Ti Bonds Research Articles

Structure and photocatalytic performance of K1−3x M x TiNbO5 (M = Fe, Ce) for ethyl mercaptan

Layered photocatalytic material K1−3xMxTiNbO5 (M = Fe, Ce) was prepared by the ion exchange of KTiNbO5 with M(NO3)3. The structure and spectral response of the as-prepared samples were characterized by powder X-ray diffraction (XRD), laser Raman spectroscopy (LRS) and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). Photocatalytic activity was evaluated by oxidizing ethyl mercaptan under natural light and UV light irradiation. Results indicated that the spectral response feature and photocatalytic oxidation activity were directly affected by the feature of the interlayer cations, including the Coulomb force field and electronic configuration. It could be related with a significant interaction between the interlayer cations and the terminal N=O (N = Nb, Ti) bond in the NO6, octahedral unit in the laminate structure. Compared to K1−3xFexTiNbO5, K1−3xNbxTiNbO5 shows a higher photocatalytic oxidation activity due to it has good adsorption ability for ethyl mercaptan and higher valance band potential.

Photodegradation of C.I. reactive red 2 in UV/TiO2–In2O3–C–N and UV/TiO2–In2O3–S–N systems

In this study, the sol–gel method is utilized to produce TiO2–In2O3 composite (Ti–In). The generated Ti–In was separately co-doped with C–N and S–N to form novel TiO2–In2O3–C–N (Ti–In–C–N) and TiO2–In2O3–S–N (Ti–In–S–N). The sources of N, C and S dopants were urea, powder activated carbon and Na2S2O3. The dye C.I. reactive red 2 (RR2) was used as a model compound that was exposed to various composites and its removal by photocatalytic degradation and adsorption was measured. The percentage of anatase phase in Ti–In–C–N and Ti–In–S–N exceeded that in Ti–In; conversely, the particle diameter and band gap energy of Ti–In exceeded those of Ti–In–C–N and Ti–In–S–N. Bonds of Ti–O–N, Ti–N–O and Ti–O–C were detected in Ti–In–C–N and bonds of Ti–O–N, Ti–N–O and Ti–O–S were found in Ti–In–S–N. The pseudo-first order RR2 removal rate constants in UV/Ti–In, UV/Ti–In–C–N and UV/Ti–In–S–N were 0.43, 1.68 and 1.70 h−1, in order. The specific oxygen uptake rates of the RR2 effluent in UV/Ti–In, UV/Ti–In–C–N and UV/Ti–In–S–N were determined to be 4.4, 7.3 and 5.3 mg O2/g-MLVSS h. Ti–In–C–N and Ti–In–S–N were more effective in decolorizing and detoxifying RR2 than was their parent Ti–In.

Effect of holmium doping on the structure and photocatalytic behavior of TiO2-based nanosheets

A series of holmium-doped TiO2-based nanosheet (Ho-TNS) photocatalysts with different Ho/Ti molar ratios were prepared via a simple hydrothermal method. The photocatalysts were characterized by field-emission scanning electron microscope, high-resolution transmission electron microscope, X-ray diffraction (XRD), Raman Spectroscopy, X-ray photoemission spectroscopy, nitrogen adsorption–desorption isotherm measurement, ultraviolet–visible light diffuse reflectance spectra (DRS), and fluorescence spectra (FL). The TEM images of Ho-TNS exhibit clearly sheet-like structures and existence of the (201) plane of H2Ti3O7. The increased (101) peak intensity in XRD spectrum and the enhanced Eg mode (141 cm−1) in Raman spectrum indicate that Ho doping has obvious influence on the formation and structure of Ho-TNS, which can be explained by the formation of Ho–O–Ti bonds. With the doping ratio (Ho/Ti molar ratio) increasing from 0 to 2.0 %, the absorption edge shifts to a longer wavelength, and the band-gap of photocatalysts reduces from 3.18 to 3.07 eV. The decline of FL intensity implies that the photocatalysts with higher Ho content have higher electron–hole separation efficiency. However, after Ho doping, the surface structure of specimens is significantly altered, which will lead to the specific surface areas and adsorption capacity decrease. Under the combined effect of the variables, the photocatalyst with a doping ratio of 1.0 % reaches the best photoactivity, which is 1.90-fold and 12.38-fold higher compared with undoped TNS and P25 under visible light, respectively. The high photoactivity of the prepared Ho-TNS indicates that it may be useful for dealing with wastewater.

Nb solution influencing on phase transformation temperature of Ni47Ti44Nb9 alloy

The effect of annealing temperature on the phase transformation temperature and microstructure of as-rolled Ni47Ti44Nb9 alloy has been investigated, and the microstructural mechanism has been systematically calculated and analyzed. The results show that annealing treatment elevates phase transformation temperature. With the increase of annealing temperature, Ms temperature increases abruptly below 900°C, yet above 900°C, Ms shows no substantial change. Nb gradually dissolves into NiTi matrix, until complete solution at 950°C. Based on first-principles pseudo-potential plane wave method, a further investigation into micro-mechanism of effect of Nb solution into NiTi(Nb) on the phase transformation temperature is studied by analyzing elasticity modulus and population. Comparing with NiTi matrix, shear modulus c′ and c44 of NiTi(Nb) are rather lower. Following Nb solution into NiTi matrix, Ni–Ti bond is depressed, meanwhile weak Ni–Nb bond and Ti–Nb bond greatly influenced by temperature are formed, as a result of Ms increasing for NiTi(Nb), maybe this is the just micro-mechanism of Nb solution into NiTi alloy.

Crystal orientation dependence of charge distributions of He ions scattered from rutile TiO2(1 1 0) surfaces

It is well known that the charge distributions of medium energy He ions scattered from solid surfaces depend on emerging energy and angle as well as surface materials. We analyzed emerging energy and angle dependence of He+ fractions for medium energy He ions scattered from top-layer Ti atoms at the [11¯0]- and [001]-azimuth of rutile TiO2(110). He+ fractions for the [001]- and [11¯0]-azimuth were equilibrated at emerging angles (scaled from surface normal) above ∼75° and ∼85°, respectively. It was also found that non-equilibrated He+ fractions observed at smaller emerging angles for the [11¯0]-azimuth were larger more than 20% than those for the [001]-azimuth and the difference between the He+ fractions for the [11¯0]- and [001]-azimuth increased with increasing emerging energy. The Ti–Ti bond length along the [11¯0]-axis is more than twice that along the [001]-axis. Thus the He ions scattered from top-layer Ti atoms at the [001]-azimuth interact with many outer electrons of the aligned top-layer Ti atoms until leaving from surfaces. A He ion immediately after a large-angle collision has no bound electron because of time–energy uncertainty. The He2+ ion then undergoes electron capture and loss processes during passing through the surface. In this regard, the non-equilibrated He+ fractions for the [001]-azimuth are smaller than those for the [11¯0]-azimuth.

Electronic and dehydrogenation properties of TiB2 cluster-doped NaAlH4 (101) surface: A first-principle approach

The crystal structures, electronic and dehydrogenation properties of TiB2 cluster-doped NaAlH4 (101) surface have been investigated by the first-principles density functional theory method. In the TiB2 cluster-doped NaAlH4 (101) surface, a Ti-centered TiB2–Al2H8–AlH5–AlH3 complex is observed, and the AlH3 and (AlH5)2− units in the TiB2–Al2H8–AlH5–AlH3 favor the first-step decomposition reaction of NaAlH4. The calculated electronic properties show that B–Ti bonds are stronger than B–Al and Ti–H bonds, which demonstrates that TiB2 does not change its configuration in catalyzing the decomposition reaction of NaAlH4. The results of hydrogen desorption energies imply that the import of TiB2 makes the strength of Al–H bonds decreases. Therefore, the removal of H atoms, especially the removal of H atoms in the Ti–H–Al bonds is easier in the TiB2 cluster-doped NaAlH4 than in pure NaAlH4.

Interface actions between TiO2 and porous diatomite on the structure and photocatalytic activity of TiO2-diatomite

TiO2-diatomite photocatalysts were prepared by sol–gel process with various pre-modified diatomite. In order to obtain diatomite with different surface characteristics, two modification approaches including calcination and phosphoric acid treatment on the micro-structure of diatomite are introduced. The photocatalysts were characterized by XRD, XPS, nitrogen adsorption–desorption isotherms and micromorphology analysis. The results indicate that, compared with pure TiO2, the anatase-to-rutile phase transition temperature of TiO2 loaded on diatomite carrier is significantly increased to nearly 900°C, depending on the different pretreatment method of diatomite. The photocatalytic activities of different samples were evaluated by their degradation rate of methyl orange (MO) dye under UV and visible-light irradiation. The samples prepared by phosphoric acid pretreatment method exhibit the highest photocatalytic activity. After 90min of UV irradiation, about 90% of MO is decomposed by the best effective photocatalyst. And after 8h visible-light irradiation, nearly 60% of MO is decomposed by the same sample. Further mechanism investigation reveals that the H3PO4 pretreatment process can obviously change the surface features of diatomite carrier, cause the formation of Si–O–Ti bond, increase the binding strength between TiO2 and diatomite, restrain crystal growth of loaded TiO2, and thus form thermal-stable mesoporous structure at the granular spaces. It helps to build micro-, meso- and macro-porous hierarchical porous structure in TiO2-diatomite, and improves the charge and mass transfer efficiency during catalyzing process, resulting in the significantly increased photocatalytic activity of TiO2-diatomite pretreated by phosphoric acid.

Incorporation of Ti(III) into the AlPO4-5 framework by direct synthesis

This work focuses on the synthesis and characterization of a conceptually innovative series of TAPO materials, particularly centered in the AFI-structured TAPO-5. Unlike the conventional TAPOs, the so-called Ti(III)APO-5 are prepared by using Ti(III) sources. This strategy aims to avoid the presence of both Ti–O–Al and Ti–O–Ti bonds in TAPOs, undesired for catalytic purposes. The thermodynamic stability of this oxidation state of Ti in water and in the presence of air is low, but the preparation of the gel and the filling of the autoclaves under N2 atmosphere allowed Ti to maintain its 3+ oxidation state in a considerable proportion in the hydrothermally-crystallized solids. The materials were characterized by powder XRD, ICP chemical analysis, SEM, DR-UV–visible spectroscopy, TGA and 31P and 27Al MAS NMR. DR-UV–visible spectroscopy certified the presence of Ti(III) in both tetrahedral and octahedral environments in the as-made samples before being exposed to air, whereas 31P MAS NMR indicated the vicinity of Ti in the second coordination sphere of P in the already oxidized sample. Although once dried and calcined in air Ti(III) is entirely oxidized to Ti(IV), Ti(III)APO-5 materials present key singularities against conventional TAPO-5. Thus, apart from the presence of Ti(OP)4 environments, the charge transfer transition detected by DR-UV–vis appears at lower wavelength, whereas both TGA and 27Al NMR indicates a peculiar hydration of the as-prepared samples, which is unprecedented in conventional TAPO-5. Based on these characterization features, the possible nature of the Ti centers generated by this synthesis approach is discussed.

Ab initio study on magnetism at TiO2/SrTiO3 interface

Using density functional theory calculations, we have studied the electronic structure and magnetic properties of the TiO2/SrTiO3 interface with oxygen vacancy. We find that the oxygen vacancy at the interface may be responsible for the unexpected ferromagnetism in pristine anatase TiO2 film grown on SrTiO3 substrate. Structural relaxation has a profound impact on the local magnetic moment. After relaxation, the system can transform from a low spin state into a high spin state with the increasing Ti–Ti bond length. Isolated oxygen vacancy produces a magnetic moment of 0.36μB. The magnetic moment mainly comes from the d-orbitals of Ti atoms adjacent to the oxygen vacancy. We also find that the two oxygen vacancies at the interface are always coupled ferromagnetically.

Structural and Thermodynamics Properties of TiC1−x N x -TiO1−x N x Solid Solutions: X-ray Diffraction and First-Principles Approaches

The structural properties and mixing thermodynamic of TiC1−xNx and TiO1−xNx (0 ≤ x ≤ 1) solid solutions have been studied by X-ray diffraction method and first-principles calculations. The TiC1−xNx and TiO1−xNx compounds were synthesized via solid-state reaction and the analysis of XRD patterns show the properties of continuous solid solutions over the whole composition range. Thermodynamic analyses and structural stability studies were performed based on the mixing enthalpies and electronic structures. The mixing enthalpies of TiC1−xNx and TiO1−xNx can be fitted using a second-degree polynomial with the increasing of supercell. The first-principles calculations results reveal that the TiO1−xNx shows large number vacancies segregated in TiO-part. The charge redistributed around Ti vacancy constitutes the main contribution to the stabilization rather than the Ti–Ti bond across the O vacancy through analyzing the electron density difference plots and PDOS . These results provide theoretical basis for the development and application of the TiC1−xNx and TiO1−xNx solid solutions.

Progresses on Synthesis and Applications of Bis(cyclopentadieny)titanacycles

Titanacycles, containing two carbon metal bonds in the molecule, have emerged as a series of significant interme- diates in organic synthesis. The structural characteristics, preparation and synthetic applications of bis(cyclopentadienyl)titana- three, four, five, or six-membered rings have been summarized in the present review, in which the selective cleavage and reac- tivity of C—Ti bond in the titanacyle have been discussed.

Intense Red Photoluminescence Emission of Sol–Gel‐Derived Nanocrystalline Mg2TiO4 Thin Films

In this work, undoped Mg2TiO4 thin films were fabricated on p‐type Si(111) substrates by the sol–gel method, and the red photoluminescence (PL) of the films is introduced and discussed. According to the experimental results, the red emission appears when the films have been thermally treated at higher temperatures, which have a long range and well‐organized crystalline arrangement. Furthermore, to have better realization of the red emission mechanism of Mg2TiO4 films, the optical band gap of Mg2TiO4 (EgMg2TiO4) was estimated at ~3.7 eV; furthermore, 325 nm (corresponding energy, hν = 3.82 eV > EgMg2TiO4) and 633 nm (corresponding energy, hν = 1.96 eV < EgMg2TiO4) excited light sources were used to clarify the position of the defect levels. In addition, the influence of annealing atmospheres (O2, air, and vacuum) on the red emission of our samples is also discussed. A significant variety of red emissions can be found between these annealing conditions: the red emission can be effectively enhanced by O2 annealing, but weakened by vacuum annealing. Results reveal that the red emission of Mg2TiO4 thin films may be highly dependent on the completeness of the O–X–O (X = Mg, Ti) bonds.

Metal bonding strength in low‐temperature processed titanium using atomic force microscopy with single‐wall carbon nanotube tip

AbstractWe report the development of a Ti–Ti bonding process at a low bonding temperature below 200 °C using chemically surface‐activated Ti thin films and a reliable evaluation method for measuring the Ti–Ti bond strength by means of atomic force microscopy (AFM). Using Ti as an interlayer enables void‐free bonding because Ti exhibits fast diffusion and oxide solubility. On the other hand, wafer bonding is an important processing step for 3D circuit integration that requires a high reliability of the process. However, the reliability of bonding‐strength values obtained by employing conventional measurement devices is limited by comparably large measurement errors and restricted the availability of suitable sample material. In this study, the use of AFM to measure the bonding strength is proposed. The interfacial bonding properties depend on the Ti deposition parameters. A bonding temperature of 200 °C was found to be appropriate for the development of a low bonding temperature wafer‐bonding process. The pretreatment methods like plasma activation and chemical activation at 200 °C result in a Ti bonding strength of approximately 8.22 J/m2, sufficient for applications in 3D circuit integration. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Preparation and Characterization of Nano-TiO2 Loaded Bamboo-based Activated Carbon Fibers by H2O Activation

As the support for loading TiO2, bamboo-based activated carbon fibers (BACFs) were obtained from Phyllostachys pubescens Mazel after liquefaction using phenol, melt-spinning, curing carbonization, and H2O activation. TiO2/BACFs were prepared by the sol–gel method and characterized by SEM, XRD, FTIR, and XPS. Anatase TiO2 film with high photocatalytic activity was formed on the surface of BACFs, and the average crystallite size of the TiO2 film was 17 to 30 nm. The characteristic absorbance peaks of anatase TiO2 were observed at 1402 and 541 to 605 cm-1 on the infrared spectrum of TiO2/BACFs. The surface of TiO2/BACFs was mainly comprised of C–C, C–O, C=O, and Ti-O bonds. With increased calcination temperature, the contents of element Ti and Ti-O bonds of lattice oxygen on the surface of TiO2/BACFs increased and then decreased. The degradation rate of TiO2/BACFs for methylene blue (MB) solution reached more than 98% after 7 h of UV illumination.

In situ synthesis of ultrathin 2-D TiO2 with high energy facets on graphene oxide for enhancing photocatalytic activity

Two kinds of TiO2 with novel structures, interpenetrating anatase TiO2 tablets (IP-TiO2), and overlapping anatase TiO2 nanosheets (OL-TiO2) with exposed {001} facets, are synthesized. The graphene oxide (GO) supported ultrathin TiO2 nanosheets (OL-TiO2/GO) is also prepared by one-pot hydrothermal method. The microscopic feature, morphology, phase, and nitrogen adsorption–desorption isotherms are characterized. The performance of photocatalytic degradation of methyl blue is also measured. Compared with IP-TiO2, the OL-TiO2 with GO possess higher photocatalytic efficiency. The GO can improve the photocatalytic property by increasing specific surface area, accelerating the separation of electron–hole pairs, as well as extending the electron life. The growth process of TiO2 nanosheets on graphene oxide layers probably follows a step-growth mechanism with F− as morphology controlling agent. The steps on the surface can improve the photocatalytic activity further due to the increase of dangling bonds of 5-coordinated Ti (Ti5c) which are considered to be the active sites in the photocatalytic reaction.

Mesoporous microspheres composed of carbon-coated TiO2 nanocrystals with exposed {0 0 1} facets for improved visible light photocatalytic activity

Mesoporous TiO2 microspheres composed of carbon-coated anatase nanocrystals w ith exposed {001} facets (TiO2(001)/C) have been successfully synthesized by a one-pot hydrothermal strategy in the presence of glucose and hydrofluoric acid (HF). It is demonstrated that the presence of HF promotes the growth of anatase nanocrystal with {001} facet exposure, while glucose induces TiO2 {001} nanocrystals to assembly into mesoporous TiO2 microspheres, as well as acts as carbon source in the formation of carbonaceous layer deposited on the TiO2 grains via C–O–Ti bond. The TiO2(001)/C microspheres show an excellent visible-light driven photocatalytic performance for the degradation of methyl blue. These results provide insight into the preparation, assembly and modification of TiO2 nanocrystals with active facets for potential application in environment protection.

Influence of oxygen content on the mechanical properties of hexagonal Ti—First principles calculations

In this work we report results of ab initio modeling of structure stability, mechanical properties, lattice distortion and electronic structures of α-Ti as a function of concentration and positions of oxygen atoms. The heats of formation for all solutions were negative and in excellent agreement with experimental data. The single crystal elastic constants, elastic modulus anisotropy and polycrystalline Voigt bulk B and shear G moduli were calculated. Based on the values of B/G ratio, the effect of oxygen on Ti ductility was estimated with the conclusion that approximately 1at% O addition improves elastic and plastic properties. This can be explained by the effect of O concentration on the Ti–Ti bonds and the value of the c/a lattice parameter.

SYNTHESIS OF MESOPOROUS OF NyTi1–xCexO2–y STRUCTURES AND ITS VISIBLE LIGHT INDUCED PHOTOCATALYTIC PERFORMANCE

The present work was addressed to study the visible light induced performance as photocatalysts of mesoporous N y Ti 1–x Ce x O 2–y structures obtained under microwave irradiation. The titanium dioxide ( TiO 2) was doped with cerium and nitrogen in order to improve the quantum efficiency of the TiO 2 and to shift its adsorption spectra to the visible region. The prepared meso-powders were analyzed by means of X-ray diffraction (XRD), scanning Electron microscopy (SEM), infrared (IR) spectroscopy, transmission electronic microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The surface area was evaluated by means of the Brunauer-Emmett-Teller (BET) method and ultraviolet (UV)-visible diffuse reflectance measurements were performed in order to determine the band gap energy. In addition, the photocatalytic activity of the samples was evaluated by monitoring the photodegradation of methylene blue (MB) under UV and visible light energy irradiation. The results show that our methodology is an effective way for incorporating cerium and nitrogen into TiO 2 compound, which in turn, increases its photocatalytic activity. The diffuse reflectance analysis confirms that the absorption edge was shifted towards the visible region of the optical spectrum. The XRD diffraction patterns indicate homogeneous solid solutions in which prevails the anatase phase. It was observed a reduction in crystal size from 13.1 nm to 7.7 nm for N y Ti 0.98 Ce 0.02 O 2–y in comparison to TiO 2. The textural properties of the synthesized compounds were determined, by means of adsorption isotherms indicating the formation of mesoporous structures. IR spectra show characteristic vibration signals attributed to Ti–O–Ti bonds, as well as vibrations assigned to cerium and nitrogen bonds. The XPS analyses evidence the presence of Ce 3+/ Ce 4+ redox couple and Ti–N bonds. The photocatalityc efficiency was evaluated in the degradation of MB monitoring the absorbance change at 664 nm. The degradation of this compound was 91.4% using N y Ti 0.98 Ce 0.02 O 2–y as photocatalyst under UV energy in 90 min. Also 38.7% of MB degradation was achieved in 150 min under visible light radiation.

Scaffolds of magnetically active 3d metals in the valence electron controlled borides Ti9−xM2+xRu18B8 (M=Cr–Ni; x=0.5–1): Structutral, electronic and magnetic properties

Polycrystalline samples of the boride series Ti{sub 9−x}M{sub 2+x}Ru{sub 18}B{sub 8} (M=Cr, Co, Mn, Ni) including single crystals of Ti{sub 8}Co{sub 3}Ru{sub 18}B{sub 8} have been prepared by arc-melting the elements. The phases were characterized by powder X-ray diffraction (Rietveld refinement), single-crystal X-ray diffraction (for M=Co), and energy-dispersive X-ray (EDX) analysis. They are substitutional variants of the Zn{sub 11}Rh{sub 18}B{sub 8} structure type, space group P4/mbm (No. 127) and contain a “scaffold” structural unit (M-ladders interacting with M/Ti-chains) as well as isolated M/Ti-chains. According to DFT calculations, the Ru–X (X=B, Ti, Ti/M) bonding interactions are nearly constant throughout the series and responsible for the structural stability of these phases, whereas the M–M and Ru–M interactions vary significantly with varying valence electron count. Furthermore, density of states (DOS) analyses predict the phases with M=Mn and Ni to develop a total magnetic moment but not the M=Co phase. Susceptibility measurements confirm the Co phase to be paramagnetic and the Mn Phase orders ferrimagnetically below 120 K and thus develops a magnetic moment, as predicted. - Graphical abstract: The crystal structures of the new phases (M=Cr, Mn, Co, Ni) are confirmed by Rietveld refinement of powder diffraction data and single crystal X-ray diffractionmore » (for M=Co) to contain beside the M-ladder also M/Ti-chains. Similar to the series Ti{sub 9}M{sub 2}Ru{sub 18}B{sub 8}, the crystal structure of the new phases are mainly stabilized by the heteroatomic Ru–B and Ru–Ti bonds that remain nearly constant throughout the series, whereas the M-containing bonds vary significantly with varying valence electron count. An experimental finding confirmed and even extended by COHP bonding analyses. In addition, the DOS analyses of the M-elements reveal the development of magnetic moments for the M=Mn, Ni cases but not for M=Co. Indeed, Ti{sub 8}Co{sub 3}Ru{sub 18}B{sub 8} was found experimentally to be a paramagnet and ferrimagnetic ordering below 120 K is found for M=Mn. Highlights: • Synthesis of the valence electron controlled borides Ti{sub 9−x}M{sub 2+x}Ru{sub 18}B{sub 8} (M=Cr–Ni). • Prediction of magnetic properties of Ti{sub 9−x}M{sub 2+x}Ru{sub 18}B{sub 8}. • Ferrimagnetic ordering found in Ti{sub 8}M{sub 3}Ru{sub 18}B{sub 8}. • Chemical bonding studied by density functional theory.« less

Enhanced Photocatalytic Activity of Chemically Bonded TiO2/Graphene Composites Based on the Effective Interfacial Charge Transfer through the C–Ti Bond

Recently, graphene-based semiconductor photocatalysts have attracted more attention because of their enhanced photocatalytic activity caused by interfacial charge transfer (IFCT). However, the effect of a chemical bond is rarely involved for the IFCT. In this work, TiO2/graphene composites with a chemically bonded interface were prepared by a facile solvothermal method using tetrabutyl orthotitanate (TBOT) as the Ti source. The chemically bonded TiO2/graphene composites effectively enhanced their photocatalytic activity in photodegradation of formaldehyde in air, and the graphene content exhibited an obvious influence on the photocatalytic activity. The prepared composite with 2.5 wt % graphene (G2.5-TiO2) showed the highest photocatalytic activity, exceeding that of Degussa P25, as-prepared pure TiO2 nanoparticles, and the mechanically mixed TiO2/graphene (2.5 wt %) composite by a factor of 1.5, 2.6, and 2.3, respectively. The enhancement in the photocatalytic activity was attributed to the synergetic effect between graphene and TiO2 nanoparticles. Other than the graphene as an excellent electron acceptor and transporter, the enhanced photocatalytic activity was caused by IFCT through a C–Ti bond, which markedly decreased the recombination of electron–hole pairs and increased the number of holes participating in the photooxidation process, confirmed by XPS analysis, the gaseous phase transient photocurrent response, electrochemical impedance spectroscopy, and photoluminescence spectra. This work about effective IFCT through a chemically bonded interface can provide new insights for directing the design of new heterogeneous photocatalysts, which can be applied in environmental protection, water splitting, and photoelectrochemical conversion.