Piezocatalytic Degradation Research Articles

Oxygen Vacancies and Lattice Distortion Synergistically Enhanced Piezocatalysis of CaZn2(BO3)2 for Nonantibiotic Pharmaceutical Degradation.

Piezocatalysis, an emerging green and advanced oxidation technology, has recently been widely researched in environmental treatment. However, the limited polarization efficiency of the piezocatalyst is a serious bottleneck for its practical application. The search for an excellent piezocatalyst with a high piezoelectric coefficient and abundant reactive sites remains an urgent task that needs to be developed. Herein, a piezocatalyst, CaZn2(BO3)2 (CZBO), obtained by quenching has an excellent piezocatalysis, which exhibited superior activity for ibuprofen (IBP) and carbamazepine (CBZ) removal with 100% and 83.8% efficiency under ultrasonic cavitation (120 W, 40 kHz) within 36 min, respectively. The outstanding piezocatalytic degradation was attributed to the strong polarization of the material under the synergistic effect of oxygen vacancies (OVs) and lattice distortion, which effectively facilitated the generation of a high concentration of reactive oxygen species (ROS). The lattice distortion induced by O-deficient [BO3] plane units can promote the e- and h+ pair separation and transportation, and the OVs with abundant electron-rich regions can significantly decrease O-O bond activation energy, thus collaboratively contributing to the high production of ROS for IBP and CBZ degradation. This work provides a simple avenue for enhancing piezoelectric polarization based on the OVs and lattice distortion and proposes insights into the reaction mechanisms for degrading nonantibiotic pharmaceuticals in wastewater.

Morphology Regulation and Oxygen Vacancy Construction Synergistically Boosting the Piezocatalytic Degradation and Pure Water Splitting of SrTiO3.

In recent years, the development of high-efficiency piezoelectric materials is an effective means to make full use of the mechanical energy widely existing in the environment. However, there are few reports on multi-strategies synergistically improving piezocatalytic activity, and the mechanism of synergistic enhancement of piezocatalytic activity also receives less attention. Herein, the SrTiO3 nanorods decorated with tunable surface oxygen vacancy concentrations are prepared. Oxygen vacancy-optimized SrTiO3 nanorods exhibit efficient and undifferentiated piezocatalytic degradation activities for both anionic and cationic dyes under ultrasonic vibration. More importantly, it can split water into H2 and H2O2 with high production rates of 540 and 332 µmol g-1 h-1 without adding any sacrificial agents and cocatalysts, respectively. Mechanism analyses demonstrate that the 1D structure is beneficial to mechanical energy harvesting, and the surface oxygen vacancy induces larger surface asymmetry and piezoelectric response, synergically enhancing the piezocatalytic activity of SrTiO3 nanorods. In addition, metal deposition experiments under different conditions show that SrTiO3 nanorods possess abundant reactive catalytic sites in the piezocatalytic reaction process. This work provides a further understanding of piezocatalysis in piezoelectric nanomaterials and is important for the development of efficient piezoelectric catalysts.

Piezoelectric Energy Harvesting in Poly(vinylidene Fluoride‐co‐hexafluoropropylene)/Barium Titanate Nanofibers and Ultrasonic Assisted Piezocatalytic Degradation of Ciprofloxacin

AbstractAn innovative approach has been adopted through the synthesis of a cost‐effective ferroelectric host polymer, which was integrated with Barium Titanate (BaTiO3) to develop an efficient electrospun Polyvinylidene Fluoride‐Hexafluoropropylene/BaTiO3 (PVdF‐HFP/BaTiO3) nanocomposite (PBT), designated for energy harvesting and piezocatalytic applications. FT‐IR affirmed the existence of the crystalline β‐phase within the nanofibers. SEM images showed that nanofiber diameter decreases as applied voltage is increased in electrospinning. The BaTiO3 nanoparticles were scattered evenly in PBT, but at lower voltages, they aggregate. PBT showed enhanced piezoelectric performance under higher voltage conditions, registering a maximum piezoelectric output of ~7.7 V and an output current of 0.77 μA. Moreover, the composite exhibited a power density of 14.15 mW/m2 at a load resistance of 20 MΩ. Fabricated piezoelectric nanogenerator (PENG) demonstrated practical utility in flexible electronics, notably in charging capacitors of 0.47 μF and 1 μF. Additionally, the piezocatalytic degradation of the antibiotic ciprofloxacin (CIP) was effectively achieved using the electrospun nanofibers, with an impressive degradation rate of up to 99.6 % within 30 minutes under acidic conditions, and the material displayed notable reusability, maintaining up to 95.5 % efficiency after five cycles. DFT calculations and COMSOL simulations alongside a comparative examination of the electronic properties of PBT.

One-step hydrothermal synthesis of ternary heterostructure stannic sulfide - bismuth sulfide - bismuth oxychloride (SnS2-Bi2S3-BiOCl) composite loaded on carbon felt for highly efficient piezocatalytic degradation of organic dyes and antibiotics

The piezoelectric catalysis technique harnesses naturally occurring vibrational energy to remove organic pollutants from water in an environmentally friendly manner. In this study, a ternary heterostructure SnS2-Bi2S3-BiOCl (S-B-B) composite was successfully synthesized via a one-step hydrothermal method and simultaneously deposited on the surface of carbon felt. The S-B-B heterojunction exhibits significantly enhanced piezoelectric catalytic activity compared to SnS2, Bi2S3, and BiOCl, achieving a k value of 2.26 × 10⁻² min⁻¹ and a degradation efficiency of 89.9 % towards methyl orange (MO) dye after 100 min of ultrasonic degradation. This performance is markedly superior to the individual components, with k values of 3.80 × 10⁻⁴ min⁻¹ for SnS2, 1.16 × 10⁻² min⁻¹ for BiOCl, and 1.31 × 10⁻² min⁻¹ for Bi2S3. Moreover, in addition to levofloxacin (LV), it demonstrates high removal efficiency for Congo red (CR), methylene blue (MB), tetracycline hydrochloride (TC-HCl), and sulfanilamide (SN). Furthermore, it can be loaded onto carbon felt for use in piezoelectric catalytic degradation of dyeing wastewater, highlighting its potential for practical applications. Trapping experiments suggest that singlet oxygen non-radicals and hydroxyl radicals play a critical role in the piezocatalytic degradation of organic contaminants. Based on LC-MS results, a possible degradation pathway for MO dye is proposed. Furthermore, DFT calculations confirm electron transfer from Bi2S3 to SnS2 and BiOCl at the interfaces between SnS2/Bi2S3 and BiOCl/Bi2S3. The piezoelectric mechanism of the S-B-B composite is also elucidated, highlighting the interaction and electron dynamics within the heterostructure.

Porous polylactide membranes with high piezo-catalytic efficiency for organic wastewater treatment

Piezo-catalysis has been emerged as a green and promising wastewater treatment technology for efficient removal of persistent organic pollutants (POPs), such as 4-nitrophenol (4-NP). However, it remains challenging to achieve advanced materials with combined advantages of high piezo-catalytic efficiency, good hydrophilicity, and environmental friendliness. In this work, highly crystalline porous polylactide (PLA) membranes possessing such exceptional advantages have been successfully prepared from biodegradable poly(L-lactide)/poly(D-lactide)/polyethylene glycol/polyoxyethylene-polyoxypropylene block copolymer (PLLA/PDLA/PEG/PEO-PPO-PEO) blends by melt processing and subsequent water etching. During the melt-processing, the two PLA enantiomers co-crystallize into stereocomplex (SC) crystals and simultaneously the PEG used as a porogen is expelled from the crystalline regions. The results show that the prepared PLA membranes have not only abundant micro-porous structures but also good hydrophilicity due to the preferential localization of PEO-PPO-PEO copolymer on the pore walls, thus giving rise to an extremely high water flux of 2400 L/m2h. More interestingly, the PLA membranes exhibit remarkable piezoelectric activity and the piezo-catalytic degradation efficiency of 4-NP can reach as high as 96 % under the triggering of water flow involved in vacuum filtration. In addition, the membranes show excellent reusability and the high catalytic efficiency can be well-maintained after five repeated uses. These findings suggest broad application prospects of our porous SC-PLA membranes in organic wastewater treatment.

Mechanical-vibration-driven piezocatalytic degradation of organic pollutants over microcrystalline SnSe with selenium vacancies

Two-dimensional piezoelectric materials are attractive candidates to trigger piezoelectric catalytic reactions for organics degradation. Microcrystalline structures can endow them with enhanced piezocatalytic activity due totheir large surface area and abundant defect structures. In this work, microcrystalline SnSe with selenium vacancies (mc-SeVs SnSe) was synthesized and employed for piezocatalytic degradation of aqueous organics for the first time. Various instrumental testing results demonstrated that this unique microcrystalline SnSe has strong piezoelectric responses, abundant selenium vacancy defects and large active edges. Compared with crystalline SnSe, mc-SeVs SnSe showed superior piezocatalytic activity for the degradation of various organics in water. More importantly, mc-SeVs SnSe could induce the piezoelectric effect through mild mechanical energy to facilitate the efficient degradation of organic pollutants. The degradation efficiency of Crystal violet, p-nitrophenol, Malachite green, Congo red and Rhodamine B approached 100 % within 60 min reaction time. Superoxide and hydroxyl radicals were detected as the main reactive oxygen species generated in the piezocatalytic process. The degradation pathways of Rhodamine B were proposed based on high performance liquid chromatography-quadrupole-time of flight mass spectrum. The impact of strain on the alterations of dipole moment and electronic structure was investigated using density functional theory. The change in electron band structure induced by the polarized electric field was the underlying reason for the generation of hydroxyl radicals. This work will enrich the piezoelectric materials for organics degradation and provide fresh light on the mechanism of mechanically driven piezoelectric catalytic reactions.

Mechanically induced built-in electric field in BCTZ nanostructures for piezocatalysis: Experiments and modeling

Ba(Ti0.80Zr0.20)O3–0.5(Ba0.7Ca0.3)TiO3 (BCTZ) piezoelectric nanofibers (NFs) and nanoparticles (NPs) were fabricated using electrospinning and sol-gel methods, respectively. The impact of BCTZ nanostructure on piezocatalysis was investigated, revealing that both poled NFs and NPs exhibit a piezocatalytic degradation rate of 2.8 × 10–2 min-1, which is significantly higher than their unpoled counterparts at 2.3 × 10–2 min-1 and 1.9 × 10–2 min-1, respectively. The enhanced piezocatalytic degradation rates of the poled BCTZ nanostructures are attributed to their superior piezoelectricity, resulting in larger built-in electric fields under external strain. Moreover, BCTZ NFs provide numerous active piezocatalytic reaction sites confined to the one-dimensional (1D) fibrous boundaries. Simulation results indicate that BCTZ NFs exhibit greater displacement and higher piezoresponse compared to nanoparticles, due to the electromechanical coupling effect facilitated by the 1D nanostructure. This study provides an efficient pathway to understanding the coupling mechanism between the poled built-in electric field and piezotronics.

Enhanced piezocatalytic degradation of cationic dyes using graphene oxide and magnetic beads Nanomaterials: Synthesis, Characterization, and mechanistic insights

Sequestration of organic pollutants by the method of degradation is one of the safest ways to completely remove them from water bodies, without generating harmful by-products. Piezocatalytic degradation for this approach has been gaining much research attention, in recent times, due to its high efficiency. The present work reports synthesis of four types of Graphene Oxide-Chitin-Magnetic Iron Oxide Beads Nanomaterials, each with a different ratio of Graphene oxide (GO) and Chitin (CH). Among these, GO-CH-MIOBs NM-4 showed a superior Piezocatalytic degradation capacity towards methylene blue (MB), crystal violet (CV) and Rhodamine 6G (R6G) dyes. Various parameters influencing the piezocatalytic performance of the material such as kinetic factors, initial dye concentration, strength of ultrasonic vibration etc., have been analyzed thoroughly. Degradation rate constant (K) values of 63.4, 59.34 and 48.36 /min were obtained for MB, CV and R6G Dyes respectively. Moreover, cycling tests for all three dyes reflected significant stability of these materials as evident from the high degradation efficiencies of 99.80, 99.24 and 99.12 % within 60 min being retained for MB, CV and Rh6G dyes even after the 5th cycle. These nanomaterials can be a good addition in the list of high efficiency piezocatalyts for water purification with no secondary wastes being produced. Comparison of the XPS spectra before and after sonication gave insight into the mechanism of piezocatalytic degradation which highlighted hydroxyl and superoxide radicals as the main attacking species which are responsible for the degradation process.

Remarkably Boosting Piezocatalytic Performance of Sr0.5Ba0.5Nb2O6 Piezoceramics via Size Optimization and Oxygen Vacancy Engineering

AbstractPiezocatalysis is capable of harnessing mechanical energy for environmental remediation, which is regarded as a green and promising technology to be exploited. Piezoceramics are struggling to be used as highly efficient piezocatalysts due to their grain size reaching tens of micrometers usually. Herein, a feasible and straightforward method is proposed to turn piezoceramic powders into highly efficient piezocatalysts by integrating size optimization and oxygen vacancy modulation. This strategy is validated by treating lead‐free Sr0.5Ba0.5Nb2O6 (SBN) piezoceramic powders with high‐energy ball‐milling (hBM). The rate constant k value of 46.95 × 10−3 min−1 for rhodamine B (RhB) piezocatalytic degradation of SBN‐hBM‐12h is almost 18 times higher than that of pristine SBN. Besides, the SBN‐hBM‐12 h catalyst performed superior antibacterial properties against Escherichia coli. The enhanced piezocatalytic efficiency is attributed to the introduced abundant oxygen vacancies absorbing and activating O2 into reactive oxygen species. Well‐modulated oxygen vacancy concentration can effectively accelerate the generation and separation of free carriers. However, the excess oxygen vacancies in SBN render the weakened piezoresponse thus suppressing the piezocatalytic activity. This study elucidates the critical role of oxygen vacancies in piezocatalysis and provides insights into the development of efficient piezocatalysts.

Water-flow driven activation flexible PANI/β-PVDF piezoelectric spheres with enhanced piezoelectric properties for efficient degradation of organic pollutants

The conductive polymer polyaniline was introduced into poly(vinylidene fluoride) to improve its piezoelectric β phase content and conductivity, and a novel polyaniline/β-poly(vinylidene fluoride) (PANI/β-PVDF) piezoelectric spheres was prepared successfully for the water-flow driven piezocatalytic degradation of levofloxacin. PANI/β-PVDF piezoelectric spheres showed excellent piezocatalytic performance, and the degradation efficiency of levofloxacin reached 98.1 % within 30 min. It was worthing note that the EE/O value of the water-flow driven piezocatalytic system was only 6.57 % of that of the ultrasonic driven system. Based on the frontier orbital theory and Liquid chromatography-mass spectrometry, the possible piezocatalytic degradation pathways of levofloxacin were deduced. The results of toxicity migration evaluation during reaction showed that the acute toxicity and developmental toxicity of levofloxacin were significantly reduced. The piezocatalytic degradation of levofloxacin by PANI/β-PVDF piezoelectric spheres is triggered by the water-flow, which provides a new idea for the sustainable development of high efficiency and low consumption treatment of antibiotic wastewater.

Enhancing production of hydrogen and simultaneous degradation of ciprofloxacin over Sn doped SrTiO3 piezocatalyst

The combination of hydrogen production from water and degradation of organic pollutants into a single reaction system is an attractive and promising solution for renewable energy generation and wastewater treatment. Herein, the piezocatalytic production of hydrogen coupled with simultaneous piezocatalytic degradation of organic antibiotic (ciprofloxacin) was successfully achieved using Sn doped SrTiO3 as the highly efficient and robust piezocatalyst through harvesting vibration energy. Results showed that 5 mol% Sn doped SrTiO3 (SrSn0.05Ti0.95O3) showed the highest piezocatalytic production rate of hydrogen (101.46 μmol g−1h−1) in water. And SrSn0.05Ti0.95O3 also exhibited remarkable piezocatalytic activity in solution containing ciprofloxacin with 151.03 μmol g−1h−1 of H2 evolution rate and 77.5 % of ciprofloxacin degradation efficiency within 60 min. In this process, the doping of Sn largely enlarged the distorted structure and conductivity of SrTiO3 to improve the piezocatalytic activity, and the organic ciprofloxacin mainly acted as the electron donors to synergistically improve the reduction process for H2 evolution. This work establishes the relationships between the piezoelectric property and the piezocatalyst structure, and provides an approach of advanced piezocatalytic technology for wastewater treatment and renewable energy generation.

Role of Bi3+ ion substitution on the piezocatalytic degradation performance of lead-free BaTi0·89Sn0·11O3 at low vibrational energy

Harnessing low ultrasonic vibration energy to initiate piezocatalytic-based reactions is increasingly becoming a significant focus due to the current environmental energy crisis. In this study, we report on the potential of heterovalent ion substitution in improving piezocatalytic degradation of Rhodamine B dye (RhB) under the application of low-power ultrasonic vibration. For this purpose, bismuth ions Bi3+ are substituted into the lead-free ferroelectric BaTi0·89Sn0·11O3 (BTSn11-xBi, x = 0, 0.02, 0.04) submicrocubes synthesized using sol-gel method. The structural, morphological, optical and piezocatalytic properties of the prepared materials appear to be significantly influenced by the substituting content. Compared to pure BTSn11 and BTSn11-0.04Bi, BTSn11-0.02Bi exhibits the lowest band gap energy value of 3.22 eV, the smallest particle size value of 283 nm, the strongest piezoelectric current of about 8 μA/cm2, and the lowest required applied field for piezoresponse force microscopy hysteresis loops. The degradation efficiency and the kinetic rate constant are substantially higher for BTSn11-0.02Bi, indicating its enhanced piezocatalytic efficiency. Total organic carbon (TOC) measurements revealed good RhB mineralization using BTSn11-xBi piezocatalysts. Furthermore, the BTSn11-0.02Bi sample demonstrates good reusability and stability by maintaining effective RhB dye degradation for five consecutive cycling tests. These findings suggest that the BTSn11-0.02Bi piezocatalytic system holds significant potential for environmental remediation applications.

MoS2@MWCNTs with Rich Vacancy Defects for Effective Piezocatalytic Degradation of Norfloxacin via Innergenerated-H2O2: Enhanced Nonradical Pathway and Synergistic Mechanism with Radical Pathway.

Molybdenum disulfide (MoS2)-based materials for piezocatalysis are unsatisfactory due to their low actual piezoelectric coefficient and poor electrical conductivity. Herein, 1T/3R phase MoS2 grown in situ on multiwalled carbon nanotubes (MWCNTs) was proposed. MoS2@MWCNTs exhibited the interwoven morphology of thin nanoflowers and tubes, and the piezoelectric response of MoS2@MWCNTs was 4.07 times higher than that of MoS2 via piezoresponse force microscopy (PFM) characterization. MoS2@MWCNTs exhibited superior activity with a 91% degradation rate of norfloxacin (NOR) after actually working 24 min (as for rhodamine B, reached 100% within 18 min) by pulse-mode ultrasonic vibration-triggered piezocatalysis. It was found that piezocatalysis for removing pollutants was attributed to the synergistic effect of free radicals (•OH and O2•-) and nonfree radical (1O2, key role) pathways, together with the innergenerated-H2O2 promoting the degradation rate. 1O2 can be generated by electron transfer and energy transfer pathways. The presence of oxygen vacancies (OVs) induced the transformation of O2 to 1O2 by triplet energy transfer. The fast charge transfer in MoS2@MWCNTs heterostructure and the coexistence of sulfur vacancies and OVs enhanced charge carrier separation resulting in a prominent piezoelectric effect. This work opens up new avenues for the development of efficient piezocatalysts that can be utilized for environmental purification.

Enhanced piezocatalytic degradation of mixed organic dyes using BaTiO3–MoS2 heterostructure nanocomposites: A mechanistic investigation

Piezocatalysis garners significant interest as a potential solution to environmental issues, specifically regarding dye pollutants. Nonetheless, the main obstacle in the piezoelectric efficiency of materials for eliminating organic pollutants from water has been the recombination of charge carriers. Here we report on the fabrication of a piezoelectric nanocomposite of BaTiO3 (BT) Nanoparticles and MoS2 (MS) Nanosheets for the enhanced piezocatalytic degradation of dye pollutants. The sample with 1.0 wt % MoS2 content (BT/MS1) demonstrates greater efficacy compared to both 2.0 wt % MoS2 (BT/MS2) and BaTiO3 (BT) alone in degrading Rhodamine B (Rh B) and Methyl Orange (MO). Specifically, BT/MS1 exhibits 1.84- and 2.8-times enhanced performance for Rh B and MO degradation respectively, in comparison to BT alone. It is demonstrated that the charge transfer system at the interface of BT and MS effectively lowers the recombination of electron-hole (e‒- h+) pairs, generated during piezocatalysis thereby enhancing the degradation. The composite sample was further used for the successful degradation of a mixture of dyes. This study introduces a novel approach to enhance catalysis by hybrid composite in piezoelectric materials.

The Piezocatalytic Degradation of Sulfadiazine by Lanthanum-Doped Barium Titanate.

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.

Highly efficient piezocatalytic degradation of organic dye over few-layer MoS2/carbon sponge composite boosted by mild mechanical stimuli

Piezocatalysis is a burgeoning sustainable technology due to its attractive potential in solving environmental and resource issues with various mechanical energies. Herein, a high-performance freestanding composite piezocatalyst was synthesized by combining few-layer MoS2 nanosheets with highly porous flexible carbonaceous matirx derived from melamine sponge (CMS), which can greatly harvest mild mechanical energies to trigger off piezoelectric effect for efficient dye degradation. Under mechanical stirring, the developed MoS2/CMS showed distinguished piezocatalytic degradation efficiency (99.8% within 10 min) for Rhodamine B (Rh B) dye solution. Besides, as a brick-shaped piezo-active platform, the MoS2/CMS is easy to be recycled and can remain excellent stability with over 90% degradation rate after 7 cycles of repeated catalytic reactions. To investigate its practical application potential, the MoS2/CMS was mounted in the pipeline of a homemade circulatory system, which was completely decolored 2.0 L Rh B aqueous solution after 2 h under a circulating flow of 30 mL min−1. Overall, this work presents an efficient and extensible strategy for construction of high-performance piezocatalytic materials with not only a desired integrated structure to produce sensitive deformations under mild mechanical stimuli, but also a freestanding form with excellent recyclability to alleviate secondary pollution. This research would provide viable guidance for promoting piezoelectric materials towards practical applications for wastewater decontamination.

PVDF-Based Piezo-Catalytic Membranes-A Net-Zero Emission Approach towards Textile Wastewater Purification.

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.

Construction of novel surfactant-modified metal-organic framework adenine-UiO-66 with enhanced piezocatalytic degradation of diclofenac sodium

Piezoelectric materials can harvest mechanical energy and convert it into electrical energy, which have lately become highly effective catalysts to sustainable eliminate pollutants. Here, by adding different surfactants to metal-organic framework adenine-UiO-66 (AD-U) materials, the metal-organic framework adenine-UiO-66 (AD-U-S) modified by sodium dodecyl benzene sulfonate (SDBS) and the metal-organic framework adenine-UiO-66 (AD-U-C) modified by cetyltrimethylammonium bromide (CTAB) were prepared for the first time. With the antibiotic diclofenac sodium (DCF) as the target pollutant, the degradation efficiencies of AD-U-S (0.30) and AD-U-C (0.30) were 98 % and 78 % in 30 min, respectively. Specially, the reaction rate constant of AD-U-S (0.30) is 3.5 times that of AD-U-C (0.30). The performance improvement is due to the larger specific surface area, stronger ferroelectric properties, enhanced oxidation capability and higher charge transfer efficiency of AD-U-S (0.30) than that of AD-U-C (0.30). The capture experiments showed that ‧OH and h+ were the main active species on AD-U-S (0.30) and AD-U-C (0.30) during the removal of DCF. In addition, possible pathways for DCF piezodegradation were obtained by liquid-phase mass spectrometry and DFT calculations. This study is benefit to promote the development of piezocatalytic technology for wastewater treatment.

Organic piezocatalyst polyimide: molecular structure tailoring and robust built-in electric field

A linear-structure polyimide with an enhanced molecular dipole was obtained by molecular structure tailoring, which has enhanced built-in electric field and was first utilized for efficient piezocatalytic degradation of organic pollutants.

Flexoelectricity in hydroxyapatite for the enhanced piezocatalytic degradation of phenanthrene in soil

Hydroxyapatite@fluorapatite prepared by ion exchange shows enhanced piezoelectric properties via flexoelectricity arising from the chemical heterogeneities in the crystal lattice.