Visible Light Photocatalytic Degradation Research Articles

Localized surface plasmon resonance enhanced charge transfer effect in MoO2/ZnSe nanocomposites enabling efficient SERS detection and visible light photocatalytic degradation

The detection of pharmaceutical residues in the environment based on surface enhanced Raman spectroscopy (SERS) technology has become a popular tool due to its superior molecular specificity and high sensitivity. However, the practical applicability of semiconductor-based SERS sensors for trace pharmaceutical contaminants is limited due to their weak and unstable SERS performance. Herein, a donor-bridge-acceptor (D-B-A) system of MoO2 and ZnSe was fabricated to enhance the separation efficiency of electron-hole pairs in ZnSe and the charge transfer between MoO2 and ZnSe, which causes the MoO2/ZnSe nanocomposites to exhibit excellent SERS sensitivity and photocatalytic activity for the detection of multi-component contaminants and the antibiotic. The LOD of ciprofloxacin hydrochloride (CIP HCl) on MoO2/ZnSe nanocomposites is 8.30 × 10−8 M, and the degradation rate of CIP HCl is 80 % after visible light irradiation for 180 min. Our research effectively improves the SERS sensitivities and expands the practical SERS application of plasma-nonmetal/semiconductor composites, and avoids secondary contamination in the detection process. The enhancement mechanism of SERS and the interpretation of photocatalytic phenomena provide promising guidance for providing a low-cost and stable composite SERS platform in the detection and treatment of emerging contaminants.

Sulfur vacancies promoted highly efficient visible light photocatalytic degradation of antibiotic and phenolic pollutants over WS2/rGO heterostructure

Antibiotic and phenolic contaminations are severe and have become a significant source of worry in recent years. A multifunctional sulfur vacancy-induced WS2/rGO heterostructure was fabricated by a simple hydrothermal process for the photocatalytic degradation of antibiotic and phenolic compounds. The sulfur-based defects can reduce bandgap energies and enhance visible light absorption. The sulfur-enriched WS2/rGO heterostructure exhibited efficient photocatalytic activity towards Ciprofloxacin (CIP) and 4-Nitrophenol (4-NP) degradation under visible light illumination, and the deceptive rate constant is about 13 and 22 times higher than pristine WS2, and the removal efficiency was 16 and 13 times higher than pristine GO catalysts. The degradation efficiency and kinetic rate constants of 4-NP and CIP were 96.95 %, 92.30 %, and 0.113 min−1, 0.027 min−1, respectively. The excellent photocatalytic activity of WS2/rGO heterostructure was due to rGO acts as an electron mediator, and helps to accelerate charge separation and reduce the recombination rates. In addition, rGO improved the surface appearance of the heterostructure and provided more adsorption and reaction sites. The photocurrent measurement and time-resolved spectrum were used to investigate the photogenerated charge separation. Furthermore, the superoxide radical was the dominant reactive species of 4-NP and CIP degradation, as demonstrated by electron spin resonance and scavenger experiments. The possible degradation pathway and mechanism of 4-NP were proposed using liquid chromatography-mass spectroscopy.

Sonochemically prepared bismuth doped titanium oxide-reduced graphene oxide (Bi@TiO2-rGO) nanocomposites for effective visible light photocatalytic degradation of malachite green

In the present work, rGO (reduced graphene oxide) was used as a support material for the preparation of Bi@TiO2-rGO nanocomposites with uniform morphology with using ultrasound assisted process. Bi@TiO2-rGO nanocomposites samples at various loading of Bi were prepared by a facile sol-gel method assisted by ultrasound waves and their performance was compared with nanocomposites prepared by conventional stirring method. Formation of Bi and Ti based nanoparticles supported with rGO sheet was confirmed by scanning electron microscopy. The successful incorporation of rGO, Bi and Ti in Bi@TiO2-rGO nanocomposites was confirmed by XRD, Raman spectroscopy and EDAX. The XRD study showed phases corresponding to Bi, Ti and rGO and indicated the formation of crystalline Bi@TiO2-rGO nanocomposite. From the morphological analysis of nanocomposites, uniformly decorated layered morphology was observed. XRD and Raman analyses confirmed the presence of Bi, Ti and formation of rGO during preparation of Bi@TiO2-rGO nanocomposite using ultrasound assisted and conventional method. Prepared Bi@TiO2-rGO nanocomposite was applied for the degradation of malachite green dye. The photocatalytic degradation experiments were carried out in sunlight using Bi@TiO2-rGO nanocomposites prepared with varied loading of Bi using ultrasound and conventional method. At the optimum condition, degradation was found to be 93.34 % in sunlight.

Congregating Ag into γ-Bi2O3 coupled with CoFe2O4 for enhanced visible light photocatalytic degradation of ciprofloxacin, Cr(VI) reduction and genotoxicity studies

The work attempts to construct a highly effective γ-Bi2O3/CoFe2O4/Ag visible active photocatalyst for the enhanced degradation of ciprofloxacin (CIP) and Cr(VI) reduction. γ-Bi2O3/CoFe2O4/Ag photocatalyst was prepared by simple solid phase and co-precipitation methods. The nanosphere shaped CoFe2O4 photocatalyst are embedded on top of γ-Bi2O3 nanotriangle. The addition of Ag into γ-Bi2O3/CoFe2O4 heterojunction primitively facilitates the photocatalytic activity in higher rate. The quantitative analysis of photocatalyst possesses to have lower e−/h+ recombination rate compared to its counterparts. The prepared γ-Bi2O3/CoFe2O4/Ag photocatalyst showed 96.6% degradation of CIP in 220 min and 99.2% reduction of Cr(VI) in 120 min. Additionally, γ-Bi2O3/CoFe2O4/Ag showed outstanding recyclability and long-term stability with a degradation efficiency of 96.5% even after six cycles. The intermediate products formed were identified and the degradation pathway was elucidated by gas chromatography-mass spectrometry analysis. Total organic carbon measurement was carried over to assess the efficiency of complete degradation and the removal percentage was found to be 98%. The end product toxicity study towards bacteria was proven to have less toxicity level when compared to parent compound. Lastly, the genotoxicity of γ-Bi2O3/CoFe2O4/Ag photocatalyst was tested in Allium cepa and the results confirmed to have no cause of toxicity impacts. Overall, the work not only tends to provide a highly visible active γ-Bi2O3/CoFe2O4/Ag photocatalyst, but also attributes to have no further negative imprints in the environment.

Preparation, Characterization, and Application of Novel Ternary PPS/PVA/Fe3O4 Nanocomposite for Enhanced Visible Light Photocatalytic Degradation of Methylene Blue

Preparation, Characterization, and Application of Novel Ternary PPS/PVA/Fe3O4 Nanocomposite for Enhanced Visible Light Photocatalytic Degradation of Methylene Blue

Surface Modification of ZnO with Sn(IV)-Porphyrin for Enhanced Visible Light Photocatalytic Degradation of Amaranth Dye.

Two hybrid composite photocatalysts, denoted as SnP/AA@ZnO and SnP@ZnO, were fabricated by a reaction of trans-dihydroxo[5,10,15,20-tetrakis(4-pyridyl)porphyrinato]tin(IV) (SnP) and ZnO with and without pretreatment of adipic acid (AA), respectively. In SnP@ZnO, SnP and ZnO are likely held together by a coordinative interaction between the pyridyl N atoms of SnP and the Zn atoms on the surface of ZnO. In the case of SnP/AA@ZnO, the SnP centers were robustly coupled with ZnO nanoparticles through the AA anchors. SnP/AA@ZnO exhibited largely enhanced photocatalytic activities for the degradation of anionic amaranth (AM) dye under a visible light irradiation, compared to SnP, ZnO, and SnP@ZnO. The degradation efficiency of AM by SnP/AA@ZnO was 95% within 60 min at a rate constant of 0.048 min-1. The remarkable photocatalytic oxidation performance of SnP/AA@ZnO was mainly attributed to the synergistic effect between SnP and ZnO. This study is valuable for the development of highly effective composite photocatalytic systems in advanced oxidation processes and is of importance for the treatment of wastewater containing dyes.

Facile Synthesis of TiO2 with a Narrow Bandgap and Low Valence Band for Efficient Visible-Light Photocatalytic Degradation of Various Phenols

Facile Synthesis of TiO₂ with a Narrow Bandgap and Low Valence Band for Efficient Visible-Light Photocatalytic Degradation of Various Phenols

PREPARATION AND PHOTOCATALYTIC PERFORMANCE OF AG3PO4/MOS2 COMPOSITE PHOTOCATALYST

Ag3PO4 and MoS2 semiconductor materials were synthesized by hydrothermal method. The composite materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), and UV–vis diffuse reflectance spectroscopy (UV–VIS DRS), and the photocatalytic degradation of organic dyes by rhodamine B was studied. The results showed that: Ag3PO4/MoS2 composite photocatalyst is formed by using MoS2 microspheres as the matrix and Ag3PO4 nanoparticles coated on its surface or embedded in its lamellar structure. When the molar fraction of Ag3PO4 in the composite product is 75%, the composite photocatalyst has better light absorption capacity and lower photogenerated carrier recombination rate (optical band gap is 1.24 eV), and shows better visible light photocatalytic degradation activity in the photocatalytic degradation of RhB experiment, the catalytic degradation rate is as high as 95.0%. At the same time, the degradation mechanism showed that H+ and O2− were the main active substances for RhB degradation. The photocatalyst has excellent performance and simple preparation method. It has broad application prospects in the field of photocatalysis.

In-situ preparation of double Z-scheme Ag6Si2O7/C3N4/NH2-MIL-125(Ti) composite for visible-light photocatalytic degradation of organic pollutants in water

To develop photocatalysts with strong reactivity under visible light irradiation, economic feasibility, and superior effectiveness, based on the optimization of the binary NH2-MIL-125(Ti)/C3N4 composite proportion, Ag6Si2O7 can be deposited in situ on the surface of NH2-MIL-125(Ti)/C3N4 composite, the ternary photocatalytic composite material Ag6Si2O7/C3N4/NH2-MIL-125(Ti) has been fabricated with success. The ternary material was characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), field emission scanning electron microscope (FESEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM), high-resolution transmission electron microscopy (HRTEM), Fourier transforms infrared spectroscopy (FT-IR), ultraviolet–visible diffuse reflectance spectrum (UV-Vis DRS), photoluminescence (PL), electrochemical impedance spectroscopy (EIS) as well as X-ray photoelectron spectroscopy (XPS) analysis. The effects of the mass proportions of NH2-MIL-125(Ti) to C3N4 as well as Ag6Si2O7 to NH2-MIL-125(Ti)/C3N4 on the visible light catalytic performance were investigated. It was found that the binary composite material with a mass proportion of 1:5 of NH2-MIL-125(Ti) to C3N4 and the tertiary material with a mass proportion of 1:20 of Ag6Si2O7 to NH2-MIL-125(Ti)/C3N4 exhibited superior photocatalytic performance towards Rhodamine B (RhB) and various colorless organic contaminants, the apparent photocatalytic rate constants of the tertiary composite material for RhB, tetracycline, and ethenzamide were 15.6, 1.69 and 1.75 times that of the Ag6Si2O7 alone, and 1.30, 1.42 and 7.98 times that of the NH2-MIL-125(Ti)/C3N4 binary composite, individually. The composite maintains high efficiency after completing three cycles. The formation of active species and the effective degradation of organic contaminants during photocatalysis can be attributed to the compact double Z-scheme heterostructure among the three semiconductors in the ternary composite. The development of the double Z-scheme composite is of great significance for the economical and highly efficient elimination of organic contaminants.

One-step synthesis of highly active cotton floc like ZnO–BiOI: Visible-light photocatalytic performance, recovery and degradation mechanism

As a new technology for wastewater treatment and new energy development, semiconductor photocatalysis technology has been widely studied in recent year. In this study, a series of ZnO–BiOI (1:1, 1:2, 1:3, 1:3, 2:1, 2:3, 3:1, 3:2) binary composite photocatalysts were synthesized by one-step solvothermal method. XRD, SEM, TEM, HR-TEM, UV–vis DRS and PL characterization methods were used to analyze the physicochemical properties. Compared with pure ZnO, the band gap of ZnO–BiOI composite was narrower, the light absorption ability was enhanced, and the photogenerated electron-hole recombination probability was reduced. Among all the samples, ZnO–BiOI (3:2) had the best activity to degrade RhB, and the degradation rate reached 98% after 240 min under visible light, and the first-order reaction rate constant was 34.8 times that of pure BiOI. In addition, ZnO–BiOI (3:2) showed good stability in the cycle experiment. The interfacial electric field was formed in the photocatalytic process of ZnO–BiOI (3:2), which promoted more photogenerated electron-holes to participate in the oxidation reaction. The degradation process of organic matter was mainly through the oxidation of ·O2− and h+.

Facile Construction of 2D/2D ZnIn2S4-Based Bifunctional Photocatalysts for H2 Production and Simultaneous Degradation of Rhodamine B and Tetracycline.

A two-dimensional/two-dimensional (2D/2D) TiO2/ZnIn2S4 photocatalyst was reasonably proposed and constructed by a two-step oil bath-hydrothermal method. TiO2 nanosheets uniformly grown on the surface of ZnIn2S4 nanosheets and a synergetic effect between the TiO2 and ZnIn2S4 could highly contribute to improving the specific surface area and hydrophilicity of ZnIn2S4 as well as accelerating the separation and transfer of photon-generated e--h+ pairs, and thus enhancing the visible-light photocatalytic degradation and H2 evolution performance of ZnIn2S4. Rhodamine B (RhB) and tetracycline (TC) were simultaneously selected as the target pollutants for degradation in the work. The optimum photocatalytic RhB and TC degradation properties of TiO2/ZnIn2S4-10 wt% were almost 3.11- and 8.61-fold higher than that of pure ZnIn2S4, separately, while the highest photocatalytic hydrogen evolution rate was also observed in the presence of TiO2/ZnIn2S4-10wt% and 4.28-fold higher than that of ZnIn2S4. Moreover, the possible photocatalytic mechanisms for enhanced visible-light photocatalytic degradation and H2 evolution were investigated and proposed in detail. Our research results open an easy pathway for developing efficient bifunctional photocatalysts.

Synthesis and photocatalytic performance of composite g-C3N4 with functionalized multi-walled carbon nanotubes

A novel g-C3N4 composite photocatalyst was synthesized by one-step calcination using melamine and different functionalized multi-walled carbon nanotubes (MWCNT) as raw materials. The effect of additives on the photocatalytic performance of the composite g-C3N4 has been investigated. The results showed that the incorporation of functionalized MWCNT led to a porous structure in g-C3N4, increasing the specific surface area and availability of active sites. The addition of hydroxylated/carboxylated MWCNT (HMWCNT/CMWCNT) affected the band structure of g-C3N4 and reduced the band gap. The visible-light photocatalytic degradation efficiency of Rhodamine B (RhB) using g-C3N4 composited with various types and amounts of MWCNT was evaluated. Among them, g-C3N4 with 1 wt% CMWCNT showed the highest photocatalytic degradation efficiency of RhB and still had 92.71% photocatalytic activity after 5 cycles of degradation.

Synergistic effect of Ag/CuO composites on g-C3N4 nanosheets towards the visible-light active photocatalytic degradation of substituted benzoic acids in novel Ag/CuO@gCN heterojunction composites

Advanced oxidation processes (AOPs) with heterojunction-based composites have been shown to be effective for a variety of water and/or wastewater treatments. In this study, a highly efficient visible-light-driven photocatalytic composite composed of Ag/CuO@gCN ternary heterojunction based composites was successfully designed and fabricated via a facile calcination route. The uniformly assembled composites, Ag/CuO on gCN sheets were confirmed using UV–vis DRS, XRD, TEM, BET surface area, and FTIR analysis. A 15 mg/L Ag/CuO@gCN photocatalyst showed the highest photocatalytic degradation of 4-hydroxybenzoic acid (4-HBA, 95.2%) and 3-phenoxybenzoic acid (3-PBA, 81.62%) in 24 min of the reaction. The Ag/CuO@gCN composite for 4-HBA and 3-PBA degradation were obtained at a maximum degradation rate of 2.64 × 10−1 s−1 and 2.11 × 10−1 s−1, respectively and follows pseudo-first-order reactions. The photocatalytic activities for degradation of 4-HBA and 3-PBA over Ag/CuO@gCN composites are distinctly enhanced, which is higher than that of gCN and Ag/CuO composite due to lamellar configuration of gCN nanosheets and heterojunction between Ag and CuO. Furthermore, a trapping experiment was conducted to estimate the main reactive species in the degradation of 4-HBA and 3-PBA for Ag/CuO@gCN composite stability. The as-proposed Ag/CuO@gCN heterojunction composites may shed light on the design and application of materials in water purification.

Green and Rapid Synthesis of Acridine-Functionalized Covalent Organic Polymers for Photocatalysis by Combining Sonochemistry and Ion Induction.

Covalent organic polymers (COPs) are powerful candidates for achieving the visible-light-driven degradation of organic pollutants by virtue of structural designability, but their synthesis relies on harmful reagents and high temperatures, which weakens their associated green merits. Here, we report a novel strategy for combining sonochemistry with ion induction for the rapid preparation of acridine-functionalized COPs in green and mild aqueous solutions with tunable high yields of 80 to 90%. Photochemical studies reveal the ability of these COPs to harvest visible light and their sufficient conduction potentials for generating superoxide radicals. Furthermore, the photodegradation of methylene blue confirms the good photocatalytic activity and reusability of the zinc ion-based acridine-functionalized COP, which achieves 90.8% removal in 150 min and retains 82.5% activity after 5 reuse cycles, with a rate constant of up to 3.2 times that of commercial titanium dioxide nanoparticles. This strategy paves the way for the green, rapid, and mild synthesis of acridine-functionalized COPs, enabling visible light photocatalytic degradation for water treatment and energy conversion to advance in a thoroughly environmentally friendly and cost-effective manner.

Influence of fuel in the bismuth oxide photocatalytic performance for the degradation of acid blue-25 under visible light

In this work, we prepared bismuth oxide (Bi2O3) nanoparticles with and without fuels (citric acid and urea) using a one-pot solid-state combustion method at 400 °C for visible light photocatalytic degradation of acid blue 25 (AB). The nanoparticle prepared with fuel greatly influences the Bi2O3 properties such as morphology, chemical, structural, and optical properties. Bi2O3 prepared with citric acid as fuel act as an effective photocatalyst for the breakdown of acid blue 25 within 60 min under visible light irradiation. The enhanced photocatalytic property of Bi2O3 is due to the narrow band gap, high crystallinity, flower-like morphology with high active sites, and light stability of the material. Furthermore, an effective photogenerated charge separation, high charge transfer, and lower band gap, improved the absorbing capacity in the visible region of Bi2O3 (1) and enhanced its photocatalytic ability. In the photocatalytic process, the superoxide radicals (O2·) anion played a significant role during the degradation of acid blue 25. The Bi2O3 (1) maintained its effectiveness after three reaction cycles without suffering any appreciable change in structural and functional stability. These findings demonstrated an easy method for treating the hazardous effluents into non-toxic small molecules, which can be potentially applied to purify the various textile effluent.

Low-cost and eco-friendly synthesis of Mn-doped Tl2WO4 nanostructures for efficient visible light photocatalytic degradation of antibiotics in water

Water contamination from industrialization, drug use, and discharged sewage containing antibiotics is a growing concern. Photocatalytic water remediation using semiconductor catalysts is a promising approach to remove antibiotics from aquatic environments. However, high-tech semiconductor photocatalysts with reasonable costs and superior performance are still needed. In this study, we demonstrate visible light photodegradation of common antibiotics using nanostructures of Mn-doped thallium tungstate, which were synthesized using a low-cost and eco-friendly method. The ultrafine Mn doped Tl2WO4 in 35 nm size achieved by ultrasonic method. The best morphology and structure were obtained using 30 W ultrasonic waves for 15 min in the presence of Triton X-100 as a capping agent. We examined the photocatalytic activities of the produced Mn-doped Tl2WO4 nanoparticles on antibiotics such as amoxicillin (AMX), penicillin G (PCN), cephalexin (CN), ciprofloxacin (CIP), and azithromycin (AZN). The percentage of the degradation was 94%, 81%, 78%, 68% and 80% for AMX, CN, CIP and AZN respectively in presence of the UV light after 90 min of photocatalysis without the use of any oxidizing agent. Also, The yield of photocatalyst in presence of the visible light was 72%, 69%, 57%,63% and 61% for AMX, CN, CIP and AZN respectively. This study presents the initial documentation of the straightforward and low-temperature synthesis process of Mn-doped Tl2WO4 and its associated photocatalytic activity.

Synergistic interaction of three-dimensional ZnCdS@MoS2 heterostructures for high-efficiency visible-light photocatalytic degradation of dyes

High-performance photocatalysts should urgently be developed to efficiently solve serious environmental problems. Herein, we successfully synthesized a novel, visible-light activated, three-dimensional ZnCdS@MoS2 photocatalyst using a simple, two-step hydrothermal process. Based on reaction time-dependence, the growth mechanism of “oriented attachment” of the ZnCdS@MoS2 heterostructure is described in detail. The photodegradation of methylene blue (MB) indicated that the prepared sample has an outstanding photocatalytic activity owing to the accelerated photogenerated electron production rate, inhibited electron–hole pair recombination, improved visible light–utilization rate, and increased specific surface area. According to our experimental results, the degradation rate of MB using the ZnCdS@MoS2 nanocomposite was as high as 99.3% after 100 ​min of visible-light irradiation. The photocatalyst remained stable without any obvious decrease in activity even after three cycles of use. This study provides a strong support for the design of high-performance photocatalysts and their application in optoelectronic devices.

Mesoporous NiO/Ni2O3 nanoflowers for favorable visible light photocatalytic degradation of 4-chlorophenol

The present study highlights the treatment of industrial effluent, which is one of the most life-threatening factors. Herein, for the first time, two types of NiO (green and black) photocatalysts were prepared by facile chemical precipitation and thermal decomposition methods separately. The synthesized NiO materials were demonstrated with various instrumental techniques for finding their characteristics. The X-ray diffraction studies (XRD) and X-ray photoelectron spectroscopy (XPS) revealed the presence of Ni2O3 in black NiO material. The transmission electron microscopic (TEM) images engrained the nanospherical shaped green NiO and nanoflower shaped black NiO/Ni2O3 materials. Further, the band gap of black NiO nanoflower was 2.9 eV compared to green NiO having 3.8 eV obtained from UV–vis spectroscopy. Meanwhile, both NiO catalysts were employed for visible light degradation, which yields a 60.3% efficiency of black NiO comparable to a 4.3% efficiency of green NiO within 180 min of exposure. The higher degrading efficiency of black NiO was due to the presence of Ni2O3 and the development of pores, which was evident from the Barrett-Joyner-Halenda (BJH) method. Type IV hysteresis was observed in black NiO nanoflowers with high surface area and pore size measurements. This black NiO/Ni2O3 synthesized from the thermal decomposition method has promoted better photocatalytic degradation of 4-chlorophenol upon exposure to visible light and is applicable for other industrial pollutants.

Synthesis of efficient light harvesting Cr, N Co-doped TiO2 nanoparticles for enhanced visible light photocatalytic degradation of xanthene dyes; eosin yellow and rose bengal.

To solve the problem of water pollution, using environment friendly and cost effective method in short time is the need of hour. In this work, chromium (Cr) and nitrogen (N) co-doped TiO2 nanoparticles were synthesized and were used for the photocatalytic degradation of dyes under visible light. The synergistic effect of metal and non-metal co-dopants added would result in appropriate reduction of band gap {from 3.2 eVof TiO2 to 2.67eV}, decrease in recombination rate of charge carriers by trapping electrons and holes, and in better light harvesting capacity. Nanoparticles were synthesized by sol-gel method and characterized using ultraviolet-visible (UV-VIS) spectroscopy, fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), zeta potential, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET)analysis, field emission scanning electron microscopy (FE-SEM), and RAMAN spectroscopy. Eosin yellow (EY) and rose bengal (RB) were subjected to photocatalytic degradation under solar light to check the photocatalytic activity of the synthesized nanoparticles. Effects of dye concentration, the concentration of nanoparticles, time, and pH were investigated to optimize the parameters. The results obtained were remarkable for 20ppm EY solution took 10min using 1 gL-1 NPs at pH 3 and 10ppm RB solution took 5min using 0.75 gL-1 NPs at pH 5.78 (original pH) for complete degradation. Kinetics studies were also performed and both dyes followed pseudo-second-order kinetics with R2 values 0.99312 and 0.99712 for EY and RB, respectively. The study of degraded products was conducted using high-performance liquid chromatography (HPLC) hyphenated with electron spray ionization mass spectroscopy (ESI-MS) (LC-MS) and possible degradation pathways were made for both dyes. A reusability test was also performed showing the efficiency of the particles was up to 88% after 3 cycles of use. These notable results can be attributed to the efficient removal of organic pollutants using the proposed dopants in this study.

Broad-bandgap porous graphitic carbon nitride with nitrogen vacancies and oxygen doping for efficient visible-light photocatalytic degradation of antibiotics

Effective degradation methods are required to address the issue of antibiotics as organic pollutants in water resources. Herein, a two-stage thermal treatment method was used to prepare porous graphitic carbon nitride (g-C3N4) modified with nitrogen vacancies and oxygen doping at the N–(C)3 position and deep in the g-C3N4 framework. Compared with bulk g-C3N4 (BCN) (7 ± 1 m2/g), the modified sample (RCN-2h) possesses a larger specific surface area (224 ± 1 m2/g), a larger bandgap (by 0.19 eV), and a mid-gap state. In addition, RCN-2h shows 15.4, 11.2, and 9.5 times higher photodegradation rates than BCN for the degradation of 100% ofloxacin (OFX) (within 15 min), tetracycline (within 15 min), and sulfadiazine (within 35 min), respectively. The RCN-2h catalyst also exhibits superior stability and reusability. Systematic characterization and density functional theory calculations demonstrate that the synergistic effect of the porous structure, nitrogen vacancies, and oxygen doping in RCN-2h provides additional reaction sites, improved charge separation efficiency, and shorter diffusion paths for reactants and photogenerated charge carriers. Trapping experiments reveal that •O2− is the main active species in OFX photodegradation, and a possible photodegradation pathway is identified using liquid chromatography–mass spectrometry. Benefiting from the simplicity of synthesis methods and the superiority of elemental doping, carbon nitride materials with functional synergy have great potential for environmental applications.