In-situ fabrication of novel flower like MoS2/CoTiO3 nanorod heterostructures for the recyclable degradation of ciprofloxacin and bisphenol A under sunlight

Constructing hollow core-shell Z-scheme heterojunction CdS@CoTiO3 nanorods for enhancing the photocatalytic degradation of 2,4-DCP and TC

Constructing Z-scheme heterojunctions incorporating an exquisite hollow structure is an effective performance regulation strategy for the realization of high quantum efficiency and a strong redox ability over photocatalysts. Herein, we report the delicate design and preparation of a core-shell hollow CdS@CoTiO3 Z-scheme heterojunction with a CdS nanoparticle (NP)-constructed outer shell supported on a CoTiO3 nanorod (NR) inner shell. The in situ growth synthetic method led to a tightly connected interface for the heterojunction between CdS and CoTiO3, which shortened the transport distance of photoinduced charges from the interface to the surface. The promoted charge carrier separation efficiency and the retained strong redox capacity caused by the Z-scheme photoinduced charge-transfer mechanism were mainly responsible for the boosted photocatalytic performance. Additionally, the well-designed core-shell structure afforded a larger interfacial area by the multiple direction contact between CdS and CoTiO3, ensuring sufficient channels for efficient charge transfer, and thus further boosting the photocatalytic activity. As an efficient photocatalyst, the optimized CdS@CoTiO3 nanohybrids displayed excellent 2,4-dichlorophenol (2,4-DCP) and tetracycline (TC) degradation efficiencies of 91.3% and 91.8%, respectively. This study presents a Z-scheme heterojunction based on ecofriendly CoTiO3, which could be valuable for the development of metal perovskite photocatalysts for application in environmental remediation, and also demonstrated the tremendous potential of integrating a Z-scheme heterojunction with the morphology design of photocatalyts.

Application of perovskite oxides and their composites for degrading organic pollutants from wastewater using advanced oxidation processes: Review of the recent progress

In the recent years, perovskite oxides are gaining an increasing amount of attention owing to their unique traits such as tunable electronic structures, flexible composition, and eco-friendly properties. In contrast, their catalytic performance is not satisfactory, which hinders real wastewater remediation. To overcome this shortcoming, various strategies are developed to design new perovskite oxide-based materials to enhance their catalytic activities in advanced oxidation process (AOPs). This review article is to provide overview of basic principle and different methods of AOPs, while the strategies to design novel perovskite oxide-based composites for enhancing the catalytic activities in AOPs have been highlighted. Moreover, the recent progress of their synthesis and applications in wastewater remediation (pertaining to the period 2016-2022) was described, and the related mechanisms were thoroughly discussed. This review article helps scientists to have a clear outlook on the selection and design of new effective perovskite oxide-based materials for the application of AOPs. At the end of the review, perspective on the challenges and future research directions are discussed.

Effective fabrication of cellulose nanofibrils supported Pd nanoparticles as a novel nanozyme with peroxidase and oxidase-like activities for efficient dye degradation

Nanozyme-based dye degradation methods are promising for the remediation of water pollution. Though Pd nanoparticles (PdNPs) are known to act as nanozymes, their dye degradation capability has not been investigated. Low nanozyme activities, easy aggregation, difficulties in recovery and reuse are the major challenges in achieving this. For the first time, cellulose nanofibrils-supported PdNPs (PdNPs/PCNF) as a novel nanozyme with good peroxidase and oxidase-mimicking activities and easy recyclability is explored for dye degradation. An efficient and rapid method of PdNPs/PCNF preparation was demonstrated by adjusting the pH and microwave irradiation. Enzyme kinetic studies revealed good kinetic parameters and specific activities of 415 and 277 U/g for peroxidase and oxidase, respectively. PdNPs/PCNF offered 99.64% degradation of methylene blue within 12 min (0.468 min^-1) with 0.4 M H₂O₂ at pH 5.0. Mechanistic studies revealed the involvement of hydroxyl and superoxide radicals. Owing to the network-like structure of PCNF, films and foams were prepared, their dye degradation potentials were compared, and recyclability was tested. Successful degradation of mixed dye solutions and spiked real water samples was achieved and a continuous flow method was demonstrated using a foam-packed column.

Molybdenum Disulfide-Based Nanomaterials for Visible-Light-Induced Photocatalysis

Visible-light-responsive photocatalytic materials have a multitude of important applications, ranging from energy conversion and storage to industrial waste treatment. Molybdenum disulfide (MoS₂) and its variants exhibit high photocatalytic activity under irradiation by visible light as well as good stability and recyclability, which are desirable for all photocatalytic applications. MoS₂-based materials have been widely applied in various fields such as wastewater treatment, environmental remediation, and organic transformation reactions because of their excellent physicochemical properties. The present review focuses on the fundamental properties of MoS₂, recent developments and remaining challenges, and key strategies for tackling issues related to the utilization of MoS₂ in photocatalysis. The application of MoS₂-based materials in visible-light-induced catalytic reactions for the treatment of diverse kinds of pollutants including industrial, environmental, pharmaceutical, and agricultural waste are also critically discussed. The review concludes by highlighting the prospects of MoS₂ for use in various established and emerging areas of photocatalysis.

Flower-like molybdenum disulfide decorated ZIF-8-derived nitrogen-doped dodecahedral carbon for electro-catalytic degradation of phenol

In this work, flower-like molybdenum disulfide was constructed on the surface of ZIF-8-derived nitrogen-doped dodecahedral carbon (ZNC) for the electrocatalytic degradation of phenol. The flower-like nanostructure of MoS₂@ZNC contributed to the exposure of more edge-active sites of MoS₂. At the same time, Mo⁴⁺ and Mo⁶⁺ co-existed in MoS₂@ZNC, which promoted the generation of H₂O₂ and •OH, and improved the catalytic activity of composite materials. In addition, electrochemical performance analysis showed that MoS₂ loaded on the surface of ZNC significantly improved the redox capacity of the material, and the composite ratio of MoS₂ and ZNC affected the structure and properties of MoS₂@ZNC composites. Moreover, the electrochemical performance of prepared MoS₂@ZNC was evaluated by the generation of hydroxyl (•OH) and the degradation efficiency of phenol. The results showed that MoS₂@ZNC-2 had an excellent phenol degradation efficiency (98.8%) and COD removal efficiency (86.8%) within 120 min. Furthermore, MoS₂@ZNC cathode still maintained good performance after being experimented with 20 times, indicated the excellent stability of MoS₂@ZNC.