TiO2 Nanofilms Research Articles

Semi-transparent nanofilms of plasmonic Au/TiO2 for visible-light photocatalysis

Conventionally supported nanoparticle (NP) of plasmonic Au/TiO2 performs well under visible light, however the problem with cost, activity and durability inevitably remains. Here we demonstrate a semi-transparent nanofilm of plasmonic Au/TiO2 by deposition-precipitation and atmospheric chemical vapor deposition methods. Onto a synthetic TiO2 nanofilm (bottom layer), Au NP is allocated (top layer) for direct exposure to light with enhanced utilization efficiency (low cost). Compared to the conventional coating film from NPs, its growth nanofilm formed from molecular assembly is considered more durable. Effects of localized surface plasmon resonance (LSPR) and Fabry-Pérot (F–P) interference are evidenced by UV–vis absorption spectra. To identify and further utilize separation efficiency of charge carriers, photoluminescence spectra and visible-light photocurrent experiment in a three-electrode electrochemical cell were conducted. Using formaldehyde oxidation as reaction model, visible-light photocatalysis over plasmonic Au/TiO2 nanofilm is conceptually verified. The presence and size of Au NP promotes light absorption, separation of charge carriers and photocurrent. Au/TiO2 exhibits up to 10 times photocurrent at applied potential compared to TiO2. Inspiringly, over Au/TiO2 nanofilm, apparent rate constant, kapp (ca. 0.49 s−1) is unprecedentedly achieved ca. 3-4 orders of magnitude larger than TiO2-based thin films reported in literatures. Our growth nanofilm of Au/TiO2, achieves reaction rate of 5.0 × 10−7 mol s−1·gcat−1 under green LED that is even higher than the conventional supported NP, which is of significance to be considered more durable with the improved interface. Consequently, our semi-transparent nanofilm of plasmonic Au/TiO2 addresses cost, activity and durability for visible-light photocatalysis, for which it may pave a way to large-scale application from a practical perspective.

Two-dimensional graphene-based Li4Ti5O12 with hierarchical pore structure and large pseudocapacitive effect as high-rate and long-cycle anode material for lithium-ion batteries

Spinel lithium titanate (Li4Ti5O12) is deemed as a promising anode material for high-rate and long-cycle lithium-ion batteries, but its practical application is hindered by its poor electrical conductivity and relatively low capacity. In this work, large-scale two-dimensional (2D) graphene-based Li4Ti5O12 with hierarchical pore structure is fabricated by controllable synthesis of amorphous TiO2 nanofilms on graphene and subsequent conversion to nanoparticle-assembled Li4Ti5O12 nanosheet by reaction with LiOH at high temperature. The small nanoparticle composition (6∼10 nm) and designed micro-mesopores (1.3∼1.6 and 2.7∼3.4 nm) of Li4Ti5O12 nanosheets not only facilitate the Li+ diffusion, but also offer a large interface for Li+ adsorption and provide considerable pseudocapacitive Li storage for Li4Ti5O12. Meanwhile, the graphene substrate serves as conductive support and preserves this 2D shape structure during cycling. Therefore, this hierarchically structured Li4Ti5O12 composite exhibits superior reversible capacity and cycling stability at high rates (e.g., 168 mA h g-1 at 10 C after 1000 cycles). This newly developed method can be employed in the design of high-performance 2D structural materials for energy storage and conversion devices.

Study on Cavitation and Tribological of TiO₂ Nano-Film on Bearing Pads Surface.

Bearings play a vital role in the operation of a two-axis system. Long-term bearing use inevitably produce bubbles and frictional damage. Therefore, the protection of bearings is critical for the stable operation of a two-axis system. In this study, a TiO₂ nanofilm is used to physically protect a bearing. The discretization method is used to analyse the cavitation process. Cavitation primarily occurs on the front surface of the pad during bearing operation. A finite element analysis of a bearing pad coated and not coated with TiO₂ nanofilms shows that TiO₂ nanofilms can effectively absorb the cavitation force exerted on pads, thereby reducing inflicted damage. Moreover, the TiO₂ nanofilm reduces the friction coefficient of the pad surface, promoting good bearing capacity of the bearing during rotation. The TiO₂ nanofilm serves as a protective layer that improves the anti-wear and bearing performance of a two-axis system.

Nanoencapsulation of isotropic and anisotropic particles through a green chemistry aerosol method: a scalable approach for ad-hoc surface tuning

The interest in core–shell materials with chemically tunable mesoporous surfaces has significantly grown in recent years. The main limitation to obtain these systems through sequential precipitation is the tuning of the core and shell sol-gel chemistry, which usually implies low concentrations and leads to high-quality colloids although in small quantities after a lengthy and costly process. Aerosol approaches can lead to faster production and easier separation of functional materials with well-defined architectures. We present a “green chemistry” general method to coat sub-micron colloidal particles with a variety of mesoporous metal oxide nanofilms via an aerosol synthesis technique. Different types of particulate supports with isotropic and anisotropic shapes were dispersed into the precursor solutions in order to synthesize a mesoporous shell keeping the shape of the support. We chose the synthesis of TiO2 and TiSiO4 nanofilms on conventional Stöber SiO2 spherical particles, and on anisotropic micronized mica particles as a case study. We used the commercial surfactant Pluronic® F127 as a porogen. The structure and composition of the obtained nanofilms were characterized by electron microscopy, X-ray diffraction, focused ion beam coupled to SEM, and nitrogen adsorption/desorption isotherms. The TiO2 shells obtained (with an anatase-like structure) have pore diameters between 3.9–4.8 nm depending on the support with film thicknesses of ~100 nm, while amorphous TiSiO4 shells have larger diameters (9.5–16 nm) with film thicknesses of between 50 and 200 nm depending on the support used. The method presented shows high reproducibility and, unlike batch methods, allows the continuous production and straightforward recovery of the materials.

ALD coated polypropylene hernia meshes for prevention of mesh-related post-surgery complications: an experimental study in animals

In this work, thermal atomic layer deposition (ALD) was used to synthesize vanadium (V)-doped TiO2 thin nanofilm on polypropylene (PP) hernia meshes. Multiple layers of (Al2O3 + TiVO x ) nano-films were coated on the PP hernia mesh surface to provide a layer with a total thickness of 38 nm to improve its antibacterial properties, thereby, prevent mesh-related post-surgery complications. Highly conformal V-doped TiO2 nanofilm were deposited on PP mesh at a temperature of 85 °C. Rats and rabbits have been used to evaluate the tissue reaction on coated PP hernia meshes and biomechanical testing of the healed tissue. Five rabbits and ten rats have been implanted with ALD coated and uncoated (control) PP meshes into the back of rats and abdominal wall of rabbits. Histology of the mesh-adjacent tissues and electron microscopy of the explanted mesh surface were performed to characterize host tissue response to the implanted PP meshes. The effect of V-doped TiO2 coating on a living organism and fibroblast functions and bacterial activities were studied. The present results indicated that ALD coating improves adhesion properties and exhibited enhanced antibacterial activity compared to uncoated PP mesh. It was shown that V-doped TiO2 coatings were highly effective in inhibiting S. aureus and E. coli adhesion and exhibited excellent antibacterial activity. We found that V-doping of TiO2, unlike bare TiO2, allows generated and further procured strong redox reactions which effectively kills bacteria under visible light. We have reported comparative analysis of the use of undoped (bare) TiO2 and V-doped TiO2 as a coating for PP meshes and their action in biological environment and preventing biofilms formation compared with uncoated PP meshes. The PP meshes coated with V-doped TiO2 showed significantly lower shrinkage rates compared with an identical PP mesh without a coating. We have shown that ALD coatings provide non-adhesive and functional (antibacterial) properties.

Synthesis of titania fibers by electrospinning and its photocatalytic degradation properties

The electrospinning precursor solution was prepared by dissolving polyvinyl pyrrolidone as template, tetrabutyl titanate as titanium source, and acetic acid as inhibitor. The TiO2 nanofilms were prepared by precursor solution electrospinning and subsequent calcination. Thermal gravimetric analysis (TG), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize and analyze the samples. The influence of technological parameters on spinning fiber morphology was also studied. The results indicate that the TiO2 nanofibers morphology is good when the parameters are as follows: voltage 1.4×104 V，spinning distance 0.2 m，translational velocity 2.5×10-3 m·s-1, flow rate 3×10-4 m·s-1, and needle diameter 3×10-4 m. The diameter of the fibers is about 150 nm. With the 1×10-4 mol·L-1 methylene blue solution used as simulated degradation target, the degradation rate is 95.8% after 180 minutes.

Highly Efficient Photocatalytic Anti‐Bacterial Ag Doped Titanium Dioxide Nanofilms with Combination of Reactive Oxygen Species and Ag Ions Releasing for Application of Vascular Implants

AbstractSilver ions (Ag) as an effective biocidal metal has commercialized various anti‐bacterial materials. However, the high toxicity of Ag ions always induces undesired tissue injuries, impeding development on biomaterials. Recently, reactive oxygen species (ROS) emerges as the most promising agent for anti‐bacterial materials by modulating cell apoptosis. Herein, highly efficient anti‐bacterial Ag‐doped TiO2 nanofilms (TiO2@Agx, x = 1, 2, 3) are reported wherein Ag ions and ROS are produced by controllable photocatalytic reaction upon UV irradiation, which mutually strengthens the anti‐bacterial efficiency to 99.7% (TiO2@Ag2). Importantly, after doping amount screen of Ag ions, the TiO2@Ag2 (Ag: 4.2%) nanofilm exhibits good hemocompatibility, synergistic suppression of smooth muscle cells proliferation with the combination of Ag ions and ROS, while having slight impacts on endothelial cells growth in vitro. Given these features, this nanofilm is applied on vascular stent which requires neointimal inhibition and re‐endothelialization healing for success of implantation. The 4‐weeks’ implantation results reveal effective neointimal inhibition and rapid re‐endothelialization, indicating excellent biocompatibility as vascular stent.

Impact of UV-LED photoreactor design on the degradation of contaminants of emerging concern

Recent developments in UV-LED technology open up new possibilities for water treatment. TiO2 photocatalysis can benefit from optimized photoreactor design to increase hydroxyl radical production and reduce its electrical energy per order (EEO) demands, which still ranks high among advanced oxidation processes. However, literature on UV-LED photoreactor design is largely lacking. In this work, a detailed investigation of photoreactor design is proposed. The simulation of a lab scale cylindrical reactor with 8 different UV-LED arrays was run with the professional version of an optic software. The increase of radiant flux and irradiance on the reactor’s middle cross section and side walls, respectively, was related to an increasing number of LEDs and to a shorter distance from the reactor but not necessarily to an increase in homogeneity of light distribution. A full factorial experimental design was applied to evaluate the degradation of a representative contaminant of emerging concern (ciprofloxacin) considering 4 independent variables and their interactive effects on kinetic rates and EEO values. The significance of these effects was evaluated with ANOVA and a prediction model was established. The results show that the presence of a TiO2 nanofilm was the most significant tested effect. The number of LEDs, their distance from the reactor’s wall and the adoption of controlled periodic illumination also greatly influenced kinetic rates but were less relevant for reducing EEO values because the energetic trade-off was not sufficient to turn the kinetic gain into lower electricity demands.

Synthesis and characterisation of nano TiO2 film for enhancing antireflection properties

ABSTRACT A nanostructured TiO2 thin film was deposited on glass substrate by using sol gel dip-coating method to improve the antireflective property and performance of the solar PV cell. In this way, TiO2 was prepared by using titanium isopropoxide (TIP) as precursor and nitric acid (HNO3) as catalyst and the corresponding structural and optical properties were studied. The film thickness was tailored by varying the withdrawal rate. The X-ray diffraction results showed that TiO2 thin film calcined at 300°C was amorphous, and was transformed into anatase phase at 450°C with crystallite size of 22.6 nm. The microstructure of the film was analysed by Scanning Electron Microscope (SEM) and the elemental composition was confirmed by Energy Dispersive X-Ray Analysis (EDAX). The surface topography was characterised by Atomic force microscopy (AFM) which reveals that the surface has many spikes which confirms the surface is not smooth. The optical properties such as absorption and reflection were investigated by using UV-VIS spectrometer which indicates that the absorption was increased from 1.2% to 1.5% at the wavelength range from 250 to 314 nm and the reflectance was reduced from 23% to 5.7% after the TiO2 deposition and the conversion efficiency was increased from 14.22% to 17.54%.

In Vitro Anti-Coagulant Effects of Fucoidan Sulfate Grafted on TiO2 Nano-Film

The objective of this study was to examine anticoagulant effects of fucoidan sulfate grafted on a TiO₂ nano-film. Using silica sol as a film-forming binding agent and high-molecular-weight polyvinyl alcohol as a film-forming aid, a nano-TiO₂ film was produced by applying a bonding film-forming method. Photocatalytic performance and resistance to heat, corrosion, and aging were investigated. Using glutaraldehyde as a cross-linking agent, brown algal polysaccharide sulfate was grafted onto the surface of NH₃ plasma-treated nano-film. The effects of pH, reaction temperature, and reaction time on grafting effects of nano-film are discussed. XPS was used to analyze chemical elements on the surface of nano-film, and partial thromboplastin time (APTT), thromboplastin time (PT), and thrombin time (TT) were used to evaluate anticoagulant activity of the graft nano-film In Vitro. The TiO₂ nano-film showed excellent resistance to heat, water, corrosion, and aging, and produced good interfacial adhesion performance. The grafting process optimum occurred at pH 2, 40 °C, and a reaction time of 6 h. Under these conditions, the optimal value of grafted silk fibroin membrane APTT was 72 s, and coagulation time of APTT and TT was increased by 37 s and 6 s, respectively, compared with the control, suggesting anticoagulant effects. Regarding stability, grafted fucoidan sulfate did not dissolve easily from the matrix; therefore, this product appears to be a promising novel biomaterial with effective anticoagulant properties.

Effect of electrolyte solution and deposition methods on TiO2/CdS core–shell nanotube arrays for photoelectrocatalytic application

In this work, TiO2 nanostructure thin films were deposited by using anodization technique, while CdS thin films were deposited on TiO2 films by two methods chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR). The structure of TiO2/CdS films were investigated and analyzed by XRD, SEM, and AFM, but the optical properties were investigated by UV–visible spectroscopy, PL spectroscopy, and spectral response. XRD analysis of all deposited films has confirmed the formation of two phases one is tetragonal phase (anatase, and rutile) for TiO2, and second hexagonal phase which belong to CdS layer. SEM images of TiO2 nanotubes arrays (NTAs)/CdS showed the TiO2 NTs walls become decorated with aggregates of fine CdS nanoparticles that partly penetrate into the TiO2 NTAs pores. AFM measurements displayed increase in the surface roughness compared with TiO2 films. PL measurement results of TiO2/CdS core–shell show two peaks, one is located at UV-region pointed to energy band gap for TiO2 nano films, and second one is located at visible region pointing to recombination of photogenerated electron–hole pairs within CdS layers. Spectral response measurements showed photocurrent peaks for all TiO2/CdS films deposited with different electrolyte solution have red-shift to visible region. When illuminated with a UV–Vis light source, the TiO2/CdS core–shell films displayed high response. A higher response to UV–Vis light was attained with the use of TiO2 NTAs/CdS films prepared by anodization /CBD. This approach offers a technique for fabricating photoelectrodes.

Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO2 Thin Films by Vapor-Phase Infiltration

In this work, we show that in order to fabricate coherent titania (TiO2) films with precise thickness control, it is critical to generate a complete polymer brush monolayer. To date, demonstrations of such dense polymer monolayer formation that can be utilized for inorganic infiltration have been elusive. We describe a versatile bottom-up approach to covalently and rapidly (60 s processing) graft hydroxyl-terminated poly(2-vinyl pyridine) (P2VP-OH) polymers on silicon substrates. P2VP-OH monolayer films of varying thicknesses can subsequently be used to fabricate high-quality TiO2 films. Our innovative strategy is based upon room-temperature titanium vapor-phase infiltration of the grafted P2VP-OH polymer brushes that can produce TiO2 nanofilms of 2-4 nm thicknesses. Crucial parameters are explored, including molecular weight and solution concentration for grafting dense P2VP-OH monolayers from the liquid phase with high coverage and uniformity across wafer-scale areas (>2 cm2). Additionally, we compare the P2VP-OH polymer systems with another reactive polymer, poly(methyl methacrylate)-OH, and a relatively nonreactive polymer, poly(styrene)-OH. Furthermore, we prove the latter to be effective for surface blocking and deactivation. We show a simple process to graft monolayers for polymers that are weakly interacting with one another but more challenging for reactive systems. Our methodology provides new insight into the rapid grafting of polymer brushes and their ability to form TiO2 films. We believe that the results described herein are important for further expanding the use of reactive and unreactive polymers for fields including area-selective deposition, solar cell absorber layers, and antimicrobial surface coatings.

Titania Nanofilms from Titanium Complex-Containing Polymer Langmuir-Blodgett Films.

This paper proposes a method of fabricating low-dimensional TiO2 nanofilms at room temperature under ambient pressure conditions. The titanium-containing polymer complex Ti-p(DDA/acac) was synthesized by reacting an amphiphilic copolymer (p(DDA/acac)) with a titanium complex. Its ultrathin films were prepared using the Langmuir-Blodgett (LB) technique. The monolayer was found to be free from hydrolysis and cross-linking side reactions, even at the air-water interface. The transferred LB films (nanosheets) were oxidized by ultraviolet irradiation at room temperature. The photo-oxidized material has an amorphous and porous structure with subnanometer-scale controllability (0.18 nm per layer). Photocatalytic performance was demonstrated by converting multilayered LB films of Ti-(DDA/acac) and the silicon-containing polymer p(DDA/SQ) into ultrathin hetero-multilayers of TiO2 and SiO2 under UV-O3 treatment. The scalability affords a uniform photopattern formation of photo-oxidized TiO2 films over several hundreds of micrometers.

Titanium mesh-supported TiO2 nano-film for the photocatalytic degradation of ethylene under a UV-LED

In this paper, TiO2 nano-films with different morphologies were synthesized on titanium mesh by a hydrothermal treatment. The crystalline structure and surface morphology of the TiO2 nano-films were characterized by X-ray photoelectron spectroscopy (XRD), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscope (HRTEM). The photocatalytic degradation of ethylene using the TiO2 catalyst was carried out. The effect of the photoreaction temperature, initial concentration of ethylene and light intensity on photodegradation under ultraviolet-light emitting diode (UV-LED) light was investigated. The photocatalytic stability of the TiO2 nano-film catalyst was also evaluated. The results revealed that the photodegradation of ethylene gas follows the pseudo-first-order kinetics model. The photoreactivity was enhanced by increasing the light intensity and the photoreaction temperature but decreased with the increase in the initial ethylene concentration. The nanowire-shaped TiO2 film showed a superior photocatalytic performance and an excellent stability. The electrochemical impedance spectroscopy and transient photocurrent response studies revealed that the nanowire-shaped TiO2 film possesses an excellent separation ability in the electron hole pair of the photogenerated electron-hole pairs due to the high degree of crystallinity and the heterojunction between the rutile and anatase phases of TiO2. We expect that the findings will have practical applications in fruit preservation and other agricultural products.

An integrated electrocoagulation – Electrocatalysis water treatment process using stainless steel cathodes coated with ultrathin TiO2 nanofilms

Anodic electrocoagulation processes can remove broad varieties of pollutants in industrial wastewater. However, some stubborn contaminants may still remain in effluents after the treatment and cause environmental issues. To further improve the efficiency of pollutant removal, we have coupled electrocatalysis with electrocoagulation and applied an atomic layer deposition (ALD) enabled TiO2 ultrathin overcoating at a nanometer scale on a stainless steel cathode. The electrocatalytic overcoating increased the elimination efficiency of organics and microorganisms, likely due to the electro-generation of adequate reactive oxygen species (ROS). The thickness of TiO2 nanofilm was controlled by the number of ALD cycles, and it was found that nanofilms processed with 50–100 cycles led to the maximum benefit of pollutant removal. By using the novel electrocoagulation–electrocatalysis cell to treat synthetic wastewater, a remarkable removal of 99.92% of E. Coli, 92.1% of suspended solids, 98.3% of heavy metal ions, and 88.8% of methylene blue was observed. This hybrid electrochemical treatment process may have the potential to treat wastewater at a larger scale.

Experimental study of pool boiling heat transfer on an annealed TiO2 nanofilm heating surface

The hydrothermal stability of titanium oxide (TiO2) made it a potential candidate in nanofilm (NF) coating on heating substrate for pool boiling enhancement ramified under passive technique. The objective is to conduct an experimental study on pool boiling of saturated water by the implementation of an annealed TiO2 micro-/nanostructured heating surface for the enhancement of heat transfer between the liquid and the heating surface envisioned as the corollary of annealing. Electron beam physical vapour deposition is employed to synthesize four TiO2 nanofilm-coated substrates of two different thicknesses (500 and 100 nm); among them, one from each thickness is annealed at an inert atmosphere. The test samples are characterized by transmission electron microscopy, scanning electron microscopy, and atomic force microscopy and contact angle metre (dynamic) to understand the morphology, topology and crystallinity and hydrophilicity of the surface. Experimental analysis of heating surfaces revealed that the annealed TiO2 1000 nm micro-/nanostructure-recorded maximum reduction in wall super heat (ΔT) of 52% and enhancement in heat transfer coefficient (h) of 74% than untreated copper substrate also exhibit superior structural stability after several runs rendering annealing a potential method for the amelioration of nucleation and structural stability of heating substrates. As hypothesized, annealing of nanofilm coating improved the structural stability of the NF rendering unwavering boiling performance evident from the results.

Atomic scale manipulation of sublayer with functional TiO2 nanofilm toward high-performance reverse osmosis membrane

Recently, engineering the sublayer of polyamide thin film composite (PA-TFC) membrane by functional nanomaterials at nanoscale has been developed as an effective strategy to control interfacial polymerization reaction to fabricate high-performance reverse osmosis (RO) membrane. However, a reliable and practical manipulation technique is still needed to overcome the limitation of conventional sublayers. In this work, an approach of using atomic layer deposited (ALD) monomer-affinitive titanium dioxide (TiO2) nanofilm to modify the sublayer of TFC was proposed to form a thin, smooth, and highly cross-linked PA selective top layer. The functional TiO2 nanofilm increases the affinity between modified sublayer and amine monomer in favor of the efficient and subtle tuning of the adsorption and diffusion of amine monomer during the interfacial polymerization process. The obtained TFC membrane with optimal ALD TiO2 coverage demonstrates well-improved RO performance in terms of high permeance of 1.8 L.m−2.h−1.bar−1 and high salt rejection rate of 96.1% in a dead-end process. This work reveals that coating functional nanomaterials by ALD is a practical manipulation technique toward the controllable fabrication of promising TFC membrane and the optimization of sublayer materials.

Preparation of TiO2/Ser filler with ultraviolet resistance and antibacterial effects and its application in SBR/TRR blend rubber

TiO2/sericite (Ser) was prepared by depositing a nano-TiO2 film onto a carrier composed of sericite, an inorganic and nonmetallic mineral. Ultraviolet-resistant and antibacterial layers were then separately loaded onto the nano-TiO2 film, forming a multifunctional composite. The obtained functional TiO2/Ser composite was used as a filler and introduced into a rubber composite. It was indicated that the functional TiO2/Ser composite was straightforward, cost-effective, and easy to prepare under a low temperature. The nano-TiO2 layer exhibited a high loading capacity and was firmly loaded onto the inorganic and nonmetallic mineral carrier. The morphology and structure of the filler were observed using transmission electron microscopy. Moreover, the air permeability, antibacterial, aging-protection, and mechanical properties were measured and analyzed using the functional TiO2/Ser as a filler for SBR/TRR blend rubber. Compared with silica, the TiO2/Ser filler could reduce the material cost and improve the density, antibacterial, aging-protection, and mechanical properties of the SBR/TRR blend rubber.

A novel hybrid system consisting of a dye-sensitized solar cell and an absorption refrigerator for power and cooling cogeneration

To improve the energy conversion efficiency of a dye-sensitized solar cell (DSSC), a novel hybrid system representatively consisting of a DSSC and an absorption refrigerator (APR) is put forward, in which the APR is used to thermally harness the part of high wavelength sunlight that not converted by the DSSC. The amount of heat from the DSSC is calculated, and mathematical formula for energy conversion efficiencies and output powers of the DSSC, APR and hybrid system are derived. Numerical calculations show that the maximum output power density and maximum energy conversion efficiency of hybrid system are enhanced by 9.93% and 9.92% in comparison with that of the single DSSC, respectively. Integration of APR to DSSC is a feasible route to effectively improve the energy conversion efficiency. Comprehensive sensitivity analyses are conducted to explore how the whole hybrid system performance depends on various working conditions and designing parameters, including porous nano-TiO2 film thickness, photoelectron absorption coefficient, internal irreversibility factor, heat transfer coefficient and various temperatures. The research results can provide some new understandings for further enhancing the DSSC performance.

The study of photocatalytic degradation of a commercial azo reactive dye in a simple design reusable miniaturized reactor with interchangeable TiO2 nanofilm

A simple design and low cost miniaturized reactor integrated with interchangeable thin film TiO2 nanolayer was successfully fabricated for the photocatalytic degradation of azo dyes. The TiO2 nanofilms were prepared by sol-gel dip-coating method, while the miniaturized reactor was fabricated on poly methyl methacrylate (PMMA) substrates, using a laser cutting machine. The performance of the miniaturized reactor for the photocatalytic degradation process was investigated for the degradation of a commercial dye (Novacron Red C-2BL). About 98% degradation of the commercial dye was achieved after 100 min in a stopped flow system, and 15% in a continuous flow system. The effect of different operating variables such as pH, initial flow rate, light intensity, layers of the nanoparticles, and temperature on the photocatalytic degradation was studied and the optimum operating conditions were determined to be: inlet flow rate of 0.05 ml/s, pH of 7, UV power 82 W and using a multi-layer of TiO2 thin film in the miniaturized reactor. The reaction kinetics was described as pseudo first order kinetics and rationalized using the Langmuir–Hinshelwood model.