Photodegradation Performance Research Articles

Boosting VOCs photodegradation performance of Co-doped WO3 nanofibers through efficient oxygen activation and localized electric field construction

Exploring efficient photocatalysts for degrading hazardous volatile organic compounds (VOCs) is gaining increasing popularity. Herein, we developed Co-doped WO3 nanofibrous photocatalysts by incorporating Co dopant into the WO3 lattice, where hexavalent W(VI) is replaced with divalent Co(II). This heterovalent substitution causes significant charge rearrangement around the Co dopant, resulting in a localized electric field (LEF) that enhances oxygen adsorption and activation. Such an electric field drives photoexcited electrons to gather at the Co dopant, thereby achieving spatial charge separation. Both the efficient oxygen activation and LEF forming contribute to the production of superoxide radicals. The Co0.8-WO3 nanofibers demonstrated improved photocatalytic oxidation of gaseous HCHO and CH3COCH3 compared to WO3. This study highlights the significant promotion of dopant-induced oxygen adsorption and LEF-induced efficient carrier separation. These findings offer a new direction for developing more efficient photocatalysts using unique doping approaches.

The study on the use of a biocatalyst based on Calcined Cow Teeth-TiO2 composite in degrading the methylene blue dye

Cow teeth are a type of natural biomaterial exhibiting a unique hierarchical porous structure that has not been widely studied in catalysis. In this work, from a simple deposition and calcination process, a Cow Teeth composite CCT-TiO2 was fabricated using Calcined Cow Teeth as a template and employed as a biocatalyst to remove a specific target dye from an aqueous solution under UV irradiation.The composite, CCT-TiO2, with a dosage of (0.2 g/L), at room temperature and a 3 h treatment time under UV light, showed a positive behavior towards the photochemical degradation of Methylene Blue (C = 0.01 g/L) mainly in a basic medium pH = 8 giving a catalytic efficiency rate up to 98%.The main parameters affecting the efficiency of the photocatalytic treatment, such as pH, the mass of catalyst added to the solution, the percentage of TiO2 in the composite, the concentration of MB at the beginning, the presence of ethanol, the addition of hydrogen peroxide and the temperature were studied to evaluate their influence on the degradation of methylene blue.The photodegradation performance is inversely proportional to the initial dye concentration. Similarly, for the temperature, the higher the temperature, the higher the photodegradation performance (removal rate 57% for a temperature of 55 °C). However, the presence of ethanol in the solution has a negative impact on the oxidation process, with a yield of 56% after 4 h30 min of treatment under UV irradiation. On the other side, the addition of oxygenated water considerably improves the photodegradation performances of methylene blue, with an efficiency of dye removal going up to 87% after 1 h of treatment.The excellent catalytic degradation performance and low cost suggest that this process has significant potential for effectively treating industrial wastewater loaded with cationic dye.

Facile assembly of CoS/Ag2MoO4 nanohybrids for visible light-promoted Z-type-induced synergistically improved photocatalytic degradation of antibiotics

Antibiotics have distinguished as hazardous emerging pollutants in environment, since they do not fully decomposed. Semiconductor photocatalysis are a promising technology for degradation of refractory organic pollutants under visible illumination. The assembly of compatible photocatalytic heterojunctions with suitable band structures achieves a promising approach for boosting the photodegradation performance. Herein, novel heterogeneous structured CoS/Ag2MoO4 nanohybrids were simply constructed via precipitation and tested by range of characterization procedures (XRD, UV–vis DRS, FESEM, TEM, PL, EIS, N2-adsorption/desorption, and EDX). At a specific conditions (photocatalyst dose 0.3 g/L, pH natural, and levofloxacin (LFX) antibiotic concentration 20 ppm), the CoS/Ag2MoO4 nanohybrid presented LFX degradation performance of 98.6 % in 90 min of solar-simulated illumination, which is exceeding that of pristine Ag2MoO4 (42%) and bare CoS (27%). The mechanism together with the photodegradation pathways were clarified in details. It is demonstrated that the extended range of visible light absorption and improved charge carriers separation induced by the plasmonic Z-type heterojunction formed between Ag2MoO4 and CoS were in charge for the enhancement of photocatalytic efficiency. The present work can contribute to develop effective and rapid photocatalysts for environmental requirements.

Synergistic Promotion of Photocatalytic Degradation of Methyl Orange by Fluorine- and Silicon-Doped TiO2/AC Composite Material.

The direct or indirect discharge of organic pollutants causes serious environmental problems and endangers human health. The high electron-hole recombination rate greatly limits the catalytic efficiency of traditional TiO2-based catalysts. Therefore, starting from low-cost activated carbon (AC), a photocatalyst (F-Si-TiO2/AC) comprising fluorine (F)- and silicon (Si)-doped TiO2 loaded on AC has been developed. F-Si-TiO2/AC has a porous structure. TiO2 nanoparticles were uniformly fixed on the surface or pores of AC, producing many catalytic sites. The band gap of F-Si-TiO2/AC is only 2.7 eV. In addition, F-Si-TiO2/AC exhibits an excellent adsorption capacity toward methyl orange (MO) (57%) in the dark after 60 min. Under the optimal preparation conditions, F-Si-TiO2/AC showed a significant photodegradation performance toward MO, reaching 97.7% after irradiation with visible light for 70 min. Even under the action of different anions and cations, its degradation efficiency is the lowest, at 64.0%, which has good prospects for practical application. At the same time, F-Si-TiO2/AC has long-term, stable, practical application potential and can be easily recovered from the solution. Therefore, this work provides new insights for the fabrication of low-cost, porous, activated, carbon-based photocatalysts, which can be used as high-performance photocatalysts for the degradation of organic pollutants.

Enhanced natural sunlight driven photocatalytic degradation under outdoor inconstant weather by Bi2WO6/WO3 heterojunctions

Weak sunlight irradiation intensity and inconstant weather conditions limit the practical application of photocatalysis in natural environment. In this work, efficient Bi2WO6 was synthesized using surfactant assistance strategy, which possesses superior photocatalytic activity under natural environment with outdoor sunlight as illumination source. Rod-like and sheet-like WO3 were synthesized by controlling rich and poor Cl− contents in precursor solutions, respectively, which were utilized to construct Bi2WO6/WO3 heterojunctions. Compared with pristine samples, Bi2WO6/WO3 exhibit enhanced tetracycline photodegradation performance under natural environment, whether on sunny day (sunlight intensity from 44.29 to 69.48 mW/cm2) or cloudy day (from 5.07 to 54.67 mW/cm2), even overcast day (from 2.83 to 18.99 mW/cm2), and the tetracycline degradation efficiencies reached 74.3% and 54.2% within 150 min on sunny and overcast days, respectively. Moreover, Bi2WO6/WO3 exhibit the effective photodegradation performances toward methyl orange and rhodamine b, with elimination efficiencies of 63.7% and 99.0% within 50 min irradiation, respectively.

Conjugated Polymer Modifying TiO2 Performance for Visible-Light Photodegradation of Organics.

Up to now, the use of TiO2 has been considered a promising advanced technology for organic pollutants removal from air or water, since it has high biological and chemical stability, high photoactivity, low toxicity, and low-cost production. However, there are issues to be addressed in enhancing TiO2 performance, and one of the current key issues is redesigning UV-active photocatalysts and making them active in the visible region of the electromagnetic spectrum. This way, solar light absorption will be insured, and thus, a more efficient photocatalyst could be obtained. For this reason, conjugated polymers and their derivatives are considered to act as photosensitizers, being able to shift the TiO2 activity from the UV to the visible region. Therefore, this study focuses on the synthesis of TiO2/conjugated polymer systems, which was accomplished by the deposition of poly-3,4-ethylene-dioxy-thiophene (PEDOT [-C6H4O2S-]n), a low-band semiconductor with an excellent stability due to its extending π-conjugated electron system, on titania nanoarchitecture. First of all, a TiO2 nanoarchitecture was synthesized by an ultrasound-assisted sol-gel method. Then, TiO2/PEDOT systems were obtained and characterized by using different techniques such as X-ray diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, UV-Vis diffuse reflectance, and N2 sorption measurements. The synthesized composites confirmed their mesoporosity and lower band gap values compared to bare titania, which clearly shows the ability to work as photocatalysts under visible-light activity. Further, we demonstrated that an organic pollutant, Congo Red dye, used as a model molecule could be photodegraded with the synthesized TiO2/PEDOT systems, with efficiencies of up to 95% in the case of TconvPEDOT under UV light and up to 99% for TconvPEDOT under visible-light irradiation, accomplishing in this way a successful synthesis of visible-light-activated titania photocatalyst.

Visible-light-driven photocatalytic ZnO@Ti3C2Tx MXene nanofiltration membranes for enhanced organic dyes removal

Two-dimensional (2D) Ti3C2Tx MXene nanosheets have been identified as promising for constructing ultrathin laminar nanostructures with nanoscale water transport channels for water purification. Herein, ZnO@Ti3C2Tx MXene nanofiltration (NF) membranes were prepared via coupling ZnO nanoflowers to the Ti3C2Tx MXene-based laminar nanostructure, which exhibited photocatalytic self-cleaning properties driven by visible light for enhanced organic dye removal. The physicochemical properties and NF performance with and without photocatalytic treatment were systematically characterized. The prepared ZnO@Ti3C2Tx MXene NF membrane could reject 95.44% Congo red (CR) and demonstrated an excellent water permeability of 138.81 L·m−2·h−1·bar−1 (LMH/bar). In comparison to the Ti3C2Tx MXene membrane and the same amount of ZnO powders, the ZnO@Ti3C2Tx MXene membrane demonstrated higher photodegradation performance to 10 ppm MB. Impressively, the membrane showed an enhanced separation performance for 6 cycles with a RhB rejection > 88.48% and a permeability of 138.69 LMH/bar. Lastly, the synergistic photocatalytic mechanism of ZnO@Ti3C2Tx MXene composite nanostructure was investigated. Such results may offer a novel insight for the fabrication of laminar structured Ti3C2Tx MXene-based NF membranes with photocatalytic induced anti-fouling performance for enhanced dye water purification.

Effect of Ag doping on photocatalytic activity of ZnO-Al2O3 derived from LDH structure: Synthesis, characterization and experimental study

In this research, Ag-ZnO-Al2O3 heterostructure catalyst was derived from the calcination of Ag-doped layered double hydroxide (LDH) through a solid-state process. With the aim of entirely understanding the structural and functional features, catalysts were analyzed by XRD, TGA/DTA, and FTIR techniques. The photocatalytic performance was evaluated by measuring the methyl orange (MO) photodegradation under UV irradiation. The impact of the key parameters, namely, irradiation time, catalyst dose, initial pH of solution, and the starting concentration of MO, were investigated and discussed. The characterization results exhibit a well crystallized hexagonal LDH structure. The experimental findings revealed approximately 95.8 % degradation yield after 210 min of irradiation for Ag-ZnO-Al2O3. The optimal conditions were found to be 20 mg/L of catalyst dose, 20 mg/L of MO initial concentration and initial pH of 4. In the whole, the results confirm that the Ag-ZnO-Al2O3 catalyst shows the highest adsorption and photocatalytic performances. After three recycling tests, the Ag-ZnO-Al2O3 photocatalyst maintained good recycling stability and a high photodegradation performance (90.7%). Finally, the use of Ag-ZnO-Al2O3 as heterostructure photocatalyst offer a promising approach for the degradation of more organic compounds in environmental remediation.

Preparation of Structure Vacancy Defect Modified Diatomic-Layered g-C3 N4 Nanosheet with Enhanced Photocatalytic Performance.

Structure self-modification of graphitic carbon nitride (g-C3 N4 ) without the assistance of other species has attracted considerable attention. In this study, the structure vacancy defect modified diatomic-layered g-C3 N4 nanosheet (VCN) is synthesized by thermal treatment of bulk g-C3 N4 in a quartz tube with vacuum atmosphere that will generate a pressure-thermal dual driving force to boost the exfoliation and formation of structure vacancy for g-C3 N4 . The as-prepared VCN possesses a large specific surface area with a rich pore structure to provide more active centers for catalytic reactions. Furthermore, the as-formed special defect level in VCN sample can generate a higher exciton density at photoexcitation stage. Meanwhile, the photogenerated charges will rapidly transfer to VCN surface due to the greatly shortened transfer path resulting from the ultrathin structure (≈1.5nm), which corresponds to two graphite carbon nitride atomic layers. In addition, the defect level alleviates the drawback of enlarged bandgap caused by the quantum size effect of nano-scaled g-C3 N4 , resulting in a well visible-light utilization. As a result, the VCN sample exhibits an excellent photocatalytic performance both in hydrogen production and photodegradation of typical antibiotics.

Construction of Bi2MoO6/CoWO4 Z-scheme heterojunction for high-efficiency photocatalytic degradation of norfloxacin under visible light: Performance and mechanism insights

In this work, we employed Bi2MoO6 and CoWO4 to fabricate a direct Z-scheme Bi2MoO6/CoWO4 (BMC-x) heterostructure with high redox potential for norfloxacin (NOR) photodegradation. Under visible light (λ > 420 nm) illumination, BMC-x composites displayed excellent photodegradation performance toward norfloxacin. The photodegradation rate of norfloxacin by BMC-30 reached 97.1% within 60 min of illumination, and the apparent rate constant (0.0588 min−1) was 2.42 and 17.8 times those of Bi2MoO6 and the CoWO4, respectively. The photocatalytic performance of BMC-x nanocomposites was mainly ascribed to the more efficient utilization of electrons (e−) and holes (h+) due to the fabrication of a direct Z-scheme heterostructure. In addition, the mechanisms of NOR degradation were investigated through active species capture experiments and ESR analyses, indicating that O− 2and h+ worked as primary components. Furthermore, the NOR photodegradation pathways were investigated by density functional theory (DFT) and intermediates analysis. More importantly, depending on the QSAR predictions and E.colicultivation, the comprehensive toxicity of the final intermediates was lower than that of the parent. Thus, this work offers a feasible idea for the design and construction of Z-scheme heterojunctions for the highly effective degradation of emerging contaminants in water.

Highly synergic adsorption and photocatalytic degradation of walnut shell biochar/NiCr-layered double hydroxides composite for Methyl orange

Methyl orange (MO) is a kind of azo dye, and will do great harm to the ecological environment. Alleviating this problem by removing MO is crucial role to prevent harmful damage to the environment. In this paper, NiCr layered double hydroxides (LDH) were prepared through hydrothermal method and then modified with different mass rations of walnut shell biochar. The structure and properties of biochar/NiCr-LDH composites were analyzed by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) coupled with energy disperse spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). Moreover, the adsorption and photocatalytic degradation behavior of composites on anionic dye MO were investigated. Characterization results indicated that NiCr-LDH was perfectly synthesized and coated on the biochar. All the biochar/NiCr-LDH composites show enhanced adsorption and photodegradation performance for MO dye compared with pure NiCr-LDH and biochar. When the biochar content was 22.3 wt.% and the biochar/NiCr-LDH (S2) dosage was 1.0 mg/mL, the maximum removal amount of MO could reach 100 % within 60 min at the natural pH, experimental data fitted well with the pseudo-second-order kinetic and Freundlich isotherm model, and the maximum adsorption capacity of S2 was 108.2 mg/g. Besides, compared with NiCr-LDH, S2 also demonstrated wonderful photodegradation activity for MO under visible-light irradiation, the rate constant of S2 (0.0173 min−1) is about 1.5 times that of NiCr-LDH (0.0118 min−1), and the enhanced performance can be due to the faster separation of electron-hole pairs, in which biochar acted as charge separation carriers. Meanwhile, the hydroxyl radical and superoxide radical played crucial roles in the dye photocatalytic degradation, and a possible photocatalytic degradation mechanism was proposed. The excellent photocatalytic activity and stability make biochar/NiCr-LDH an ideal photocatalyst to solve environmental crisis.

In-Situ Synthesis of CQDs/BiOBr Material via Mechanical Ball Milling with Enhanced Photocatalytic Performances

Designing simple, efficient, and environmentally friendly methods to construct high-efficient photocatalysts is an important strategy to promote the further development of the field of photocatalysis. Herein, flower-like carbon quantum dots (CQDs)/BiOBr composite photocatalysts have been prepared via in-situ synthesis by mechanical ball milling in the existence of ionic liquid. The CQDs/BiOBr composites exhibit higher photo-degradation performance for tetracycline (TC) than BiOBr monomer and the commercial Bi2O3 under visible light irradiation. For comparison, the different Br sources and synthetic methods are chosen to prepare BiOBr and CQDs/BiOBr composites. Photocatalysts prepared by ball milling and ionic liquid present significantly enhanced photocatalytic performance for removing TC. In addition, the introduction of CQDs could distinctly enhance the photocatalytic performances of pure BiOBr. The reason is that CQDs as electron acceptor effectively separate electrons and holes and inhibit their recombination. The intermediates during photocatalytic degradation were tested using liquid chromatography-mass spectrometry (LC-MS) and possible degradation pathways were given. During degradation, •OH, O2·- and h+ were identified to be the main active species based on electron spin resonance (ESR) spectra and free radical trapping experiments. A possible mechanism of CQDs/BiOBr with enhanced photocatalytic performances was further proposed.

Development of biohybrid Ag2CrO4/rGO based nanocomposites with stable flotation properties as enhanced Photocatalyst for sewage treatment and antibiotic-conjugated for antibacterial evaluation

The proposed research outlines a facile method to synthesize Silver Chromate/reduced graphene oxide nanocomposites (Ag2CrO4/rGO NCs) with a narrow dissemination size for the ecological treatment of hazardous organic dyes. The photodegradation performance toward the decontamination of model artificial methylene blue dye was assessed under solar light irradiation. The crystallinity, particle size, recombination of photogenerated charge carriers, energy gap and surface morphologies of synthesized nanocomposites were determined. The experiment objective is to use rGO nanocomposites to increase Ag2CrO4 photocatalytic efficiency in the solar spectrum. Tauc plots of ultraviolet-visible (UV–vis) spectrum were used to calculate the optical bandgap energy of the produced nanocomposites ∼1.52 eV, which resulted in a good photodegradation percentage of ∼92 % after 60 min irradiation of Solar light. At the same time, pure Ag2CrO4 and rGO nanomaterials showed ∼46 % and ∼ 30 %, respectively. The ideal circumstances were discovered by investigating the effects of several parameters, including catalyst loading and different pH levels, on the degradation of dyes. However, the final composites maintain their ability to degrade for up to five cycles. According to the investigations, Ag2CrO4/rGO NCs are an effective photocatalyst and can be used as the ideal material to prevent water pollution. Furthermore, antibacterial efficacy for the hydrothermally synthesized nanocomposite was tested against gram-positive (+ve) bacteria viz. Staphylococcus aureus and gram-negative (−ve) bacteria viz. Escherichia coli. The maximum zone of inhibition for S. aureus and E. coli were 18.5 and 17 mm, respectively.

Boosting the performance of solar light driven CeO2/BiVO4 anchored g-C3N4 nanocomposites: A systematic study toward the development of a photocatalytic and antibacterial activity

The ever-growing human population the energy and environmental crises are the top-most problems in this society. A grateful method of the photocatalytic process was initiated to remove the organic materials from the waste water to resolving environmental pollution challenges. In the process we creating the innovative photocatalysts with effective light transformation and harvesting capabilities in the waste water treatment process. Herein, the hydrothermal route followed by annealing method was used to synthesize the novel photocatalyst of CeO2/BiVO4/g-C3N4 nanocomposites (CBG NCs). The structural, surface morphological, and optoelectronic properties of the CBG nanocomposites were examined using XRD, FE-SEM, UV-Vis, and PL to confirm the material composition. Furthermore, the prepared CBG nanocomposites were subjected to evaluate the photodegradation performance using with methylene orange (MO) dye under the visible light. As a result, the CBG NCs demonstrates the maximum photodegradation performance of 90% with remarkable stability after five consecutive cycles. Additionally, antimicrobial activities were detail explored with the synthesized catalyst against the gram-positive Staphylococcus aureus (S.aureus) and gram-negative Escherichia coli (E.coli) microorganisms. As demonstrated in results, the CBG NCs (75 g/mL) had a considerable zone of inhibition of 21 ± 1.1 mm in E. coli and 15 ± 1.2 mm in S.aureus. Based on this effective performance of the photocatalytic and antibacterial response of the synthesized CBG nanocomposites were considered as the one of the highly active photocatalyst. The present research offers a possible approach to increase the photocatalytic activity and remove aquatic pollutants for this advanced dye-degradation and antibacterial activity.

Concentration Dependence of TiO2 Nanoparticles in Carbon Xerogels on Adsorption-Photodegradation Applications.

A suite of composite materials comprising carbon xerogel content and TiO2 was synthesised via a modified sol-gel method. The textural, morphological, and optical properties of the composites were extensively characterised and correlated with the observed adsorption and photodegradation performances. The homogeneity and porous structure of the composites depended on the amount of TiO2 deposited in the carbon xerogel. During polymerisation, Ti-O-C linkages were formed, which favoured the adsorption and photocatalytic degradation of the target methylene blue dye. Adsorption was deemed favourable, and most accurately fitted by the Sips model, exhibiting a maximum uptake of 209 mg g-1 estimated for the sample containing 50% TiO2. However, the synergistic effect of adsorption and photocatalytic degradation for each composite depended on the amount of TiO2 deposited in the carbon xerogel. The dye degradation process for the composites with 50%, 70%, and 90% TiO2 improved by 37%, 11%, and 2%, respectively, after exposure to visible light after adsorption. Repeated runs demonstrated over 80% of activity was retained after four cycles. Thus, this paper provides insight into the optimal amount of TiO2 required within such composites for maximum removal efficiency via adsorption and visible light photocatalysis.

Enhanced visible-light-responsive photodegradation of ciprofloxacin by direct Z-scheme ZnFe2O4@g-C3N4 nanocomposites

The zinc ferrite@graphitic carbon nitride (ZnFe2O4@g-C3N4, ZFO@CN) nanocomposites were fabricated as the direct Z-scheme heterostructured photocatalysts for the enhanced visible-light-driven photodegradation of ciprofloxacin (CIP). The 15 – 30 nm ZFO, fabricated from the nonaqueous hydrothermal method, is well-distributed on the sheet-like CN structure, resulting in the high specific surface and mesoporosity with increased surface-to-volume ratio and reactive sites. Moreover, the heterojunction interface between ZFO and CN enhances the visible light response as well as decreases the electron–hole recombination, and subsequently increases the photodegradation performance of CIP over ZFO@CN. A nearly complete removal efficiency with a rate constant of 0.047 min−1 for CIP photodegradation is observed. The environmental parameters including pH, initial CIP concentration, inorganic anions and water matrices were examined to optimize the photocatalytic activity of the ZFO@CN nanocomposite. The ZFO@CN nanocomposite exhibits excellent structural and physicochemical stability and good reusability over 5 cycles. The radical trapping results signify that O2− and h+ are the primarily responsible radicals for the enhanced degradation of CIP over direct Z-scheme ZFO@CN heterojunction. Results clearly elaborate on the superiority of ZFO@CN over the photodegradation of CIP, which can serve as the platform for the fabrication of metal oxide@CN as the Z-scheme heterojunction for water and wastewater purification.

Ti4+-dopamine/sodium alginate multicomponent complex derived N-doped TiO2@carbon nanocomposites for efficient removal of methylene blue

A one-pot route for the preparation of TiO2@carbon nanocomposite from Ti4+/polysaccharide coordination complex has been developed and shown advantages in operation, cost, environment, etc. However, the photodegradation rate of methylene blue (MB) needs to be improved. N-doping has been proven as an efficient means to enhance photodegradation performance. Thus, the present study upgraded the TiO2@carbon nanocomposite to N-doped TiO2@carbon nanocomposite (N-TiO2@C) from Ti4+-dopamine/sodium alginate multicomponent complex. The composites were characterized by FT-IR, XRD, XPS, UV–vis DRS, TG-DTA, and SEM-EDS. The obtained TiO2 was a typical rutile phase, and the carboxyl groups existed on N-TiO2@C. The photocatalyst consequently showed high removal efficiency of MB. The cycling experiment additionally indicated the high stability of N-TiO2@C. The present work provided a novel route for preparing N-TiO2@C. Moreover, it can be extended to prepare N-doped polyvalent metal oxides@carbon composites from all water-soluble polysaccharides such as cellulose derivatives, starch, and guar gum.

Phases evolution and photocatalytic activity of Cu2O films electrodeposited from a non-pH-adjusted solution.

A pure-phase Cu2O film photocatalyst was successfully prepared by the electrodeposition technique from a non-pH-adjusted solution. To investigate the phase evolution and photocatalytic activity of the film, the electrodeposition was conducted at different deposition temperatures. Photocatalytic activity of the films was evaluated from methylene blue (MB) dye degradation. The Cu2O phase initially appeared at room temperature and its fraction was found to increase with increasing the deposition temperature, while the impurity phase was successfully diminished. A pure Cu2O film with a narrow optical bandgap energy of 1.96 eV was obtained at 75°C. The multi-faceted crystals were found to form at 45°C and became a truncated octahedral structure that possessed {111} and {100} facets as deposition temperature further increased. A preferred orientation growth of {110} facet, which is known to possess a relatively high surface energy, was produced at 75°C. The performance of MB photodegradation enhanced gradually by increasing the deposition temperature. The increase of photocatalytic activity could be attributed to the rise of photoelectrochemical response and the decrease of resistance charge transfer because of narrowing bandgap energy, increasing Cu2O fraction, and growing a relatively high catalytic activity facet which had escalated redox reaction that decomposed MB at the photocatalyst-solution interface.

Cost-effective and rapid synthesis of ZnO photocatalyst with the high performance of dye photodegradation as application in minimizing chemical risks used in industry

Cost-effective and rapid synthesis of ZnO photocatalyst with the high performance of dye photodegradation as application in minimizing chemical risks used in industry

Tailoring Black TiO2 Thin Films: Insights from Hollow Cathode Hydrogen Plasma Treatment Duration

In this study, we report the use of a radiofrequency plasma-assisted chemical vapor deposition (RF-CVD) system with a hollow cathode geometry to hydrogenate anatase TiO2 thin films. The goal was to create black TiO2 films with improved light absorption capabilities. The initial TiO2 was developed through magnetron sputtering, and this study specifically investigated the impact of hollow cathode hydrogen plasma (HCHP) treatment duration on the crucial characteristics of the resulting black TiO2 films. The HCHP treatment effectively created in-bandgap states in the TiO2 structure, leading to enhanced light absorption and improved conductivity. Morphological analysis showed a 24% surface area increase after 15 min of treatment. Wettability and surface energy results displayed nonlinear behavior, highlighting the influence of morphology on hydrophilicity improvement. The anatase TiO2 phase remained consistent, as confirmed by diffractograms. Raman analysis revealed structural alterations and induced lattice defects. Treated samples exhibited outstanding photodegradation performance, removing over 45% of methylene blue dye compared to ~25% by the pristine TiO2 film. The study emphasized the significant impact of 15-min hydrogenation on the HCHP treatment. The research provided valuable insights into the role of hydrogenation time using the HCHP treatment route on anatase TiO2 thin films and demonstrated the potential of the produced black TiO2 thin films for photocatalytic applications.