Direct Z-scheme anatase/rutile bi-phase nanocomposite TiO2 nanofiber photocatalyst with enhanced photocatalytic H2-production activity

Design and preparation of direct Z-scheme anatase/rutile TiO₂ nanofiber photocatalyst to enhance photocatalytic H₂-production activity via water splitting is of great importance from both theoretical and practical viewpoints. Herein, we develop a facile method for preparing anatase and rutile bi-phase TiO₂ nanofibers with changing rutile content via a slow and rapid cooling of calcined electrospun TiO₂ nanofibers. The phase structure and composition, surface morphology, specific surface area, surface chemical composition and element chemical states of TiO₂ nanofibers were analyzed by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), nitrogen adsorption and X-ray photoelectron spectroscopy (XPS). By a rapid cooling of 500 °C-calcined electrospun TiO₂ precursor, anatase/rutile bi-phase TiO₂ nanofibers with a roughly equal weight ratio of 55 wt.% anatase and 45 wt.% rutile were prepared. The enhanced H₂ production performance was observed in the above obtained anatase/rutile composite TiO₂ nanofibers. A Z-scheme photocatalytic mechanism is first proposed to explain the enhanced photocatalytic H₂-production activity of anatase/rutile bi-phase TiO₂ nanofibers, which is different from the traditional heterojunction electron–hole separation mechanism. This report highlights the importance of phase structure and composition on optimizing photocatalytic activity of TiO₂-based material.     

One-pot synthesis of Cu–TiO2/CuO nanocomposite: Application to photocatalysis for enhanced H2 production,dye degradation & detoxification of Cr (VI)

Photocatalytic hydrogen production under the visible spectrum of solar light is an important topic of research. To achieve the targeted visible light hydrogen production and improve the charge carrier utilization, bandgap engineering and surface modification of the photocatalyst plays a vital role. Present work reports the one-pot synthesis of Cu–TiO₂/CuO nanocomposite photocatalyst using green surfactant -aided -ultrasonication method. The materials characterization data reveals the TiO₂ particle size of 20–25 nm and the existence of copper in the lattice as well as in the surface of anatase TiO₂. This is expected to facilitate better optical and surface properties. The optimized photocatalyst shows enhanced H₂ production rate of 10,453 μmol h⁻¹ g⁻¹ of the catalyst which is 21 fold higher than pure TiO₂ nanoparticles. The photocatalyst was tested for degradation of methylene blue dye (90% in 4 h) in aqueous solution and photocatalytic reduction of toxic Cr⁶⁺ ions (55% in 4 h) in aqueous solution. A plausible mechanistic pathway is also proposed.     

Facile synthesis of anatase/rutile TiO2/g-C3N4 multi-heterostructure for efficient photocatalytic overall water splitting

Rational design of high-efficiency heterostructure photocatalyst is an effective strategy to realize photocatalytic H₂ evolution from pure water, but remains still a considerable challenge. Herein, an anatase/rutile TiO₂/g-C₃N₄ (A/R/CN) multi-heterostructure photocatalyst was prepared by a facile thermoset hybrid method. The combination of two type-II semiconductor heterostructures (i.e., A/R and R/CN) significantly improve the separation and transfer efficiency of photogenerated carriers of anatase TiO₂, rutile TiO₂ and g-C₃N₄, and A/R/CN photocatalyst with high activity is obtained. The optimal A/R/CN photocatalyst exhibits significantly increased photocatalytic overall water splitting activity with a rate of H₂ evolution of 374.2 μmol g⁻¹h⁻¹, which is about 8 and 4 times that of pure g-C₃N₄ and P25. Moreover, it is demonstrated to be stable and retained a high activity (ca. 91.2%) after the fourth recycling experiment. This work comes up with an innovative perspective on the construction of multi-heterostructure interfaces to improve the overall photocatalytic water splitting performance.     

Enhanced photocatalytic hydrogen evolution from reduced graphene oxide-defect rich TiO2-x nanocomposites

Solar-driven photocatalytic hydrogen generation by splitting water molecules requires an efficient visible light active photocatalyst. This work reports an improved hydrogen evolution activity of visible light active TiO_2-x photocatalyst by introducing reduced graphene oxide via an eco-friendly and cost-effective hydrothermal method. This process facilitates graphene oxide reduction and incorporates intrinsic defects in TiO₂ lattice at a one-pot reaction process. The characteristic studies reveal that RGO/TiO_2-x nanocomposites were sufficiently durable and efficient for photocatalytic hydrogen generation under the visible light spectrum. The altered band gap of TiO_2-x rationally promotes the visible light absorption, and the RGO sheets present in the composites suppresses the electron-hole recombination, which accelerates the charge transfer. Hence, the noble metal-free RGO/TiO_2-x photocatalyst exhibited hydrogen production with a rate of 13.6 mmol h^?1g^?1_cat. under solar illumination. The appreciable photocatalytic hydrogen generation activity of 947.2 μmol h^?1g^?1_cat with 117 μAcm^?2 photocurrent density was observed under visible light (>450 nm).     

Insights into the visible light photocatalytic activity of S-doped hydrated TiO2

Cationic doping of TiO₂ anatase with sulphur represents a facile method to improve catalytic and photocatalytic activity for hydrogen production and extend the action spectrum of TiO₂ into the visible light region. However, there is a lot of misunderstanding when trying to explain the experimental findings and suggest theoretical models. In the present computational research work, novel theoretical models are put forward representing fully hydroxylated small anatase nanoparticles with S(IV) and S(VI) doping in various surface positions and in the bulk. It was found that sulfur in the doped anatase nanoparticles preserves its typical coordination geometries of trigonal pyramid for S(IV) and tetrahedron for S(VI). Doping in the anatase surface is much more energetically favorable compared to doping in the bulk. Doping with S(IV) causes decrease of the band gap from 3.22 to 2.65 eV while S(VI) doping could decrease E_g only to 2.96 eV. Location of photogenerated electrons and holes depends strongly on the position of dopant atoms and their valent state. Contrary to some experimental works, no strong and extended visible light absorption bands could be found with cationic doped hydroxylated anatase nanoparticles. However, improved charges separation is observed indeed and causes improved photocatalytic hydrogen production.     

Structural properties of CuO/TiO2 nanorod in relation to their catalytic activity for simultaneous hydrogen production under solar light

CuO was introduced into porous TiO₂ nanorod through impregnation method. Before the impregnation step, TiO₂ nanorod was hydrothermally synthesized from TiO₂ powder in aqueous NaOH solution and followed by thermal treatment at 450 °C. The structures and properties of impregnated samples were characterized using various techniques, including XRD, BET, XAS, TEM, and UV-DRS. Their photocatalytic performance on simultaneous hydrogen production from pure water and aqueous methanol solution was also investigated under solar light. It was found that CuO/TiO₂ nanorod possessed a high surface area, good photocatalytic property and excellent hydrogen generation activity. Incorporation of Cu ions into the lattice framework of anatase TiO₂ nanorod enhanced the efficiency in visible region at 438–730 nm. Moreover, the XAS results showed that some Cu ions formed solid solution in the TiO₂ nanorod (Cu_xT_1−xO₂). However, the excessive incorporation of Cu ions did not improve any ability of anatase TiO₂ nanorod for production of hydrogen from pure water splitting. This could be due to the excessive CuO agglomeration at outside-pores which blocked the sensitization of TiO₂ nanorod. Only 1% Cu/TiO₂ nanorod was found to be a remarkable and an efficient photocatalyst for hydrogen production under solar light from both pure water and sacrificial methanol splitting. The highest rate of hydrogen production of 139.03 μmol h⁻¹ g_catalyst⁻¹ was found in sacrificial methanol which was 3.24% higher than in pure water.     

Development of copper-doped TiO2 photocatalyst for hydrogen production under visible light

The advantage of copper doping onto TiO₂ semiconductor photocatalyst for enhanced hydrogen generation under irradiation at the visible range of the electromagnetic spectrum has been investigated. Two methods of preparation for the copper-doped catalyst were selected – complex precipitation and wet impregnation methods – using copper nitrate trihydrate as the starting material. The dopant loading varied from 2 to 15%. Characterization of the photocatalysts was done by thermogravimetric analysis (TGA), temperature programmed reduction (TPR), diffuse reflectance UV-Vis (DR-UV-Vis), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Photocatalytic activity towards hydrogen generation from water was investigated using a multiport photocatalytic reactor under visible light illumination with methanol added as a hole scavenger. Three calcination temperatures were selected – 300, 400 and 500 °C. It was found that 10 wt.% Cu/TiO₂ calcined at 300 °C for 30 min yielded the maximum quantity of hydrogen. The reduction of band gap as a result of doping was estimated and the influence of the process parameters on catalytic activity is explained.     

Enzymatic hydrogen production by light-sensitized anodized tubular TiO2 photoanode

Preliminary experiments with a slurry system of enzyme and powdery photocatalyst mixed in one compartment suggested that the electron transfer from light-sensitized photocatalyst to enzyme is the rate-determining step. Hence, in this study an anodized tubular TiO₂ electrode (ATTE) on a titanium substrate was examined as a photoanode in an anodic cell for enzymatic hydrogen production in a cathodic cell. Anodization of Ti foil in a two-electrode electrochemical cell followed by annealing in an O₂ atmosphere led to the formation of a tube-shaped TiO₂ arrays, destroyed tube arrays, or spongelike TiO₂ dense film. Samples were proven based on methylene blue (MB) discoloration to be photocatalytically active. The rate of photocatalytic hydrogen production in one of the samples (20 V–25 °C in a mixed electrolyte/350 °C–5 h) was 40 μmol/(h cm²) with a 0.1 M Na₂S electrolyte in one compartment reactor system, while the enzymatic hydrogen production rate with light-sensitized photoanode was 30 μmol/(h cm²) in the cathodic compartment with an oxygen production rate of 15 μmol/(h cm²) in the anodic compartment. These results confirmed the successful evolution of stoichiometric H₂ and O₂ separately. For the system with a sample (20 V–5 °C in 0.5% HF/650 °C–5 h), a hydrogen production rate was ca. 43 μmol/(h cm²) in the cathodic compartment and an oxygen production rate was ca. 20 μmol/(h cm²) in the anodic compartment. X-ray diffraction (XRD) results clearly indicated that the samples showing the highest evolution rate were composed of both anatase and rutile, while those made of either anatase or rutile showed a lower evolution rate. Higher annealing temperatures increased the thickness of the oxide barrier layer and obstructed the charge transfer to the back contact.     

Carbon-incorporated TiO2 microspheres: Facile flame assisted hydrolysis of tetrabutyl orthotitanate and photocatalytic hydrogen production

We report a novel and facile energy-saving method to prepare microspherical carbon-incorporated titania powders by flame assisted hydrolysis of tetrabutyl orthotitanate. The as-prepared samples were fully characterized by XRD, SEM, XPS, UV-Vis absorption spectra and photocatalytic hydrogen production. Anatase TiO₂ can be obtained directly without any post heat treatment. The as-prepared TiO₂ is formed of microspheres with sizes in a range of 0.5∼2.0 μm. XPS measurement shows the presence of carbon species which come from the incomplete combustion of organic compounds. Enhanced photocatalytic hydrogen production rates were observed for the as-prepared samples. A maximum hydrogen production rate was 8.1 μmol h⁻¹, which was 1.8 times larger than that of Degussa P25. The improved photocatalytic activity is attributed to enhanced light absorption behavior, which is caused by carbon incorporation and microspherical structure. This work demonstrates a novel and efficient strategy to synthesize microspherical anatase TiO₂ photocatalyst without any special equipment or setup.     

Mo-doped,Cr-Doped,and Mo–Cr codoped TiO2 thin-film photocatalysts by comparative sol-gel spin coating and ion implantation

Uniformly codoped anatase TiO₂ thin films of varying (equal) Mo and Cr concentrations (≤1.00 mol% for each dopant) were fabricated using sol-gel spin coating and deposited on fused silica substrates. All films were annealed at 450 °C for 2 h to recrystallise anatase. Undoped anatase films have been subjected to dual ion implantation for the first time, using Mo, Cr, and sequential Mo + Cr at 1 × 10¹⁴ atoms/cm². The films were characterised by GAXRD, AFM, SIMS, XPS, and UV–Vis and the performance was assessed by dye degradation. Despite the volumetric doping by sol-gel and the directional doping by ion implantation, neither method resulted in homogeneous dopant distributions. Both methods caused decreasing crystallinities and associated partial amorphisation. The XPS signal of the uniformly codoped films is dominated by undissolved dopant ions, which is not the case for the ion-implanted films. Increasing Ti valences are attributed to the fully oxidised condition of the Ti⁴⁺ ions that diffuse to the surface from Ti vacancy formation compared to the Ti valence of the bulk lattice, which contains Ti³⁺. Increasing O valence is attributed to the electronegativity of O^2?, which is higher than that of Ti⁴⁺. Detailed structural mechanisms for the solubility and energetics mechanisms involve the initial formation of Mo and Cr interstitials that fill the two voids adjacent to the central Ti ion in the TiO₆ octahedron, followed by integrated solid solubility (ISS) and intervalence/multivalence charge transfer (IVCT/MVCT). The sequential order of the last two is reversed for the two different doping methods. These two effects are likely to be the source of synergy, if any, between the two dopant ions. The photocatalytic performances of the uniformly codoped films are relatively poor and correlate well with the band gap (E_g). The performances of the ion-implanted films do not correlate with the E_g, where TiO₂–Mo performs poorly but TiO₂–Cr and TiO₂–Mo–Cr outperform the undoped film. These results are interpreted in terms of the competition between the effects of Mo doping, which causes partial amorphisation and/or blockage of active sites, and Cr doping, which may cause Mo–Cr synergism, Cr-based heterojunction formation, and/or improved charge-carrier separation owing to the surface-deposition nature of ion implantation.     

Highly dispersed phase of SnO2 on TiO2 nanoparticles synthesized by polyol-mediated route: Photocatalytic activity for hydrogen generation

TiO₂–SnO₂ mixed oxides (Ti:Sn = 98:2 (TS2), 95:5 (TS5) and 90:10 (TS10) by atomic weight) of large surface area and small particle size, in which SnO₂ is in a dispersed phase on TiO₂, have been synthesized by a polyol-mediated route. Characterization by various techniques has shown that a highly dispersed phase of SnO₂ on anatase TiO₂ is formed in TS2 sample. No separate discernible phases corresponding to cassiterite SnO₂ or rutile TiO₂ is seen in TS2 sample, whereas rutile TiO₂ and SnO₂ are observed besides the anatase phase of TiO₂ in TS5 and TS10 samples. The average particle size of the mixed oxide samples is ～20 nm. All samples absorb visible light and the onset of absorption was ～425 nm. These mixed oxides show emission from defect levels arising due to the anion vacancies present in TiO₂. The visible light absorption of these samples is attributed to the presence of defect levels in the bandgap of TiO₂. Photocatalytic activity of these samples for hydrogen generation from water using methanol as sacrificial reagent was studied under sunlight type radiation. The results indicate that mixed oxides have better activity compared to pure TiO₂ synthesized by the same method and the activity decreases with increasing SnO₂ concentration in TiO₂. The enhanced activity of TS2 sample is ascribed to the efficient charge separation from TiO₂ to SnO₂ owing to the high dispersion of SnO₂ in TiO₂. The decreased photocatalytic activity with increased SnO₂ concentration is due to the aggregation of SnO₂ on TiO₂, which results in relatively poor dispersion of SnO₂ and decreased charge transfer efficiency, but still maintains better photocatalytic activity compared to TiO₂. In addition loading Pd co-catalyst produces a pronounced increase in the hydrogen yield due to the accumulation of electrons in the metal from the TiO₂ and SnO₂ semiconductors and the increased reductive power of the Pd loaded mixed oxide nanoparticles.     

Activity and stability of TiO2 samples with different phase compositions in the decomposition of formaldehyde in SCW

TiO₂ samples with different crystal sizes and compositions were synthesized using a sol-gel method at different calcination temperatures (350–900 °C). The activity and stability of TiO₂ samples were determined by the gasification of formaldehyde in supercritical water (SCW) and by treatment in SCW. Increasing calcination temperature and SCW gasification (SCWG)/SCW treatment decreased the surface area of anatase TiO₂ samples due to growing crystallite size via agglomeration and sintering. Among anatase TiO₂ samples, the TiO₂ calcinated at 450 °C was found as the most suitable material under SCW conditions. However, the surface area of rutile TiO₂ slightly increased from 17.2 m² g^?1 to 19.8 m² g^?1 with the weakly crumbling of particles during SCWG. The highest hydrogen formation (63%) from formaldehyde in the SCW was obtained in the presence of anatase TiO₂ calcined at 350 °C and rutile TiO₂ calcined at 800 °C. CO₂ formation in the presence of anatase TiO₂ is higher than rutile TiO₂ because of the presence of active lattice oxygen species (O^?, O^2?) based on O₂-TPD.     

S-doped ZnO nanorods on stainless-steel wire mesh as immobilized hierarchical photocatalysts for photocatalytic H2 production

S-doped ZnO nanorods were grown on stainless steel mesh as immobilized hierarchical photocatalysts for hydrogen production. Properties of the photocatalysts were investigated by field-emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), photoinduced current, and photocatalytic hydrogen evolution test. Effects of polymer additive and doping on the surface texture, surface property, and H₂ production performance of the photocatalysts were studied. Polyethyleneimine helps the growth of nanorods on the entire surface of wire mesh. Photocatalytic H₂ production activity of the photocatalysts changes with dopant content and surface texture modification. Due to increased surface area of the hierarchical photocatalyst, enhanced light trapping and liquid flow among wire-mesh, the highest hydrogen evolution rate of 3640 μmol g⁻¹ h⁻¹ is obtained. The photocatalytic activity of photocatalyst remained at 87% of its original performance after five cycles.     

Hierarchical TiO2 spheroids decorated g-C3N4 nanocomposite for solar driven hydrogen production and water depollution

A novel hierarchical TiO₂ spheroids embellished with g-C₃N₄ nanosheets has been successfully developed via thermal condensation process for efficient solar-driven hydrogen evolution and water depollution photocatalyst. The photocatalytic behaviour of the as-prepared nanocomposite is experimented in water splitting and organic pollutant degradation under solar light irradiation. The optimal ratio of TiO₂ spheroids with g-C₃N₄ in the nanocomposite was found to be 1:10 and the resulting composite exhibits excellent photocatalytic hydrogen production of about 286 μmol h^?1g^?1, which is a factor of 3.4 and 2.3 times higher than that of pure TiO₂ and g-C₃N₄, respectively. The outstanding photocatalytic performance in this composite could be ascribed as an efficient electron-hole pair's separation and interfacial contact between TiO₂ spheroids with g-C₃N₄ nanosheets in the formed TiO₂/g-C₃N₄ nanocomposite. This work provide new insight for constructing an efficient Z-scheme TiO₂/g-C₃N₄ nanocomposites for solar light photocatlyst towards solar energy conversion, solar fuels and other environmental applications.     

Ag-doped TiO2 photocatalysts with effective charge transfer for highly efficient hydrogen production through water splitting

The development of efficient metal doped semiconductors for solar energy harvesting to produce hydrogen has attracted significant attention. Herein, the H₂ generation over Ag-doped TiO₂ photocatalyst, synthesized using a simple and cost-effective method based on chemical reduction, was reported. The Ag/TiO₂ exhibited an absorption peak in the visible region and the reduction of the bandgap to 2.5 eV due to surface plasmonic resonance (SPR). X-ray photoelectron spectroscopy revealed the presence of oxygen vacancies and 11% of Ag in Ti–Ag–O phase. The effect of reaction time and photocatalyst loading in the absence and presence of sacrificial reagents (alcohols and sulfur) on water splitting was studied and compared the activity of Ag/TiO₂ with that of bare TiO₂. The H₂ production rate of 23.5 mmol g⁻¹ h⁻¹ (with an apparent quantum yield of 19%), over 1.5Ag/TiO₂, was the highest ever reported so far. The observed higher activity could mainly be attributed to the existence of oxygen vacancies and the Ti–Ag–O phase. The photocatalyst was stable for three consecutive cycles in both the presence and absence of sacrificial reagents. This study offers new insights into the rational design of metal-support hybrid structures for hydrogen production through photocatalytic water splitting.     

Visible light-sensitized photocatalyst immobilized on beads by CVD in a fluidizing bed

In this work, chemical vapor deposition in a fluidized bed was employed for the immobilization of a photocatalyst on beads. By introducing carbon (TiOC), nitrogen (TiON) and iron (Fe/TiO₂) into TiO₂ matrix, samples were prepared, respectively. The X-ray diffractometer pattern of TiOC revealed a mixture of the anatase and rutile crystalline forms (65% and 34%, respectively) at the reaction temperature of 600 °C. TiOC absorbed in the visible region and showed photocatalytic activity in terms of isopropyl alcohol (IPA) degradation under a fluorescent lamp and blue light-emitting diode. TiON exhibited a shoulder in the absorption near 520 nm and was photocatalytically active under visible light at 460 nm. In the case of the Fe/TiO₂ species, lowering the bubbler temperature, i.e. reducing the amount of doped-iron, caused the rate of CO₂ evolution to increase during IPA degradation. Among studied species, Fe/TiO₂ under the condition of the bubbler temperature at 109 °C with a flow rate of 10 cm³/min showed highest photocatalytic activity in IPA degradation.     

Photocatalytic H2 production from water splitting under visible light irradiation using Eosin Y-sensitized mesoporous-assembled Pt/TiO2 nanocrystal photocatalyst

Sensitized photocatalytic production of hydrogen from water splitting is investigated under visible light irradiation over mesoporous-assembled titanium dioxide (TiO₂) nanocrystal photocatalysts, without and with Pt loading. The photocatalysts are synthesized by a sol–gel process with the aid of a structure-directing surfactant and are characterized by N₂ adsorption–desorption analysis, X-ray diffraction, UV–vis spectroscopy, scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray analysis. The dependence of hydrogen production on the type of TiO₂ photocatalyst (synthesized mesoporous-assembled and commercial non-mesoporous-assembled TiO₂ without and with Pt loading), the calcination temperature of the synthesized photocatalyst, the sensitizer (Eosin Y) concentration, the electron donor (diethanolamine) concentration, the photocatalyst dosage and the initial solution pH is systematically studied. The results show that in the presence of the Eosin Y sensitizer, the Pt-loaded mesoporous-assembled TiO₂ synthesized by a single-step sol–gel process and calcined at 500 °C exhibits the highest photocatalytic activity for hydrogen production from a 30 vol.% diethanolamine aqueous solution with dissolved 2 mM Eosin Y. Moreover, the optimum photocatalyst dosage and initial solution pH for the maximum photocatalytic activity for hydrogen production are 3.33 g dm⁻³ and 11.5, respectively.     

TiO2-rutile/anatase homojunction with enhanced charge separation for photoelectrochemical water splitting

The mismatched interfaces of heterojunction usually have lots of defects, deriving in recombination of generated electron-hole pairs. On the other hand, homojunction interfaces are considered to be beneficial to the separation of charge carriers due to the similar characteristics in two sides of homojunction. TiO₂ have rutile and anatase two typical photoactive phases in nature. In this work, TiO₂-rutile/anatase (TiO₂-R/A) homojunction photoanode is fabricated by in situ growth of anatase TiO₂ on TiO₂-R surface. By contrast with TiO₂-rutile/rutile (TiO₂-R/R) photoanode, TiO₂-R/A displays higher photocurrent density (1.70 mA cm^?2 at 0.6 V vs. SCE). Deep insight into the mechanism suggests that TiO₂-R/A homojunction has intense band bending and enhanced surface area, which facilitate the charge separation and transmission. This study offers some novel insights to design and fabricate semiconductors photoanodes for highly efficient photocatalytic reactions.     

A facile nonaqueous route for preparing mixed-phase TiO2 with high activity in photocatalytic hydrogen generation

A facile and simple method was developed to prepare amorphous titanium oxalate from nonaqueous reaction of tetrabutyl titanate and oxalic acid in ethanol at room temperature. This complex was converted to mixed-phase TiO₂ (anatase/rutile) by calcinations. The mixed-phase TiO₂ obtained at the optimum calcination temperature (600 °C) consisting of 67 wt% anatase and 33 wt% rutile exhibited superior photocatalytic hydrogen production activity (1026 μmol h^?1) with high stability, which can be ascribed to the phase-junctions (anatase/rutile) and high crystalline.     

Enhanced photocatalytic activity in water splitting for hydrogen generation by using TiO2 coated carbon fiber with high reusability

In this study, TiO₂ coated carbon fiber (TiO₂@CF) was synthesized and used for the improvement of hydrogen (H₂) evolution. Obtained results from scanning electron microscopy (SEM), X-ray diffraction (XRD), gas adsorption analysis (BET), UV–vis diffuse (UV–vis), and X-ray photoelectron spectroscopy (XPS) confirmed that the surface area and light absorption of the material was significantly improved. The synthesized TiO₂@CF photocatalyst exhibited improved photocatalytic performance toward hydrogen generation. The enhancement of photocatalytic H₂ evolution capacity by TiO₂@CF was ascribed to its narrowed bandgap energy (2.76eV) and minimized recombination of photogenerated electron-hole pairs The hydrogen production rate by the TiO₂@CF reached 3.238 mmolg^?1h^?1, which was 4.8 times higher than unmodified TiO₂ (0.674 mmolg^?1h^?1). The synthesized TiO₂@CF was relatively stable with no distinct reduction in photocatalytic activity after five recycling runs. The photoluminescence and photocurrent were employed to support the photocatalytic H₂ production mechanism proposed mechanism.Based on these results, TiO₂@CF with unique properties, easy handle, and high reusability could be suggested as an efficient strategy to develop a high-performance photocatalyst for H₂ production.