Si 2p Binding Energy Research Articles

Effect of alumina on formation mechanism and structure characteristic of sodium calcium silicate compounds with different stoichiometric coefficients

In order to illustrate the effects of Al2O3 on silicate structure for synthesizing sodium calcium silicate compounds, the formation characteristics, lattice parameters, molecular structure and element chemical state of sodium calcium silicates with different Al2O3 proportions through solid-state reaction were investigated using XRD, SEM-EDS, Raman spectroscopy and XPS analyses. Increasing the Al2O3 content facilitates the formation of Na2CaSiO4 and converts the polymorph of Na2Ca6Si4O15 from γ-type into β-type. The product particles aggregate to form clumps by increasing the Al2O3 content when the molar ratios of Na2O and CaO to SiO2 are 0.5 and 1.5, and the network orderliness of silicates deteriorates to form glassy phase at the low CaO and Na2O contents. Al2O3 can engage in the bonding process with silicate crystals to produce a finite solid solution. Increasing the Al2O3 porportion is advantageous for facilitating the participation of [AlO6] in the Si-O-Al bonding reaction, which leads to the depolymerization of [Si2O7]6-, [Si3O10]8- and [Si6O18]12− and promotes the formation of silicate chains of [SiO4]4- and [Si2O7]6-. Moreover, increasing the contents of Na2O and CaO promote the formation of [AlO4] and the depolymerization within silicate chains, which increases the bonding number of Si-Oter and Al-Oter and then reduces the binding energies of Si2p and Al2p orbits.

Analysis of calcination activation modified coal gangue and its acid activation mechanism

Acid activation and utilization of coal gangue is of great significance for effective treatment of bulk solid waste in the environment. However, most gangue is quite inert and requires calcination to induce acid activation. In this paper, coal gangue was calcined, and the optimal calcination temperature for activation of the coal gangue acid was explored. Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry/thermal differential analysis (TG/DTG) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the crystal structures of the gangue samples formed at different calcination temperatures, which showed that increases in the amorphous content and structural degradation of the coal gangue samples occurred during calcination. The solubility of silicon and aluminum in acid solution was demonstrated with inductively coupled plasma optical emission spectroscopy (ICP‒OES). XRD and TG/DTG were used to characterize the acid activation products formed at different calcination temperatures. The results show that with the increase of calcination temperature, the compressive strength first increases and then decreases, and reached the maximum value at 650 °C; the compressive strengths at 7 d, 28 d and 90 d were 1.32 MPa, 3.22 MPa and 5.14 MPa. At 650 °C, the kaolinite in the gangue was converted into metakaolin, the aluminum-oxygen octahedra had the hydroxyl groups removed, the silicon-oxygen tetrahedra were depolymerized, the absorption bands for Si–O, Si–O–Al and Al–O bonds were broadened, the Al2p and Si2p binding energies were reduced, the splitting were increased, and more Al dissolved in the acid solution, so it has the highest acid reactivity.

Research on reactivity evaluation and micro-mechanism of various solid waste powders for alkali-activated cementitious materials

Alkali-activated cementitious material (AACM) based on the utilization of solid waste is a new type of environmentally friendly inorganic material, which has the advantages of early strength, fast hardening, high strength, and better durability. The reactivity of solid waste powder is a key factor for its appropriate utilization in alkali-activated cementitious materials, necessitating a rational evaluation of its reactivity. The reactivity evaluation was conducted on various solid waste powders, including fly ash (FA), red mud (RM), recycled micro-powder (RMP), red brick powder (RBP), coal gangue powder (CGP), and cement kiln dust (CKD). The effects of NaOH concentration, weight ratio of water to solid waste powder (W/P) and curing humidity on the compressive strength were investigated，then the compressive strength under optimal conditions was determined based on response surface analysis. The compressive strength under optimal conditions was used to evaluate the reactivity of solid waste powders. Moreover, microscopic tests (e.g., XPS test, ICP test, and NMR test) were carried to evaluate the reactivity of the solid waste. The relative number of bridging oxygen (RBO) measured by the NMR method in conjunction with chemical composition analysis serves as an effective method for evaluating the reactivity of solid waste powders. The leaching rate of Silicon (Si) and Aluminum (Al) ions in the ICP method depended mainly on the NaOH concentration and the elemental content in the raw material. In addition, the binding energies of O1s, Si 2p, and Al 2p tested by the XPS method had no particular correlation with the compressive strength.

Powdered and beaded zeolite A from recycled coal fly ash with modified iron (III) oxide-hydroxide for lead adsorptions

Lead is a highly toxic metal and bioaccumulation through food chain, so it causes human health effects. Thus, contaminated lead in wastewater is required to treat below the water quality standard. This study was to synthesize zeolite A powder (Z), zeolite A powder mixed iron (III) oxide-hydroxide (ZF), zeolite A beads (ZB), and zeolite A powder mixed iron (III) oxide-hydroxide beads (ZFB), characterize with various techniques, investigate their lead removal efficiencies by batch experiments, and study their adsorption patterns and mechanisms. All characterizations of Z have matched to the zeolite A standard (STD) which confirmed the ability to synthesize zeolite A. ZF had the highest specific surface area and smallest pore size than others, and they were mesoporous materials. Silicon, aluminum, and sodium were observed in all materials. The specific crystalline formation of zeolite A was found in all materials corresponding to the STD. Z was a cubic structure representing the specific zeolite A structure, and ZF, ZB, and ZFB had rough surfaces with presenting traces of cubic shapes confirmed being zeolite A. OH, Si or Al–O, and D4R were their main chemical functional groups, and Si–O–Fe was found in ZF and ZFB. In addition, –COOH was observed in ZB and ZFB. The binding energies of Na 1s, O 1s, Si 2p, and Al 2p were found in all materials, and Fe 2p3/2 and Fe 2p1/2 were observed in ZF and ZFB. In addition, Pb 4f7/2 and Pb 4f5/2 were detected after lead adsorptions. The point of zero charges of Z, ZF, ZB, and ZFB were 6.45, 8.65, 6.04, and 8.12. They could remove lead at 50 mg/L of more than 97.5 %. They corresponded to Langmuir and pseudo-second-order kinetic models. Moreover, they could reuse more than 5 cycles. Finally, ZFB is a good offer for real industrial applications.

Study on the composite gravel preparation and the synergistic absorption of CO2 by fly ash of CFB boiler

The cooperative treatment of fly ash and fuel gas of coal-fired plants is a promising way. In this study, circulating fluidized bed fly ash (CFBFA), gypsum, Portland Cement (PC) and water were mixed and pelleted, with carbonation curing by fuel gas to prepare the composite gravel. Experimental results showed that CSH gel and ettringite were the main hydration products and calcite was the main carbonation product. The highest strength of the composite gravel reached 11.11 MPa at 28d which was positively related to the absorption rate of CO2, and the CO2 absorption rate reached 4.789 %. Both hydration and carbonation reactions contributed positively to strength. The carbonation process caused a higher Si 2p binding energy, and the addition of gypsum led to a higher binding energy of Ca 2p. The addition of gypsum increased the porosity and main pore diameter. The porosity and main pore diameter determined the strength of composite gravel. It was observed that gypsum acted as a catalyst to promote the formation of hydration products and carbonation products. This study provided a theoretical support for the preparation of composite gravel which was a substitute for river sand and natural gravel.

Nanoporous Mg-doped SiO2 nanoparticles with tunable infrared emissivity toward effective radiative cooling coatings

SiO2 is the hotspot radiative cooling material due to its selective radiation or the Mie resonance effect generated by micro/nanospheres of a specific size. Herein, we demonstrate the modulation of the infrared emissivity of the intrinsic SiO2 at the atmospheric window by doping Mg2+ in nanoporous SiO2 nanoparticles via a modified stöber method. The effects of the Mg-doping on the crystallinity, morphology, infrared emissivity of the nanoparticles and the radiative cooling properties of the corresponding coatings are investigated. Results show that the Mg-doping at a level of 0.226–2.26 % can induce cristobalite nanocrystals after sintering at 1000 ℃, transform the morphology from spheres to irregular nanoporous particles, and improve the infrared emissivity up to 0.96. XPS proves the formation of Mg-O bonds and the change of the binding energy of Si 2p and O 1s, supporting the successful doping of Mg2+ in the lattice of SiO2. All-inorganic Mg-doped SiO2 coatings on FTO substrates are prepared via tape casting, which exhibit rough and porous microstructure and high solar reflectivity up to ∼86 %, with the thickness of ∼90 µm. The Mg-doping improves the radiative cooling capacity of the coatings obviously, and the best temperature reduction of 17.8 ℃ compared with the empty space is achieved, 3–5 ℃ lower than the pure SiO2 coating and 4.5 ℃ lower than the commercial SiO2 coating. Our work offers an effective way to modulate the infrared emission of emitter, enriching the technical measures to improve the overall performance of the sub-ambient radiative cooling devices.

Study on the Synthesis and Structural Properties of Zeolite A-MgO Composite for Defluoridation of Water

Zeolite A-MgO composite was synthesized in presence of zeolite A particles, MgCl2 and urea solution under hydrothermal reaction at 150oC for 5 h followed by calcination at 600°C/2 h. XRD and FTIR results showed the crystallization of MgO along with NaA zeolite crystals. Nano-sheet like MgO particles (50-70 nm) were grown onto the surface of NaA zeolite crystals (1 μm). BET surface area and pore size of the sample were found to be 69 m2.g−1 and 3.9 nm, respectively. XPS analysis showed the binding energies of O1s, Si2p, Na1s, Al2p and Mg2p as 531.6, 102.4, 1072.2, 74.2 and 49.9 eV, respectively. The synthesized product (1 g.L−1 dose) showed 72% adsorption of fluoride (7.24 mg.L−1) within 5 min and reached up to 94% for 90 min at pH 6.8. The adsorption capacity of the sample was calculated as 107.64 mg.g−1 from Langmuir isotherm. The sample could be regenerated up to 5th cycle. A tentative mechanism for the adsorption of fluoride from aqueous solution by the synthesized zeolite A-MgO composite was proposed.

Effect of Silane A-174 Modifications in the Structure, Chemistry, and Compressive Strength of PLA-HAP and PLA-β-TCP Biocomposites: Toward the Design of Polymer–Ceramic Implants with High Performance

The effect of silane A-174 (3-(trimethoxysilyl)propyl methacrylate (methacryloxypropyl trimethoxysilane)) modifications of the ceramic surface on the structural characteristics and mechanical performance of hydroxyapatite (HAP)–polylactic acid (PLA) and β-tricalcium phosphate (β-TCP)–PLA composite systems was investigated employing a combination of Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), compressive strength measurements, and statistical models constructed via projection to latent structures (PLS) analysis. The composites were synthesized by solvent casting method at ambient conditions employing ceramic/PLA ratios of 60/40 and 50/50, and silane A-174 percentages of 0, 1, and 3 wt %. Peak positions of O 1s, Ca 2p, P 2p, Si 2p, and C 1s in XP spectra of ceramics, surface-modified ceramics, and the corresponding composites and compressive strength values were used as the predictors and response variables in PLS models. It was found that Ca 2p, P 2p, and Si 2p binding energies of the ceramic component employed in composite synthesis played the most significant role in determining compressive strength. PLA-HAP composite with a ceramic/PLA ratio of 50/50, synthesized employing 3 wt % silane A-174 treated HAP (HAP50PLA50Si3), resulted in enhancement of the compressive strength up to 365 MPa, which is the highest compressive strength value reported in the literature to the best of our knowledge. Additional P 2p, Ca 2p, and C 1s features positioned at 129.64, 350.08, and 280.74 eV in the XP spectra of this specimen together with significant shifts of Si 2p and C 1s bands toward lower binding energies and polymer-bridge-like surface characteristics signaled improved polymer–ceramic interaction in this composite. Attaining mechanical performance comparable with and even higher than that of cortical bone upon silane A-174 modifications might provide opportunities for clinical applications toward developing bioresorbable PLA-HAP-based implants that can be employed in load-bearing applications such as knee and hip replacements.

Mechanical Transformation of Fly Ash toward Its Utilization in Cemented Paste Backfill

Fly ash (FA) showed low reactivity when being used to prepare the binder for cemented paste backfill (CPB). In the present work, wet‐grinding treatment was used to increase the pozzolanic reactivity of FA and promote its sustainable utilization. The results showed that wet‐grinding could be a suitable and efficient technology for FA pretreatment. Wet‐grinding strongly modified the structure of FA by decreasing the crystalline phase content and the binding energy of Si 2p and Al 2p, contributing to the increase in pozzolanic reactivity of FA. The performance of CPB samples prepared by wet‐ground FA was then optimized. This was reflected by the acceleration in the sample setting and increase in the strength development. The compressive strength of the CPB samples prepared by wet‐ground FA for 120 min was increased by around 40% after curing for 28 d compared with the control samples.

Sol-gel control on mixed network silica membranes for gas separation

Sol-gel derived Ti-incorporated methyl-linked silica mixed network membranes were successfully prepared by acid catalyzed co-polymerization of methyltriethoxysilane, tetraethylorthosilicate and titanium isopropoxide. The particle size of polymeric mixed oxide sols was in the range of 2–6 nm depending on the titanium content in the sol. As Ti4+/Si4+ mole ratio in the sol increases, DLS polymer cluster size increases slightly due to the different reactivity of precursors. Ti2p and Si2p binding energy values obtained by XPS confirmed the evolution of Si-O-Ti bond in the membrane network. Macroporous α-alumina ceramic supports with different pore size as a support and mesoporous γ-alumina coating as an intermediate layer were used for the fabrication of thin titania/methyl-linked mixed network silica membranes. Increase in the number of coating led to an increase in the membrane thickness from 80 nm to 220 nm and this provided an enhancement in the H2/C3H8 ideal selectivity (from 53 to 124). Decrease in the H2 permeance, on the other hand, with increased membrane thickness was overcome with the use of coarser supports inhibiting the transport resistance. The membrane exhibited higher H2 permeance value of 1.6 × 10−6 mol/m2 s Pa with almost same H2/C3H8 ideal selectivity at 150 °C compared to its finer counterpart.

Tuning of Schottky barrier height using oxygen-inserted (OI) layers and fluorine implantation

The effects of oxygen-insertion technology and low-energy fluorine (F) implantation on the Schottky barrier height (ΦBp) of a Pt/Ti/p-type Si metal–semiconductor contact are studied via electrical characterizations of Schottky diodes, physical analyses by secondary ion mass spectrometry , and chemical analyses by x-ray photoelectron spectroscopy. It is found that both oxygen-inserted (OI) layers and F can reduce ΦBp due to Ti 2p and Si 2p binding energy shifts before forming gas anneal (FGA) and due to retarded Pt diffusion into Si (facilitating low-ΦBp Pt mono-silicide formation) during FGA. The experimental findings also suggest that OI layers are more effective than F for reducing ΦBp.

Self-solidification/stabilisation of electrolytic manganese residue: Mechanistic insights

Electrolytic manganese residue (EMR) is a type of industrial solid waste with high content of sulphur and heavy metals (HMs). In this study, a novel cementitious material composite is synthesised from ground granulated blast furnace slag, clinker, lime and EMR. It is used to solidify and stabilise EMR. The solidified products are characterised by mechanical properties and environmental effect. The solidification/stabilisation mechanism is revealed by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy with energy dispersive X-ray analyser. The experiment results show that the UCS of solidified bodies increases with the curing age and dosage of cementitious materials. HMs in solidified samples meet the standard threshold. HMs switch to a stable form during curing, that is, S/S has a significant inactivation effect on HMs and can protect HMs from leaching in long-term. The contents of gypsum, charmarite and calcium manganese silicate gradually appear with curing time. Charmarite and gypsum can contribute the increasing trend of compressive strength with curing time. The formation of calcium manganese silicate shows that the presence of HMs in EMR can be involved in the hydration reaction. The binding energy of Si 2p decreases over curing time due to the enlarged degree of polymerisation of Si. The Si–O energy of S/S samples verifies the formation of zeolite-like structure, which can provide sufficient adsorption capacity to HMs and mechanical strength. The microstructure of S/S samples becomes dense with curing time. Gypsum is conducive to the rapid stabilisation of HMs (except Mn). Meanwhile, CSH gel can effectively immobilise all HMs by HM–gel reaction. Incorporating EMR into cementitious materials to solidify/stabilise itself is one way of utilising solid wastes as construction materials for civil engineering applications.

Microstructure of cement paste incorporating high volume of low-grade metakaolin

The influence of low-grade metakaolin (MK) on the mechanical and microstructural properties of cement paste was studied through compressive strength test and microstructural analyses, including thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). The results indicated that cement paste incorporating MK with around 40 wt.% kaolinite content in raw clays achieved comparable 28-day strength to that of the reference even at 40 wt.% replacement level. Microstructural studies showed a considerable amount of portlandite consumption after 3 d and a refinement of pore structure in backscattered micrographs. The Al/Ca ratio of calcium-aluminosilicate-hydrate (C-A-S-H) increased upon the increased replacement levels, while Ca/Si decreased due to the introduction of MK, but it did not further reduce with the increased MK content. The binding energy of Si 2p, Al 2p and Ca 2p spectra increased due to the incorporation of MK.

Influence of Magnesia on Demoulding Strength of Colloidal Silica-Bonded Castables

AbstractThe change in demoulding strength of colloidal silica-bonded castables with and without magnesia is investigated with emphasis on the relationship between the demoulding strength and chemical bond changes. It was confirmed that the demoulding strength was raised with the presence of magnesia in colloidal silica-bonded castables because of the increased chemical bonding between the sol particles. The X-ray photoelectron spectroscopy (XPS) and the Fourier transformation infrared spectroscopy (FTIR) results indicate the formation of new Si–O–Mg chemical bond from the decreased O 1s and Si 2p binding energy, and the appearance of weak vibration peaks at 668 and 419 cm−1 in the spectrum of colloidal silica with the addition of MgO after curing at 30°C for 24 hours. The reaction between colloidal silica and magnesia could promote the formation of –Si–O–Mg–O–Si–bonds, which is the primary reason for the demoulding strength improvement.

Physical and chemical characterization of Chinese maize stalk leaf ash: Calcining temperature and aqueous solution

This study focused on the physical and chemical characterization of Chinese maize stalk leaf ash (MSLA) calcined at 500, 700, and 850 °C and MSLA residual leaching in aqueous solutions. The grain size distribution, chemical composition, and microstructure of MSLA were investigated using a laser Mastersizer, X-ray fluorescence, and scanning electron microscopy. The ash samples obtained before and after dissolving were analyzed using X-ray powder diffraction and X-ray photoelectron spectroscopy to identify the present minerals and observe the 2p atomic orbit of surface silicon and aluminum (Si 2p and Al 2p) transformation behaviors. The zeta potential and pH values of hybrid solutions were tested for various dissolving times. Silica was the predominant component observed in the MSLA. As dissolving time increased, the pH value gradually decreased, and the zeta potentials first slightly decreased and then remarkably increased. Quartz was identified in the MSLA. Another polymorphous crystalline form of silica, cristobalite, only appeared in the 850 °C sample. The binding energies of Si 2p and Al 2p shifted, which transformed the XPS peaks after the thermal and aqueous solution treatment of MSLA. These findings can be utilized to study the application potential of MSLA in cementing systems.

Effects of Cr3+ addition on the structure and optical properties of α-Zn2SiO4 synthesized by sol-gel method

The α-Zn2SiO4 (willemite) structure is known as an extremely versatile host matrix for phosphors. Here we show that Cr3+ has very low solubility in α-Zn2SiO4， and powder x-ray diffraction confirms that ZnCr2O4 spinel is segregated even at 0.05mol% Cr addition， while Raman spectroscopy shows that a silicate phase is segregated at the same 0.05mol% Cr addition and these results confirm that both Zn2+ and Si4+ vacancies occur with the addition of Cr3+ to α-Zn2SiO4 and charge neutrality requires that two Cr3+ ions are needed for each Zn2+ and Si4+ vacancy. The small addition of Cr3+ to α-Zn2SiO4 results in a small lattice expansion and because the Cr–O and Zn–O bond lengths are similar, and the Si–O bond length is shorter, it is expected that the Cr3+ ion is closer to the Si4+ vacancies resulting in a lattice expansion. This is supported by X-ray photoelectron spectrometry which shows that the binding energy of Si 2p, and especially O 1s, are more affected by Cr3+ addition than Zn 2p binding energy. The UV–vis absorption spectrum for α-Zn2SiO4:Cr3+ confirms that the Cr3+ d3 ion is in its preferred octahedral coordination but the photoluminescence (PL) measurements show emission in the yellow red region (CIE coordinates x = 0.52 and y = 0.45), rather than red, suggesting that the octahedral coordination for Cr3+ is distorted. The results confirm that the Cr3+ is not sited in either of the non-equivalent tetrahedral sites for Zn2+ in α-Zn2SiO4, as is typically reported for the other cations added to the host lattice.

Arsenic vitrification by copper slag based glass: Mechanism and stability studies

In the present work, the (100−x)(58SiO2-20Fe2O3-10B2O3-12Na2O)−xAs (x=0, 2, 4, 6, 8wt%) glasses, which are main constituents of the copper slag based glasses, were produced by conventional melting method to study the arsenic vitrification mechanism and stability. X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR) and X-photoelectron spectroscopy (XPS) were used to investigate the mechanism of arsenic vitrification. The XRD analysis for the x≤wt 8% samples shows that all the samples form homogeneous glasses and the arsenic is compatible with the copper slag based glass. The FTIR spectrum of the glasses have revealed that the arsenic exists in the form of AsO4 tetrahedra and the Qn structure of the copper slag based glass has been strengthened with the increase addition of arsenic. The changes of the binding energies of Si2p, O1s, As3d and Fe2p directly indicate the formation of SiOAs and FeOSi/As bonds in the glass, which strengthens the chemical stability of the glass. Lastly, USEPA toxicity characteristics leaching procedure (TCLP) and differential scanning calorimetry (DSC) tests were used to study the chemical durability and thermal stability of the glasses containing arsenic. The leaching concentrations of As, B, Fe, Na, and Si are under safety thresholds and the increase addition of arsenic into the glasses can decrease the leaching concentrations, indicating that the arsenic can improve the chemical stability of the glass. The arsenic added into the glass can improve the ΔT, which strengthens the thermal stability of the glasses.

Band alignment of Ga2O3/Si heterojunction interface measured by X-ray photoelectron spectroscopy

Ga2O3 thin films were deposited on (111) Si substrate by pulsed laser deposition method. X-ray photoelectron spectroscopy has been used to determine the valence band offset at Ga2O3/Si heterojunction interface. We measured the binding energies of Si 2p and Ga 2p3/2 core levels and the valence band maxima energies. The valence band offset is determined to be 3.5 ± 0.1 eV. As a consequence a type Ι heterojunction with a conduction band offset of 0.2 ± 0.1 eV is found. The determination of the band alignment of Ga2O3/Si heterojunction facilitates the design of optical and electronic devices based on the Ga2O3/Si structure.

Mg-O-Si Chemical Bond Formation in Light Burned Magnesia and Fumed Silica Mixture During Mechanical Activation

Mg-O-Si chemical bond formation in a light burned magnesia (MgO) and fumed silica (SiO2) mixture during mechanical activation was investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), magic angle spinning nuclear magnetic resonance (MAS-NMR), and X-ray photoelectron spectroscopy (XPS). Crystallinity and intrinsic structure changes of the starting mixture during high-energy milling were examined by XRD. The formation of new Mg-O-Si chemical bonds of the ground mixture was illustrated by the incorporation of Mg2+ in Si-O-Si linkages, the appearance of new resonance in the 29Si NMR spectrum and the decrease of the Si 2p binding energy. The formation of Mg-O-Si chemical bonds created during grinding partly contributed to the lowered temperature of complete forsterite formation from 1400 to 1100°C.

Al-O-Si Bond Formation in Boehmite-Fumed Silica Mixtures during Mechanochemical Activation

Al-O-Si bond formation in boehmite-fumed silica mixtures during mechanochemical activation was investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), magic angle spinning nuclear magnetic resonance (MAS-NMR) and X-ray photoelectron spectroscopy (XPS). The intrinsic structure deformation of the boehmite was examined with XRD. Formation of new Al-O-Si bonds was illustrated by the incorporation of Al3+ in Si-O-Si linkages, the change in the Al coordination number of boehmite, and the appearance of new resonance in the 29Si NMR spectrum of the ground mixture. The presence of Al-O units in silica frameworks was verified by the increase of Al 2p binding energy and the decrease of Si 2p binding energy.