Search

• V@S-Ta 3 N 5 /PANI is successfully prepared via mechanical and in-situ polymerization methods. • Various techniques were used to reveal the structural and morphological of materials. • Light-driven water splitting via V@S-Ta 3 N 5 /PANI composite was favorably demonstrated. • Improvements due to efficiency in separation, low recombination, and a prolonged period of e–-h+ pairs. The rising global demand for energy and the associated environmental problems calls for the rapid development of renewable and eco-friendly energy systems. Due to advantages like low cost, and high catalytic efficiency, V, S co-doped Ta 3 N 5 protected with polyaniline (PANI) photocatalyst as a photocatalyst has attracted more and more attention. Herein, co-doped V@S-Ta 3 N 5 /PANI composite materials were synthesized by two different approaches. Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) were used to analyze the structural and morphological properties of the synthesized composites. In contrast, the optical properties were analyzed with the help of UV–Vis diffuse reflectance spectroscopy (DRS) techniques. Electrical impedance spectroscopy (EIS) and photoluminescence (PL) tests were used to investigate charge separation efficiency and the degree of recombination. As a dopant, V and S were incorporated into the lattice of Ta 3 N 5 , where their presence as an intermediate between the valance and conduction band of Ta 3 Na 5 narrowed down its band gap. These intermediate bands of the metal (V) and non-metal (S) dopant also exhibit superior efficiency in electron-hole pair separation and prevent their recombination, extending the period of the electron-hole pairs. As a sensitizer/protector PANI, a conducting polymer, acted as a covering agent for the doped Ta 3 N 5 particles to develop the charge transfer efficiency for relocating the photogenerated electrons and holes to the photocatalyst surface. Remarkably, synthesized composites have a higher photocatalytic activity of 3.8-folds higher than pure Ta 3 N 5 at 98.4 mmol g −1 h −1 for H 2 generation. [Display omitted] [ABSTRACT FROM AUTHOR]

Photocatalytic degradation using TiO2 is one of the most effective techniques for treating residual emerging compounds present in water. However, practical applications are limited since it only absorbs ultraviolet irradiation. Nitrogen and sulfur (N, S) co-doped TiO2 nanomaterials (N,S-TiO2) were prepared by a controlled sol–gel method; the characterization and photocatalytic activity have been studied for the removal of ciprofloxacin antibiotic under UV–Visible light. The interstitial doping of nitrogen and sulfur substitute oxygen and titanium into the TiO2 lattice, which increases the valence band and decreases the conduction band, respectively. The lowest value band-gap of 2.5 eV and the crystallite size of 5.13 nm compared to other available synthesis methods was observed on N,S-TiO2 which allowed to broaden the light absorption to the visible region. The low level electron and hole recombination was related by the N, S doping. The optimal ciprofloxacin removal was obtained at pH 5.5, a dosage of 0.05 g, initial concentration of 30 mg L−1 with a removal efficiency of 78.7%. A comparison of the effectiveness of antibiotic treatment of N,S-TiO2 with synthetic TiO2 and commercial TiO2 was also made, taking the potential for regeneration into account. The photocatalytic degradation of ciprofloxacin catalyzed by N,S-TiO2 was described by pseudo-first-order kinetics. [ABSTRACT FROM AUTHOR]

A perfluorooctanoic acid (PFOA), as the most important representative of perfluorocarboxylic acids (PFCAs), is environmentally persistent and bioaccumulative. Among treatment techniques for PFOA decomposition, photocatalytic degradation of PFOA has received considerable attention. A series of candidate photocatalytic materials, including TiO2‐, carbonaceous‐, Ga2O3‐, In2O3‐based, etc., have been successfully proposed to eliminate PFOA. Overall, there are two types of mechanisms for photocatalytic degradation of PFCAs, including conventional mechanism and charge transfer mechanism. For a conventional mechanism, the mechanism of PFOA photodegradation over bulk TiO2 via two pathways: photo‐redox and β‐scission. For the charge transfer mechanism, the PFOA degradation pathway in water‐soluble H3PW12O40 is mainly via charge‐transfer excited complex ([PW12O40]3−*). Finally, attention on critical challenges and prospects for photodegradation of PFOA are also intensified. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Organic–inorganic metal halide perovskites (HPs) have emerged as new frontier materials for optoelectronic and energy applications. In addition to various well‐known applications, such as solar cells, light‐emitting diodes, photodetectors, and resistive switching memories, HPs can be utilized as efficient photocatalysts for numerous electrochemical reactions, including carbon dioxide (CO2) reduction reactions, hydrogen evolution reaction, photosynthesis, and wastewater treatment. However, the use of HPs toward photo‐driven catalysis remains a tremendous challenge owing to their poor stability in polar solvents. Nevertheless, huge progress has been made to counter this critical issue for improving the performance of HPs as efficient photocatalysts in a wide range of applications. In this review, we first introduce the structures and properties of HPs. Next, we highlight the recent approaches on the fabrication of HPs, including thin films and nanostructures. Strategies for implementing HPs in catalysis systems and their working mechanisms are thoroughly summarized and discussed. Lastly, the current challenges and prospects of the application of HPs toward photocatalytic reactions are fully addressed. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Hydrogen gas has been attracting significant interest as an emerging energy source that is clean, sustainable, and renewable. Primarily, it can be produced via photoelectrochemical (PEC) splitting of water using solar energy. Among the various catalysts employed for the photoreduction of water, two‐dimensional transition metal dichalcogenides (2D‐TMDs) are inarguably the best candidates toward industrialization because they have extraordinary physical, optical, and electric properties, and are solution‐processable at low costs. In this review, we focus on the development of 2D‐TMDs and their PEC properties toward the hydrogen evolution reaction. First, the synthesis and properties of 2D materials are summarized and discussed. Next, the strategies for improving the photocatalytic activity of the 2D material‐based catalysts for water splitting are thoroughly investigated. Finally, the remaining challenges and direction for the future development of 2D‐TMDs in PEC catalysis‐derived hydrogen evolution reaction are addressed. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The particular role of reactive facets TiO 2 on photocatalytic NOx removal was systematically explored. The photo selective catalytic reduction (photo-SCR) of NOx was studied using titania nanosheet photocatalysts. The titania nanosheets were synthesized by hydrothermal method with titanium n -butoxide (TBOT) and hydrofluoric acid (HF). The synthetic pathway of transformation from TBOT (Ti precursor) to TiO 2 nanosheet was clearly revealed that TiOF 2 is the intermediate during the hydrothermal process. The NO conversion of titania nanosheets was found to be higher than the conversion of commercial P25 and TiO 2 synthesized by the sol-gel method. Moreover, one of the titania nanosheets, FT1.5, displayed the highest efficiency of NOx removal at 393 K, but there was a trade-off relationship between NO conversion and NO 2 selectivity. Our results suggest that the optimal synthetic process for highest efficiency of TiO 2 nanosheet in photocatalysis is to use TBOT and HF with the F/Ti atomic ratio = 1.5 (FT1.5) at 453 K for 24 h. In summary, the synthesized TiO 2 nanosheet exhibits great potential to be applied in NOx abatement. [ABSTRACT FROM AUTHOR]

Three types of photocatalytic NO removal reaction including photo-assisted selective catalytic reduction (photo-SCR), photo-oxidation and photo-decomposition, were designated in the flue gas under elevated temperatures. The reliability of reaction pathways is supported by the excellent agreement of the change in the thermodynamic properties of individual catalytic reactions. The presence of O 2 could further effectively improve the photocatalytic activity at the low reaction temperature. However, an excess consumption of both O 2 and C 4 H 10 was recognized by oxidation of C 4 H 10 at the higher reaction temperature, resulting in the drop of the NO removal. This study provides the basis for designing the photocatalytic removal of NO with a hydrocarbon in the flue gas. [ABSTRACT FROM AUTHOR]

In developing a higher activity for NOx abatement from stationary emission sources, photo-assisted selective catalytic reduction (photo-SCR) was systematically investigated over TiO 2 supported on a spherical α-Al 2 O 3 /γ-Al 2 O 3 . The formation of NO 2 was virtually suppressed in the reaction temperature range of 110–200 °C. The NOx removal efficiencies of TiO 2 /γ-Al 2 O 3 photocatalyst at 120 °C for real flue gas (in pilot-scale photoreactor) and simulated flue gas (in lab-scale photoreactor) were 68–75% and 43.5%, respectively, in the presence of reducing reagent (C 4 H 10 ). SEM and XPS techniques revealed that sulfur temporarily occupied the active sites of the photocatalyst, causing deactivation. Spent TiO 2 /γ-Al 2 O 3 photocatalyst was regenerated via desulfurization by either air or hydrogen at 400–500 °C. The effects of regeneration temperature and regeneration time on the photocatalytic activity are methodically investigated, demonstrating that using hydrogen at 500 °C in 1 h could completely regenerate the spent photocatalyst. [ABSTRACT FROM AUTHOR]

Pesticides have been frequently used in agricultural fields. Due to the expeditious utilization of pesticides, their excessive usage has negative impacts on the natural environment and human health. This review discusses the successful implications of nanotechnology-based photocatalysis for the removal of environmental pesticide contaminants. Notably, various nanomaterials, including TiO 2 , ZnO, Fe 2 O 3 , nanoscale zero-valent iron, nanocomposite-based materials, have been proposed and have played a progressively essential role in wastewater treatment. In addition, a detailed review of the crucial reaction condition factors, including water matrix, pH, light source, temperature, flow rate (retention time), initial concentration of pesticides, a dosage of photocatalyst, and radical scavengers, is also highlighted. Additionally, the degradation pathway of pesticide mineralization is also elucidated. Finally, the challenges of technologies and the future of nanotechnology-based photocatalysis toward the photo-degradation of pesticides are thoroughly discussed. It is expected that those innovative extraordinary photocatalysts will significantly enhance the performance of pesticides degradation in the coming years. • Nanotechnology-based photocatalysis could remove environmental pesticide contaminants. • Studies elucidate the degradation pathway of pesticide mineralization. • Studies discuss challenges of nanotechnology toward the degradation of pesticides. • Innovative extraordinary photocatalysts could significantly enhance the pesticides degradation. [ABSTRACT FROM AUTHOR]

Parabens are a class of compounds primarily used as antimicrobial preservatives in pharmaceutical products, cosmetics, and foodstuff. Their widely used field leads to increasing concentrations detected in various environmental matrices like water, soil, and sludges, even detected in human tissue, blood, and milk. Treatment techniques, including chemical advanced oxidation, biological degradation, and physical adsorption processes, have been widely used to complete mineralization or to degrade parabens into less complicated byproducts. All kinds of processes were reviewed to give a completed picture of parabens removal. In light of these treatment techniques, advanced photocatalysis, which is emerging rapidly and widely as an economical, efficient, and environmentally-friendly technique, has received considerable attention. TiO 2 -based and non-TiO 2 -based photocatalysts play an essential role in parabens degradation. The effect of experimental parameters, such as the concentration of targeted parabens, concentration of photocatalyst, reaction time, and initial solution pH, even the presence of radical scavengers, are surveyed and compared from the literature. Some representative parabens such as methylparaben, propylparaben, and benzylparaben have been successfully studied the reaction pathways and their intermediates in their degradation process. As reported in the literature, the degradation of parabens involves the production of highly reactive species, mainly hydroxyl radicals. These reactive radicals would attack the paraben preservatives, break, and finally mineralize them into simpler inorganic and nontoxic molecules. Concluding perspectives on the challenges and opportunities for photocatalysis toward parabens remediation are also intensively highlighted. [Display omitted] • Parabens, emerging contaminants, have been found in various environmental matrices. • Photocatalysis is a promising, sustainable alternative to eliminate paraben preservatives. • Different side-chain structures have a difference in mechanism and catalytic efficiency. • Several types include ZnO-, ABO 3 - perovskite, Ag-, Bi-, WO 3 -based photocatalysts, are proposed. • Many types of reactive species, such as.●OH, ●O 2 −, ●OOH, etc., are responsible for photocatalysis [ABSTRACT FROM AUTHOR]

In this study, perovskite ZnTiO3 photocatalysts were fabricated by the sol–gel method. The photocatalytic capability was verified by the degradation of the emerging contaminant, the antibiotic amoxicillin (AMX). For the preparation, the parameters of the calcination temperature and the additional amount of polyvinylpyrrolidone (PVP) and ammonia are discussed, including the calcining temperature (500, 600, 700, 800 °C), the volume of ammonia (750, 1500, 3000 μL), and the weight of PVP (3 g and 5 g). The prepared perovskite ZnTiO3 was characterized by XRD, FESEM, BET, and UV-Vis. It is shown that the perovskite ZnTiO3 photocatalysts are structurally rod-like and ultraviolet light-responsive. Consequently, the synthesis conditions for fabricating the perovskite ZnTiO3 photocatalysts with the highest photocatalytic performance were a calcining temperature of 700 °C, an additional ammonia amount of 1500 μL, and added PVP of 5 g. Moreover, the photocatalytic degradation of perovskite ZnTiO3 photocatalysts on other pollutants, including the antibiotic tetracycline (TC), methyl orange (MO), and methylene blue (MB) dyes, was also examined. This provides the basis for the application of perovskite ZnTiO3 as a photocatalyst to decompose emerging contaminants and organic pollutants in wastewater treatment. [ABSTRACT FROM AUTHOR]

Effective La-doped SrTiO3 (Sr1−xLaxTiO3, x = 0–0.1 mol.% La-doped) nanocubes were successfully synthesized by a hydrothermal method. The influence of different La dopant concentrations on the physicochemical properties of the host structure of SrTiO3 was fully characterized. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) revealed that the Sr2+ in the crystal lattice of SrTiO3 was substituted by La3+. As a result, the absorption region of the Sr1−xLaxTiO3 could be extended to visible light. Scanning electron microscopy (SEM) images confirmed that their morphologies are associated with an increased surface area and an increased La-doping concentration. The decrease in the photoluminescence (PL) intensity of the dopant samples showed more defect levels created by the dopant La+3 cations in the SrTiO3 structure. The photocatalytic activities of Sr1−xLaxTiO3 were evaluated with regard to the degradation of 2-naphthol at typical conditions under artificial solar light. Among the candidates, Sr0.95La0.05TiO3 exhibited the highest photocatalytic performance for the degradation of 2-naphthol, which reached 92% degradation efficiency, corresponding to a 0.0196 min−1 degradation rate constant, within 180 minutes of irradiation. Manipulating the structure of Sr1−xLaxTiO3 nanocubes could produce a more effective and stable degradation efficiency than their parent compound, SrTiO3. The parameters remarkably influence the Sr1−xLaxTiO3 nanocubes' structure, and their degradation efficiencies were also studied. Undoubtedly, substantial breakthroughs of Sr1−xLaxTiO3 nanocube photocatalysts toward the treatment of organic contaminants from industrial wastewater are expected shortly. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs), which are in the class of persistent organic pollutants, are considered as hazardous pollutants. To date, these compounds were detected globally in soil, sludge, water, and other contamination sources. A variety of treatment methods have been used in recent years to degrade PAHs in the environment. Photocatalysis, among advanced techniques, is proposed as the most effective method for the treatment of PAHs. In this context, we introduce the classification of PAHs, summarize, and highlight the recent studies on photodegradation of various types of PAHs. A series of efficient photocatalysts, including TiO 2 -, Ag 3 PO 4 -, ZnO-, MHCFs-based, and others, have been reported with the potential result for photodegradation of PAHs. Focus is also placed on revealing several possible reaction pathways for different types of PAHs that have been proposed in the literature. Particular attention to current status, challenges, and prospects in the future for enhanced photodegradation of PAHs are also discussed. Image 1 • Polycyclic aromatic hydrocarbons (PAHs) are considered as hazardous pollutants. • Photocatalysis is proposed to degrade PAHs in water, soil and other sources. • Recent studies on photodegradation of PAHs is summarized and highlighted. • A series of photocatalysts have been widely proposed with the potential result. • Possible reaction pathways for various PAHs, photocatalysts have been fully revealed. [ABSTRACT FROM AUTHOR]

The epoxidation of propylene to produce propylene oxide (PO) has a vital role in the industrial production of several commercial compounds and the synthesis of numerous intermediates, fine chemicals, and pharmaceuticals. However, the current PO production processes pose significant problems regarding the environment and economy. The direct photo-epoxidation of propylene using molecular oxygen (an ideal oxidant with active oxygen of 100 wt %) under light irradiation is a promising technology to produce PO. This process offers numerous advantages, including the use of simple technologies, low-cost methods, and environmental friendliness. Many efforts have focused on the design of new photocatalyst systems, optimizing the conditions for a photocatalytic reaction, and elucidating the mechanisms of photo-epoxidation. This review is expected to serve as a comprehensive background, providing researchers with insight into the recent developments regarding the direct photo-epoxidation of propylene. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel dual-function photocatalytic twin-reactor is designed. • H 2 production rate increased 2.7 times when using a twin-reactor, compared to that in a single reactor. • The oxidation of phenol simultaneously enhances the production of H 2. • Pt was photo-deposited on SrTiO 3 which was prepared by the solid-state fusion reaction. Abstract Coupling photocatalytic H 2 evolution and phenol degradation have drawn much attention on H 2 as clean energy and phenol as an organic pollutant to the environment. Such dual-function reaction can utilize the chemical potential of phenol oxidation to make up the chemical potential required for hydrogen evolution from water splitting. The production of H 2 thus was enhanced via the phenol oxidation. However, H 2 is still needed to be purified from the reaction products by traditional methods. In this study, we demonstrated the simultaneous separation of H 2 using a photo twin-reactor under artificial sunlight, in which the photocatalytic efficiency was substantially increased due to the inhibition of backward reaction by separating H 2 from the products directly. Three Rh-doped SrTiO 3 (STO) photocatalysts calcined at 900, 1100, 1200 °C (named as STO:Rh900, STO:Rh1100, and STO:Rh1200, respectively) were prepared by solid-state fusion reaction, then photo-deposition method was applied to synthesize Pt loading STO:Rh. All photocatalysts were fully characterized by XRD, XPS, UV–vis, SEM, TEM, and DLS. A single reactor and a twin-reactor (Z-scheme system) were systematically designed by using Pt/STO:Rh for H 2 evolution photocatalyst and WO 3 for phenol oxidation photocatalyst, where Fe3+/Fe2+ pairs were served as electron transfer mediators to conduct the dual-function reaction. In the single reactor, the stoichiometric of the dual-function reaction was proposed and with high consistency to the experimental data. By using the twin-reactor, H 2 production rate increased 2.7 times, reaching 1.90 μmol g−1 h−1, compared to that in the single reactor. Moreover, the H 2 concentration of the gas-phase products increased from 70% (in the single reactor) to 94% owing to the separation function of the twin-reactor, which would significantly reduce the cost for further purification. The effect of phenol concentration on H 2 production in the twin-reactor was also thoroughly investigated. The results showed that increased phenol initial concentration would enhance the production of H 2. With 200 μmol L−1 phenol, the H 2 yield (11.37 μmol g−1 in 6-h reaction) was increased by 20% compared to that of pure water splitting. [ABSTRACT FROM AUTHOR]

Hydrogen (H 2) production in water-splitting could be significantly increased by designing cost-effective photocatalysts with remarkable performance. The main objective of this study is to recognize the behavior of soot carbon-based metal nitrides nanocomposites on its photocatalytic activity when exposed to solar lights. This study synthesized a p-n heterojunction Ta 3 N 5 /PANI composite photocatalyst modified by eco-friendly and low-cost biomass soot carbon (BSC) using hydrothermal and chemisorption methods. BSC materials are photoactive when exposed to UV light because of their band gap (E g < 4 eV), indicating they behave as semiconductors. Compared to pure Ta 3 N 5 , the hydrogen production rate of a photocatalyst containing polyaniline (PANI) can reach up to 76.9 μmol g−1 h−1, equivalent to 3.42 times superior to pristine Ta 3 N 5. The formation of a p-n heterojunction at the interface of PANI and Ta 3 N 5 was primarily responsible for improving the H 2 evolution activity. This successfully prevents the self-photocorrosion of Ta 3 N 5 by providing a rapid route for the migration and separation of photogenerated charges. It also confirms the long-term stability of the materials by repeating the experiments up to 6 cycles with more than 95 %. [Display omitted] • Ta 3 N 5 /BSC@PANI have been successfully prepared via mechanical and chemisorption techniques. • Various characterization methods were used to reveal the structural and morphological of materials. • Light-driven water splitting via Ta 3 N 5 /BSC@PANI composite was favorably demonstrated. [ABSTRACT FROM AUTHOR]

The 2D MXenes (carbides, nitrides, carbonitrides) is an emerging class of atomic layered nanomaterials that calls for intensive investigation. The tunable structures, large-surface to volume ratio, high electrical conductivity, rich surface chemistries, hydrophilicity and large redox active sites are some vital features which makes MXenes the suitable catalyst for water splitting. However, MXenes suffers from the key limitation of agglomeration, reduced long term stability and recyclability. The coupling of MXenes with metal organic frameworks (MOFs) is an effective strategy owing to the high surface area, porosity, diverse functionalities, pore-confinement effect, and tunable coordination space of MOFs provides a preferential environment for hosting MXene to prevent its agglomeration. The review aims to showcase the synergistic effects of MXenes and MOFs hybrids by exploiting the inherent features of both frameworks for water splitting application. Herein, the electronic, structural and optical properties of MXenes and MOFs frameworks are elaborated. A detailed discussion on the synthetic strategies of MXenes and MOFs hybrids explains the importance of etching technique. Lastly, variant future challenges have been highlighted to better understand the present research and progression of MXenes and MOFs hybrids. [Display omitted] • Synergistic effects of MXenes and MOFs hybrids as emerging catalysts for water splitting. • Structural and optoelectronic properties of MXenes and MOFs frameworks are elaborated. • Etching is the most commonly opted synthetic strategy for MXenes and MOFs hybrids. • Perspective challenges for water splitting efficiency improvement are mentioned. [ABSTRACT FROM AUTHOR]

• Biomolecule-capped CdTe nanoparticles were prepared through simple hydrothermal method. • L-arginine capped CdTe nanoparticles showed enhanced photoactivity under visible-light. • The hydroxyl and superoxide radical play a chief role in the degradation of methyl orange dye. In this study, L-arginine-capped cadmium telluride (CdTe) nanoparticles (NPs) were successfully prepared using the hydrothermal process. The formation, morphology, and physicochemical properties of the prepared samples were successfully characterized using different analytical techniques, such as X-ray diffraction (XRD), Fourier transforms infrared (FTIR), High-resolution transmission electron microscopy (HRTEM), Ultraviolet–visible spectroscopy (UV–Visible) and Photoluminescence spectroscopy (PL). The photocatalytic activity of the prepared samples was evaluated by the degradation of methyl orange (MO) dye under visible-light. It was observed that 86.3% MO dye removal efficiency was achieved over L-arginine-capped CdTe NPs, which was 1.6 times higher than that of the bare CdTe NPs. Interestingly, the L-arginine-capped CdTe photocatalyst was recycled in four consecutive runs without significant activity loss. [ABSTRACT FROM AUTHOR]