Enhancement Of Photocatalytic Efficiency Research Articles

Photocatalytic degradation of methylene blue using chitosan/NiO nanocomposite: A comprehensive exploration

The present research work aims to illustrate the potential power of chitosan nanoparticles and chitosan/nickel oxide (NiO) nanocomposite for the photocatalytic degradation of methylene blue (MB). Initially, chitosan nanoparticles and chitosan/NiO nanocomposite were prepared using ball milling technique, focusing on the theory of top-down preparation. It was observed that, the as-prepared chitosan/NiO nanocomposite exhibited spherical shape with small size. Meanwhile, chitosan nanoparticles were prepared with irregular shape as depicted from TEM analysis. XRD affirmed the pure phase and crystalline structure of chitosan nanoparticles as a result to the observation for two peaks at 11.3o and 20.11o. New characteristic peaks at 35.3o, 38.5o, 49o, and 63o were noticed owing to the presence of NiO blended with chitosan nanoparticles. The estimated values of optical band gap energy for chitosan nanoparticles and chitosan/NiO nanocomposite are (3.6 eV, 3.5 eV), respectively. The photocatalytic degradation of MB dye employing chitosan nanoparticles and chitosan/NiO nanocomposite achieved 21 % and 96.1 %, respectively. The enhancement of photocatalytic efficiency of MB dye was mainly attributed to the potential effect of NiO nanoparticles. The findings also demonstrated that the photocatalytic performance of both chitosan nanoparticles and chitosan/NiO nanocomposite was pH, time, and catalyst doses dependent and obey Langmuir-Hinshelwood model. The photocatalytic activity of chitosan/NiO nanocomposite lost 14.9 % of its performance after first two cycles. Therefore, chitosan/NiO nanocomposite has emerged as a pioneering agent in sustainable water treatment, promising a transformative approach to combat water pollution. This study can guide future research, industry practices, and policy decisions towards a future where water treatment is synonymous with environmental harmony and innovation.

Striking the balance: Unveiling the interplay between photocatalytic efficiency and toxicity of La-incorporated Ag3PO4

Persistent molecules, such as pesticides, herbicides, and pharmaceuticals, pose significant threats to both the environment and human health. Advancements in developing efficient photocatalysts for degrading these substances can play a fundamental role in remediating contaminated environments, thereby enhancing safety for all forms of life. This study investigates the enhancement of photocatalytic efficiency achieved by incorporating La3+ into Ag3PO4, using the co-precipitation method in an aqueous medium. These materials were utilized in the photocatalytic degradation of Rhodamine B (RhB) and Ciprofloxacin (CIP) under visible light irradiation, with monitoring conducted through high-performance liquid chromatography (HPLC). The synthesized materials exhibited improved stability and photodegradation levels for RhB. Particularly noteworthy was the 2% La3+-incorporated sample (APL2), which achieved a 32.6% mineralization of CIP, nearly three times higher than pure Ag3PO4. Toxicological analysis of the residue from CIP photodegradation using the microalga Raphidocelis subcapitata revealed high toxicity due to the leaching of Ag + ions from the catalyst. This underscores the necessity for cautious wastewater disposal after using the photocatalyst. The toxicity of the APL2 photocatalysts was thoroughly assessed through comprehensive toxicological tests involving embryo development in Danio rerio, revealing its potential to induce death and malformations in zebrafish embryos, even at low concentrations. This emphasizes the importance of meticulous management. Essentially, this study adeptly delineated a thorough toxicological profile intricately intertwined with the photocatalytic efficacy of newly developed catalysts and the resultant waste produced, prompting deliberations on the disposal of degraded materials post-exposure to photocatalysts.

Nitrogen-doped carbon quantum dot as electron acceptor anchored on graphitic carbon nitride nanosheet for improving rhodamine B degradation

Carbon quantum dots (CQDs) hold significant promise for wastewater treatment because of their remarkable attributes, including robust stability, outstanding biocompatibility, minimal toxicity, superior water dispersibility, cost-effective production, and exceptional photo-stability.In this study, CQDs were synthesized using microplasma and tested for the degradation of rhodamine B (RhB) (5 mg/L) under different conditions, with a Solar simulator and UVA illumination. Specifically, graphitic carbon nitride nanosheets (NCN) in conjugation with carbon quantum dots (NCN@CQD) were prepared with different amounts of CQD. The synthesized CQD, NCN, and NCN@CQD underwent characterization using various compositional and structural analytical techniques. The results show that nitrogen species were effectively incorporated into the CQDs framework and CQDs are anchored on NCN forming NCN@CQD successfully. Subsequently, all samples were then investigated in degrading Rhodamin B, RhB, to assess the photocatalytic activity. The results reveal that the presence of CQDs substantially improved the photocatalytic efficiency of NCN. Specifically, the CQDs anchored on NCN exhibited a substantial enhancement in the photoactivity for RhB decomposition under a solar light simulator, surpassing that of pure NCN. The amount of CQD in the NCN@CQD sample exerted a strong influence on the photocatalytic activity. All NCN@CQD samples exhibited remarkable enhancements in both adsorption and photocatalytic performance compared to pure CQD and NCN samples. In an optimization study, a best NCN@CQ photocatalyst was identified, showing a 40 % enhancement of photocatalytic efficiency compared to the use of NCN alone. A visible light photocatalytic activity of 91 % can be attained within 150 min, exhibiting a reaction rate constant of 0.0135 min−1 toward RhB decomposition, which was double as for the individual NCN (0.0067 min−1). The boosted photocatalytic activity resulting from the synergistic effect between NCNs and CQDs can be attributed to the efficient function of CQD as an electron acceptor. The proposed mechanism of photocatalytic degradation of RhB is illustrated in detail.

Synergistic enhancement of photocatalytic efficiency and durability in CoNi-decorated Cu2O/Cu films for superior synthetic dye degradation

The Cu2O/Cu emerges as a promising candidate for photocatalytic application owing to its efficient photon absorption in the visible light spectrum. However, the susceptibility of Cu2O-based photocatalysts to self-decomposition diminishes their effectiveness. This study introduces CoNi as co-catalyst to enhance the durability of Cu2O/Cu photocatalyst. Electrodeposition was employed to decorate the Cu2O/Cu crystal surface with Co, Ni and CoNi. The deposition potential of CoNi was optimized to produce a high-performance photocatalyst. The utilization of CoNi co-catalyst resulted in significant enhancements in photoelectrochemical properties under light irradiation when compared to using a single Co or Ni co-catalyst, suggesting a synergistic effect between Co and Ni within the system. The enhancement is evidenced by a noteworthy increase in the photocurrent of the photocatalyst, rising from 10.24 mA/cm2 to 20.81 mA/cm2. In addition, the decoration of CoNi resulted in a reduction of the charge transfer resistance from 4.2 kΩ to 0.7 kΩ, while simultaneously increasing the electrochemically active surface area of the photocatalyst from 15.49 cm2 to 157.69 cm2. The observed modifications lead to a substantial improvement in the photocatalytic efficiency, resulting in an impressive 88 % degradation of methylene blue, which is 3.4 times higher than achieved in the absence of the co-catalyst. Moreover, there was a significant improvement in the photostability of the photocatalyst, with an increase from 16.81 % to 50.55 %. These findings demonstrate the significance of CoNi co-catalyst decoration in producing a highly active and durable photocatalyst, making it a promising candidate for efficient synthetic dyes degradation.

Role of metal (Fe(III), Zn(II), and Co(III)) and porphyrin in enhancing photocatalytic performance of MTCPP/TiO2 photocatalysts

Metal-porphyrin complexes modified TiO2 photocatalyst, called MTCPP@P25, shows excellent photocatalytic activity under visible light irradiation. Metal-porphyrin is successfully utilized to broaden the photo response range of TiO2 from ultraviolet (3.2 eV) to visible light (2.43 eV to 2.65 eV) resulting in significant enhancement of photocatalytic efficiency. MTCPP@P25 exhibited the higher photocatalytic activity than bare TiO2. Additionally, introduction of different metals, like Fe, Zn, and Co into porphyrin ring can effectively adjust the photocatalytic activity of MTCPP@P25 due to the increasing the electron density of porphyrin rings. The degradation order for MB followed as FeTCPP@P25≧ZnTCPP@P25 > CoTCPP@P25. This finding demonstrated that FeTCPP@P25 and ZnTCPP@P25 possess higher photo-excited electrons under visible irradiation resulting in higher photocatalytic performance. Based on the PL and EIS analysis, FeTCPP@P25 exhibited longest lifetime and fast electron transition compared to ZnTCPP@P25. The spent FeTCPP@P25 were reusable after three cycles, the efficiency remained at approximately 80 %.

Advancements in organic pollutant remediation: The role of nitrogen-doped rGO-CeO2 in photocatalytic efficiency enhancement

In this work, a novel nitrogen-doped reduced graphene oxide-ceria (N-doped rGO-CeO2) photocatalyst was successfully synthesized and exhibited a notable capability in degrading various organic pollutants. Among the synthesized samples, rGO-CeO2-900 N2 demonstrated the most efficient photocatalytic activity, achieving a 77.43% degradation rate for tetracycline (TC) fitting the modified Elovich model (R2 = 0.99). The CeO2 addition can increase defects and amorphous carbon species in rGO in Raman spectra. The rGO adding and N doping can contribute to more effective separation of photo-excited electrons/holes (e-/h+) and a faster rate of charge transfer via the results of photochemical tests. With the combination between rGO and CeO2, the N doped rGO-CeO2 catalyst gains certain anti-H+ ability in TC degradation and more·O2- can be generated under light, while the N doping can form an impurity level N 2p in CeO2 and create additional reactive sites on the rGO. This N doped rGO-CeO2 photocatalyst is well-suited for the harmless degradation and offers significant potential in wastewater treatment and pollution control.

A novel two-dimensional GaN/InGaN heterostructure for photocatalytic water splitting: A first-principles calculation

The pursuit of optimal bandgap and band edge positions is crucial for effective photocatalytic catalysts, leading to significant attentions in both experimental and theoretical research on modulating the band structure of semiconductor photocatalysts. In this study, the electronic, optical and photocatalytic properties of 2D monolayer GaN and GaN/InGaN heterostructures are investigated using DFT calculations. It reveals that introducing strain is an effective approach to not only alter the band gap type from indirect to direct but also influence the magnitude of the band gap. At a 10% tensile strain, a Z-type heterostructure is formed for the 2D GaN/InGaN heterostructures, which proves favorable for enhancing the efficiency of photocatalytic water splitting. However, it is worth noting that the band gap type remains indirect, necessitating additional energy for electron transitions. On the other hand, when increasing the compressive strain from − 2.5% to − 5%, the 2D GaN/InGaN heterostructure transforms from type I to type II, exhibiting direct band gaps with an enhanced light absorption range. This results in a significant redshift and increased optical absorption intensity within the visible light range, leading to a substantial enhancement in photocatalytic efficiency. Consequently, our findings demonstrate that the 2D GaN/InGaN heterostructure holds promising potential as a candidate material for efficient photocatalytic water splitting applications.

Cobalt modified enhancement in photocatalytic efficiency of SnO2 nanoparticles for removal of industrial dyes

Cobalt modified enhancement in photocatalytic efficiency of SnO2 nanoparticles for removal of industrial dyes

Large enhancement of visible light photocatalytic efficiency of ZnO films doped in-situ by copper during atomic layer deposition growth

In the present study, we investigate the photocatalytic activity of ZnO thin films doped by copper atoms in successive steps during the film growth by the atomic layer deposition method. Scanning electron microscopy and x-ray diffraction measurements reveal a polycrystalline structure of samples with degrading crystallinity for films with higher Cu content. X-ray photoelectron spectroscopy analysis is consistent with the presence of copper in the Cu+ state for samples with a relative Cu content lower than 1 at.%. Those samples exhibit p-type conductivity indicating that copper ions occupy substitutional, CuZn, acceptor sites in ZnO. As established from UV–vis measurements, Cu-doped ZnO films also show enhanced optical absorption in the visible region. A reduced electron-hole recombination rate, due to much lower intrinsic free charge carrier concentrations in the doped samples, and the increased light absorption in the visible region, lead to a large enhancement of photocatalytic efficiency observed in doped films under simulated sunlight irradiation.

Infrared light induced sustainable enhancement of photocatalytic efficiency by thermoelectric effect

Hindering the recombination of photoinduced electron-hole pairs is of significance for enhancing photocatalytic performance. Applying a voltage to separate carriers offers an option to realize it. Thermoelectric materials own the ability to continuously sustain a voltage when a temperature difference exists between its two sides. However, maintaining the thermoelectric effect without wasting additional energy remains a challenge. Herein, a C3N4/Polyaniline/Poly(vinylidene fluoride) cilia array was fabricated to reach efficient photocatalysis through thermoelectric effect and photothermal effect. The cilia array structure offers more than 40% of light absorbance compared to the film. Hence, the infrared light in sunlight, which was usually omitted in photocatalysis, was transformed into heat. Through the unique design which draws upon the huge difference in thermal conductivity of air and water, a temperature gap was formed between the top and bottom sides of the cilia array by half-submerging it in water. Therefore, the photocatalytic efficiency was improved by 84.4%. This work achieves an energy-saving method to enhance photocatalytic performance by activating thermoelectric effect through infrared light, shedding light on the application of multi-modes enhanced photocatalysis.

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.

Hydrothermal Synthesis of Bimetallic (Zn, Co) Co-Doped Tungstate Nanocomposite with Direct Z-Scheme for Enhanced Photodegradation of Xylenol Orange

In the present study, pristine ZnWO4, CoWO4, and mixed metal Zn0.5Co0.5WO4 were synthesized through the hydrothermal process using a Teflon-lined autoclave at 180 ℃. The synthesized nanomaterials were characterized by various spectroscopic techniques, such as TEM, FTIR, UV–vis, XRD, and SEM-EDX-mapping to confirm the formation of nanocomposite material. The synthesized materials were explored as photocatalysts for the degradation of xylenol orange (XO) under a visible light source and a comparative study was explored to check the efficiency of the bimetallic co-doped nanocomposite to the pristine metal tungstate NPs. XRD analysis proved that reinforcement of Co2+ in ZnWO4 lattice results in a reduction in interplanar distance from 0.203 nm to 0.185 nm, which is reflected in its crystallite size, which reduced from 32 nm to 24 nm. Contraction in crystallite size reflects on the optical properties as the energy bandgap of ZnWO4 reduced from 3.49 eV to 3.33 eV in Zn0.5Co0.5WO4, which is due to the formation of a Z-scheme for charge transfer and enhancement in photocatalytic efficiency. The experimental results suggested that ZnWO4, CoWO4, and Zn0.5Co0.5WO4 NPs achieved a photocatalytic efficiency of 97.89%, 98.10%, and 98.77% towards XO in 120 min of visible solar light irradiation. The kinetics of photodegradation was best explained by pseudo-first-order kinetics and the values of apparent rate const (kapp) also supported the enhanced photocatalytic efficiency of mixed metal Zn0.5Co0.5WO4 NPs towards XO degradation.

MOF-derived CdS/CoO S-type heterojunctions for improving the efficiency of photocatalytic evolution.

The aggravating extreme climate changes and environmental pollution problems have stimulated the exploration of green alternatives to conventional fossil fuels and green environmental treatments. Photocatalysis is recognized as an outstanding green tool for solving the energy crisis and environmental rehabilitation issues. Restricted by the high cost of precious metals, researchers expect to obtain low-cost, efficient and stable photocatalysts. Herein, CdS materials were derived through MOFs and subsequently combined with CoO to form CdS/CoO heterojunctions. The catalytic ability was evaluated by the photocatalytic degradation of tetracycline hydrochloride (TC) and the photocatalytic production of hydrogen. With the integration of CoO, in terms of TC degradation, CdS/CoO heterojunctions can degrade over 90% of TC within 1 hour. In terms of hydrogen production, compared to CdS alone, the hydrogen production efficiency of the CdS/CoO heterojunction increased by 1.7 times. The initial analysis of the reasons for the enhancement of photocatalytic efficiency was conducted by TEM, XPS and other characterization means. Density functional theory (DFT) calculations verified the existence of a built-in electric field in the CdS/CoO heterojunction, which was the essential reason for the improved catalytic performance, and finally, the presence of ˙O2- and ˙OH in the photocatalytic system was demonstrated by the ESR technique. Based on the carrier separation/transfer pathway in the heterojunction, a simple and novel S-type heterojunction scheme was proposed.

BiOBr cluster spheres grown on conductive glass for a recyclable and efficient photocatalytic reactor

In this paper, the growth of BiOBr cluster spheres on Fluorine-doped Tin Oxide (FTO) substrates was achieved by ethanol dispersion of BiOBr powder and subsequent roasting treatment. After ultraviolet (UV) illumination for 30 min, the BiOBr/FTO composite film could degrade 68 % of 10 mg/L rhodamine B (RhB), which was 36 % higher than that realized by BiOBr powder. The good photocatalytic stability of the composite film was maintained after three cycles. This study revealed the advantages of photocatalytic efficiency enhancement and easy integration of photocatalytic reactors brought about by the thin-film composite of FTO and cluster spheres BiOBr and provided a promising solution for photocatalysts.

In Situ Assembly of Hydrogen-Bonded Organic Framework on Metal-Organic Framework: An Effective Strategy for Constructing Core-Shell Hybrid Photocatalyst.

The hydrogen-bonded organic frameworks (HOFs) have rarely been considered for photocatalytic application, given their weak stability and low activity. One presumably effective strategy to improve the photocatalytic performance of the HOFs is to produce a core-shell composite by fabricating a particular nanostructure using stable HOFs. To this end, the surface-functionalized metal-organic frameworks (MOFs) are used as the host matrix to support the in situ assembly and subsequent multisite growth of the stable HOFs. MOF@HOF eventually obtains core-shell hybrids, i.e., NH2 -UiO-66@DAT-HOF. This newly synthesized core-shell nanostructure exhibits excellent stability and superb photocatalytic performance. For example, in terms of tetracycline degradation, the optimal composite presents an apparent reaction rate constant of 60.7 and 7.6 times higher than its parent materials NH2 -UiO-66 and DAT-HOF. Such a pronounced enhancement in photocatalytic efficiency of the hybrid material is attributed to the broader visible-light utilization range compared to its individual parent material as well as the efficient separation of charge carriers supported by the S-scheme heterojunction. In addition, it is particularly notable that the photocatalytic efficiency of the yielded core-shell nanostructure can remain high after several-cycle applications. This work provides a universal scheme for synthesizing the MOF@HOF core-shell hybrids.

Carbonitrides-modified silver phosphotungstate photocatalysts constructed by thermal post-treatment of self-assembled polyoxometalate hybrids for efficient visible-light photocatalytic activity

Carbonitrides-modified silver phosphotungstate (CN-AgPW) photocatalysts were synthesized by self-assembly and solid-phase thermal polymerization. The microstructural and optical properties of the synthesized photocatalysts were systematically investigated, and the photocatalytic activity was evaluated by the degradation of Aflatoxin B1 (AFB1) under visible light (λ ≥ 420 nm) irradiation. The synthesis process, the interaction of compounds, and Z-scheme charge transfer path of the synthesized photocatalysts were investigated. The rate constants k of CN-AgPW-5 are 12.95 and 12.50 times higher than those of CN-390 and AgPW-390, respectively. This study provides a new strategy for the synthesis and enhancement of photocatalytic efficiency of insoluble polyoxometalate photocatalysts.

Enhancement in Photocatalytic Efficiency of Commercial TiO2 Nanoparticles by Calcination: A Case of Doxycycline Removal

In this study, the pure and calcined forms of Degussa TiO2 were applied for photocatalytic removal of doxycycline - a broad-spectrum tetracycline antibiotic. The calcination of TiO2 at 500 °C enhanced the photocatalytic efficiency of the TiO2 under optimal operational conditions of 5 ppm of doxycycline, 0.25 g/L of TiO2, pH 6.5, 120 min, and room temperature. In addition, the changes in morphology, crystal structure, and optical properties of the materials before and after calcination were observed by scanning electron microscopy, X-ray diffraction, and UV-Visible spectroscopy. The reaction kinetics of the doxycycline removal was also investigated based on the Langmuir-Hinshelwood model with a correlation coefficient R2 of >80%. Results showed that the photocatalytic ability of TiO2 is stable and enhanced after being calcined at a suitable temperature of 500 °C. This opens up the potential application of TiO2 in the treatment of emerging organic pollutants in water. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Enhanced Visible-Light-Driven Photocatalysis of Ag/Ag2O/ZnO Nanocomposite Heterostructures.

Visible-light-driven photocatalysis is one promising and efficient approach for decontaminating pollutants. Herein, we report the combination of localized surface plasmon resonance (LSPR) and p-n heterojunction structure Ag-Ag2O-ZnO nanocomposite synthesized by a hydrothermal process for the suppression of photogenerated electron-hole pair recombination rates, the extension of the absorption edge to the visible region, and the enhancement of photocatalytic efficiency. The prepared nanocomposites were investigated by standard analytical techniques and the results revealed that the synthesized powders were comprised of Ag, Ag2O, and ZnO phases. Photocatalytic activity of the photocatalyst tested for methylene blue, methyl orange, and rhodamine B showed the highest photocatalytic degradation efficiency: 97.3%, 91.1%, and 94.8% within 60 min under visible-light irradiation. The average lifetime of the photogenerated charge carriers was increased twofold in the Ag-Ag2O-ZnO photocatalyst (~10 ns) compared to the pure ZnO (~5.2 ns). The enhanced photocatalytic activity resulted from a decrease of the charge carrier recombination rate as inferred from the steady-state and time-resolved photoluminescence investigations, and the increased photoabsorption ability. The Ag-Ag2O-ZnO photocatalyst was stable over five repeated cyclic photodegradation tests without showing any significant changes in performance. Additionally, the structure indicated a potential for application in environmental remediation. The present study showcases the robust design of highly efficient and reusable visible-light-active photocatalysts via the combination of p-n heterojunction and LSPR phenomena.

Magnetic cobalt ferrite/reduced graphene oxide (CF/rGO) porous balls for efficient photocatalytic degradation of oxytetracycline

Photocatalytic degradation is an effective technique for removing antibiotics from contaminated water. The kernel of photocatalytic degradation lies in the design and preparation of high-performance and recyclable catalysts. Herein, magnetic porous cobalt ferrite/reduced graphene oxide (CF/rGO) balls were prepared by calcination of spherical composites obtained via modified microfluidic method for effective photocatalytic degradation of oxytetracycline (OTC). The strong interfacial interaction between rGO and cobalt ferrite nanoparticles in porous balls enhanced electron transfer, charge separation and light absorption. Porous spherical structure was favorable for light harvesting. The catalyst could rapidly and efficiently absorb OTC. These characteristics were beneficial to the enhancement of photocatalytic efficiency. The optimized sample (CF/rGO-0.2) exhibited an excellent apparent rate constant (0.0410 min−1) for OTC degradation under visible light irradiation, which was 3.73 times that of CF/rGO-0 (0.0110 min−1). CF/rGO-0.2 had excellent stability in cycle experiments and could be quickly recovered by magnets. The trapping experiments showed that hole (h+) and superoxide radicals (·O2-) acted an extremely important role in degradation of OTC, thus suggesting a possible photocatalytic reaction mechanism. This work provides a potential photocatalyst for antibiotic removal from water.

Preparation of BiVO4/RGO‐TNT Nanomaterials for Efficient and Recyclable Photocatalysis of Imidacloprid Insecticide

AbstractThe photocatalytic composites based on BiVO4, TiO2 nanotubes (TNT) and reduced graphene oxide (RGO) were synthesized by a one‐step hydrothermal synthesis method. The properties and structures of the samples were characterized by SEM, XRD, UV‐Vis DRS, Raman spectroscopy, photoluminescence spectroscopy and XPS. The effects of RGO‐TNT loading, pH, and dosage of catalysts on degradation efficiency were tested. The best removal results were occured on the condition that loading amount of RGO‐TNT was 10 %, solution pH 10, and catalyst dosage was 1.4 g L−1. The obtained ternary composite with 10 wt% RGO‐TNT exhibited a significant enhancement in photocatalytic efficiency due to the lower band gap with enhanced light absorption and a suppression in the recombination rates of the photogenerated charge carriers, and about 73 % of imidacloprid was degraded within 30 min under UV irradiation. Furthermore, BiVO4/RGO‐TNT‐10 can be reused for 6 times without obvious catalysis loss. Trapping experiments showed that hydroxyl radicals were the main active species in the imidacloprid photocatalytic degradation, and a possible photocatalytic mechanism was proposed based on the results of trapping experiments.