TiO2 Nanowires Research Articles

Synchronously nucleated inducing deposition of Zn2+ and homogenized electric field endowed by 3D porous host for dendrite-free Zn metal anodes

Aqueous rechargeable Zn-metal batteries have great potential in the field of energy storage owing to high theoretical capacity, low electrochemical potential, low cost, and good safety performance of the Zn anodes. However, Zn anode has a series of problems such as dendrite growth, surface passivation and corrosion, which limits its further development. To address these issues, a new zinc anode with a 3D porous host compounded with TiO2 nanowire arrays (NWAs) decorated with rGO and CNTs (TGC) was constructed. Density functional theory result demonstrates that the TiO2 exhibits superior binding energies of zinc, as the super-zincophilic nucleation sites, which can be conducive to a uniform deposition of the zinc and give an effective guidance to construct 3D novel dendrite-free Zn metal anodes. The 3D porous conductive network formed by rGO and CNTs homogenized the electric field and alleviated the volume expansion during the cycle. As expected, the TGC host guarantees the steady Zn plating/stripping with a long-term stability over 3000 h at the current density of 1 mA cm−2. As a validation, a Zn@TGC//MnO2 full cell shows long lifespan over 1000 cycles at 1.0 A g−1.

Integration of fluorescence and MALDI imaging for microfluidic chip-based screening of potential thrombin inhibitors from natural products

The microfluidic technology provides an ideal platform for in situ screening of enzyme inhibitors and activators from natural products. This work described a surface-modified ITO glass-PDMS hybrid microfluidic chip for evaluating thrombin interaction with its potential inhibitors by fluorescence imaging and matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI). The fluorescence-labeled substrate was immobilized on a conductive ITO glass slide coated with gold nanoparticles/thiol-β-cyclodextrin modified TiO2 nanowires (Au-β-CD@TiO2 NWs) via Au–S bonds. A PDMS microchannel plate was placed on top of the modified ITO slide. The premixed solutions of thrombin and candidate thrombin inhibitors were infused into the microchannels to form a microreactor environment. The enzymatic reaction was rapidly monitored by fluorescence microscopy, and MALDI MS was used to validate and quantify the enzymatic hydrolysate of thrombin to determine the enzyme kinetic process and inhibitory activities of selected flavonoids. The fluorescence and MALDI MS results showed that luteolin, cynaroside, and baicalin have good thrombin inhibitory activity and their half-maximal inhibitory concentrations (IC50) were below 30 μM. The integration of fluorescence imaging and MALDI MSI for in situ monitoring and quantifying the enzymatic reaction in a microfluidic chip is capable of rapid and accurate screening of thrombin inhibitors from natural products.

Catalytic CO2 hydrogenation to produce methane over NiO/TiO2 composite: Effect of TiO2 structure

In this study, TiO2 was morphologically engineered into three distinct structures, namely three-dimensional microparticles (MPs), zero-dimensional nanoparticles (NPs) and one-dimensional nanowires (NWs) to examine the effect of structure on CO2 methanation. Firstly, thermodynamic analysis was conducted, whereby it was observed that CH4 production is favoured at low temperature. Higher temperature will cause the CH4 selectivity to drop, in turn increasing the formation of other side products such as CO, C2H6 and solid coke. Then, Ni loaded on three different TiO2 supports, namely 3D TiO2 microparticles (MPs), 0D nanoparticles (NPs) and 1D nanowires (NWs), were prepared. It was noticed that the NPs have the smallest support particle size, followed by NWs and MPs. Despite TiO2 NWs having a larger particle size than NPs, the 15% Ni/TiO2 NWs boasted a higher surface area, smaller NiO crystalline and particle size, which resulted in an augmented NiO dispersion. Superior CO2 methanation performance with CO2 conversion, CH4 yield and selectivity of 88.44%, 87.53% and 98.97%, respectively was achieved over 15% Ni/TiO2 NWs. The stability of the TiO2 NWs counterpart over a 40 hours reaction time was the best among the three samples. Spent catalyst analysis also indicated that 15% Ni/TiO2 NWs are highly resistant to catalyst deactivation and coke formation. The prolonged durability was attributed to the 1D wire-like structure, which promoted a higher dispersion of active sites, facilitating an intimate contact between catalyst and reactants. The ameliorated dispersion also mitigates catalyst deactivation via sintering and coke formation. The findings elucidated that the morphology of the catalyst is more influential in enhancing the hydrogenation reaction than the support size.

Novel physical sunscreen from one-dimensional TiO[formula omitted] nanowire: Synthesis, characterization and the effects of morphologies and particle size for use as a physical sunscreen

The performance of the one-dimensional (1D) morphology as an inorganic UV filter for sunscreens of titanium dioxide (TiO2) was evaluated in this research. The 1D TiO2 nanowires were prepared using solid TiO2 and 10 M NaOH as precursors via a modified hydrothermal method, followed by calcination at 400–900°C for 5 h. The influences of TiO2 loading, hydrothermal time and calcination temperature were studied on the morphologies of the as-prepared samples. The morphologies of the TiO2 nanowires were investigated using SEM and TEM techniques. The results found all the variables directly affected the particle size and shape of the TiO2 nanowires. The hydrothermal synthesis conditions using a TiO2 loading of 0.2 g at 220°C for 24 h (HTiO2) resulted in a particle size that was the longest and narrowest in length and diameter, respectively. The first product from the hydrothermal synthesis is H2Ti3O7, which can transform into TiO2(B) (TiO2@400), anatase (TiO2@700) and rutile (TiO2@900) by calcination at 400, 700 and 900 °C, respectively. The calcined samples were selected for a porcine skin penetration study. The 1D morphology particles were localized on the stratum corneum of the skin, while the comparison spherical particle penetrated the deeper layer. From the SPF test, the highest SPF is TiO2 anatase.

Surface metal ion doped TiO2 nanowire arrays by low energy ion implantation for enhanced photoelectrochemical performance

Various metal ions, including Mg, Co, Nb, and W, were chfosen for ion implantation to modify TiO2 nanowire arrays. The introduction of metal ions was confirmed by both simulations and transmission electron microscopy (TEM) morphology characterization. A doped TiO2 shell on the surface was formed by the ion implantation process. Furthermore, the unbonded metal W was found in the doped TiO2 nanowires. The XPS results implied a special mechanism of heavy ions chosen for low-energy ion implantation. The presence of non-bonded metal restricted water splitting ability evidently. PEC results provided brief evidence that Nb doped TiO2 nanowire arrays is a promising choice with a 60% improvement in current density. The charge transfer resistance and the flat band potential are more benefit to water splitting than other doped metal ions. The theoretical calculation also supported efficient band gap narrowing of TiO2 caused by Nb dopant.

Highly Efficient Visible-Blind Ultraviolet Photodetector Based on Scalably Produced Titanium Dioxide Nanowire Arrays.

Here, we report a novel, feasible, and cost-effective method for the preparation of one-dimensional TiO2 nanowire arrays using a super-aligned carbon nanotube film as a template. Pure-anatase-phase TiO2 nanowires were scalably prepared in a suspended manner, and a high-performance ultraviolet (UV) photodetector was realized on a flexible substrate. The large surface area and one-dimensional nanostructure of the TiO2 nanowire array led to a high detectivity (1.35 × 1016 Jones) and an ultrahigh photo gain (2.6 × 104), respectively. A high photoresponsivity of 7.7 × 103 A/W was achieved under 7 μW/cm2 UV (λ = 365 nm) illumination at a 10 V bias voltage, which is much higher than those of commercial UV photodetectors. Additionally, by taking advantage of its anisotropic geometry, we found the TiO2 nanowire array showed polarized photodetection. The concept of using nanomaterial systems shows the potential for realization of nanostructured photodetectors for practical applications.

Fabrication of an in situ-grown TiO2 nanowire thin film and its enhanced photocatalytic activity.

TiO2 is a promising photocatalyst used in practical environmental remediation. TiO2 photocatalysts are usually implemented in two forms: suspended powder and immobilized thin films. A simple technique for fabricating TiO2 thin film photocatalyst was developed in this work. The fabricated TiO2 thin film photocatalyst featured a homogeneous nanowire layer grown in situ on the parent Ti plate. The optimized fabrication protocol was to soak the ultrasonically cleaned and acid-washed Ti plate in 30% H2O2 solution containing 3.2mM melamine and 0.29M HNO3 at 80°C for 72h and then anneal at 450°C for 1h. TiO2 nanowires with uniform diameters were homogeneously arrayed on the Ti plate surface. The thickness of the TiO2 nanowire array layer was 1.5μm. The pore properties of the TiO2 thin film were close to those of P25. The band gap of the fabricated photocatalyst was 3.14eV. The photocatalytic activity of the fabricated photocatalyst toward 10mg/L RhB and 1mg/L CBZ demonstrated greater than 60% degradation under 2h UVC irradiation. The RhB and CBZ degradation efficiencies remained at a good level after 5 consecutive cycles. Mechanical wearing, such as 2min sonication, will not lead to significant suppression of the photocatalytic activity. Photocatalytic RhB and CBZ degradation using the fabricated photocatalyst favored an acidic > alkaline > neutral environment. The presence of Cl- slightly suppressed the photocatalytic degradation kinetics. However, RhB and CBZ photocatalytic degradation kinetics were promoted in the copresence of SO42- or NO3-.

Visible light promoted low temperature photothermal CO2 methanation over morphologically engineered Ni/TiO2 NWs catalyst

Mankind is currently faced with two ongoing major issues, namely the energy crisis and climate change. This is due to the growing human population, causing a steep increase in energy demand which is usually catered via the combustion of depleting fossil fuels. In accordance with the Sustainable Development Goals (SDGs), the utilization of carbon dioxide greenhouse gas to produce green methane fuels is deemed to be a promising approach to tackle both the aforementioned issues. Here, we successfully engineered the morphology of 3D TiO2 microparticles (TiO2 MPs) into wire-like 1D TiO2 nanowires (TiO2 NWs) via a facile solvothermal method. The nickel dispersed Ni/TiO2 NWs catalyst was then compared with its microparticle counterpart for visible light promoted low temperature photothermal CO2 methanation. Various characterization methods were conducted such as BET, BJH, FE-SEM, EDX, HR-TEM, XRD, UV–vis DRS and H2-TPR to investigate the physical and chemical properties of the catalyst samples. Initial temperature screening (150 to 300 °C) under dark and visible light irradiated conditions revealed that photothermal CO2 hydrogenation was not feasible below 250 °C. Nevertheless, the promotional effect of visible light was diminished at elevated temperatures. It was observed that the structurally modified 1D TiO2 NWs yielded a higher production rate (19.8 mmol gcat-1h−1) and selectivity (84 %) as compared to its 3D microparticle counterpart. This is mainly due to the 1D wire like structure which possesses a high surface area which increased the exposed area to visible light irradiations while promoting the dispersion of Ni active metals while limiting the growth of NiO particles. The porosity and wire like structure of 10Ni/TiO2 NWs also promoted an intimate contact between catalyst and reactants, in turn showing a prolonged durability up to 4 reaction cycles. Interestingly, the methanation performance over the 1D catalyst gradually improved over time, suggesting the visible light assisted photoreduction of NiO to metallic Ni. Thus, our findings elucidated the significance of catalyst support morphology on the photothermal driven CO2 methanation reaction.

Highly photocatalytic performance of TiO2 nanowires in the conversion of benzaldehydes to benzoic acid

The synthesis of environmentally friendly-based chemicals such as solvent-free continues to be developed. A critical precursor in chemical synthesis is benzoic acid. This research developed a synthesis method by utilizing TiO2 nanomaterials with different morphologies as photocatalysts, namely nanoparticles (NPs) and nanowires (NWs). Titanium (IV) oxide with nanowires morphology was synthesized by hydrothermal method under alkaline conditions. SEM, XRD, and FT-IR images confirmed the morphologies of TiO2 NPs and TiO2 NWs. Photocatalytic performance in converting benzaldehyde to benzoic acid showed a significant difference of up to 38% using TiO2 NPs and 94% using TiO2 NWs.

Core-shell ferroelectric nanowire arrays for photovoltaic applications

Bismuth ferrite (BFO), as an inorganic perovskite metal oxide without Pb, is a potential photovoltaic material for solar cells. However, the low optical absorption and carrier transport ability of BFO limits the improvement of its photoelectric conversion efficiency. In this work, a transmission layer/ferroelectric layer/transmission layer shell-core nanowire array is constructed to verify its application in photovoltaics. With its large specific surface area, this structure can enhance light absorption. In particular, TiO2 nanowire arrays are used as an electron transport layer, BFO as a light absorption layer, and WO3 as a hole transport layer. With an increase in external bias, the device's photovoltaic performance first increases before decreasing. TiO2/BFO/WO3 device produced an open-circuit voltage (Voc) and short-circuit current density (Jsc) of 1.32 V and 1.14 mA/cm2, respectively, when the scanning bias is 1.75 V. The photoelectric conversion efficiency (PCE) reached 0.93 %, which is significantly higher than that of previous reports on BFO-based photovoltaic devices. As a result of this work, core-shell nanowire arrays have potential applications in the photovoltaics field.

Promotional role of tungstate in the integrated synthesis of C2 and C3 alcohols and understanding the bond functionality for a series of cascade reactions

AbstractIn this work, TiO2 nanowires (TNWs) were synthesized using a plasma‐assisted method, and then Pt clusters were impregnated onto these TNWs. The nanowires supported Pt when combined with various tungsten‐based co‐catalysts, which improved the catalytic performance. The direct conversion of cellulose to C2‐C3 alcohols using tungsten‐based co‐catalysts was enhanced, even at low temperatures. X‐ray photoelectron spectroscopy (XPS) and Raman analysis showed oxygen vacancy (Ov) enrichment on the surface of Pt/TiO2 in the presence of tungsten co‐catalysts, which improved their catalytic activity. The role of metallic platinum (Pto) was also investigated and was found to have a linear relationship with their activity as follows: H2WO4 > (NH4)6H2W12O40 · xH2O > H3PW12O40. Maximum yields of 32.33% and 51.52% of ethanol and propane‐2‐ol at optimum temperatures of 220 and 250 °C, respectively, were obtained with H2WO4. A catalytic reaction performed using tandem catalytic system gave a high ethanol yield of 25.56%, which is low in comparison with an integrated catalytic system. Cellulose conversion was also quantified here by probe electrospray ionization (pESI) coupled with Fourier transform mass spectroscopy (FTMS), which was never reported earlier for these reactions. This method provides evidence of negligible fragmentation of high molecular‐weight compounds, and the maximum cellulose conversion reported here is 100%. A reaction pathway is proposed, based on the experimental results, which elaborates the activation and cleavage of specific C‐C and C‐O bonds. © 2023 Society of Industrial Chemistry and John Wiley & Sons Ltd.

TiO2 nanowire formation and GO reduction through a hydrothermal reaction to improve the thermal conductivity of epoxy composites

AbstractThe thermal path must be properly configured to improve the thermal properties of polymer composites. Three‐dimensional (3D) thermally conductive networks can be used as an excellent means for building high‐speed conductive pathways in polymer composites. Titanium dioxide (TiO2) nanowire (NW)/reduced graphene oxide (rGO)/epoxy (EP) composite material has a 3D foam structure and focuses on TiO2 NW formation and rGO gelation through a hydrothermal process. The thermal conductivity of the synthetic composite material through filler loading at 50 wt.% and heat transfer path formation was 805% higher than that of pure EP, and the thermal conductivity was superior to that of the composite material with randomly dispersed fillers. Therefore, this work describes an advanced process to improve the thermal conductivity of polymer composites significantly.

Dielectric and mechanical properties of TiO2/polyimide composites with low dielectric constant

AbstractWith the advent of 5G era, the high millimeter‐wave frequency band, poor signal penetration and large loss make 5G communication more dependent on low dielectric constant materials. Therefore, the research and development of low dielectric polymer materials has become a hot spot in recent years. With its good chemical corrosion resistance, thermal stability, high dispersion and high mobility, titanium dioxide (TiO2) as a high function fine inorganic material is doped in polymer systems to improve the electrical properties of polymer composites. In recent years, a large number of studies have used spherical TiO2 nanoparticles doped on the polymer matrix, however, there is almost no research on doping nanolinear TiO2 nanoparticles on the polymer matrix. Here, TiO2 nanowires were prepared by hydrothermal method, and the prepared TiO2 nanowires were added to polyimide (PI). TiO2/PI monolayer and three‐layer composite films with good dielectric and mechanical properties were prepared by in‐situ polymerization. Fourier transform infrared spectoscopy, scanning electron microscopy and X‐ray diffraction were used to characterize the structure and test the properties of the composites. During the initiation process, the thermal initiation reaction of the composite membrane was completed. The composite film with good mechanical properties and excellent dielectric properties were obtained by adding titanium oxide nanowires, which can meet the requirements of its use in the field of microelectronic devices.

Polyoxometalate/MXene hybrid film with a 3D porous structure for high-performance electrochromic supercapacitors

MXenes (2D transition metal carbides, nitrides, and carbonitrides) are attractive pseudocapacitive electrode materials for electrochemical energy conversion and storage applications. The layered structure of MXenes provides intercalation pseudocapacitance properties and numerous reaction sites; however, nanosheet agglomeration and stacking reduce the reaction site availability and limit the electrochemical reaction dynamics of the interlayer ions. In this study, a unique electrochromic-energy storage hybrid film (NW/P2W17Ni/Ti3C2Tx), based on a Ni mono-substituted Dawson-type polyoxometalate (P2W17Ni) and a 2D transition metal carbide (Ti3C2Tx), was produced by the combination of a hydrothermal process and layer-by-layer self-assembly method. With positively charged polyelectrolyte polyetherimide (PEI) as a linker, negatively charged Ti3C2Tx layered sheets and P2W17Ni polyanions were deposited on a TiO2 nanowire (NW) array to form a 3D porous structure which prevented the stacking of nanoparticles and sheets, provided more ion transmission paths, and enhanced the ion transfer kinetics. The NW/P2W17Ni/Ti3C2Tx hybrid film demonstrated elevenfold higher areal capacitance (16.1 mF cm−2, 0.6 mA cm−2) than a pure Ti3C2Tx film (1.4 mF cm−2, 0.6 mA cm−2), and the retention rate reached 100% after 1000 cycles. The asymmetric electrochromic supercapacitor (ECSC) assembled with the NW/P2W17Ni/Ti3C2Tx film as the cathode exhibited a high capacity with significant dual-band regulation in the visible and near-infrared regions. The ECSC illuminated a light-emitting diode and achieved high-speed color switching between olive green and dark azure blue during the charging and discharging processes, demonstrating the energy storage status. These results could lead to considerable advances in the development of MXene-based ECSCs.

Synthesis of superacid sulfated TiO2 nanowires for esterification of waste cooking oil

Synthesis of superacid sulfated TiO2 nanowires for esterification of waste cooking oil

Platinum quantum dots-decorated MXene-derived titanium dioxide nanowire/Ti3C2 heterostructure for use in solar-driven gas-phase carbon dioxide reduction to yield value-added fuels

Solar-driven photocatalytic CO2 reduction to produce valuable chemicals and fuels offers an attractive strategy in alleviating the energy crisis. Pt quantum dots (PtQDs) with TiO2 nanowire (TiO2NW)/Ti3C2 MXene heterostructures (Pt-TiO2NW/Ti3C2) with tight interfacial contacts between the various components were prepared at room temperature via oxidation reactions. The incorporated PtQDs played crucial roles as electron conduction bridges supported by the cocatalyst effect, effectively enhancing the separation efficiencies of photoinduced electron/hole pairs and improving CO2 reduction under simulated solar light irradiation. The Pt-TiO2NW/Ti3C2 heterostructures exhibited remarkable carbon monoxide (CO) and methane (CH4) production at respective rates of 38.14 and 36.15 μmol g−1 after 10 h of simulated solar light irradiation, an apparent quantum yield of 1.68%, and 79.2% selectivity for CH4. The photocatalytic activities of the Pt-TiO2NW/Ti3C2 heterostructures for CO2 reduction were significantly enhanced compared to those of TiO2NW/Ti3C2 and the single-component photocatalysts, and they exhibited remarkable stabilities even after five cycles. In addition, the densities of states and electronic characteristics of Ti3C2 MXene and Pt-TiO2NW/Ti3C2 were studied using density functional theory, and a synergistic mechanism of the improvement in CO2 photoreduction is proposed.

Dialysate regeneration via urea photodecomposition with TiO2 nanowires at therapeutic rates.

The standard weekly treatment for end-stage renal disease patients is three 4-h-long hemodialysis sessions with each session c'onsuming over 120 L of clean dialysate, which prevents the development of portable or continuous ambulatory dialysis treatments. The regeneration of a small (~1L) amount of dialysate would enable treatments that give conditions close to continuous hemostasis and improve patient quality of life through mobility. Small-scale studies have shown that nanowires of TiO2 are highly efficient at photodecomposing urea into CO2 and N2 when using an applied bias and an air permeable cathode. To enable the demonstration of a dialysate regeneration system at therapeutically useful rates, a scalable microwave hydrothermal synthesis of single crystal TiO2 nanowires grown directly from conductive substrates was developed. These were incorporated into 1810 cm2 flow channel arrays. The regenerated dialysate samples were treated with activated carbon (2min at 0.2g/mL). The photodecomposition system achieved the therapeutic target of 14.2g urea removal in 24 h. TiO2 electrode had a high urea removal photocurrent efficiency of 91%, with less than 1% of the decomposed urea generating NH4 + (1.04 μg/h/cm2 ), 3% generating NO3 - and 0.5% generating chlorine species. Activated carbon treatment could reduce total chlorine concentration from 0.15 to <0.02 mg/L. The regenerated dialysate showed significant cytotoxicity which could be removed by treatment with activated carbon. Additionally, a forward osmosis membrane with sufficient urea flux can cut off the mass transfer of the by-products back into the dialysate. Urea could be removed from spent dialysate at a therapeutic rate using a TiO2 based photooxidation unit, which can enable portable dialysis systems.

Sea-Cucumber-like Microstructure Polyoxometalate/TiO2 Nanocomposite Electrode for High-Performance Electrochromic Energy Storage Devices.

The key challenge in the practical application of electrochromic energy storage devices (EESDs) is the fabrication of high-performance electrode materials. Herein, we deposited K7[La(H2O)x(α2-P2W17O61)] (P2W17La) onto TiO2 nanowires (NW) to construct an NW-P2W17La nanocomposite using a layer-by-layer self-assembly method. In contrast to the pure P2W17La films, the nanocomposite exhibits enhanced electrochromic and electrochemical performance owing to the 3D sea-cucumber-like microstructure. An EESD using the NW-P2W17La film as the cathode exhibited outstanding electrochromic and energy storage properties, with high optical modulation (48.6% at 605 nm), high switching speeds (tcoloring = 15 s, tbleaching = 4 s), and high area capacitance (5.72 mF cm-2 at 0.15 mA cm-2). The device can reversibly switch between transparent and dark blue during the charge/discharge process, indicating that electrochromic contrast can be used as a quantitative indicator of the energy storage status.

Carbon quantum dots induced one-dimensional ordered growth of single crystal TiO2 nanowires while boosting photoelectrochemistry properties

TiO2 nanowire arrays (TNWAs) thin film of flexible substrates has great application potential in photoelectrochemical (PEC) hydrogen evolution. Moreover, the photoquantum efficiency of TNWAs can be effectively enhanced by reducing the nanoscale as much as possible or combining with other co-catalysts. This work presents a simple and effective strategy for the synthesis of ultrafine TiO2 nanowire arrays by a one-step hydrothermal method using CQDs as an inducer for single crystal growth. Meanwhile, CQDs recombine on the surface of TNWAs to form CQDs/TNWAs heterojunction during the synthesis process. The synthesized TNWAs have well ordered separability, whose average diameter is regulated at 11.21 nm with an average aspect ratio of 1097. PEC analysis showed that the performance of TNWAs was significantly improved compared with initial TiO2 with unregulated morphology. The charge separation efficiency increased by 120%, applied bias photon-to-current efficiency (ABPE) reached 0.37%(0.68 v vs RHE), and incident photon-to-current conversion efficiency (IPCE) reached 50.31% (380 nm). The influence of TiO2 nano-morphology optimization and formation of CQDs/TiO2 heterojunction on the PEC performance were discussed in detail.

Enhancing the photocatalytic properties of doped TiO2 nanowires grown by seed-assisted thermal oxidation

In the present paper, an investigation of the structural, optical, and photo-catalytical properties of TiO2 nanowires (NWs) was conducted. The NWs were synthesized on a Si substrate by thermal oxidation of a thick (4 µm) Ti film covered by a thin (∼ 5 nm) Au film. The annealing process at 750 °C produced a 1.7 μm thick NWs TiO2 layer over a 3 μm thick TiO2 film. Characterization techniques show that TiO2 NWs are in rutile phase and have gold nanoparticles on top. Fe-doped TiO2 NWs were synthesized to increase photoactivity in the visible range. The doping was performed using an unusual strategy, that is, implanting Fe+ ions into the Ti layers before the growth of the TiO2 NWs. The defectiveness introduced by the ion implantation is avoided and precise control of the doping is achieved. The photocatalytic properties were studied by following the degradation of methylene blue. In order to increase the photo-degradation rate under UV light of undoped NWs, two different strategies have been followed: 1) deposition of Pt nanoparticles on the front or on the rear side of the samples, and 2) thermal annealing in a reductive environment. A three-fold activity enhancement is obtained and discussed. Photocatalytic activity in the visible range was also measured for the Fe-doped samples, showing good activity, which was further improved by using the same strategies implemented under UV irradiation.