the modified PR improved the characteristics of the foams. Moreover, the introduction of silicon whiskers and lignin made the foam cells smaller and more homogeneous.The char yield of lignin-based PF modified by the silicon whiskers (55.6%) increased by ca. 27% compared with PF. The mechanical properties were optimized at silicon whisker and lignin contents of 0.6% (based on PR weight) and 10% (based on phenol weight), respectively. Compared with PF, the LWSPF bending and compressive strengths increased by 80.5% and 81.1%, respectively.

Effect of graphene oxide on in-situ surface growth of pure α-Si3N4 microbelts and their blue luminescent performance

In-situ surface grown pure α-Si3N4 microbelts have been successfully obtained by graphene oxide-assisted pyrolysis of polyvinylsilazane at 1550 °C under H2/N2 atmosphere. The α-Si3N4 microbelts are 10–500 μm length, ∼500 nm thickness and ∼5 μm width with smooth surface. The surface growth mechanism of α-Si3N4 microbelts is supposed to be vapor-solid growth. GO addition promotes not only the formation of Si-O bond and free carbon at 1000 °C but also the reaction to SiC and N2 at 1550 °C. GO as an additive increases the yield of α-Si3N4 microbelts. The photoluminescence (PL) spectra of α-Si3N4 microbelts contain two emission peaks at 421 nm and 441 nm at room temperature.

Hydrophobic and hydrophilic SiO2-based hybrids in the protection of sandstone for anti-salt damage

Abstract The anti-salt damage of sandstone protected by hydrophobic and hydrophilic SiO2-based hybrids is evaluated in NaCl, Na2SO4 and NaCl-Na2SO4 salt-loaded hydrothermal aging (SLHA) cycles. Although both hydrophobic and hydrophilic SiO2-based hybrids could prevent the sandstone from salt damage through improving the matrix strength, the hydrophobic hybrid performs much better protection than hydrophilic one. The sandstone protected by hydrophobic SiO2-based hybrid shows nearly no salt-damage, which is attributed to its excellent water repellence, high adhesive strength and good compatibility with sandstone matrix. However, the hydrophilic SiO2-based hybrid tends to induce an exterior-to-interior salt-damage behaviour due to the frequent circulation movement of water with salt to result in the formation of surface efflorescence and interior sub-efflorescence in the protected sandstone. Furthermore, the hydrophobic-protective effect is also confirmed by another alternative hydrophobic POSS-based hybrid to offer stronger protection in anti-salt damage than that protected by hydrophilic hybrid. Nevertheless, there lies the difference, the hydrophobic SiO2-based hybrid penetrates into the inner pores of the sandstone and develops a strong cohesion with sand-grain through the formation of Si-O bonds, but the hydrophobic POSS-based hybrid protects the sandstone with a weaker physical interaction between hybrid and sand-grains resulting in a fractured damage. Therefore, SiO2-based hybrid is superior to POSS-based hybrid in promoting the anti-salt ability of sandstone. It is believed that these results could contribute much to the future protection of stone monuments by different hybrids.

Synthesis and investigations on correlation between EPR and optical properties of Fe doped Li2SiO3

Iron doped lithium metasilicate sample was synthesized using a combustion technique and characterized by XRD (X ray diffraction), SEM (scanning electron microscopy), FTIR (Fourier transform infrared spectroscopy), optical, and EPR (electron paramagnetic resonance) analyses. The phase purity of the combustion synthesized products was confirmed by XRD analysis. SEM data suggested the formation of a porous compound by virtue of the entrapment of the gases that evolved during the sample synthesis. FTIR data confirmed the formation of SiO bonds in the system. Optical data confirmed the existence of both divalent and trivalent iron in the system. Characteristic absorption bands in the region 215–270 nm and 535–620 nm were observed due to the presence of Fe3+ in Oh and Td geometry respectively. On the other hand, the presence of bands at 967 and 1442 nm suggested the stabilisation of Fe2+ also in both Oh and Td geometries, respectively. The divalent iron being a non-Kramer ion, could not be observed by EPR. However, strong temperature-dependent EPR signals were observed in the sample owing to Fe3+. By analyzing the EPR data, super-paramagnetic type of behaviour was observed in the system. Furthermore, the relaxation times along with other EPR spectroscopic parameters were estimated for the system.

Controlled growth of MoS2 nanopetals on the silicon nanowire array using the chemical vapor deposition method

In order to get a physical/chemical insight into the formation of nanoscale semiconductor heterojunctions, MoS2 flakes are deposited on the silicon nanowire (SiNW) array by chemical vapor deposition (CVD). In this study, H2O2 treatment provides a favorable place where the formation of SiO bonds on the SiNW surfaces that play important roles (i.e., the nucleation centers, catalyst control centers or “seeds”) can dominate the growth of MoS2 on the SiNWs. Using this configuration, the effect of a change in the S/MoO3 mass ratio (MS/MMoO3) on the surface morphology of MoS2 is studied. It is shown that an increase in the value of MS/MMoO3 leads to the increased nucleation rate, increasing the size of MoS2 nanopetals. This study provides valuable scientific information for directly CVD-grown edge-oriented MoS2/SiNWs heterojunctions for various nanoscale applications, including hydrogen evolution reaction and electronic and optoelectronic devices.

Cu3(BTC)2 catalyzed dehydrogenative coupling of dimethylphenylsilane with phenol and homocoupling of dimethylphenylsilane to disiloxane

Cu3(BTC)2 (BTC: 1,3,5-benzenetricarboxylic acid) showed to be an efficient and reusable heterogeneous solid catalyst for the formation of SiO bond through dehydrogenative coupling of dimethylphenylsilane (1) with phenol under mild reaction conditions. It is observed that Fe(BTC), MIL-101(Cr) and UiO-66(Zr) are not able to promote this cross coupling between 1 and phenol. Cu3(BTC)2 exhibits higher stability and activity compared to other MOFs studied here. Furthermore, Cu3(BTC)2 is reused for three consecutive cycles with a slight decay in its activity. Comparison of the powder XRD patterns of the fresh with three times used Cu3(BTC)2 showed no significant difference in the crystalline structure, thus, indicating the catalyst stability under the optimized reaction conditions. Furthermore, EPR, FT-IR and SEM images of the fresh and reused Cu3(BTC)2 did not show any change in the oxidation state of copper or structural morphology. Also, no leaching of copper is detected under optimized reaction conditions. In addition, Cu3(BTC)2 showed higher activity compared to Pt, Pd, Au and Cu supported on active carbon as heterogeneous catalysts in the synthesis of disiloxane from 1 through SiH activation.

ReaxFF reactive molecular dynamics on silicon pentaerythritol tetranitrate crystal validates the mechanism for the colossal sensitivity.

Recently quantum mechanical (QM) calculations on a single Si-PETN (silicon-pentaerythritol tetranitrate) molecule were used to explain its colossal sensitivity observed experimentally in terms of a unique Liu carbon-silyl nitro-ester rearrangement (R3Si-CH2-O-R2→ R3Si-O-CH2-R2). In this paper we expanded the study of Si-PETN from a single molecule to a bulk system by extending the ReaxFF reactive force field to describe similar Si-C-H-O-N systems with parameters optimized to reproduce QM results. The reaction mechanisms and kinetics of thermal decomposition of solid Si-PETN were investigated using ReaxFF reactive molecular dynamics (ReaxFF-RMD) simulations at various temperatures to explore the origin of the high sensitivity. We find that at lower temperatures, the decomposition of Si-PETN is initiated by the Liu carbon-silyl nitro-ester rearrangement forming Si-O bonds which is not observed in PETN. As the reaction proceeds, the exothermicity of Si-O bond formation promotes the onset of NO2 formation from N-OC bond cleavage which does not occur in PETN. At higher temperatures PETN starts to react by the usual mechanisms of NO2 dissociation and HONO elimination; however, Si-PETN remains far more reactive. These results validate the predictions from QM that the significantly increased sensitivity of Si-PETN arises from a unimolecular process involving the unusual Liu rearrangement but not from multi-molecular collisions. It is the very low energy barrier and the high exothermicity of the Si-O bond formation providing energy early in the decomposition process that is responsible.

Multiple Reaction Pathways Operating in the Mechanism of Vinylogous Mannich-Type Reaction Activated by a Water Molecule

A systematic search for reaction pathways for the vinylogous Mannich-type reaction was performed by the artificial force induced reaction method. This reaction affords δ-amino-γ-butenolide in one pot by mixing 2-trimethylsiloxyfuran, imine, and water under solvent-free conditions. Surprisingly, the search identified as many as five working pathways. Among them, two concertedly produce anti and syn isomers of the product. Another two give an intermediate, which is a regioisomer of the main product. This intermediate can undergo a retro-Mannich reaction to give a pair of intermediates: an imine and 2-furanol. The remaining pathway directly generates this intermediate pair. The imine and 2-furanol easily react with each other to afford the product. Thus, all of these stepwise pathways finally converge to give the main product. The rate-determining step of all five (two concerted and three stepwise) pathways have a common mechanism: concerted Si-O bond formation through the nucleophilic attack of a water molecule on the silicon atom followed by proton transfer from the water molecule to the imine. Therefore, these five pathways have comparable barriers and compete with each other.

Preparation and Characterization of a Graphene Oxide Film Modified by the Covalent Attachment of Polysiloxane

Hybrid materials consisting of polydimethylsiloxane (PDMS) and polycyclohexyl-methylsiloxane (PCHMS) grafted graphene oxide (GO) were obtained by condensation polymerization in toluene. Fourier transform infrared spectroscopy indicates that the composites were synthesized through the formation of Si-O bond. The X-ray diffraction, scanning electron microscopy and thermogravimetric indicate that the hydrolysis polycondensation can accelerate the graft reaction. The hybrid films were prepared by simple filtration of the dispersed system of PDMS/GO/water, PCHMS/GO and PCHMS/GO/water in dimethylformamide. Tensile tests indicate the mechanical properties of the films varied with their structure. The rigid PCHMS/GO/water films have a tensile strength of 17.83 MPa, and the pliant PDMS/GO/water films have an elongation at break of 3.14%. UV-Vis spectra of GO and the hybrids indicate that the addition of polysiloxane caused a red-shift (10–20 nm) of the absorption peak.

Electronic transport for polymer/Si-nanowire arrays/n-type Si diodes with and without Si-nanowire surface passivation

Polymer/nanowires /Si diodes without H2O2 treatment show a poor rectifying behavior.Polymer/nanowires /Si diodes with H2O2 treatment show a good rectifying behavior.The interfacial defects of heterojunction devices were controlled by H2O2 treatment.Such an improvement indicates that a good passivation is formed at the interface. The effect of Si-nanowire (SiNW) surface passivation on electronic transport of heterojunction diodes based on the poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) and n-type Si with SiNW arrays was investigated in this study. The PEDOT:PSS/SiNWs/n-type Si diode without SiNW surface passivation shows a poor rectifying behavior with an ideality factor (?) of 7.8 and high leakage. However, the PEDOT:PSS/SiNWs/n-type Si diode with SiNW surface passivation shows a good rectifying behavior with ? of 1.7 and low leakage. Such an improvement indicates that a good passivation is formed at the interface as a result of a combined effect of the formation of Si-O bonds and the removal of the short-lifetime charge traps. Note that SiNW surface passivation plays a significant role in the photoconduction by providing the contribution of long-lifetime charge trapping to the decay process.

Theoretical characterizations of the mechanism for the dimerization of monosilicic acid in basic solution

The anionic mechanisms for the elementary dimerization reaction of monosilicic acid in basic aqueous solution have been characterized comprehensively using various ab initio methods. Many new insights into the silicate oligomerization reaction, which is fundamentally important in sol-gel chemistry, zeolite synthesis, and cement hydration, are presented in this work. Conformational dependence of the dimerization reaction is proposed in view of hundreds of conformations with various inter- and intramolecular hydrogen bonding patterns along the reaction routes. An alternative water cleavage route from the five-coordinated silicon intermediate is revealed. The detour involves a six-center cyclic transition state, which is more preferable energetically than the well-known four-center water removal step. By including explicit water molecules, the activation barrier of the four-center water cleavage path can be reduced considerably to be even lower than the first barrier of the Si-O bond formation. In contrast, the six-center detour is less affected by the additional water molecules due to the unfavorable geometric distortion. The new understanding of the dimerization mechanism could have considerable impact on the initial stages of silica nucleation.

Effect of moisture on electron transport in Si[sbnd]C nanotubes: An ab-initio study

We investigate the effect of moisture-adsorption on the electronic transport properties of a silicon-carbide nanotube (SiCNT). The results obtained by relaxing an H2O (water) molecule over an (8,0) SiCNT show that water molecule binds with SiCNT. The formation of SiO bond (bond length ∼1.95 Å) between the SiCNT and H2O molecule was discovered. However, previous studies on H2O adsorbtion in carbon nanotubes (CNTs) have shown the formation of CH bond at the CNT surface. Current–voltage (I–V) characteristics show a reduction in SiCNT conductivity when the number of H2O molecules over SiCNT were increased.