In2S3 nanoparticles coupled to In-MOF nanorods: The structural and electronic modulation for synergetic photocatalytic degradation of Rhodamine B

Incorporating nickel-substituted polyoxometalate into a photoactive metal-organic framework for efficient photodegradation of thiamethoxam insecticide

Hydrogen bonding enhances the interactions between host and guest molecules and facilitates electron transfer between them. In this study, a series of hydrogen-bonded Z-scheme photocatalysts were prepared via impregnation. Nickel (Ni)-substituted polyoxometalate (POM) Na6K4[Ni4(H2O)2(PW9O34)2]∙32H2O (Ni4P2) was anchored within the pores of Zr6(μ3-OH)8(-OH)8(TBAPy)2 (NU-1000) via hydrogen bonding interactions (H4TBAPy = 1,3,6,8-tetrakis(p-benzoic acid)pyrene). Hydrogen bonding not only effectively prevented the leakage of Ni4P2 from NU-1000 pores but also facilitated electron transfer from Ni4P2 to NU-1000. The optimized 0.3-Ni4P2@NU-1000 photocatalyst delivered remarkable performance toward thiamethoxam (TMX) photodegradation, achieving a degradation efficiency of 75.1 % after 120 min. The effects of the photocatalyst dose, pH, coexisting ions, and water sample on TMX degradation were investigated. Radical scavenging experiments and electron spin resonance data revealed that superoxide radicals and holes are the primary species responsible for photodegradation. Moreover, the reaction mechanism and degradation pathways of TMX were thoroughly investigated. Density functional theory calculations confirmed that TMX is adsorbed onto Ni4P2 via hydrogen bonding, structurally changing TMX and increasing its susceptibility to degradation. Chia seed growth experiments and Toxicity Estimation Software Tool analysis indicated that the aquatic toxicities of TMX intermediates and final products are lower than that of the undegraded TMX. This study advances the application of substituted POM-modified NU-1000 for treating TMX-contaminated wastewater.

One-Pot Synthesis of Hydrophobic Porphyrin Zirconium-Based MOFs for the Photoreduction of CO2 to Formate

Using zirconium tetrachloride as a metal source and tetra(4-carboxyphenyl)porphyrin as a ligand and by in situ introducing octadecylphosphonic acid (OPA), three hydrophobic porphyrin zirconium metal-organic frameworks (MOFs) with different structural topologies were constructed, where these MOFs are labeled as OPA@PCN-222, OPA@PCN-223, and OPA@PCN-224. Compared with the original Zr-MOFs without the modification of OPA, the modified porphyrin Zr-MOFs show excellent hydrophobic properties and can maintain excellent stability in a long-term humidity environment. Meanwhile, OPA@PCN-222, OPA@PCN-223, and OPA@PCN-224 exhibit wide absorption of visible light and steadfast and expeditious photocurrent response by leveraging the properties of porphyrin ligands. When illuminated by visible light, the hydrophobic Zr-MOFs demonstrate an efficient reduction of CO2 to HCOO-, achieving average reaction rates of 330, 260, and 258 μmol·h-1·g-1 for OPA@PCN-222, OPA@PCN-223, and OPA@PCN-224. These rates are 1.13-1.41 times higher than that of the original porphyrin Zr-MOFs. The mechanism study shows that both the porphyrin ligands and the Zr-O clusters serve as catalytically active sites, enabling the conversion of CO2 to HCOO-. This research shows that the introduction of hydrophobic alkyl chains can effectively enhance the stability of MOFs under a humid environment while maintaining their catalytic activity, which provides a reference for improving the comprehensive performance of MOF catalysts.

Enhancing the Photocatalytic Activity of Lead-Free Halide Perovskite Cs3Bi2I9 by Compositing with Ti3C2 MXene

In recent years, halide perovskite materials have become widely used in solar cells, photovoltaics, and LEDs, as well as photocatalysis. Lead-free perovskite Cs3Bi2I9 has been demonstrated as an effective photocatalyst; however, the fast recombination of the photogenerated carriers hinders further improvements of its photocatalytic activity. In this work, Ti3C2 was composited with Cs3Bi2I9 to promote the transfer and separation of photogenerated carriers, and thus the pollutant degradation efficiency was effectively improved. The visible-light photocatalytic reduction of Cs3Bi2I9/Ti3C2 on rhodamine B (RhB), methylene blue (MB), and malachite green (MG) was as high as 97.3%, 96%, and 98.8%, respectively, improvements of almost 31.2%, 37.8%, and 37.2% compared to that of sole Cs3Bi2I9. Our study provides a simple way to enhance the photocatalytic activity of lead-free halide perovskites.

Integration of Carbon Dots on Nanoflower Structured ZnCdS as a Cocatalyst for Photocatalytic Degradation

The application of catalysts is one of the most effective methods in the oil refining, chemical, medical, environmental protection, and other industries. In this work, carbon dots (CDs) were selected as an initiator and doped into the main catalyst, Zn_0.2Cd_0.8S, and a novel Zn_0.2Cd_0.8S@CD composite catalyst with a nanoflower structure was successfully obtained. The synthesized composites (Zn_0.2Cd_0.8S@CDs) were characterized by means of SEM, TEM, XRD, FT-IR, XPS, and UV-Vis DRS. Transient photocurrent response and Nyquist curve analysis further proved that the carrier separation efficiency of the composite catalyst was significantly improved. In addition, the photocatalytic activity of Zn_0.2Cd_0.8S@CDs for rhodamine B removal from aqueous solution was tested under visible-light irradiation. When the amount of Zn_0.2Cd_0.8S@CDs composite catalyst reached 50 mg, the degradation rate of rhodamine B was 79.35%. Finally, the photocatalytic degradation mechanism of the Zn_0.2Cd_0.8S@CDs complex was studied. CD doping enhances the adsorption capacity of Zn_0.2Cd_0.8S@CDs composite catalysts due to the increase in surface area, effectively inducing charge delocalization and enhancing the photocatalytic capacity. Zn_0.2Cd_0.8S@CDs composites with low cost and high carrier separation efficiency have broad application prospects in the photocatalytic degradation of dyes.

A novel Fe/Mo co-catalyzed graphene-based nanocomposite to activate peroxymonosulfate for highly efficient degradation of organic pollutants

A novel 3D α-FeOOH@MoS₂/rGO nanocomposite was successfully fabricated by a simple in situ hydrothermal method. It is a highly efficient heterogeneous catalyst in activation of peroxymonosulfate (PMS) for rapid degradation of rhodamine B (RhB), with 99.9% of RhB removed within 20 min. The introduction of rGO contributes to uniform dispersion and sufficient contact of α-FeOOH and MoS₂ nanosheets. Highly active Mo(IV) enhances the reduction of Fe(III), improves Fe(III)/Fe(II) conversion and promotes the generation of O₂1, which ensures an improved catalytic activity. MoS₂/rGO hybrid can effectively solve the problem of material reunion and make α-FeOOH exhibit excellent catalytic performance. The α-FeOOH@MoS₂-rGO/PMS system is a co-catalytic system based on the active components of α-FeOOH and MoS₂. The main reactive oxygen species in the α-FeOOH@MoS₂-rGO/PMS system are O₂1, SO₄^.- and ⋅O₂^-, which contribute to a high reactivity over a wide range of pH (5-9). Besides, this system is highly resistant to anions (Cl^-, SO₄^2-) and natural organic matter (humic acid), and can be widely used for degradation of common organic pollutants. The α-FeOOH@MoS₂/rGO is a promising Fenton-like catalyst for refractory organic wastewater treatment.

In2S3 nanoflakes grounded in Bi2WO6 nanoplates: A novel hierarchical heterojunction catalyst anchored on W mesh for efficient elimination of toluene

Toxic toluene can be completely oxidized in CO₂ and H₂O with novel three-dimensional (3D) In₂S₃@Bi₂WO₆ hierarchical crystals under visible light. Dense and uniform In₂S₃ nanoflakes are rooted in Bi₂WO₆ nanoplates which intercross with each other and are anchored on a pliable tungsten mesh. This leads to the construction of a stable and porous interface for adsorbing and decomposing target gaseous toluene. The firm contact between In₂S₃ and Bi₂WO₆ initiates the formation of a built-in electric field that helps in channeling the photogenerated electrons in Bi₂WO₆ CB to quench the holes in₂S₃ VB. This results in highly capable electrons and holes, as well as notable increase in the yields of •O₂^- and •OH. 99.7% of toluene is removed and 93.4% is converted to CO₂ when it is degraded in simulated air. This validates its remarkable efficacy in detoxifying toluene.

Photocatalytic Behavior of Supported Copper Double Salt: The Role of Graphene Oxide

The design of a photocatalyst that may work efficiently with sunlight is a fundamental concern to fight against environmental pollution and electrochemical hydrogen storage devices. In this work, it has been found that the green microwave-assisted decoration of graphene by copper double salt (DS) enhances visible sunlight photocatalysis efficiency. Nanohybrids of graphene oxide decorated with Cu(I) and Cu(II) oxides and copper hydroxy nitrate double salt were selected as photocatalysts for the degradation of rhodamine B in aqueous solution to study the effect of the graphene oxide support. The photodegradation process followed a pseudo–first-order kinetics for the bare catalysts, but the supported catalysts were best fitted to the Langmuir-Hinshelwood model. Supported systems were more efficient in terms of turnover and apparent rate constants. Diffuse reflectance spectroscopy with the use of Kubelka-Munk function allowed to measure bandgap energies. It was found that the absorption edge was reduced about 30% for the supported systems.

Functionalized MOF PCN-222-loaded quantum dots as an electrochemiluminescence sensing platform for the sensitive detection of p-nitrophenol

The composite PCN-222@CdSe was used to detect PNP.