High piezocatalytic capability in CuS/MoS2 nanocomposites using mechanical energy for degrading pollutants

Application of catalytic technology based on the piezoelectric effect in wastewater purification

The demands of human life and industrial activities result in a significant influx of toxic contaminants into aquatic ecosystems. In particular, organic pollutants such as antibiotics and dye molecules, bacteria, and heavy metal ions are represented, posing a severe risk to the health and continued existence of living organisms. The method of removing pollutants from water bodies by utilizing the principle of the piezoelectric effect in combination with chemical catalytic processes is superior to other wastewater purification technologies because it can collect water energy, mechanical energy, etc. to achieve cleanliness and high removal efficiency. Herein, we briefly introduced the piezoelectric mechanisms and then reviewed the latest advances in the design and synthesis of piezoelectric materials, followed by a summary of applications based on the principle of piezoelectric effect to degrade pollutants in water for wastewater purification. Moreover, water purification technologies incorporating the piezoelectric effect, including piezoelectric effect-assisted membrane filtration, activation of persulfate, and battery electrocatalysis are elaborated. Finally, future challenges and research directions for the piezoelectric effect are proposed.

Glutathione-mediated copper sulfide nanoplatforms with morphological and vacancy-dependent photothermal catalytic activity for multi-model tannic acid assays

Interface engineering and vacancy engineering play an important role in the surface and electronic structure of nanomaterials. The combination of the two provides a feasible way for the development of efficient photocatalytic materials. Here, we use glutathione (GSH) as a coordination molecule to design a series of CuxS nanomaterials (CuxS-GSH) rich in sulfur vacancies using a simple ultrasonic-assisted method. Interface engineering can induce amorphous structure in the crystal while controlling the formation of porous surfaces of nanomaterials, and the formation of a large number of random orientation bonds further increases the concentration of sulfur vacancies in the crystal structure. This study shows that interface engineering and vacancy engineering can enhance the light absorption ability of CuxS-GSH nanomaterials from the visible to the near-infrared region, improve the efficiency of charge transfer between CuxS groups, and promote the separation and transfer of optoelectronic electron-hole pairs. In addition, a higher specific surface area can produce a large number of active sites, and the synergistic and efficient photothermal conversion efficiency (58.01%) can jointly promote the better photocatalytic performance of CuxS-GSH nanomaterials. Based on the excellent hot carrier generation and photothermal conversion performance of CuxS-GSH under illumination, it exhibits an excellent ability to mediate the production of reactive oxygen species (ROS) through peroxide cleavage and has excellent peroxidase activity. Therefore, CuxS-GSH has been successfully developed as a nanoenzyme platform for detecting tannic acid (TA) content in tea, and convenient and rapid detection of tannic acid is achieved through the construction of a multi-model strategy. This work not only provides a new way to enhance the enzyme-like activity of nanomaterials but also provides a new prospect for the application of interface engineering and vacancy engineering in the field of photochemistry.

Piezoelectric catalytic driven advanced oxidation process using two-dimensional metal dichalcogenides for wastewater pollutants remediation

The public and society have increasingly recognized numerous grave environmental issues, including water pollution, attributed to the rapid expansion of industrialization and agriculture. Renewable energy-driven catalytic advanced oxidation processes (AOPs) represent a green, sustainable, and environmentally friendly approach to meet the demands of environmental remediation. In this context, 2D transition metal dichalcogenides (TMDCs) piezoelectric materials, with their non-centrosymmetric crystal structure, exhibit unique features. They create dipole polarization, inducing a built-in electric field that generates polarized holes and electrons and triggers redox reactions, thereby facilitating the generation of reactive oxygen species for wastewater pollutant remediation. A broad spectrum of 2D TMDCs piezoelectric materials have been explored in self-integrated Fenton-like processes and persulfate activation processes. These materials offer a more simplistic and practical method than traditional approaches. Consequently, this review highlights recent advancements in 2D TMDCs piezoelectric catalysts and their roles in wastewater pollutant remediation through piezocatalytic-driven AOPs, such as Fenton-like processes and sulfate radicals-based oxidation processes.

One-step hydrothermal synthesis of CuS/MoS2 composite for use as an electrochemical non-enzymatic glucose sensor

Early diagnosis may be crucial for the prevention of chronic diabetes mellitus. For that herein, we prepared a CuS/MoS2 composite for a non-enzymatic glucose sensor through a one-step hydrothermal method owing to the synergetic effect of CuS/MoS2. The surface morphology of CuS/MoS2 was studied by Field Emission Scanning Electron Microscopy (FESEM) and Cs-corrected Scanning Transmission Electron Microscopy (Cs-STEM). The crystallinity and surface composition of CuS/MoS2 were analyzed by X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) respectively. The working electrode was prepared from CuS/MoS2 electrocatalyst, and for that dispersed solution of electrocatalyst was used to fabricate the material-loaded glassy carbon electrode (GC). CuS/MoS2 composite shows the viability of electrocatalyst to oxidize glucose in an alkaline solution with sensitivity and detection limit of 252.71 μA mM-1 cm-2 and 1.52 μM respectively. The proposed glucose sensor showed reasonable stability and potential selectivity during electrochemical analysis. Accordingly, the CuS/MoS2 composite has potential as a viable material for glucose sensing in diluted human serum.

Review of Bi-based catalysts in piezocatalytic, photocatalytic and piezo-photocatalytic degradation of organic pollutants

Photocatalysis, as an effective advanced oxidation process, has been widely carried out in water waste treatment, especially in the degradation of organic pollutants. However, the photocatalytic process is limited by the high recombination rate of photo-generated carriers. To improve photocatalytic efficiency, piezocatalysis has attracted increasing attention, especially that using lead-free piezoelectric materials, which avoids the secondary pollution of lead toxicity in the environment. Bi-based materials have both photocatalytic activity and piezocatalytic activity, which can perfectly combine the advantages of these two catalytic processes to promote the degradation of organic pollutants. Under an external mechanical action, the Bi-based catalyst produces a polarized electric field due to the piezoelectric effect, and the photo-generated carriers can be effectively separated under electrostatic attraction, thus obtaining more efficient photocatalytic performance. However, there are still many gaps in the design, reaction mechanism, and development prospects of Bi-based piezo-photocatalysts. Therefore, to acquire a deeper understanding of the research status of Bi-based piezo-photocatalysts, we summarize the existing literature to provide effective ways to improve piezo-photocatalytic performance. Moreover, this paper points out the developmental direction of piezo-photocatalysis in the future. Last but not least, we also look forward to the prospect of piezo-photocatalysis in the degradation of organic pollutants.

Facile and eco-friendly fabrication of biocompatible hydrogel containing CuS@Ser NPs with mechanical flexibility and photothermal antibacterial activity to promote infected wound healing

Bacterial infections can significantly impede wound healing and pose a serious threat to the patient's life. The excessive use of antibiotics to combat bacterial infections has led to the emergence of multi-drug-resistant bacteria. Therefore, there is a pressing need for alternative approaches, such as photothermal therapy (PTT), to address this issue. In this study, for the first time, CuS NPs with photothermal properties were synthesized using sericin as a biological template, named CuS@Ser NPs. This method is simple, green, and does not produce toxic and harmful by-products. These nanoparticles were incorporated into a mixture (XK) of xanthan gum and konjac glucomannan (KGM) to obtain XK/CuS NPs composite hydrogel, which could overcome the limitations of current wound dressings. The composite hydrogel exhibited excellent mechanical flexibility, photothermal response, and biocompatibility. It also demonstrated potent antibacterial properties against both Gram-positive and negative bacteria via antibacterial experiments and accelerated wound healing in animal models. Additionally, it is proved that the hydrogel promoted tissue regeneration by stimulating collagen deposition, angiogenesis, and reducing inflammation. In summary, the XK/CuS NPs composite hydrogel presents a promising alternative for the clinical management of infected wounds, offering a new approach to promote infected wound healing.

Piezoelectric materials and techniques for environmental pollution remediation

With the rapid development of industrialization and agriculture, a series of critical imminent environmental problems and water pollution have caught wide attention from the public and society. Piezoelectric catalysis technology with piezoelectric materials is a green and environmental method that can efficiently improve the separation of electron-hole pairs, then generating the active substances such as OH, H₂O₂ and O₂^-, which can degrade water pollutants. Therefore, we firstly surveyed the piezoelectric catalysis in piezoelectric materials and systematically concluded and emphasized the relationship between piezoelectric materials and the piezoelectric catalytic mechanism, the goal to elucidate the effect of polarization on piezoelectric catalytic performance and enhance piezoelectric catalytic performance. Subsequently, the applications of piezoelectric materials in water treatment and environmental pollutant remediation were discussed including degradation of organic pollutants, removal of heavy mental ions, radionuclides, bacteria disinfection and water splitting for H₂ generation. Finally, the development prospects and future outlooks of piezoelectric catalysis were presented in detail.

Ni-doped MoS2 embedded in natural wood containing porous cellulose for piezo-catalytic degradation of tetracycline

Wood is a natural material with low cost and easy recovery, which porous, layered, excellent structure and mechanical properties make it possible to apply in wastewater treatment. We have successfully grown MoS₂ on natural wood containing porous cellulose and introduced the high conductivity circuit path provided by Ni nanoparticles to construct a new piezoelectric three-dimensional wood block for the efficient degradation of tetracycline. Ni/MoS₂/Wood exhibited excellent piezo-catalytic degradation performance, and the degradation rate of tetracycline reached 95.96 % (k = 0.0411 min^-1) under ultrasonic vibration. After 5 cycles, the degradation rate still reached 90.20 %. In addition, Ni/MoS₂/Wood was used as the reactor filler to degrade tetracycline through piezoelectric response triggered by hydrodynamic force, and the degradation rate reached 90.27 % after 60 min. Further, the mechanism and the possible degradation pathways of tetracycline degradation were proposed. This low-cost, recyclable and stable three-dimensional wood block piezoelectric material provides a new idea for the practical application of wastewater treatment.

Piezocatalytic Techniques in Environmental Remediation

As a consequence of rapid industrialization throughout the world, various environmental pollutants have begun to accumulate in water, air, and soil. This endangers the ecological environment of the earth, and environmental remediation has become an immediate priority. Among various environmental remediation techniques, piezocatalytic techniques, which uniquely take advantage of the piezoelectric effect, have attracted much attention. Piezoelectric effects allow pollutant degradation directly, while also enhancing photocatalysis by reducing the recombination of photogenerated carriers. In this Review, we provide a comprehensive summary of recent developments in piezocatalytic techniques for environmental remediation. The origin of the piezoelectric effect as well as classification of piezoelectric materials and their application in environmental remediation are systematically summarized. We also analyze the potential underlying mechanisms. Finally, urgent problems and the future development of piezocatalytic techniques are discussed.