Construction of Ag nanocluster-modified Ag3PO4 containing silver vacancies via in-situ reduction: With enhancing the photocatalytic degradation activity of sulfamethoxazole

Dual-function reusable SERS substrate based on Ag/Ag3PO4/MXene heterojunction: Efficient detection and photocatalytic degradation of organic pollutants

A flexible cotton-based Ag/Ag3PO4/MXene (APMX) ternary composite material was successfully synthesized, serving as a dual-function and reusable surface-enhanced Raman scattering (SERS) substrate for both sensitive detection and efficient organic dye degradation. The remarkable SERS properties of the composite can be attributed to the combined effects of electromagnetic enhancement by Ag nanoparticles (Ag NPs), charge transfer enhancement from Ag3PO4, and the chemical enhancement mechanisms associated with MXene. When employed for the detection of crystal violet (CV), the material exhibits outstanding sensitivity, achieving a limit of detection (LOD) as low as 3.82 × 10-11 M. Moreover, the synergistic effects between the localized surface plasmon resonance (LSPR) of Ag NPs and the high electrical conductivity of MXene significantly improve charge transfer on the Ag3PO4 surface, thereby enhancing photocatalytic efficiency. Under visible light irradiation, the composite achieves an 83.64 % degradation rate of CV within 90 min. By integrating the composite material onto cotton, its flexibility and practical applicability are enhanced, allowing for in-situ SERS detection and effective analysis on irregular surfaces. Additionally, the photocatalytic degradation function imparts a self-cleaning property, greatly improving its reusability and sustainability. As a high-performance, dual-function material, the APMX cotton shows great potential in environmental monitoring and pollution control by providing sensitive SERS detection and efficient wastewater pollutant degradation.

Novel Ag@NH2-UiO-66(Zr) photocatalyst with controllable charge transfer pathways for efficient Cr(VI) remediation

Rational fabrication of core-shell photocatalysts to hamper the charge recombination is extraordinarily essential to enhance photocatalytic activity. In this work, core-shell Ag@NH2-UiO-66 (Ag@NU) Schottky heterojunctions with low Ag content (1 wt%) were constructed by a two-step solvothermal method and adopted for Cr(VI) reduction under LED light. Typically, the one with the Ag: NH2-UiO-66 mass ratio (1 : 100) led to 100% Cr(VI) removal within 1 h, superior to bare NH2-UiO-66 and Ag/NH2-UiO-66 (Ag was directly decorated on NH2-UiO-66 surface). The enhanced photocatalytic activity was related to the migration of the electrons on the CB of NH2-UiO-66 to Ag NPs through a Schottky barrier, and thus the undesired charge carriers recombination was avoided. This result was also evidenced by Density functional theory (DFT) calculations. The computational simulations indicate that the introduction of Ag effectively narrowed the band gap of NH2-UiO-66, facilitating the transfer of photo-generated electrons, expanding the light absorption area, and significantly enhancing photocatalytic efficiency. Most importantly, such a core-shell structure can inhibit the formation of •O2-, letting the direct Cr(VI) reduction by photo-excited e-. In addition, this structure can also protect Ag from being oxidized by O2. Ten cyclic tests evidenced the Ag@NU had excellent chemical and structural stability. This research offers a novel strategy for regulating the Cr(VI) reduction by establishing core-shell photocatalytic materials.

Light-driven photocatalysis as an effective tool for degradation of antibiotics

Antibiotic contamination has become a severe issue and a dangerous concern to the environment because of large release of antibiotic effluent into terrestrial and aquatic ecosystems. To try and solve these issues, a plethora of research on antibiotic withdrawal has been carried out. Recently photocatalysis has received tremendous attention due to its ability to remove antibiotics from aqueous solutions in a cost-effective and environmentally friendly manner with few drawbacks compared to traditional photocatalysts. Considerable attention has been focused on developing advanced visible light-driven photocatalysts in order to address these problems. This review provides an overview of recent developments in the field of photocatalytic degradation of antibiotics, including the doping of metals and non-metals into ultraviolet light-driven photocatalysts, the formation of new semiconductor photocatalysts, the advancement of heterojunction photocatalysts, and the building of surface plasmon resonance-enhanced photocatalytic systems.

Promoting the suitability of graphitic carbon nitride and metal oxide nanoparticles: A review of sulfonamides photocatalytic degradation

The widespread consumption of pharmaceutical drugs and their incomplete breakdown in organisms has led to their extensive presence in aquatic environments. The indiscriminate use of antibiotics, such as sulfonamides, has contributed to the development of drug-resistant bacteria and the persistent pollution of water bodies, posing a threat to human health and the safety of the environment. Thus, it is paramount to explore remediation technologies aimed at decomposing and complete elimination of the toxic contaminants from pharmaceutical wastewater. The review aims to explore the utilization of metal-oxide nanoparticles (MONPs) and graphitic carbon nitrides (g-C3N4) in photocatalytic degradation of sulfonamides from wastewater. Recent advances in oxidation techniques such as photocatalytic degradation are being exploited in the elimination of the sulfonamides from wastewater. MONP and g-C3N4 are commonly evolved nano substances with intrinsic properties. They possessed nano-scale structure, considerable porosity semi-conducting properties, responsible for decomposing wide range of water pollutants. They are widely applied for photocatalytic degradation of organic and inorganic substances which continue to evolve due to the low-cost, efficiency, less toxicity, and more environmentally friendliness of the materials. The review focuses on the current advances in the application of these materials, their efficiencies, degradation mechanisms, and recyclability in the context of sulfonamides photocatalytic degradation.

Double-Solvent-Induced Derivatization of Bi-MOF to Vacancy-Rich Bi4O5Br2: Toward Efficient Photocatalytic Degradation of Ciprofloxacin in Water and HCHO Gas

MOF-derived photocatalytic materials have potential in degrading ciprofloxacin (CIP) in water and HCHO gas pollutants. Novel derivatization means and defect regulation are effective techniques for improving the performance of MOF-derived photocatalysis. Vacancy-rich Bi4O5Br2 (MBO-x) were derived in one step from Bi-MOF (CAU-17) by a modified double-solvent method. MBO-50 produced more oxygen vacancies due to the combined effect of the CAU-17 precursor and double solvents. The photocatalytic performance of MBO was evaluated by degrading CIP and HCHO. Thanks to the favorable morphology and vacancy structure, MBO-50 demonstrated the best photocatalytic efficiency, with 97.0% removal of CIP (20 mg L-1) and 90.1% removal of HCHO (6.5 ppm) at 60 min of light irradiation. The EIS Nyquist measurement, transient photocurrent response, photoluminescence spectra, and the calculation of energy band information indicated that the vacancy sites can effectively capture photoexcited electrons during the charge transfer process, thus limiting the recombination of electrons and holes, improving the energy band structure, and making it easier to produce superoxide anion radical (·O2-) and to degrade CIP and HCHO. The improvement of photocatalytic performance of MBO-50 in HCHO degradation due to the bromine vacancy generation and filling mechanism was discussed in detail. This work provides a promising new idea for the modulation of MOF-derived photocatalytic materials.

ZnS/CuFe2O4/MXene ternary heterostructure photocatalyst for efficient adsorption and photocatalytic degradation of azo dyes under visible light: Synergistic effect, mechanism, and application

ZnS/CuFe2O4/MXene (ZSCFOM) composite with ternary heterostructures was prepared by solvothermal methods for the first time to effectively adsorb and photodegrade the azo dyes. ZSCFOM mainly adsorbed azo dyes through the hydrogen bonding and electrostatic interactions, with saturated adsorption capacities of 377 mg g-1 for direct brown M and 390 mg g-1 for direct black RN. ZSCFOM exhibited both characteristics of Schott heterostructure and p-n heterostructure, but it is not a simple superposition of the two heterostructures, but rather achieves better photocatalytic property. ZSCFOM performed a higher separation efficiency of electrons and holes than pure CuFe2O4 and pure ZnS. Under visible light, ZSCFOM was more effective in removing the azo dyes than MXene, CuFe2O4, ZnS, CuFe2O4/MXene, ZnS/MXene, and ZnS/CuFe2O4. The migration pathways of photogenerated carriers in ZSCFOM were inferred as that the electrons were concentrated in MXene and conduction band of ZnS, and holes were gathered in valence band of CuFe2O4. MXene served as a cocatalyst to accelerate the separation of electrons and holes. ZSCFOM mainly degraded DBM and DBRN by catalyzing the generation of holes, superoxide radicals, and hydroxyl radicals. The 100% of 0.05 g L-1 azo dyes were removed by ZSCFOM within 30 min from the environmental water systems.

Highly Enhanced Photocatalytic Performances of Composites Consisting of Silver Phosphate and N-Doped Carbon Nanomesh for Oxytetracycline Degradation

Photocatalytic technology based on silver phosphate (Ag₃PO₄) has excellent potential in removing antibiotic pollutants, but the low separation rate of photogenerated hole-electron pairs restricts the application of the photocatalyst. In this study, it was found that the combination of nitrogen-doped carbon (NDC) with carbon defects and Ag₃PO₄ can significantly enhance the photocatalytic ability of Ag₃PO₄. After it was exposed to visible light for 5 min, the photocatalytic degradation efficiency of oxytetracycline (OTC) by the composite photocatalyst Ag₃PO₄@NDC could reach 100%. In addition, the structure of NDC, Ag₃PO_4, and Ag₃PO₄@NDC was systematically characterized by SEM, TEM, XRD, Raman, and EPR. The XPS results revealed intense interface interaction between Ag₃PO₄ and NDC, and electrons would transfer from Ag₃PO₄ to the NDC surface. A possible mechanism for enhancing the photocatalytic reaction of the Ag₃PO₄@NDC composite catalyst was proposed. This study provides a highly efficient visible light catalytic material, which can be a valuable reference for designing and developing a new highly efficient visible light catalyst.