Search Results (29)

The long-term stability of dental implants is limited by multiple factors, including peri-implant infection, impaired osseointegration, and poor soft tissue sealing. Compared with conventional passive surface modification strategies, piezoelectric materials can convert mechanical energy into local electrical signals under occlusal loading, cell traction, or ultrasonic stimulation. With the aid of defect engineering, heterostructure construction, and co-catalytic design, these materials can also induce the generation of reactive oxygen species and reactive nitrogen species, thereby enabling on-demand antibacterial activity. This review systematically summarizes the bioelectric basis of bone tissue and clarifies how piezoelectricity and piezocatalysis may be used in dental implant surface engineering. Their applications are discussed in terms of antibiofilm and antibacterial activity, osteogenesis and osseointegration, osteoimmunomodulation, soft tissue healing, and temporally programmed therapy. In addition, this review also discusses issues that remain unresolved, such as polymer-based composite systems, realistic activation windows, evaluation standards, device–material integration, and multi-omics validation. Overall, piezoelectric surface engineering is evolving from a single osteogenesis-oriented strategy into an integrated platform that coordinates infection control, immune remodeling, and osseointegration. However, the actual effectiveness of its clinical application still needs to be determined through more rigorous mechanism analysis, long-term stability assessment, biosafety assessment, and standardized preclinical research. Full article

Cephalexin is a widely used antibiotic frequently detected in hospital wastewater and aquatic environments near pharmaceutical facilities, where its persistence contributes to the spread of antibiotic resistance. Mechanically driven advanced oxidation processes, including piezocatalysis and tribocatalysis, represent sustainable alternatives for pollutant removal because they operate without external light or heat sources. In this study, ZnO catalysts with controlled morphologies were synthesized via sol–gel and mechanochemical methods using different solvents and activation times (1 and 5 h). The influence of structural characteristics, surface area, and friction conditions on catalytic performance was systematically evaluated. The results demonstrated that tribocatalytic efficiency strongly depends on stirring rate and reactor material, with PTFE systems exhibiting superior performance. Mechanochemically activated ZnO (1 h) showed the highest degradation efficiency due to optimized defect density and surface accessibility. All catalysts exhibited high stability, while radical scavenging experiments identified superoxide radicals as the primary reactive species in the degradation process. Full article

Piezo-enhanced photocatalysis is progressively considered an eco-friendly technology for contaminant removal, harvesting not only solar energy but also mechanical vibrations found in nature. Multiferroic materials present a coupled effect of various properties and can potentially increase the applicability of this process. In this study, Cr- doped bismuth ferrite thin film was deposited on SrTiO₃ substrate by HiPIMS, and its photo-, piezo-, and piezo-photocatalytic efficiencies in Rhodamine B (RhB) degradation were analyzed. The highest removal percentage was found under the simultaneous exposure of visible light and mechanical vibrations, reaching 86.2% after 180 min. The calculated efficiencies for photo- and piezocatalysis were 12.2% and 83.7%, respectively. The rate constant (k) for piezo-photocatalysis was 16.1 times higher than that found during photocatalytic experiments. To assess the contribution of each reactive species to the decomposition process, different reagents were added to the Rhodamine B contaminated solution. The results revealed that when p-benzoquinone was used, the degradation efficiency declined significantly from 86.2% to 37.6%, suggesting that superoxide radicals (O₂^•−) play a key role in decomposing RhB molecules. The structural, chemical, optical, and ferroelectric changes caused by the catalytic processes were analyzed and linked to the proposed degradation mechanisms. The poor photocatalytic efficiency was linked to an improper band structure and an improper polarization orientation of the ferroelectric domains in the as-deposited film. The degradation mechanisms in piezo-photocatalysis were driven partly by the band bending caused by mechanical vibrations and partly by the reorientation of the induced polarization of the domains in the unstrained film. Full article

Mechanical energy, a ubiquitous renewable resource, can be effectively harnessed via piezocatalysis to convert physical stimuli into chemical energy for sterilization. As a promising green technology, piezocatalysis employs external mechanical force to physically disrupt bacterial membranes while simultaneously triggering redox reactions to generate bactericidal reactive oxygen species (ROS). Recent advances highlight the superior performance and broad applicability of this technology in the antibacterial domain. This review systematically elucidates the antibacterial mechanisms of piezocatalysis, followed by a comprehensive survey of prevalent piezoelectric biomaterials (e.g., amino acids, cellulose, proteins) and their synthesis strategies. Furthermore, specific applications of these bio-piezoelectric composites in sterilization are consolidated. Finally, we critically assess the primary challenges and outline future developmental trajectories, offering a prospective pathway for next-generation eco-friendly disinfection strategies. Full article

Given the increasing environmental degradation, this study investigates advanced zinc oxide (ZnO)-based materials for the mineralization of toxic compounds through the combined action of photo- and piezocatalysis. Two complementary strategies were employed to enhance catalytic efficiency. First, ZnO_1−xN_x thin films were deposited by reactive high-power impulse magnetron sputtering (R-HiPIMS) to reduce the band gap energy. Second, flower-like ZnO nanostructures were synthesized using the pulsed thermionic vacuum arc (p-TVA) technique to increase the specific surface area. Both systems were further modified by decoration with Ag₂O nanoparticles to improve charge separation. The R-HiPIMS technique offers significant advantages in terms of precise control over processing parameters, enabling accurate tuning of film properties, including microstructure, chemical composition, and electronic structure. However, films produced via R-HiPIMS generally exhibit lower photo-piezocatalytic activity compared to nanostructured counterparts, primarily due to their comparatively reduced effective surface area and limited charge separation efficiency. In contrast, the p-TVA technique enables the synthesis of nanostructured thin films with substantially enhanced photo-piezocatalytic performance. This improvement is attributed to the increased effective surface area and the promotion of more efficient electron–hole pair separation. The materials were comprehensively characterized in terms of optical properties (UV–Vis spectroscopy), chemical composition and bonding (XPS), crystalline structure (XRD), surface morphology (FE-SEM), and photo-piezocatalytic performance. Catalytic activity was evaluated via the degradation of methylene blue (MB) under visible light irradiation and mechanical vibrations. Nitrogen incorporation in ZnO_1−xN_x thin films led to an increase in photocatalytic efficiency from 20% to 28.7%, while the simultaneous application of light and mechanical stimulation increased efficiency to approximately 50%. Under identical irradiation conditions, Ag₂O-decorated ZnO and Ag₂O-decorated ZnO_1−xN_x exhibited photo-degradation reaction rate constants up to 65% higher than bare counterparts, attributed to reduced electron–hole recombination. ZnO nanostructures achieved degradation efficiencies of 59%, rising to 88.3% with Ag₂O decoration under solar illumination for 120 min. When combined with mechanical vibrations, after 60 min, the degradation efficiencies reached 93% for ZnO and 98% for Ag₂O/ZnO systems. A photodegradation mechanism of Ag₂O NPs-decorated ZnO heterostructures was proposed. Full article

In this work, we investigate advanced photocatalyst Bi₃TiNbO₉ as promising piezophotocatalyst in terms of the effect of synthesis methods on the surface chemistry, structure, and catalytic performance in process of contaminant removal. Samples were prepared via solid-state reaction (BTNO-900) and molten salt synthesis (BTNO-800), leading to distinct morphologies and defect distributions. SEM imaging revealed that BTNO-900 consists of agglomerated, irregular particles, while BTNO-800 exhibits well-faceted, plate-like grains. Nitrogen adsorption analysis showed that the molten-synthesized sample possesses a significantly higher specific surface area (5.9 m²/g vs. 1.4 m²/g) and slightly larger average pore diameter (2.8 nm vs. 2.6 nm). High-resolution XPS revealed systematic shifts in binding energies for Bi 4f, Ti 2p, Nb 3d, and O 1s peaks in BTNO-900, accompanied by a higher content of adsorbed oxygen species (57% vs. 7.2%), indicating an increased concentration of oxygen vacancies and surface hydroxylation due to the solid-state synthesis route. Catalytic testing demonstrated that BTNO exhibits enhanced piezocatalytic efficiency of Methylene Blue degradation (~78% for both samples), whereas BTNO-800 shows significantly reduced photocatalytic activity (45.6%) compared to BTNO-900 (84.1%), suggesting recombination effects dominate in the more defective material. Synergism of light and mechanical stress results in piezophotocatalytic degradation for both samples (92.4% and 93.4%, relatively). These findings confirm that synthesis-controlled defect engineering is a key parameter for optimizing the photocatalytic behavior of Bi₃TiNbO₉-based layered oxides and crucial role of its piezocatalytic activity. Full article

The metal-free polymeric semiconductor graphitic carbon nitride (g-C₃N₄) has emerged as a promising material for photocatalytic applications due to its responsiveness to visible light, adjustable electronic structure, and stability. This review systematically summarizes recent advances in preparation strategies, including thermal polycondensation, solvothermal synthesis, and template methods. Additionally, it discusses modification approaches such as heterojunction construction, elemental doping, defect engineering, morphology control, and cocatalyst loading. Furthermore, it explores the diverse applications of g-C₃N₄-based materials in photocatalysis, including hydrogen (H₂) evolution, carbon dioxide (CO₂) reduction, pollutant degradation, and the emerging field of piezoelectric photocatalysis. Particular attention is given to g-C₃N₄ composites that are rationally designed to enhance charge separation and light utilization. Additionally, the synergistic mechanism of photo–piezocatalysis is examined, wherein a mechanically induced piezoelectric field facilitates carrier separation and surface reactions. Despite significant advancements, challenges persist, including limited visible-light absorption, scalability issues, and uncertainties in the multi-field coupling mechanisms. The aim of this review is to provide guidelines for future research that may lead to the development of high-performance and energy-efficient catalytic systems in the context of environmental and energy applications. Full article

Ultrasound-responsive nanomaterials represent a promising approach for achieving non-invasive and localized drug delivery within tumor microenvironments. In this study, we developed a piezocatalysis-assisted hydrogel system that integrates reactive oxygen species (ROS) generation with stimulus-responsive drug release. The platform combines piezoelectric barium titanate (BTO) nanoparticles with a ROS-sensitive hydrogel matrix, forming an ultrasound-activated dual-function therapeutic system. Upon ultrasound irradiation, the BTO nanoparticles generate ROS—predominantly hydroxyl radicals (^•OH) and singlet oxygen (¹O₂)—through the piezoelectric effect, which triggers hydrogel degradation and facilitates the controlled release of encapsulated therapeutic agents. The composition and kinetics of ROS generation were evaluated using radical scavenging assays and fluorescence probe techniques, while the drug release behavior was validated under simulated oxidative environments and acoustic fields. Structural and compositional characterizations (TEM, XRD, and XPS) confirmed the quality and stability of the nanoparticles, and cytocompatibility was assessed using 3T3 fibroblasts. This synergistic strategy, combining piezocatalytic ROS generation with hydrogel disintegration, demonstrates a feasible approach for designing responsive nanoplatforms in ultrasound-mediated drug delivery systems. Full article

Piezoelectric catalytic technology has attracted much attention in the field of dye wastewater treatment, in which inorganic piezoelectric materials have been widely studied. Its core mechanism involves utilizing the piezoelectric effect to generate positive and negative charges, which react with oxygen ions and hydroxyl radicals, respectively, to generate reactive oxygen species to degrade organic pollutants. Currently, while organic piezoelectric catalysts theoretically offer significant advantages such as low cost and high processability, there has been a notable lack of research in this area, which presents an innovative opportunity for the exploration of new organic piezoelectric catalytic materials. In this study, new research using natural nanocellulose (FC) suspension as an efficient organic piezoelectric catalyst is reported for the first time. The experimental results showed that the catalyst exhibited excellent degradation performance for Rhodamine B (RhB), Acid Orange 7 (AO7), and Methyl Orange (MO) under ultrasonic vibration (40 kHz, 200 W): the degradation rates reached 95.4%, 72.4%, and 31.2%, respectively, for 150 min, and the corresponding first-order reaction kinetic constants were 0.0205, 0.00858, and 0.00249 min⁻¹, respectively. It is noteworthy that the RhB solution can achieve the optimal degradation efficiency without adjustment under neutral initial pH conditions, which significantly enhances the practical application feasibility. The experimental results showed that the catalyst, with a measurable piezoelectric coefficient (d33 = 4.4 pm/V), exhibited excellent degradation performance for Rhodamine B (RhB), Acid Orange 7 (AO7), and Methyl Orange (MO) under ultrasonic vibration (40 kHz, 200 W). This organic piezoelectric catalyst, based on renewable biomass, innovatively converts mechanical vibration energy in the environment into the power to degrade pollutants. It not only expands the application boundaries of organic piezoelectric materials but also provides a new solution for sustainable water treatment technology, demonstrating extremely promising application prospects in the field of green and environmentally friendly water treatment. Full article

Piezocatalysis is a promising technology for converting mechanical energy to chemical energy. Two-dimensional (2D) piezoelectric materials, with their large surface area, high charge mobility, and good flexibility, are among the most promising candidates in piezocatalysis. In this work, for the first time, we report Bi₂O₂Se nanosheets (NSs) with an average thickness of ~8 nm and a lateral size of ~160 nm for efficient piezocatalytic H₂O₂ production from water and oxygen under mechanical force induced by ultrasonication. The Bi₂O₂Se NSs achieved a high H₂O₂ production rate of 1033.8 μmol/g/h using ethanol as the sacrificial agent, significantly surpassing that of its bulk-sheet counterpart. Our results provide a novel potential 2D piezocatalytic material and offer valuable guidance for the design and development of high-efficiency H₂O₂ production driven by mechanical energy from water. Full article

Emerging pollutants, such as N-acetyl-para-aminophenol, pose significant challenges to environmental sustainability, and Bi₂Fe₂O₂ (BFO) nanomaterials are an emerging class of piezoelectric materials. This study presents a novel piezoelectric-driven Fenton system based on Bi₂Fe₄O₉ nanosheets for the efficient degradation of organic pollutants. BFO nanosheets with varying thicknesses were synthesized, and their piezoelectric properties were confirmed through piezoresponse force microscopy and heavy metal ion reduction experiments. The piezoelectric electrons generated within the BFO nanosheets facilitate the in situ production of hydrogen peroxide, which in turn drives the Fenton-like reaction. Furthermore, the piezoelectric electrons enhance the redox cycling of iron in the Fenton process, boosting the overall catalytic efficiency. The energy band structure of BFO nanosheets is well-suited for this process, enabling efficient hydrogen peroxide generation and promoting Fe³⁺ reduction. The findings demonstrate that thinner BFO nanosheets exhibit superior piezoelectric activity, leading to enhanced catalytic performance. Additionally, the incorporation of gold nanodots onto BFO nanosheets further boosts their piezocatalytic efficiency, particularly in the reduction of Cr (VI). The system exhibited robust oxidative capacity, stability, and recyclability, with reactive oxygen species (ROS) verified via electron paramagnetic resonance spectroscopy. Overall, BFO nanosheets, with their optimal energy band structure, self-supplied hydrogen peroxide, and enhanced Fe³⁺ reduction, represent a promising, sustainable solution for advanced oxidation processes in wastewater treatment and other applications. Full article

Piezocatalytic materials have attracted widespread attention in the fields of clean energy and water treatment because of their ability to convert mechanical energy directly into chemical energy. In this study, γ-AlON particles synthesised using carbothermal reduction and nitridation (CRN) were used for the first time as a novel piezocatalytic material to degrade dye solutions under ultrasonic vibration. The γ-AlON particles exhibited good performance as a piezocatalytic material for the degradation of organic pollutants. After 120 min under ultrasonic vibration, 40 mg portions of γ-AlON particles in 50 mL dye solutions (10 mg/L) achieved 78.06%, 67.74%, 74.29% and 64.62% decomposition rates for rhodamine B (RhB), methyl orange (MO), methylene blue (MB) and crystal violet (CV) solutions, respectively; the fitted k values were 13.35 × 10⁻³, 10.79 × 10⁻³, 12.09 × 10⁻³ and 8.00 × 10⁻³ min⁻¹, respectively. The piezocatalytic mechanism of γ-AlON particles in the selective degradation of MO was further analysed in free-radical scavenging activity experiments. Hydroxyl radicals (•OH), superoxide radicals (•O₂⁻), holes (h⁺) and electrons (e⁻) were found to be the main active substances in the degradation process. Therefore, γ-AlON particles are an efficient and promising piezocatalytic material for the treatment of dye pollutants. Full article

Piezocatalysis, a heterogeneous catalytic technique, leverages the periodic electric field changes generated by piezoelectric materials under external forces to drive carriers for the advanced oxidation of organic pollutants. Antibiotics, as emerging trace organic pollutants in water sources, pose a potential threat to animals and drinking water safety. Thus, piezoelectric catalysis can be used to degrade trace organic pollutants in water. In this work, BaTiO₃ and La-doped BaTiO₃ were synthesized using an improved sol–gel–hydrothermal method and used as piezocatalytic materials to degrade sulfadiazine (SDZ) with ultrasound activation. High-crystallinity products with nano cubic and spherical morphologies were successfully synthesized. An initial concentration of SDZ ranging from 1 to 10 mg/L, a catalysis dosage range from 1 to 2.5 mg/mL, pH, and the background ions in the water were considered as influencing factors and tested. The reaction rate constant was 0.0378 min⁻¹ under the optimum working conditions, and the degradation efficiency achieved was 89.06% in 60 min. La-doped BaTiO₃ had a better degradation efficiency, at 14.98% on average, compared to undoped BaTiO₃. Further investigations into scavengers revealed a partially piezocatalytic process for the degradation of SDZ. In summary, our work provides an idea for green environmental protection in dealing with new types of environmental pollution. Full article

Among the various water purification techniques, advancements in membrane technology, with better fabrication and analysis, are receiving the most research attention. The piezo-catalytic degradation of water pollutants is an emerging area of research in water purification technology. This review article focuses on piezoelectric polyvinylidene difluoride (PVDF) polymer-based membranes and their nanocomposites for textile wastewater remediation. At the beginning of this article, the classification of piezoelectric materials is discussed. Among the various membrane-forming polymers, PVDF is a piezoelectric polymer discussed in detail due to its exceptional piezoelectric properties. Polyvinylidene difluoride can show excellent piezoelectric properties in the beta phase. Therefore, various methods of β-phase enhancement within the PVDF polymer and various factors that have a critical impact on its piezo-catalytic activity are briefly explained. This review article also highlights the major aspects of piezoelectric membranes in the context of dye degradation and a net-zero approach. The β-phase of the PVDF piezoelectric material generates an electron–hole pair through external vibrations. The possibility of piezo-catalytic dye degradation via mechanical vibrations and the subsequent capture of the resulting CO₂ and H₂ gases open up the possibility of achieving the net-zero goal. Full article

Defect engineering constitutes a widely-employed method of adjusting the electronic structure and properties of oxide materials. However, controlling defects at room temperature remains a significant challenge due to the considerable thermal stability of oxide materials. In this work, a facile room-temperature lithium reduction strategy is utilized to implant oxide defects into perovskite BaTiO₃ (BTO) nanoparticles to enhance piezocatalytic properties. As a potential application, the piezocatalytic performance of defective BTO is examined. The reaction rate constant increases up to 0.1721 min⁻¹, representing an approximate fourfold enhancement over pristine BTO. The effect of oxygen vacancies on piezocatalytic performance is discussed in detail. This work gives us a deeper understanding of vibration catalysis and provides a promising strategy for designing efficient multi-field catalytic systems in the future. Full article