Doped TiO2 Nanorods Research Articles

Preparation of TiO2 Nanorods Composites Doped with Silver Nanoparticles and Their Bactericidal Properties under Visible Light Irradiation

AbstractTiO2 is a widely used photocatalytic antibacterial material and shows good antibacterial properties under ultraviolet light. However, its antibacterial efficacy under visible light still remains limited. To develop low‐cost and biocompatible antibacterial materials, this article provides a facile method for in situ preparation of a trace amount of silver (Ag) doped TiO2 nanorods (TiO2NR–Ag) composites, which cannot only enhance the antibacterial properties under visible light, but also has good biocompatibility. Two representative epidemic strains, Staphylococcus aureus and Escherichia coli, are selected for analysis of the antibacterial properties of the obtained TiO2NR–Ag composite nanoparticles. The results demonstrate that even if the Ag doping level is as low as 2.5 × 10−4 wt% (i.e., Ag/TiO2 = 2.50 µg g−1), the TiO2NR–Ag composite nanoparticle coatings are transparent and exhibit exceptional antibacterial properties, which is attributed to synergistic enhanced bactericidal effect of the active substances generated by TiO2NR–Ag under visible light. The cytotoxicity and hemolysis rate results indicate that TiO2NR–Ag composite exhibit excellent biocompatibility. This study effectively improves the antibacterial effect of TiO2 photocatalytic nanomaterials while maintaining their biocompatibility, and the prepared TiO2NR–Ag composite nanoparticles can be applied in various fields such as window glasses, medical device surfaces, furniture surfaces, and optical devices, etc.

Iron-doped TiO2 nanorods coupled with naphthalenediimide (NDI) and 3,4-ethylenedioxythiophene (EDOT)-based donor-acceptor-donor type small organic molecule for visible-light water oxidation

The present article reports an inorganic/organic type of nano-heterostructure (NHs)—Fe-TiO2/NDIHEDOT) as a photoanode with good photoelectrochemical (PEC) water splitting efficiency driven by visible light. This heterostructured photoanode consists of iron (Fe)-doped TiO2 nanorods (NRs) as inorganic part and a donor-acceptor-donor (D-A-D) type organic molecule—N,N-bis(2-hexyl)-2,6-(3,4-ethylenedioxythiophene)-1,4,5,8-naphthalenediimide (NDIHEDOT)—as an organic part. The 10% iron (Fe)-doped TiO2 (Fe–TiO2) nanorods (NRs) were grown hydrothermally on fluorine-doped tin oxide (FTO) substrates. The consequence of heterostructure formation on optical and PEC properties of the Fe–TiO2 and Fe–TiO2/NDIHEDOT photoanode were explored through PEC responses under visible light irradiation. The result shows that photocurrent densities of Fe–TiO2 and Fe–TiO2/NDIHEDOT photoanodes measured at 1 V vs. Ag/AgCl are 0.25 μA cm–2 and 0.49 μA cm–2, respectively, increase in the photocurrent density by Fe–TiO2/NDIHEDOT concerning photocurrent density shown by Fe–TiO2. The hybrid photoanode also exhibits high photostability and faradaic efficiency for water splitting. This work paves the way to develop a new inorganic/organic heterostructure for high-performance water splitting.

Structural, luminescence emission and photocatalytic properties of pure and Dy3+ doped anatase TiO2 nanorods

White light emitting and highly efficient photocatalytic active dual functional 1%Dy3+ ions doped TiO2 (DTH) nanorods (NRs) have been prepared by the simple hydrothermal method at different operating temperatures. The obtained samples were further subjected to different annealing temperatures. X-ray diffraction results revealed the polycrystalline nature and having a tetragonal crystal structure with anatase phase. DTH NRs show the declined crystallite size with doping of Dy (III) ions and increased with annealing temperature. SEM pictures of pure TiO2, and DTH NRs endorsed the particles with rod like structure. The IR bands at 669 cm−1 and 485 cm−1 are assigned to the Ti–O–Ti bending and Ti–O stretching vibrations of TiO2. The DTH NRs have high refractive indices and narrow band gap energies. At ultraviolet (385 nm) excitation, the DTH NRs display visible photoluminescence (PL) emission and exhibit the suitable color coordinates for white light emission. The DTH NRs exhibited enhanced visible light-derived photocatalytic activity (PCA) for the decolorization of methylene blue (MB), methyl orange (MO).

Nickel-doped TiO2 and thiophene-naphthalenediimide copolymer based inorganic/organic nano-heterostructure for the enhanced photoelectrochemical urea oxidation reaction

To overcome the global challenges of energy crises and environmental threats, urea oxidation is a hopeful route to utilize urea-rich wastewater as an energy source for hydrogen production. Herein, we report an inorganic/organic type of nano-heterostructure (NHs–Ni-TiO2/p-NDIHBT) as a photoanode with excellent urea oxidation efficiency driven by visible light. This heterostructured photoanode consists of nickel (Ni)-doped TiO2 nanorods (NRs) arrays as an inorganic part and a D-A-D type organic polymer i.e p-NDIHBT as an organic part. The as-prepared photoanode was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The morphological studies of TEM confirm the coating of p-NDIHBT on Ni–TiO2 NPs (∼1 μm). The consequence of heterostructure formation on optical and photoelectrochemical (PEC) properties of photoanode were explored through photoelectrochemical responses under visible light irradiation. The photoelectrochemical activity of Ni–TiO2 and Ni–TiO2/p-NDIHBT photoanode from linear sweep voltammetry (LSV) shows the ultrahigh photocurrent density of 0.36 mA/cm2 and 2.21 mA/cm2, respectively measured at 1.965 VRHE. Electrochemical impedance spectroscopy (EIS) of both photoanodes shows a highly sensitive nature toward the urea oxidation reaction. The hybrid photoanode also exhibits high photostability, good solar-to-hydrogen conversion efficiency, and high faradaic efficiency for urea oxidation.

Fluorine enhanced nucleophilicity of TiO2 nanorod arrays: A general approach for dendrite-free anodes towards high-performance metal batteries

The effective depress dendrite growth of metal anodes (such as lithium (Li), sodium (Na), potassium (K) and zinc (Zn)) have been widely considered for metal-based batteries. However, regarding varied metal batteries accompanied with different chemical environment (e.g, solvent effect, electronegativity and ion radius), it is a huge challenge to develop a general approach for construction of dendrite-free metal anodes. Herein, we report a strategy to induce Li, Na, K and Zn homogenous nucleation by ‘F’ heteroatom doped TiO2 nanorod arrays. Theoretical calculations reveal that Li+, Zn2+, Na+ and K+ can be strong adhered to electronegative F heteroatom, giving rise to an enhanced nucleophilicity. Consequently, the CC/TiO2-F based Li, Zn, Na and K symmetric cells exhibit remarkably enhanced long service life of 1100 h, 530 h, 720 h and 510 h at 2 mA cm–2 with a low voltage hysteresis, which is 4.4, 26.5, 24.1 and 25.5 times higher than that of bare CC based anodes. Moreover, the CC/TiO2-F dendrite-free anode allows for construction of Li-LiFePO4/Sulfur full-batteries with a high capacity of 152 mA h g–1 and 1070 mA h g–1, respectively. Additionally, the assembled Li–S pouch cells also realized high stable capacity with high flexibility. This work provides an important strategy to develop general method for dendrite-free metal anodes towards high-performance metal batteries.

Influence of Tin Doped TiO2 Nanorods on Dye Sensitized Solar Cells.

The one-step hydrothermal method was used to synthesize Sn-doped TiO2 (Sn-TiO2) thin films, in which the variation in Sn content ranged from 0 to 7-wt % and, further, its influence on the performance of a dye-sensitized solar cell (DSSC) photoanode was studied. The deposited samples were analyzed by X-ray diffraction (XRD) and Raman spectroscopy, which confirmed the existence of the rutile phase of the synthesized samples with crystallite size ranges in between 20.1 to 22.3 nm. In addition, the bare and Sn-TiO2 thin films showed nanorod morphology. A reduction in the optical band gap from 2.78 to 2.62 eV was observed with increasing Sn content. The X-ray photoelectron spectroscopy (XPS) analysis confirmed Sn4+ was successfully replaced at the Ti4+ site. The 3-wt % Sn-TiO2 based DSSC showed the optimum efficiency of 4.01%, which was superior to 0.87% of bare and other doping concentrations of Sn-TiO2 based DSSCs. The present work reflects Sn-TiO2 as an advancing material with excellent capabilities, which can be used in photovoltaic energy conversion devices.

Influence of Ce doping on morphology, crystallinity and photoelectrochemical charge transfer characteristics of TiO2 nanorod arrays grown on conductive glass substrate

Doping of rare earth elements into TiO2 nanorods allows tailoring of the electrical and optical properties, which in turn, modifies the photoelectrochemical behavior. This study presents hydrothermal synthesis of Ce doped TiO2 nanorod arrays on FTO coated glass substrate. XRD pattern confirms the rutile phase in both pristine and Ce doped samples; however, Ce doping results in an enhancement of peak intensity compared to that of pristine TiO2 nanorods. FESEM shows a significant change in the growth rate and the surface morphology of the nanorods with an apparent clustering of grains caused by Ce doping. HRTEM of the Ce doped sample shows regions of different crystallographic orientations. EDX data also confirms a uniform presence of Ce in the TiO2 nanorods. The optical absorption spectra show a slight redshift in the band gap from 3.08 eV for the pristine sample to 3.02 eV for the Ce doped nanorods that is attributed to the presence of shallow energy states within the band gap. Photoelectrochemical measurements indicate a negative shift in the flat-band potential from −0.80 V (for pristine) to −0.94 V (for Ce doped nanorods), resulting in a lower charge transfer resistance at the semiconductor/electrolyte interface, which is also corroborated by impedance spectroscopy. Although there is a reduction in the charge density, Ce doping facilitates better interfacial charge transport at the semiconductor/electrolyte interface.

A Facile Synthesis of Anatase Ni2+ Doped TiO2 Nanorods with Highly Improved Visible-Light Photocatalytic Performance

Objective: Herein, we reported a simple and effective approach to synthesis of pure and Ni2+ doped TiO2 nanorods by a photon-induced method (PIM) followed by calcination at 850 ºC in air atmosphere. Methods: Basically, the PIM was used to tuning the properties of as-prepared TiO2 photocatalyst. These obtained samples were further characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and UV-visible diffuse reflectance spectroscopy (UV-vis DRS) analysis. XRD results reveals that the both pure TiO2 and Ni doped TiO2 nanorods has anatase phase up to 850°C. Results: The HR-TEM analysis indicates that doping Ni is favourable to the formation of rod-like TiO2 sample. Also, the observed photocatalytic results demonstrates that the Ni doped TiO2 can be achieved a complete degradation of methylene blue (MB) within 30 min under direct sunlight irradiation as compared to pure TiO2. Conclusion: Therefore, this work revealing the doped Ni has a good potential to modification of TiO2 with an excellent photocatalytic activity for water treatment applications.

Structural Properties of Fe Doped TiO2 Nanorods Prepared by Low Cost Hydrothermal Method

In this work, titanium dioxide films were deposited on fluorine tin oxide (FTO)-glass substrates using Hydrothermal method. A low-cost homemade autoclave was used to fabricate pure TiO2 and Fe-doped (0.1%, 0.3%, 0.5%, 0.7% and 1.5%) films. X-ray diffraction patterns showed that the predominant phase is rutile (R-TiO2) with peaks at (101), (002) and (112). The Field Emission Scanning Electron Microscope (FESEM) top and cross-sectional images indicated that the films have vertically aligned nanorods structures with parallelogram cross-sectional areas and aspect ratio range (9.2-15.3).

An economic approach to produce iron doped TiO2 nanorods from ilmenite for photocatalytic applications

Titanium dioxide (TiO2) is one of the most promising photocatalytic materials, but its practical applications are always limited since it could only be excited in the UV range and has low photocatalytic efficiency due to its wide band gap and fast recombination rate. To overcome these problems, transition metals have been used as dopants to improve the photocatalytic performance of titanium dioxide. However, previous investigations have shown that doping by hydrothermal, sol-gel or other synthetic pathways in the catalyst synthesis are difficult to scale-up for mass production. In this work, ilmenite (FeTiO3), the most abundant titanium mineral, was used as the raw material to produce iron-doped titanium oxide nanorods by an economic acid treatment approach. Compared with commercial titanium oxide nanomaterials, the photocatalytic performance for Rhodamine B (RHB) degradation of as-prepared materials were significantly improved and could be activated by visible light irradiation. The results from characterization also show the band gap and recombination rate are modified by the iron dopant. This work provides a possible method which can significantly reduce the cost for producing iron doped TiO2 in high yield for photocatalytic applications.

Enhanced photostability of anthocyanin dye for increased efficiency in natural dye sensitized solar cells

To improve the performance of anthocyanin based dye sensitized solar cells (DSSC), it is essential to passivate the photocatalytic activity (PCA) induced by photoelectrode that activates dye degradation. In the present work, red color astaxanthin pigments extracted from green color Haematococcus Pluvialis is used as a cosensitizer with anthocyanins extracted from rose petals to scavenge the free radicals (antioxidant) generated as a result of PCA, thereby minimizing photodegradation of anthocyanins by 60 %. Herein we have hydrothermally prepared rutile TiO2 nanostructures that appear as distorted TiO2 nanospheres (NS) and the cosensitizer ratio is optimized for maximum astaxanthin efficacy. The least molecular interaction of astaxanthin with anthocyanins as measured from fluorescence life time studies suggest that astaxanthin encircle anthocyanins as a shield against photodegradation. The structure of DSSC with Fluorine doped Tin Oxide/TiO2 NS/algal buffer layer / cosensitized dye (Rose:Astaxanthin - 70 :30) /iodine-iodide/ Pt /glass shows a higher efficiency of 2.82 %. Relatively higher efficiency of 3.31 % was also observed for DSSC with 3% Ca doped TiO2 nanorods as photoelectrode using cosensitized dye as sensitizer due to the passivation of PCA by the astaxanthins and the photoelectrode by itself.

Toxic-free surface level sulphur doped 1D Ti-Ox-Sy nanorods for superstrate heterojunction CZTS thin-film solar cells

Surface level sulphur (S) doped TiO2 nanorods (S-TNRs) were fabricated via toxic-free novel three-step processes such as low-temperature hydrothermal method followed by thermal evaporation (S layer) and post-annealing (350 °C, 450 °C and 550 °C) techniques. Present work focuses on the comprehensive studies of surface level doping, structure, morphology and compositional properties of different temperature annealed S-TNRs for CZTS thin-film (Au/CZTS/S-TNRs/TNRs/FTO) solar cells. The oxidation states of incorporated S atoms in the TiO2 matrix were identified from X-ray photoelector spectroscopy (XPS) analysis. A reduction in bandgap for 350 °C annealed S-TNRs film was observed from UV-Vis spectroscopy. The electrical characteristics showed the fabricated solar cells strongly depend on the S-TNRs annealing temperature. Proposed technique would be useful in effective and controlled (surface level) doping of S atoms into any desired nanostructured metal oxides for optoelectronic applications and, further useful in fabricating cadmium (Cd) free buffer layer in chalcogenide solar cells.

A Facile and Controllable Vapor-Phase Hydrothermal Approach to Anionic S2--doped TiO2 Nanorod Arrays with Enhanced Photoelectrochemical and Photocatalytic Activity.

Anionic S2−-doped TiO2 nanorod arrays (S2−-TiO2) were synthesized by a facile and controllable vapor-phase hydrothermal (VPH) approach based on the sulfur source of H2S gas. After the VPH treatment of TiO2 nanorod arrays (TNA), the isolated O2− species replaces the S2− ion in TiO2 (TiO2−xSx). The structural, morphological, optical, compositional, photocatalytic and photoelectrochemical (PEC) properties of the obtained samples were investigated in detail. It was found that S2−-TiO2 can enhance the separation rate of electron–hole pairs, improve the absorption of visible light, and augment the photocatalytic and photoelectrochemical properties. Anionic S2− doping can significantly adjust the absorption cut-off wavelength (409.5–542.5 nm) and shorten the bandgap (3.05-2.29 eV) of TNA. For the degradation of methylene orange (MO) under mercury lamp light, the 0.24 At%S2−-TiO2 (0.24S2−-TiO2) sample exhibited the best photogradation efficiency of 73% in 180 min compared to bare TiO2 (46%). The 0.24S2−-TiO2 showed the highest photocurrent of 10.6 μA/cm2, which was 1.73 times higher than that of bare TiO2 (6.1μA/cm2). The results confirmed that the visible light absorption, photocurrent and photocatalytic activity optimization of TNA are closely related not only to anionic S2−-doped but also different ratios of anionic S2−-doped. It is noteworthy that the VPH approach is very promising for applications in low cost and highly efficient ion doping into nanomaterials for energy devices.

Inverted pyramid Er3+ and Yb3+ Co-doped TiO2 nanorod arrays based perovskite solar cell: Infrared response and improved current density

In this study, a Yb3+, Er3+ co-doped TiO2 inverted pyramid nanorod (NR) array and a compact TiO2 film are simultaneously fabricated as the mesoporous support layer and electron-blocking layer, respectively, by a one-pot hydrothermal method. The scanning electron microscopy results show that the incorporation of Er3+ and Yb3+ causes changes not only in the growth rate of the NRs, but also in the TiO2 NR morphology. The Er3+, Yb3+ co-doped TiO2 NRs exhibit an inverted pyramidal morphology, which is beneficial for perovskite permeation and light utilization. Notably, the Er3+, Yb3+ co-doping causes changes in the band gap of TiO2 and leads to 25% increase in the current density. The electrochemical impedance spectroscopy results show that the device based on the doped TiO2 NRs has a higher recombination resistance and a lower transfer resistance than those of the undoped device, and thereby, the doped device exhibits a lower electron recombination rate. In addition, the upconversion Er and Yb co-doped device exhibits 25% higher current density and 17% higher photon-to-electron conversion efficiency, as revealed by the J-V test results. Moreover, the optimized efficiency of the TiO2 NR array-based perovskite solar cell is determined to be 10.02%. Furthermore, the Er and Yb co-doped device exhibits a near-infrared response, an efficiency of 0.1% is achieved under infrared light (800–1100 nm) irradiation. This upconversion material can widen the photovoltaic responses of solar cells into the near-infrared region and improve the utilization of sunlight.

Niobium doped TiO2 nanorod arrays as efficient electron transport materials in photovoltaic

One-dimensional (1-D) rutile TiO2 nanorod arrays (NRAs) synthesized by a hydrothermal method suffer from low electrical conductivity and large amounts of surface defects, hindering their further applications. Nb doping is thus introduced to modify their electronic properties. Results indicate that light Nb doping reduces rod nanosizes, increases electron concentrations, decreases surface defective oxides and lowers conduction band of the TiO2 NRAs, while heavy doping induces transformations of morphologies and crystalline orientations as well as occurrences of compositional deviations and low oxidative states of Ti3+. After 0.1 mol% and 1 mol% Nb incorporations, device efficiencies are substantially improved by ~16% and ~33% for the model perovskite and dye-sensitized solar cells, respectively, which are ascribed to reduced recombination at the perovskite/TiO2 interfaces (e.g. charge lifetime increasing from 62 μs to 107 μs) and improved electron transport through the photoanode of TiO2 NRAs (e.g. electron diffusion length increasing from ~14 μm to ~50 μm). Our study verifies that Nb doped 1-D TiO2 NRAs are versatile electron transporting materials in different kinds of emerging solar cells, and are also potential for other fields including photocatalysis, sensors and batteries etc.

Sn4+ doping combined with hydrogen treatment for CdS/TiO2 photoelectrodes: An efficient strategy to improve quantum dots loading and charge transport for high photoelectrochemical performance

We demonstrate that Sn4+ doping and hydrogen treatment can be used as effective strategies to fundamentally improve the loading of CdS quantum-dots per-unit-area and the charge transport of TiO2 nanorods. By tuning doping concentration, the Sn4+ doped TiO2 nanorods which are prepared by one-pot hydrothermal method enhance light absorption, decrease electron transport resistance, then improve photon-to-charge conversion owing to the generation of doping energy level and mixed-cation composition of SnxTi1-xO2. Moreover, after hydrogen treatment at various temperatures, many oxygen vacancies and hydroxyl groups are formed on the surface of SnxTi1-xO2 nanorods, which have broadened light absorption to visible region and facilitated charge separation and transport, thus improving the photoelectrochemical properties. Remarkably, the surface active center density of TiO2 nanorods increases arising from Sn4+ doping and hydrogen treatment, which is beneficial to sensitize more uniform and dense CdS quantum-dots. Additionally, the Sn4+ doped and hydrogen treated CdS/TiO2 photoelectrodes show the maximum photocurrent density of 7.72 mA cm−2 at 0 V versus Ag/AgCl, which is 15.8 and 2.3 times higher than that of conventional TiO2 and CdS/TiO2 photoelectrodes, respectively, due to the enhanced optical absorption, increased heterojunction areas and superior charge transport properties, demonstrating their promising potential in various solar-energy driven applications.

Investigations on the photo catalytic activity of calcium doped TiO2 photo electrode for enhanced efficiency of anthocyanins based dye sensitized solar cells

The rich photo catalytic activity (PCA) of TiO2 deteriorates the photovoltaic performance of natural dye sensitized solar cells (DSSC) on irradiation. To improve the stability of natural dye in DSSC, the PCA of TiO2 must be passivated or reduced, without affecting the electron transfer kinetics. UV filters can be employed to avoid the direct band gap excitation in TiO2. But the blocking of photons in UV region decreases the Incident Photon to current Conversion Efficiency (IPCE) of the solar cell. Taking this factor into consideration, virgin and calcium (1%, 2%, 3%, 4% and 5%) doped TiO2 photo electrodes were grown by one step hydrothermal method on Fluorine doped Tin Oxide (FTO) substrates. The structural, morphological and optical properties of Ca doped nanorods passivate the free electrons on the TiO2 surface, thereby minimizing the PCA in the film. The 3% Ca doped TiO2 nanorods exhibited higher resistance to PCA when compared undoped TiO2 photo electrode. This increased the photovoltaic conversion efficiency of rose dye sensitized DSSC to 2.32%.

Visible-light-driven photoelectrochemical water oxidation with Al doped TiO2 nanorod arrays

Doping TiO2 with impurity elements is a common strategy to improve its photoelectrochemical water splitting performance, however, it is still challenging to unambiguously illustrate its fundamental effects. In this work, Al doped TiO2 nanorod arrays are grown hydrothermally on fluorine-doped tin oxide substrates and acted as an example system to study the effects of acceptor-type dopant on the photoelectrochemical water oxidation behavior of n-type TiO2, which usually is benefit from donor doping. A strategy that introducing hole scavenger into the electrolyte confirms that the diffusion-controlled charge-transport is the rate-determining step of the photoelectrochemical process. Electronic structure information extracted from electrochemical impedance spectroscopy verifies that Al ions as acceptor compensate for the n-type carrier in the TiO2 and result in the decrease of the donor density, however, the electrochemical impedance measurements also confirm that the charge transport resistance of TiO2 is dramatically decreased after Al doping, which actually plays the decisive role and thereby leading to the significantly enhanced photoelectrochemical water oxidation performance. Such exploration presented in this work is envisioned to provide valuable reference for deep understanding the effects of doping on improving the photocatalytic properties of oxide semiconductors and thus it is helpful for designing and preparing other advanced semiconductor photoelectrodes.

Hierarchical Ta-Doped TiO₂ Nanorod Arrays with Improved Charge Separation for Photoelectrochemical Water Oxidation under FTO Side Illumination.

TiO2 is one of the most attractive semiconductors for use as a photoanode for photoelectrochemical (PEC) water oxidation. However, the large-scale application of TiO2 photoanodes is restricted due to a short hole diffusion length and low electron mobility, which can be addressed by metal doping and surface decorating. In this paper we report the successful synthesis of hierarchical Ta doped TiO2 nanorod arrays, with nanoparticles on the top (Ta:TiO2), on F-doped tin oxide (FTO) glass by a hydrothermal method, and its application as photoanodes for photoelectrochemical water oxidation. It has been found that the incorporation of Ta5+ in the TiO2 lattice can decrease the diameter of surface TiO2 nanoparticles. Ta:TiO2-140, obtained with a moderate Ta concentration, yields a photocurrent of ∼1.36 mA cm−2 at 1.23 V vs. a reversible hydrogen electrode (RHE) under FTO side illumination. The large photocurrent is attributed to the large interface area of the surface TiO2 nanoparticles and the good electron conductivity due to Ta doping. Besides, the electron trap-free model illustrates that Ta:TiO2 affords higher transport speed and lower electron resistance when under FTO side illumination.

Effect of nitrogen doping on the photocatalytic activity and hydrophobic property of rutile TiO2 nanorods array

Pure titanium dioxide (TiO2) and nitrogen (N)–doped TiO2 nanorods array were prepared using polished Ti substrates and hydrothermal synthesis method. Prepared nanorods films were characterized by different techniques including X‐ray diffractometer (XRD), field‐emission scanning electron microscope, Fourier‐transform infrared spectroscopy, and XPS. The photocatalytic activities of both prepared films were evaluated by their capacity to degrade methylene blue (MB) in solution, and an attempt to associate it with their surface wetting properties is achieved. The XRD results showed that the prepared TiO2 is of rutile phase. Furthermore, the 3%N‐doped TiO2 nanorods films show similar high crystallinity and photocatalytic activity compared with prepared films of TiO2 rutile phase. Additionally, their surface wetting properties were studied and showed hydrophobic behavior with contact angle higher than 120°. The hydrophobicity of 3%N‐doped TiO2 nanorod films is shown to be enhanced because of TiO2 nanorods diameter decreasing. Additionally, the results clearly show that the prepared 3%N‐doped TiO2 nanorods films exhibit both higher hydrophobicity and the best photocatalytic activity toward the degradation of MB under visible light irradiation.