Reduced Recombination Rate Research Articles

Investigation of heterojunction between α-Fe2O3/V2O5 and g-C3N4 ternary nanocomposites for upgraded photo-degradation performance of mixed pollutants: Efficient dual Z-scheme mechanism

In this present work, a g-C3N4 decorated dual Z-scheme α-Fe2O3 and V2O5 heterojunction of magnetically recoverable GFV (g-C3N4/α-Fe2O3/V2O5) composite was rationally synthesized using facile calcination and hydrothermal approach. The crystal structure, surface morphology, chemical composition and optical properties of the as-obtained composite photocatalysts (PCs) were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra high-resolution scanning electron microscopy (HR-SEM, high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS) measurement, UV-Vis diffuse reflectance spectra (DRS) and photoluminescence (PL) analyses respectively. Benefiting from these structural and compositional features, the optimum GFV heterostructured PCs sample revealed that the superior photo-degradation performance of methyl yellow (MY) and methylene blue (MB) mixed dye under visible-light, while the degradation rates were 93.4% for MY and 87.5% for MB dye at 90 min, respectively. Moreover, the enhanced photo-degradation performance of GFV composite PCs displayed an extended visible-light fascination due to lower bandgap, reduced recombination rates, high charge separation and good charge transfer capacity with the efficient dual Z-scheme heterojunction. Meanwhile, high photo-degradation stability is continued after five successive reusability tests. A possible photo-degradation mechanism of dual Z-scheme charge transfer paths was also been proposed. This study is also capable of emerging visible-light active facile heterojunction photocatalysts for various organic pollutants removal with great efficiency.

High-performance 2D/3D hybrid dimensional p–n heterojunction solar cell with reduced recombination rate by an interfacial layer

A high-performance 2D/3D hybrid dimensional p–n heterojunction solar cell has been designed with efficiency enhanced by 11.8% using h-BN as an interfacial layer; the improvement is due to interface quality and reduction in recombination rate.

Insight into the photodegradation mechanism of bisphenol-A by oxygen doped mesoporous carbon nitride under visible light irradiation and DFT calculations.

Oxygen doped mesoporous carbon nitride (O-MCN) was successfully synthesized through one-step thermal polymerization of urea and glucose utilizing nanodisc silica (NDS) from rice husk ash as a hard template. The CO2 gas, NH3 and water vapor produced during the thermal process reshaped the morphology and textural properties of the of O-MCN compared to pristine mesoporous carbon nitride (MCN). Highest bisphenol A (BPA) removal achieved under visible light irradiation was 97%, with 60% mineralization ([BPA] = 10 mg L−1: catalyst dosage = 40 mg L−1; pH = 10; 180 min). In addition to mesoporosity, the sub-gap impurity states created from the oxygen doping reduced recombination rate of photogenerated carriers. Holes (h+) and superoxide (O2˙−) were identified as the predominant active species responsible for the photodegradation process. The photodegradation route was proposed based on the intermediates detected by LC-time-of-flight/mass spectrometry (LC/TOF-MS). The Density of States (DOS) showed that oxygen doping resulted in a higher photoactivity due to the stronger localization and delocalization of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). The adsorption pathway of the BPA on the O-MCN and MCN was successfully predicted using the DFT calculations, namely molecular electrostatic potential (MEP), global and local descriptors.

N, S-CDs decorated mesoporous TiO2 composite with improved photocatalytic activity under visible light

The development of photocatalysts for efficient utilization and conversion of solar energy is the main strategy for photocatalytic degradation of pollutants. In this study, for the first time, novel N,S doped carbon quantum dots decorated mesoporous TiO2 composites (N,S-CDs/TiO2) with high specific surface areas were successfully prepared via a simple procedure, which exhibited excellent visible activity in the degradation of organic contaminants (Rhodamine B, oxytetracycline and phenol). The excellent photocatalytic performance of the catalysts was mainly ascribed to their large specific surface area, the enhanced visible light absorption and the reduced recombination rate of the photo-generated electron-hole pairs. The photocatalytic performance was affected by the N,S-CDs content and solution pH. The superoxide radicals played a dominant role in the photocatalytic process. Furthermore, a probable mechanism for the enhanced activity of N,S-CDs/TiO2 nanocomposite materials was proposed.

Facile and novel synthesis of nitrogen doped TiO2/Acid soluble collagen-polyvinyl pyrrolidone (ASC-PVP) hybrid nanocomposite for rapid and effective photodegradation of naphthalene from water under visible light irradiation

A highly efficient, eco-friendly, and visible-light-driven photocatalyst, namely nitrogen doped titanium dioxide (N-TiO2)/collagen-polyvinyl pyrrolidone (ASC-PVP) hybrid nanocomposite is prepared via facile sol–gel method. The ASC-PVP steadily covers the N-TiO2. The XPS data confirmed the oxygen vacancies and nitrogen interstitial-type doping in N-TiO2 prepared by the sol–gel route. Furthermore, the O 1s and N 1S XPS data prove that both nitrogen and oxygen atoms of ASC-PVP are participated in hydrogen bonds with N-Ti-O and/or Ti-O-N bonds in N-TiO2 nanoparticles. Moreover, the N-TiO2/ASC-PVP is shown an obvious red shift of absorption band edge and reduced recombination rate of electron-hole in comparison with N-TiO2 nanoparticles. N-TiO2/ASC-PVP was used to study photocatalytic degradation of a typical polycyclic aromatic hydrocarbon (PAHs), namely naphthalene in water under visible light irradiation. N-TiO2/ASC-PVP possessed high photocatalytic activity for the naphthalene degradation (86%) within 100 min under visible light. The inhibitory effect on the naphthalene photodegradation indicated that O2-. and h+·are the major reactive species. Also, the N-TiO2/ASC-PVP exhibited very good visible light photocatalytic efficiency for the removal of naphthalene at very low concentrations from seawater.

Visible light driven g-C3N4/Bi4NbO8X (X[dbnd]Cl, Br) heterojunction photocatalyst for the degradation of organic pollutants

A highly potential visible light active g-C3N4/Bi4NbO8X (Cl, Br) heterojunction photocatalysts were constructed at the interface of the coupling between Bi4NbO8X (Cl, Br) and g-C3N4. The band gap value of heterojunctions g-C3N4/Bi4NbO8Br-20% (CNBNB-3), g-C3N4/Bi4NbO8Cl-20% (CNBNC-3), and pristine materials g-C3N4 (CN), Bi4NbO8Cl and Bi4NbO8Br were analyzed to be 2.68 eV, 2.69 eV and 2.74 eV, 2.46 eV and 2.48 eV, respectively. The degradation performance of optimized CNBNC-3 and CNBNB-3 photocatalysts revealed much superior removal efficiency of 97% and 84% than the pristine material for rhodamine B. The synthesized photocatalysts maintained good recyclable stability after five consecutive cycles and potentially capable of pollutant degradation. The electrochemical impedance and photoluminescence spectroscopy revealed that the migration and separation efficiency of photogenerated charge carriers of photocatalyst were boosted, while reduced recombination rate was observed. The photocatalytic reaction mechanism also revealed the superoxide ·O2− and •OH radicals are the main active species responsible for the pollutant degradation.

Cu doped NiO thin film photocathodes for enhanced PEC performance

The present report describes the fabrication of undoped NiO and Cu doped NiO based photocathodes synthesized by sol gel spin coating technique. Mott-Schottky, LSV and EIS measurements have been carried out to investigate the PEC properties of these photocathodes. 3% Cu doped NiO film exhibits the highest PEC performance among all photocathodes. The p-type semiconducting nature of all thin film samples has been confirmed from the M-S plots. Also, the values of carrier density have been tuned from 1.18 × 1020 to 1.36 × 1020 cm−3 for undoped NiO and 3% Cu doped NiO thin films. VB CB levels of the as-prepared photocathodes have been calculated from absorption spectra. 3Cu:NiO exhibits a significantly higher photocurrent density of −6.97 mA/cm2 at −1.5 V vs. Ag/AgCl in 0.1M NaOH solution under UV illumination. The superior PEC performance is due to efficient charge transport and reduced recombination rate of the photogenerated electron-hole pairs. These findings demonstrate the potential of Cu doped NiO photocathodes in water splitting applications.

Effect of large graphene particle size on structure, optical property and photocatalytic activity of graphene-titanate nanotube composites

In this work we investigate the crystal transformation and optical properties of hydrothermal titania nanotube (TNT) when combining with large size of exfoliated graphene achieved by electrochemical process (EC-Gr). The TNT monoclinic structure has been changed to TiO2 anatase phase when TNT was grown in the presence of graphene dispersion. The effect of graphene on the evolution of TNT crystal could be understood by the interaction of carbon elements in graphene and Ti4+ ions in the titania structure. Due to the carrier separation which reduced recombination rate of excited photoelectrons and holes revealed by photoluminescence characterizations, the visible light photocatalytic activity in degradation of methylene blue in solution of the composite was enhanced. The photocatalytic enhancement was discussed and clarified based on UV–vis diffuse absorption spectra and time-resolved photoluminescence investigation.

Enhanced H2 evolution through water splitting using TiO2/ultrathin g-C3N4: A type II heterojunction photocatalyst fabricated by in situ thermal exfoliation

Designing a photocatalyst material with reduced recombination of photogenerated charges is one of the most important aspects of hydrogen generation through solar water splitting. Here, we report hydrogen generation using the TiO2/ultrathin g-C3N4 (U-g-CN) heterostructure fabricated using a unique in situ thermal exfoliation process. Multilayer g-CN is converted into U-g-CN having a high surface (∼190 m2/g) area by calcination at ∼550 °C through oxygen-induced exfoliation, which also forms a robust heterostructure with TiO2. In addition, the presence of g-CN also inhibits further growth of TiO2 nanoparticles, thereby retaining a high specific surface area. The presence of U-g-CN causes a redshift (∼0.13 eV) in the absorption edge of heterostructure compared to that of bare TiO2, which extends the light absorption capability. Addition of 40 wt. % of multilayer g-CN to TiO2 shows an enhanced H2 evolution rate, which is ∼15 times and ∼4 times higher compared to that of bare TiO2 and U-g-CN, respectively. Photoluminescence (PL) and time-resolved PL (TRPL) studies indicate a reduced recombination rate of photogenerated charge carriers with an increase in the average lifetime from 10.53 (TiO2) to 13.32 ns (TiO2/U-g-CN40). The interfacial charge transport characteristics studied through impedance spectroscopy reveal a reduced charge transfer resistance at the semiconductor–electrolyte interface, which facilitates faster charge separation due to the heterostructure formation. The band edge positions are estimated through flatband potential from the Mott–Schottky measurements and optical absorption data, indicating a type-II heterojunction. More light absorption and enhanced separation of photogenerated charges at the heterojunction interface lead to better photocatalytic H2 generation.

Laser‐Induced Surface Reconstruction of Nanoporous Au‐Modified TiO2 Nanowires for In Situ Performance Enhancement in Desorption and Ionization Mass Spectrometry

AbstractThe physicochemical properties of nanostructured substrates significantly impact laser desorption/ionization mass spectrometry (LDI‐MS) performance. Fundamental understanding of the substrate properties can provide insights into the design and development of an efficient LDI matrix. Herein, a hybrid matrix of nanoporous Au‐modified TiO2 nanowires (npAu‐TNW) is developed to achieve enhanced LDI‐MS performance. Its origin is investigated based on hybrid matrix properties including photo–thermal conversion and electronic band structure. Notably, further improvement is obtained in the npAu‐TNW than in the pristine TNW and non‐porous Au nanoisland‐modified TNW (Au‐TNW) hybrid, which is attributed to the laser‐induced surface restructuring/melting phenomenon. Noticeable surface restructuring/melting occurs in the npAu by laser exposure through efficient photo–thermal conversion of the highly porous npAu. At this instant of npAu structural changes, internal energy transfer from the npAu to the adsorbed analyte is promoted, which facilitates desorption. Moreover, strain is developed in situ in the TNW adjacent to the restructuring npAu, which distorts the TNW lattice. The strain development reduces recombination rates of charge carriers by introducing shallow trap levels in the bandgap, which enhances the ionization process. Ultimately, the high LDI‐MS performance based on the npAu‐TNW hybrid matrix is demonstrated by analyzing neurotransmitter.

Preparation of g-C3N4/diatomite composite with improved visible light photocatalytic activity

With the aid of mixing melamine and diatomite in hydrochloric acid aqueous solution, g-C3N4/diatomite (CN/DE-X, X = 2, 4, 6, 10, 14, which represented the mass ratio of melamine to diatomite) composites were synthesized by calcining the mixture at 550℃ for 2 h. Samples were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope, X-ray photoelectron spectroscopy, nitrogen adsorption–desorption measurement, ultraviolet–visible diffuse reflectance spectrum, and photoluminescence spectrum, etc. Rhodamine B (RhB) was used as trial pollutant to evaluate the photocatalytic activity of CN/DE-X composites. The results reveal that CN/DE-X composite is composed of g-C3N4 and diatomite. The photocatalytic activities of CN/DE-X composites are much better than that of pure g-C3N4 and varied with X. CN/DE-10 composite owns the best photocatalytic property in this study, which prohibited the agglomeration of g-C3N4 and had a specific surface area of 47.03 m2/g. 100 mg CN/DE-10 degraded more than 95% of RhB solution (10 mg/L, 100 mL) in 50 min, and its reaction rate constant was about 6.4 times that of pure g-C3N4. CN/DE-10 presents satisfactory stability and reusability since it degraded 90.01% of RhB molecules after 5 cycles of photocatalytic reaction. The outstanding photocatalytic performance of CN/DE-10 is attributed to the enhanced specific surface area, improved UV–Vis light absorption ability, narrowed band gap, reduced recombination rate of the photo-generated electrons and holes, which are brought about by the evenly anchoring of large amount of g-C3N4 on the surface of diatomite.

Versatile Fabrication of Binary Composite SnO2-Mn2O3 Thin Films by AACVD for Synergistic Photocatalytic Effect

In the present study, we prepared a SnO2-Mn2O3 binary composite thin-film electrode by a single-step solution-based aerosol assisted chemical vapor deposition (AACVD) technique for photovoltaic applications. The grown composite thin films were characterized to determine their properties, such as structure, composition, morphology and band gap by field emission scanning electron microscopy (FESEM), x-ray diffractometry (XRD), Raman scattering, energy-dispersive x-ray spectrometry (EDX), x-ray photoelectron spectroscopy (XPS) and UV-Vis absorption spectrophotometry. The evaluation of photoelectrochemical (PEC) response of as-synthesized SnO2-Mn2O3 composite photoelectrode, in comparison to the individual thin films of pristine SnO2 and Mn2O3 prepared from their respective precursors under the same conditions, engendered a promising improvement in photocurrent density. The synergistic effect between SnO2 and Mn2O3, the relevance of ball-like morphology, suitable and tunable energy band gap, and better absorbance under the visible range of light resulted in improved photocurrent of ~6.6 mA cm-2 at +0.7 V versus Ag/AgCl electrode of the binary composite, which was 16.5- and 3.4-fold higher than that of the pure SnO2 and Mn2O3, respectively. No apparent photocurrent decrease was observed during prolonged stability measurements for 300 s under one-sun illumination of 100 mW cm-2. The results confirmed the enhancement in PEC activity due to reduced recombination rate of photoinduced electron-hole pairs and improved interfacial charge transfer between electrode/electrolyte interface, which boost the PEC performance of SnO2-Mn2O3 binary composite thin film electrode towards water cleavage.

The Effect of the Recombination Rate between Adaptive Loci on the Capacity of a Population to Expand Its Range.

AbstractPrevious theoretical work on range expansions over heterogeneous environments showed that there is a critical environmental gradient where range expansion stops. For populations with freely recombining loci underlying the trait under selection (hereafter, "adaptive loci"), the critical gradient in one-dimensional habitats depends on the fitness cost of dispersal and the strength of selection relative to genetic drift. Here, we extend the previous work in two directions and ask, What is the role of the recombination rate between the adaptive loci during range expansions? And what effect does the ability of selfing as opposed to obligate outcrossing have on range expansions? To answer these questions, we use computer simulations. We demonstrate that while reduced recombination rates between adaptive loci slow down range expansions as a result of poor purging of locally deleterious alleles at the expansion front, they may also allow a species to occupy a greater range. In addition, we find that the allowance of selfing may improve the ability of populations to expand their ranges, for example, because selfing among potentially rare high-fitness individuals facilitates the establishment and maintenance of locally well-adapted genotypes. We conclude that during range expansions there is a trade-off between positive and negative effects of recombination within and between individuals.

Homogenously Rare-Earth-Ion-Doped Nanoceria Synthesis in KOH-NaOH Molten Flux: Characterization and Photocatalytic Property

Homogeneously rare-earth (RE=La, Sm and Y) ions doped CeO2 nanoparticles (NPs) with enhanced photocatalytic performance were synthesized by a facile KOH-NaOH molten flux method. XRD, TEM, EDS mapping and XPS results demonstrate that RE cations have been successfully doped into the CeO2 lattice, which leads to the lattice expansion/shrinking, and more oxygen vacancies are generated after RE ions doping. The UV-Vis DRS and PL spectra indicate that RE-doped CeO2 samples have slightly narrower band gaps and significantly reduced photo-generated electron-hole recombination rates. 5% RE ions doped CeO2 NPs show excellent photocatalytic performances and the photodegradation ratio of methylene blue (MB) increases from 71.63% of undoped CeO2 to 76.35%, 77.51% and 77.37% for 5%-La, 5%-Sm and 5%-Y-doped CeO2 NPs, respectively. The obviously reduced recombination rate of e−/h+ pairs after RE ions doping may be the critical factor for the enhanced photocatalytic performance.

Core level X-ray photoelectron emission spectra and structure-surface related multi-excitonic photoluminescence with reduced recombination rate in mesoporous TiO2/RuO2/CuO nanomaterials

Highly textured mixed metal oxide nano systems consisting of TiO2, RuO2, and CuO (TiO2/RuO2/CuO) were developed through triblock copolymer and Pluronic P123 assisted sol–gel method followed by calcinations at relatively lower temperature from the corresponding inorganic precursors. The powder X-ray diffraction pattern connotes the formation of mixed TiO2 structure made up of anatase and rutile phases with reduced crystal symmetry when the compounds aggregate from TiO2/RuO2 to TiO2/RuO2/CuO phase. The X-ray Photoelectron spectra is conspicuously indicated growth of both tertiary and quaternary configuration of elements in the specimens. The Gaussian–Lorentzian Sum peaks obtained in O1s and Ru3d elemental scanning were deconvoluted for corresponding individual components raised due to multivalent state or mixed emissions. N2 sorption studies using BET analysis shows the specific surface area of TiO2/RuO2/CuO is 53 m2/g and the same for TiO2/RuO2 is 40 m2/g. The textural property asseverates both compounds exhibit type IV adsorption isotherms with hysteresis loop analogous to the features of mesoporous materials. The surface topography retrieved using scanning electron microscopy (SEM) exhibit the formation of agglomerated nanostructures with average particle size of 21 and 35 nm respectively for mesoporous TiO2/RuO2 and TiO2/RuO2/CuO. The near band edge emissions are cumulative emissions from excited and de-excitation electron or due to the formulation of electron–hole pairs. These emissions are resolved and reported. Photoluminescence intensity of TiO2/RuO2 is significantly higher than TiO2/RuO2/CuO, this is mainly attributed to reduced recombination of photo-excited electron–hole pairs in TiO2/RuO2/CuO.

Local maladaptation of the anther-smut fungus parasitizing Dianthus carthusianorum

Pathogens are generally expected to evolve faster than their hosts and are therefore likely to be locally adapted. However, some pathogens might lag behind in the co-evolutionary arms race because they do not have some of the advantages shared by most other pathogens (e.g., high mutation or recombination rates, short generation time, high dispersal ability). This is the case of Microbotryum fungi that cause the anther smut disease in plants of the family Caryophyllaceae. We investigated the patterns of local adaptation and maladaptation in Microbotryum carthusianorum and its host plant Dianthus carthusianorum. We performed a full cross-inoculation experiment using half-sib plant families and fungal samples originating from three naturally infected populations in the Czech Republic. We specifically asked, which components of pathogen fitness (i.e., infectivity and host manipulation) are affected by local (mal)adaptation. The pathogen was on average 1.6 times more successful in infecting plants from foreign populations compared to plants from its home population. Once the infection was successful, the pathogen accelerated the plant’s flowering and thus increased the opportunity for transmission to new hosts. However, the level of manipulation of host flowering did not differ between home and foreign populations. This study showed that the pathogen’s infectivity followed a clear pattern of local maladaptation, whereas the host manipulation did not. Our study taken together with previous studies of a related anther smut species reveals the pervasiveness of local maladaptation in this group of pathogens that arises as the result of their restricted gene flow and reduced recombination rates.

Effects of transition metal (Fe, Co & Ni) doping on structural, electronic and optical properties of CuO: DFT + U study

To investigate the structural, electronic and optical properties of CuO and transition metal (Ni, Fe & Co) doped CuO, first-principles calculation is performed based on standard DFT and DFT + U. The use of DFT + U calculations confirm that the growth of the CuO films is p-type in nature with an indirect bandgap of 1.58 eV which is in good agreement with the experimental results. When doped with transition metals, the band gap value decreased to be 1.51 eV with iron (Fe). While the band gap increased to be 1.6 eV with Co doping, by directly contributing in valence band maxima (VBM) formation. Shallow impurity states also formed on top of valance band when doped with Fe and Co and which in turn can reduce recombination rate acting as carrier traps leading to better quantum efficiency. Net effective magnetic moment for Co, Ni and Fe doping was measured to be 1.958 μ B , 0.972 μ B and 0.997 μ B respectively originating from spin splitting of valance and conduction bands which may improve the photocatalytic efficiency and raise the recycle rate of photocatalysts. Calculated real and imaginary part of dielectric constant also matched with experimental literatures. Significant absorptivity of CuO with low reflectivity and maximum refractive index in visible range along with excellent tunability through doping was also observed. Thus, it can be concluded that, these changes in band structure and optical properties accompanied by generation of net magnetic moment due to doping open up wide window for novel strategies of tailoring properties for desired applications.

Light-storing assisted photocatalytic composite g-C3N4/Sr2MgSi2O7:(Eu,Dy) with sustained activity

The dependency of photocatalyst on light limits the large-scale application of photocatalysis technology. Thus, it was explored that the feasibility of the blue long afterglow phosphor and g-C3N4 for constructing a light-storing assisted photocatalytic composite with sustained activity in this study. The g-C3N4/Sr2MgSi2O7:(Eu,Dy) composite was prepared by a simple thermal polymerization method and the photocatalytic removal of NO under illumination and dark was studied. The experimental phenomena were explained from the aspects of optical properties, afterglow brightness and photoelectrochemical results. For the first time, the concept of cumulative pollutant degradation concentration(SC) was defined, which could be used as a quantitative index to evaluate the photocatalytic effect under illumination and dark. The results revealed that g-C3N4/Sr2MgSi2O7:(Eu,Dy) exhibited an enhanced photocatalytic activity under illumination due to the reduced recombination rate of carriers and the improved light absorption capacity. The existence of Sr2MgSi2O7:(Eu,Dy) as an internal light source endowed the composite with the ability to degrade pollutants continuously in the dark. The duration of photocatalysis in the dark was related to the brightness of afterglow and the photocatalytic activity. This study is helpful to promote the development of photocatalytic system with sustained activity.

Enhanced photocatalytic activity of Ce-doped β-Ga2O3 nanofiber fabricated by electrospinning method

Herein, β-Ga2O3 photocatalyst was designed to improve the photocatalytic activity. Therefore, two strategies were employed: chemical modification by Ce doping and morphological control by formation of nanofibers. Therefore, Ce-doped β-Ga2O3 nanofibers were successfully synthesized using a sol–gel derived electrospinning. These synthesized nanofibers were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV–vis spectroscopy. The SEM and XRD results indicated that Ce doping slightly influence on the morphology and crystal structure of nanofibers. In addition, the UV–vis transmittance spectra result indicates that the bandgap energy of Ce-doped β-Ga2O3 nanofibers was significantly reduced from 4.92 eV to 4.54 eV. In specific, the 0.7 mol % Ce-doped β-Ga2O3 nanofibers exhibits the lowest optical band gap energy as 4.54 eV. Moreover, the photodegradation properties of β-Ga2O3 nanofibers were evaluated by using the Methylene Blue (MB) under UV light. Interestingly, the β-Ga2O3 nanofibers doped by 0.7 mol% cerium atom exhibited the highest photocatalytic activity than other synthesized nanofibers. Consequently, from the overall characterizations, it was found that improved activity of photocatalytic degradation will be attributed to the narrow optical bandgap energy and reduced recombination rate arising from the cerium doping.

A review on TiO2-based composites for superior photocatalytic activity

Abstract Heterogeneous photocatalysts was a promising material for removing organic pollutants. Titanium dioxide (TiO2) was a suitable photocatalyst for its cost efficiency and high stability to reduce various pollutants. Enhancing TiO2 photocatalyst performance by doping with changed metals or non-metal ions and organic compounds have been reviewed. These methods could enhance photoelectrochemical activity via: (i) by a donor of electrons via electron-donor agents that would produce particular defects in TiO2 structure and capture transporters of charge; (ii) by reducing recombination rate of the charge transporters and increasing degradation of pollutants. This study investigates the modification approaches of TiO2 that comprise methods for overcoming the essential TiO2 restrictions and enhancing the photocatalytic degradation of organic pollutants. Consequently, it emphasized on the current progress of modified-TiO2 used for different pollutants in ambient conditions. Amendment techniques, such as inorganic and organic parts as doping, are studied. The reported experimental results obtained with the photocatalytic oxidation process for degrading organic pollutants were also collected and assessed.