Visible Photocatalytic Activity Research Articles

Study on Fe-doped BiOBr with enhanced visible photocatalytic activity for the degradation of levofloxacin

In this study, Fe-doped BiOBr photocatalysts were prepared by hydrothermal method. Due to the unique flower-like structure of the composite materials, when the Fe-ions doping amount was 3 mol%, the degradation rate of levofloxacin was 85.06 % within 30 min. After 5 cycles, the degradation rate of Fe-BiOBr could still reach 83.46 %, it exhibited good photocatalytic activity. In addition, the possible degradation products and pathways were predicted by LC–MS, and toxicity analysis of intermediates was carried out. In addition, the free radical capture experiments and electron paramagnetic resonance (EPR) revealed that h+, ∙OH and ∙O2- were the main reactive species, which in turn suggested the possible photocatalytic mechanism for the Fe-doped BiOBr system.

Potato peel carbon dots produced via fixed bed pyrolysis reactor decorated 1-D TiO2 nanorods for rapid removal of methylene blue, Cr (VI), Escherichia coli, and Aspergillus niger

In this work, new type carbon quantum dots produced from waste of biomass were used as a dopant molecule in order to investigated photocatalytic properties of TiO2 nanorods structures. Low-cost and eco-friendly carbon quantum dots (CQDs) were obtained via slow pyrolysis of potato peels (PP) as a biomass waste without any chemicals by fixed bed pyrolysis. Potato peel quantum dots (P-CQDs) decorated TiO2 nanorods (P-CQDs/TNRs) were synthesized were by utilizing their high specific surface area, good dispersion, abundant surface functional groups. (P-CQDs) were imposed on the surface of the one-dimensional TiO2 nanorods fabricated via chemical impregnation method for P-CQDs/TiO2 nanorods (P-CQDs/TNRs) that TiO2 nanorods have been fabricated by hydrothermal route. Characteristic properties of as-prepared P-CQDs/TNRs photocatalysts were characterized employing TGA, XRD, XPS, FE-SEM/EDS, HRTEM, FTIR, fluorescence and UV–vis spectroscopy, resp. The photocatalytic activity of as-prepared P-CQDs/TNRs were investigated for methylene blue, hexavalent chromium, Escherichia coli and Aspergillus niger under UV-A. The obtained results suggest that the photocatalytic activity of P-CQDs/TNRs composites was slightly enhanced as compared to that of TNRs. The scenario behind the superior photocatalytic activity of P-CQDs/TNRs may be having a synergetic effect between P-CQDs molecules and the surface of TNRs, and also the design of the charge-transfer channel of TNRs. Moreover, the carbon derived from a natural green source possesses the various functional groups such as CC, C-OH, C-O-C, CO, and when these functional groups deposited to the surface of the TiO2 nanorods, newly formed nanocomposites can improve the visible light-driven photocatalytic activity.

Fe3O4/ZnO/L-lysine functionalized graphene oxide a promising nanocomposite with double Z-scheme visible photocatalytic and dark catalytic activity for water remediation

Developing multifunctional catalysts for efficient pollutant degradation in dark and visible light conditions represents a significant advancement in water remediation technology. This study reports the synthesis of a novel Fe3O4/ZnO/Lys-rGO nanocomposite via environmentally friendly methods that exhibit catalytic-photocatalytic activity for efficient degradation of organic pollutants. The synergistic effect of compositing Lys-rGO, a bio-organic component with a narrow band gap (1.08 eV), into the Fe3O4/ZnO inorganic composite induces a double Z-scheme mechanism by providing two pathways for effective charge separation in the visible photocatalytic activity of the nanocomposite. Additionally, the stored electrons in the very conductive Lys-rGO layers offer active sites for the catalytic activity of the nanocomposite in the dark. Meanwhile, ZnO generates reactive oxygen species (ROS) through surface oxygen vacancies, further contributing to the nanocomposite’s dark catalytic activity. The degradation of various organic pollutants (Methylene Blue, Tetracycline, Ciprofloxacin, Rhodamine B, and their mixture), as well as Congo Red, with low catalyst dosage and visible light irradiation time, demonstrates the high performance and versatility of this nanocomposite. This research highlights the potential of Lys-rGO in compositing with semiconductors to design multifunctional catalysts for cost-effective sustainable water purification technologies.

Visible light-responsive vitamin B2 functionalized ZnO with dual-mechanism bactericidal effects for perishable agrofood preservation

Recent advances in functionalized micro-nanostructures have enlightened promising non-thermal-dependent antibacterial strategies with broad applications in preventing agrofood spoilage, clinical infections, and environmental pollution caused by pathogens. These advances highlight the need for precise design of efficient and multi-mode bactericides. Herein, photosensitive vitamin B2 (VB2) was exploited to functionalize semiconductors with limited visible-light response and intrinsic antibacterial activity, while ZnO served as a paradigm for the fabrication of VB2-functionalized zinc oxide (VB2-ZnO) with persistent antibacterial effects. The enhanced visible photocatalytic activity and the released Zn2+ in VB2-ZnO contribute to potent antibacterial and anti-biofilm effects by disrupting bacterial structures and inducing oxidative stress. Furthermore, the successful fabrication of composite films incorporating VB2-ZnO and natural locust bean gum (LBG) exhibited improved physicochemical properties and persistent antibacterial effects, resulting in the shelf-life extension of perishable berries. This work pioneers a novel approach to functionalizing semiconductor photocatalysts with VB2 photosensitizer, offering novel solutions for ensuring agrofood safety through multi-mechanism antibacterial materials.

Modulating photocatalytic activity of nitrogen doped TiO2 nanoparticles via magnetic field

The effect of the magnetic field on the photocatalytic activity of TiO2-based nanoparticles is analyzed using a magnetically-assisted photoreactor with permanent magnets to generate a controlled uniform magnetic field, B (≈ 82 mT). Nitrogen doped TiO2 nanoparticles (sizes around 10 nm) were synthesized through a solvothermal method employing Ti(IV) butoxide and HNO3 (x = 0, 0.5, 1, 1.5 and 2 mL) as precursors and their structural, optical and magnetic properties were analyzed. Specifically, nitrogen doping is confirmed through Hard X-ray Photoelectron Spectroscopy (HAXPES) in those samples synthesized with low HNO3 concentrations (x = 0.5, 1). The correlation between spin polarization (magnetic susceptibility) and visible photocatalytic activity (methyl orange as a model organic pollutant) is particularly analyzed. Surprisingly, opposite effects of the magnetic field on the photocatalytic performance are found in the visible range (above 400 nm) or under UV-Vis irradiation (decrease and increase in the photocatalytic activity, respectively, under magnetic field). The Langmuir-Hinshelwood model allows us to conclude that the strong decrease in adsorption under the magnetic field (around 42 % for x = 0.5) masks the increase in the kinetic constant (close to 58 % for x = 0.5) related mainly to the effect of Lorentz forces on the reduction of the electron-hole recombination.

Visible-Light Photocatalytic Degradation Efficiency of Tetracycline and Rhodamine B Using a Double Z-Scheme Heterojunction Catalyst of UiO-66-NH2/BiOCl/Bi2S3.

BiOCl is a promising photocatalyst, but due to its weak visible light absorption capacity and low photogenerated electron-hole pair separation rate, its practical application is limited to a certain extent. In this study, a novel double Z-scheme heterojunction UiO-66-NH2/BiOCl/Bi2S3 catalyst was constructed to broaden the visible light response range and promote high photogenerated hole-electron separation of BiOCl. Its photocatalytic performance is evaluated by dissociating tetracycline (TC) and rhodamine B (RhB) in visible light. The optimal proportion of UiO-66-NH2/BiOCl/Bi2S3 hybrids exhibits the best degradation efficiency of visible light illumination (∼93% in 120 min for TC and ∼98% in 60 min for RhB). The synergistic effect of a large visible light response range and the Z-scheme charge transfer mechanism ensure the excellent visible photocatalytic activity of UiO-66-NH2/BiOCl/Bi2S3. It is proven that h+ and •O2- are the main active substances in the photocatalysis process by active substance capture experiments and electron spin resonance tests. The intermediates and degradation processes are analyzed by high-performance liquid chromatography-mass spectrometry. This study proves that the new UiO-66-NH2/BiOCl/Bi2S3 photocatalyst has great application potential in the field of water pollution degradation and will provide a new idea for the optimization of BiOCl.

Synthesis of heterojunction BiVO4/MnO2 graphene ternary nanocomposites with enhanced photocatalytic activities through degradation of rhodamine B and tetracycline hydrochloride

Our research has resulted in synthesizing highly efficient BiVO4/MnO2 graphene ternary heterostructures prepared with a simple hydrothermal technique. These structures demonstrate exceptional performance in the photodegradation of rhodamine B (RhB) dye and tetracycline hydrochloride (TC). Adding MnO2 and graphene oxide significantly enhanced the absorption of visible light, photocatalytic activity, and surface area of the nanocatalyst. The prepared materials were characterized by XRD, SEM, BET, DRS, and PL spectroscopy. The PL spectra of G/MnBV-4 show less intensity and lower recombination rate, which is beneficial for photocatalytic activity. The as-synthesized G/MnBV-4 material exhibits outstanding photocatalytic activities toward the TC and RhB dye degradation under visible light irradiation. The reaction rate constant of G/MnBV-4 was estimated in the case of RhB and TC as 0.094 min−1 and 0.021 min−1 respectively, showcasing the material's high efficiency. The optimized material (BiVO4/MnO2 graphene) is stable and reusable, with only a 10 % reduction in removal efficiency after five consecutive cycles. Furthermore, the OH− and O2− are active species for removing organic pollutants. In contrast, holes are attributed to a lower effect. This study describes a photocatalytic approach to effectively removing the TC from waste bodies. The enhanced degradation efficiencies were ascribed to developing heterostructures and fast electron transfer between interfaces. Moreover, graphene increased photogenerated charge carriers' surface adsorption properties and charge separation efficiency. Hence, graphene works as an electron trapper and tuning bandgap energy, which plays a significant role in addition to photocatalytic activity.

Defects induced SnOx-TiO2 nanocomposite thin films for improved visible light driven photocatalysis and photoelectrochemical applications

Advanced oxidative removal of organic pollutants from water bodies using nanoparticles of metal oxide photocatalysts is a concurrent hot topic. In the present study, SnOx-TiO2 heterogeneous nanocomposite thin film photocatalysts have been synthesized using SnO and TiO2 precursors by binder-free doctor blade technique. X-ray diffraction was used to confirm the presence of anatase TiO2 as a major phase at elevated temperatures. Raman spectra analysis confirmed phase transformation and defect induction. X-ray photoelectron spectroscopy was utilized to determine the purity and chemical condition of the synthesized thin films. The porous nature of the thin film surface was observed using field emission scanning electron microscopy. UV–Vis-NIR spectroscopy results showed a reduction of bandgap from 3 eV to 2.6 eV with enhanced light absorption. The superior oxygen evolution reaction, redox nature and charge carrier generation were demonstrated using photo-electrochemical techniques. Improved photoresponse of the photocatalysts was observed using chrono-amperometry technique. The superior visible light-driven photocatalytic activity of the samples was demonstrated utilizing cationic and anionic model pollutant dyes. The reusability of the catalyst is ensured through successive photodecomposition processes. These results show a facile fabrication of defects induced heterogenous nanocomposite photocatalyst thin films with improved visible light activity.

Synthesis and full-spectrum-responsive photocatalytic activity from UV/Vis to near-infrared region of S-O decorated YMnO3 nanoparticles for photocatalytic degradation of ibuprofen.

The oxalic acid complexation method and sulfuric acid heat treatment method were used to synthesize the YMnO3 (YMO) and YMO-SO4 2- (YMO-SO) photocatalysts. The YMO-SO photocatalyst maintained the crystal structure of YMO, but the particle size increased slightly and the optical band gap decreased significantly. The YMO-SO photocatalyst demonstrates a wide range of light absorption capabilities, covering ultraviolet, visible and near-infrared light. The photocatalytic activity of YMO-SO was investigated with ibuprofen as the target pollutant. The YMO-SO photocatalyst exhibits high ultraviolet (UV), visible and near-infrared photocatalytic activity. Experiments with different environmental parameters confirmed that the best catalyst content was 1g/L, the best drug concentration was 75mg/L and the best pH value was 7. The capture experiment, free radical detection experiment and photocatalytic mechanism analysis confirmed that the main active species of YMO-SO photocatalyst were hole and superoxide free radical.

Fe-Doped g-C3N4/Bi2MoO6 Heterostructured Composition with Improved Visible Photocatalytic Activity for Rhodamine B Degradation.

The binary heterostructured semiconducting visible light photocatalyst of the iron-doped graphitic carbon nitride/bismuth molybdate (Fe-g-C3N4/Bi2MoO6) composite was prepared by coupling with Fe-doped g-C3N4 and Bi2MoO6 particles. In the present study, a comparison of structural characteristics, optical properties, and photocatalytic degradation efficiency and activity between Fe-doped g-C3N4 particles, Bi2MoO6 particles, and Fe-g-C3N4/Bi2MoO6 composite was investigated. The results of X-ray diffraction (XRD) examination indicate that the hydrothermal Bi2MoO6 particles have a single orthorhombic phase and Fourier transform infrared (FTIR) spectroscopy analysis confirms the formation of Fe-doped g-C3N4. The optical bandgaps of the Fe-doped g-C3N4 and Bi2MoO6 particles are 2.74 and 2.73 eV, respectively, as estimated from the Taut plots obtained from UV-Vis diffuse reflectance spectroscopy (DRS) spectra. This characteristic indicates that the two semiconductor materials are suitable for absorbing visible light. The transmission electron microscopy (TEM) micrograph reveals the formation of the heterojunction Fe-g-C3N4/Bi2MoO6 composite. The results of photocatalytic degradation revealed that the developed Fe-g-C3N4/Bi2MoO6 composite photocatalyst exhibited significantly better photodegradation performance than the other two single semiconductor photocatalysts. This property can be attributed to the heterostructured nanostructure, which could effectively prevent the recombination of photogenerated carriers (electron-hole pairs) and enhance photocatalytic activity. Furthermore, cycling test showed that the Fe-g-C3N4/Bi2MoO6 heterostructured photocatalyst exhibited good reproducibility and stability for organic dye photodegradation.

Regulation of photoelectric properties of multi-element (Sn, Fe, Ce) co-doped anatase TiO2: The first principles study

The energy band structure, density of states and optical properties of multi-element (Sn, Fe, Ce) co-doped anatase titanium dioxide have been calculated using the first principles method. The results show that two-element (Sn, Fe, Ce) doping affects the energy band structure more than the single doping behaviour. Co-doping of two of the three elements (Sn, Fe, Ce) reduced the energy band gap values of TiO2 compared to pure anatase TiO2.The forbidden bandwidths of Sn and Ce were smaller than those of mono-doped Sn, but the co-doped system had higher bandwidth narrowing than that of the mono-doped system. The co-doping of Sn and Ce is 0.206 eV smaller than the single doping of Sn, and the co-doping of Sn and Fe is 0.56 eV smaller than the single doping of Sn. The utilization of the regional light absorption is increased, and the absorption spectra are red-shifted. It can be seen that the co-doping method is more favourable to the improvement of visible light response and visible photocatalytic activity of TiO2 than the single doping method.

Tailored Polymeric Carbon Nitride Coupled with Bi2O3 for Constructing Z‐Scheme Heterojunction with Enhanced Photocatalytic Activity

AbstractThe great demand for visible‐light‐induced catalysts with high photocatalytic performance has stimulated extensive interest in constructing g‐C3N4‐based Z‐Scheme heterojunctions. In this research work, the g‐C3N4/Bi2O3 Z‐Scheme heterojunction by precipitation‐hydrothermal method was constructed, and characterized by various techniques. The g‐C3N4/Bi2O3‐1 composite exhibited a transient photocurrent response approximately 7 and 5 times higher than that of bare g‐C3N4 and Bi2O3, respectively, and showed higher visible photocatalytic activity with 99.8 % degradation of methylene blue (MB) within 75 min. Meanwhile, the pH effect on the photocatalytic degradation of MB was investigated. Radicals trapping experiments showed that •OH free radical played a predominant role for the degradation of MB, EPR analysis confirmed the presence of superoxide radicals, which combined with the band structure of the composites, confirmed the Z‐Scheme of the heterojunction. A possible mechanism for photocatalytic degradation of MB dyes in g‐C3N4/Bi2O3‐1 composites was also proposed. This study provided a new avenue for the development of novel g‐C3N4‐based Z‐Scheme heterojunction materials with prospective applications in the fields of energy and environment.

Bismuth-rich BiOBr/Bi24O31Br10/Ti3C2 polyheterojunction for visible photocatalytic degradation of dyes and Cr(VI) reduction and hydrogen production applications

The construction of bismuth-rich heterostructures is an important strategy to improve the performance of bismuth-based visible photocatalytic materials. In this study, the binary heterojunction BiOBr/Bi24O31Br10 (BOB) with efficient visible photocatalytic activity was constructed by in situ induced growth of BixOyBrz on the surface of BiOBr, and the multivariate heterojunction composite BiOBr/Bi24O31Br10/Ti3C2 (BOBT) was synthesized by using Ti3C2 as an electron acceptor. It was shown that the solvothermal pH, Bi/Br and calcination temperature had a strong influence on the composition and crystalline structure of BOBT. The optimized synthesis conditions were pH=8, Bi/Br=1/1 (molar ratio), and calcination temperature of 400℃. The introduction of Mxene significantly enhanced the visible-light responsiveness and photoelectric efficiency of BOBT. The visible light-catalyzed degradation of complex conjugated systems containing aromatic and azo structures by BOBT was synchronously accompanied by benzene ring opening, demonstrating an efficient visible light degradation capability. BOBT has a reduced reduction current peak compared to BOB, can rapidly reduce Cr (VI), and improves the photocatalytic hydrogen production efficiency by nearly three times compared to BiOBr without the addition of Pt additives. This study provides fundamental data for the construction of efficient bismuth-based visible photocatalytic materials and their applications.

Impact of Co-Doping on the Visible Light-Driven Photocatalytic and Photoelectrochemical Activities of Eu(OH)3.

The microwave-assisted synthesis approach was used to synthesize Eu(OH)3 and Co-Eu(OH)3 nanorods. Various techniques were used to investigate the structural, optical, and morphological features of the Eu(OH)3 and Co-Eu(OH)3 NRs. Both Eu(OH)3 and Co-Eu(OH)3 NRs were found to be hexagonal with crystallite sizes ranging from 21 to 35 nm. FT-IR and Raman spectra confirmed the formation of Eu(OH)3 and Co-Eu(OH)3. Rod-shaped Eu(OH)3 and Co-Eu(OH)3 with average lengths and diameters ranging from 27 to 50 nm and 8 to 12 nm, respectively, were confirmed by TEM. The addition of Co was found to increase the particle size. Furthermore, with increased Co doping, the band gap energies of Co-Eu(OH)3 NRs were lowered (3.80-2.49 eV) in comparison to Eu(OH)3, and the PL intensities with Co doping were quenched, suggesting the lessening of electron/hole recombination. The effect of these altered properties of Eu(OH)3 and Co-Eu(OH)3 was observed through the photocatalytic degradation of brilliant green dye (BG) and photoelectrochemical activity. In the photocatalytic degradation of BG, 5% Co-Eu(OH)3 had the highest response. However, photoelectrochemical experiments suggested that 10% Co-Eu(OH)3 NRs showed improved activity when exposed to visible light. As a result, Co-Eu(OH)3 NRs have the potential to be a promising visible-light active material for photocatalysis.

Zn-Doped MnCO3/CS Composite Photocatalyst for Visible-Light-Driven Decomposition of Organic Pollutants.

Zn-doped MnCO3/carbon sphere (Zn-doped MnCO3/CS) composites were synthesized using a simple hydrothermal procedure. Among various samples (ZM-50, ZM-05, and ZMC-0), the ternary Zn-doped MnCO3/CS (ZMC-2) catalyst demonstrated excellent visible light-induced photocatalytic activity. This improvement comes from the Zn addition and the conductive CS, which facilitate electron movement and charge transport. The catalyst exhibited efficient degradation of methylene blue (MB) over a wide pH range, achieving a removal efficiency of 99.6% under visible light. Radical trapping experiments suggested that •OH and •O2- played essential roles in the mechanism of organic pollutant degradation. Moreover, the catalyst maintained good degradation performance after five cycles. This study offers valuable perspectives into the fabrication of carbon-based composites with promising photocatalytic activity.

Magnetically separable and visible light-driven photocatalytic activity of graphene oxide based α-Fe2O3 nanocomposite

This work investigates the impact of graphene oxide (GO) on the structural, morphological, optical, and photocatalytic investigations of Fe2O3, an excellent photocatalyst for industrial wastewater treatment. Using the straightforward and inexpensive sol-gel auto-combustion, hummer's method and sonication method, Fe2O3 nanoparticle (NPs), GO nanosheet, and GO-based Fe2O3 (GO/Fe2O3) nanocomposite have been synthesized, respectively. The XRD patterns, Raman spectra, and FTIR spectroscopy were used for the structural analysis, which verifies the single phase hexagonal geometry of Fe2O3 NPs. The average size of the crystallites is seen to have reduced from 50 nm to 44 nm for Fe2O3 and GO/Fe2O3. The SEM along with EDS were applied to investigate the surface morphology and confirm the existence of the elements Fe and O in pure Fe2O3, and C, Fe and O in GO/Fe2O3. From UV–vis absorbance spectra, the decrease in optical band gap (2.5 eV–1.9 eV) caused by GO incorporation has been inferred, as clearly displayed in the Tauc plots. X-ray photoelectron spectroscopy (XPS) confirms the presence of Fe2+/Fe+3 ionic states and large oxygen vacancies in the GO/Fe2O3 nanocomposite. The photocatalytic properties of both materials for the toxic MB (methylene blue) dye photodegradation in an aqueous solution was evaluated while being exposed to sunlight. It makes an excellent choice for wastewater treatment due to the high photocatalytic activity of magnetically separable GO/Fe2O3 nanocomposite for decomposing the MB dye.

Localized surface plasmon resonance-induced bidirectional electron transfer of formic acid adsorption for boosting photocatalytic hydrogen production on Ni/TiO2

Photocatalytichydrogenproduction from formic acid (FA) is a daunting challenge, yet an essential taskforthedevelopmentofhydrogenenergy. In this study, a p-NiO/n-TiO2 heterojunction incorporating 7-nm metallic Ni was fabricated, which demonstrated a remarkable localized surface plasmon resonance (LSPR) effect. Notably, 5 wt% Ni/TiO2 exhibited 1271-fold higher photocatalytic activity (2416 μmol⋅g−1⋅h−1) than TiO2 alone under light radiation at room temperature. The experimental investigations revealed the excitation of distinct components via irradiation by different light sources. Visible light-driven hydrogen production was predominantly influenced by the LSPR-induced hot electrons and holes effects of Ni. Further, FA molecules simultaneously lost and accepted electrons at the Ni0–Ti3+ and Ni0–O2− sites, respectively, generating a bidirectional electron transfer behavior with “valley-shaped” gas-sensitive responses, which was crucial toboosttheactivity. Moreover, the photocatalytic activity was mainly attributed to the heterojunction and defects structure under UV light irradiation, and Ti3+, VOs, and O2− as adsorption sites for FA. Thus, the synergistic interplay among different light sources could effectively boost the photocatalytic hydrogen production performance. Significantly, this research reveals that the LSPR effect of metallic Ni can effectively regulate electron transfer behavior and enhance visible light-driven photocatalytic activity.

One-dimensional Bi2MoO6 nanosheets/TiO2 hollow tubes:Controllable synthesis and enhanced visible photocatalytic activity

By electrostatic spinning technology combined with solvothermal method, Bi2MoO6 nanosheets were loaded on TiO2 hollow tubes, and Bi2MoO6/TiO2 nanocomposite photocatalytic materials were successfully prepared. The products were characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM),X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–vis) and photoluminescence spectroscopy (PL). The results show that the lamellar Bi2MoO6 nanostructures were successfully grown on TiO2 hollow tubes. The photocatalytic experiments showed that the Bi2MoO6/TiO2 nanocomposites exhibited higher visible light photocatalytic activity than both pure TiO2 and pure Bi2MoO6, which may be due to the effective photogenerated electron-hole separation generated by the Bi2MoO6/TiO2 heterojunction, the photocatalytic degradation of detetracycline, doxycycline and aureomycin by Bi2MoO6/TiO2 photocatalytic system was also compared. In addition, the Bi2MoO6/TiO2 photocatalyst maintained good photocatalytic performance after five cycles, and it was demonstrated by the capture experiments that the superoxide radical played a dominant role in the photocatalytic degradation process, and the contributions of light-generated holes and hydroxyl radicals were approximately the same, and the possible mechanism of its photocatalytic system was proposed.

Construction of oxidation-reduction bifunctional nano-purifiers: S-scheme faceted heterojunction BiOCl(110) nanosheets/TiO2(001) hollow nanocubes with abundant oxygen vacancies for balancing visible photocatalytic activity

The development of photocatalytic nano-purifiers with high electrons and holes separation efficiency and high-photocatalytic activity is essential in treating water and air pollution. In this paper, novel nano-purifiers with S-scheme faceted heterojunction created between BiOCl nanosheets (110) facets and TiO2 hollow nanocubes (001) facets were successfully fabricated. In nano-purifiers, BiOCl nanosheets are enriched with oxygen vacancies capable of trapping electrons, which synergize with the unique S-scheme faceted heterojunction charge transfer mechanism to facilitate carrier separation and migration to a large extent. Herein, BiOCl(110) nanosheets/TiO2(001) hollow nanocubes nano-purifiers (BTHNs) were significantly enhanced in photocatalytic treatment of water and air pollution and were not inferior to other cleaning agents. The obtained 15BTHNs showed the best photocatalytic purification ability among the same series of products. 15BTHNs could degrade 99.9% of RhB in 70 min, which was 25 times higher than that of pure THNs, and effectively removed 44.8% of NO. Moreover, the reduction rate of Cr (Ⅵ) for 15BTHNs reached 99.9% in 90 min, with a kinetic constant 21.5 times higher than that of pure THNs. Active species trapping experiments revealed that four active species of BTHNs contributed to the RhB oxidation reaction in the following order:·OH>h+>·O2->e-, and the contribution rates of 15BTHNs were 45.0%, 38.0%, 12.3%, and 4.7%, respectively. The appropriate ratios of oxidizing TiO2 to reducing BiOCl in 15BTHNs allowed the generated active species to be fully utilized, achieving oxidation-reduction equilibrium as well as improving the photocatalytic efficiency. This work reveals that the S-scheme faceted heterojunction formed in the BiOCl/TiO2 nano-purifier was a progressing approach for water and air cleaning.

SnS2 based SnS2/rGO/g-C3N4 Z-scheme ternary nanocomposites for efficient visible light-driven photocatalytic activity

Novel ternary composite photocatalyst SnS2/rGO/g-C3N4 in a Z-scheme configuration was synthesized using hydrothermal method for the degradation of dye pollutants from the industrial wastes. To enhance photocatalytic effectiveness, we employed Z-scheme architecture by utilizing SnS2 as a semiconductor with the unique electronic properties of rGO and g-C3N4 for promoting efficient charge separation. The synthesized ternary composite materials were characterized by various spectroscopic and microscopic techniques. The photocatalytic activities of these samples were evaluated through the degradation of Methylene Blue (MB) dye under visible light. Notably, the catalysts SnS2, SnS2/rGO, SnS2/g-C3N4, and SnS2/rGO/g-C3N4 exhibited degradation efficiencies of 55%, 57%, 64%, and 86%, respectively, after 70 min. Among these, the ternary composite catalyst of SnS2/rGO/g-C3N4 exhibited enhanced degradation performance. Furthermore, when exposed to visible light, the unique crisscross morphology and Z scheme architecture effectively promote light utilization efficiency, providing ample reactive sites and leading to a higher degradation percentage. Further optimization of experiments for this composite material involved in varying catalyst loadings, dye concentrations, and pH levels. The SnS2/rGO/g-C3N4 composite exhibited optimal degradation performance with 5 mg catalyst in a 25 ppm MB solution within 100 ml. This composite was identified for the first time as an excellent visible light-driven photocatalyst for MB, displaying high degradation efficiencies. These findings emphasize the promising potential of the SnS2/rGO/g-C3N4 ternary nanocomposite for applications in visible light-driven photocatalysis.