Piezocatalytic Activity Research Articles

Engineering piezoelectricity and strain sensitivity in CdS to promote piezocatalytic hydrogen evolution

Piezocatalytic hydrogen evolution has emerged as a promising direction for the collection and utilization of mechanical energy and the efficient generation of sustainable energy throughout the day. Hexagonal CdS, as an established semiconductor photocatalyst, has been widely investigated for splitting water into H 2 , while its piezocatalytic performance has attracted less attention, and the relationship between the structure and piezocatalytic activity remains unclear. Herein, two types of CdS nanostructures, namely CdS nanorods and CdS nanospheres, were prepared to probe the above-mentioned issues. Under ultrasonic vibration, the CdS nanorods afforded a superior piezocatalytic H 2 evolution rate of 157 μmol g −1 h −1 in the absence of any co-catalyst, which is nearly 2.8 times that of the CdS nanospheres. The higher piezocatalytic activity of the CdS nanorods is derived from their larger piezoelectric coefficient and stronger mechanical energy harvesting capability, affording a greater piezoelectric potential and more efficient separation and transfer of intrinsic charge carriers, as elucidated through piezoelectric response force microscopy, finite element method, and piezoelectrochemical tests. This study provides a new concept for the design of efficient piezocatalytic materials for converting mechanical energy into sustainable energy via microstructure regulation. CdS spheres and CdS nanorods with different lengths were constructed by hydrothermal method and solvothermal process varying reaction time, respectively. The medium-length CdS nanorods subjected to ultrasonic stimulation exhibits excellent piezocatalytic H 2 evolution performance due to the strong induced piezoelectric potential and benign mechanical strain collecting ability.

Heterostructured BiFeO3@CdS nanofibers with enhanced piezoelectric response for efficient piezocatalytic degradation of organic pollutants

Piezocatalysis converting mechanical energy into chemical energy is deemed as an emerging technology for degradation of organic pollutants in water or air. In this work, BiFeO3@CdS nanofibers with heterostructure and enhanced piezoelectric response were prepared for efficient piezocatalytic degradation of organics in water. The optimal BiFeO3@CdS-10% achieved nearly complete removal of bisphenol A (BPA) within 60 min with the degradation rate constant of 0.098 min−1, which was 9.4 and 4.9 times higher than that of pristine BiFeO3 and CdS, respectively. The excellent piezocatalytic activity of the composite can be attributed to the construction of heterojunction and the enhanced piezoelectric response from the synergistic effect of the two piezoelectric components, which can accelerate the internal transfer of free carriers. It gives an insight into the feasible construction of efficient piezocatalysts and opens up a new way for BiFeO3-based piezoelectric materials to be utilized in purification of wastewater.

(1 − x)Bi0.5Na0.5TiO3–xBiFeO3 solid solutions with enhanced piezocatalytic dye degradation

Piezocatalysis has received tremendous interest due to the catalytic effect can be triggered by mechanical vibration. Herein, (1 − x)Bi0.5Na0.5TiO3–xBiFeO3 solid solution piezocatalysts were synthesized by a sol–gel method aim to improve the piezocatalytic activities of Bi0.5Na0.5TiO3 (BNT) and BiFeO3 (BFO). The piezocatalytic efficiencies of all obtained solid solution catalysts were improved compared with pure BNT and BFO for methyl orange (MO) degradation as expected. Among them, 0.5BNT–0.5BFO catalyst exhibited outstanding piezocatalytic activity and reusability, the reaction rate constant (0.0615 min−1) was about 5.2 and 3.2 times larger than that of BNT and BFO. Trapping experiments demonstrated that O2− and OH were the main species for MO degradation. Electrochemical measurements indicated that 0.5BNT–0.5BFO exhibited more efficient charge separation efficiency than that of BNT and BFO, which accounts for its efficient catalytic performance. A possible piezocatalytic reaction mechanism was proposed based on band structure and reactive oxygen species (ROS) detection. This work provides a new perspective for designing highly efficient piezocatalysts.

Piezocatalytic oxidation of 5-hydroxymethylfurfural to 5-formyl-2-furancarboxylic acid over Pt decorated hydroxyapatite

Selective oxidation of 5-hydroxymethylfurfural (HMF) to 5-formyl-2-furancarboxylic acid (FFCA) is a critical reaction for producing value-added chemicals from biomass. The challenge for this reaction is to develop an efficient catalytic process that can be conducted under mild conditions. Herein, we first propose piezocatalytic HMF oxidation using a Pt decorated hydroxyapatite (HAP) piezocatalyst (Pt/HAP). The introduction of Pt on HAP creates an interfacial electric field. The couple of nonlocal piezoelectric field and localized interfacial electric field greatly promotes both the bulk and surface charges transfer. Moreover, Pt not only promotes the separation of piezo-induced charges but also activates oxygen molecules and organic functional groups of the substrates. Compared with pristine HAP, Pt/HAP exhibits outstanding piezocatalytic activity, which reached 96% HMF conversion and 70% FFCA yield in 2 h under room temperature. A wide range of aldehydes and alcohols, such as fatty aldehydes, furan aldehydes, fatty alcohols, and ethylene glycol, were all oxidized to carboxylic acids. This work provides a novel method on utilizing piezocatalysis for biomass conversion.

Lattice origin of few-layer edge-on MoS2@TiO2 octahedral clusters for piezoelectric enhancement

Imaging the lattice origin of few-layer edge-on MoS2/TiO2 heterostructure at different growth stages could provide direct information for understanding the mechanism of its enhanced piezoelectric property. Via modifying the substrate surface to grow anatase TiO2 nanoparticles with truncated octahedron structure, few-layer MoS2 was exquisitely grown along the {101} basal planes of TiO2 by Van der Waals contact, and finally form an edge-on structure at the top edge of TiO2 nanoparticles due to steric hindrance. The vertical growth of few-layer MoS2 on the TiO2 surface endows not only better electronic contact between MoS2 and TiO2 substrate for fast electrons transfer but also high structure stability of piezoelectric properties. The piezocatalytic degradation ability is enhanced with the increase of hydrothermal reaction time, and the MoS2/TiO2-24 h sample exhibits the highest piezocatalytic activity under dark condition which demonstrates a high removal efficiency of 96.0% Rhodamine B within 60 min. This study establishes a relationship between the piezoelectric property of few-layer edge-on MoS2/TiO2 heterostructure and its growth mechanisms, and sheds light on the rational design of electric contact between transition metal dichalcogenide and semiconductor with specific crystal plane which is significant to the improvement of carrier separation and transport.

Effect of poling on piezocatalytic and electrochemical properties of Pb(Zr0.52Ti0.48)O3 ceramics

Piezocatalysis has garnered considerable attention as a novel catalytic effect due to its potential to breakdown organic contaminants in the presence of mechanical vibration. However, piezocatalysis efficiency optimization remains a struggle. Polarized Pb(Zr0.52Ti0.48)O3 (PZT), with its non-centrosymmetry structure and high ferroelectric polarisation, offers enormous promise as a piezocatalyst amongst other piezoelectric materials. We evaluated the piezocatalytic effectiveness of the as-prepared samples by analysing the breakdown of rhodamine B (RB), methylene blue (MB) and their equimolar composition aquous solutions in the dark using ultrasonic vibration. The results revealed that poled PZT exhibits significantly improved piezocatalytic activity for MB and RB decomposition. The degradation of MB and RB, as well as the probable by-products and active radical species created in the piezocatalytic system, were studied in detail. Additionally, the effect of residual polarisation on the oxygen evolution reaction (OER) for alkaline fuel cells was also studied . An explanation for the enhanced effect of polarization on the piezocatalytic performance of PZT was given based on the experimental data.

Piezoelectric BaTiO3 with the milling treatment for highly efficient piezocatalysis under vibration

The hydrothermally-synthesized barium titanate (BaTiO3) nanofibers are mechanically milled and used to for the piezocatalytic RhB dye decomposition. It is found that the mechanical milling can improve the piezocatalytic performance of BaTiO3 nanofibers. With the increasing of the milling time from 0 to 120 min, the RhB dye decomposition ratio of BaTiO3 nanofibers first increases and then decreases. When the milling time is 30 min, for the 20 min vibration time, the RhB decomposition ratio of BaTiO3 is 94%, which is much higher than that (~65%) of the unmilled BaTiO3. On one hand, the enhancement in piezocatalysis of BaTiO3 may be originated from the exposure of active sites due to the increasement of the specific surface area after the mechanical milling. On the other hand, it is also found that the ferroelectric polarization strength of BaTiO3 nanofibers obviously increases after the mechanical milling, which is helpful to reduce the recombination of these positive and negative carriers in the catalytic process, resulting in the enhanced piezocatalysis performance. The mechanical milling provides a convenient, fast, and effective method for improving the piezocatalytic activity of BaTiO3 nanofibers.

Synergistic Enhancement of Piezocatalytic Activity of BaTiO3 Convex Polyhedrons Nanocomposited with Ag NPs/Co3O4 QDs Cocatalysts.

Piezocatalysis is one of the green and promising catalytic technologies for the degradation of organic pollutants. Surface modifications such as exposed facet engineering and surface decoration of nanoparticles (NPs) are simple but useful enhancement strategies for a catalytic system. However, the synergistic effect and mechanism of facet engineering and dual-cocatalyst decoration on piezocatalytic activity are still ambiguous and more investigations are expected. Herein, the piezocatalytic activities of BaTiO3 (BTO) polyhedrons with anisotropic {001} and {110} facets and BTO cubes with isotropic {001} facets were compared. Furthermore, BaTiO3 (BTO) convex polyhedrons with selectively deposited Ag NPs and uniformly loaded Co3O4 quantum dots (QDs) are rationally synthesized through photochemical deposition. The individual and synergistic effects of Ag NPs and Co3O4 QDs on the piezocatalytic activities are systematically studied. It was found that dual-cocatalyst-modified BTO possesses the highest piezocatalytic activity in methyl orange degradation, with a reaction constant k of 0.0539 min-1, around 5, 2.2, and 1.3 times higher than that of nonmodified and Ag NP- and Co3O4 QD-modified BTO, respectively. Moreover, dual-cocatalyst-decorated BTO also exhibits excellent piezocatalytic performance in nondye pollutant degradation, with ∼100% tetracycline hydrochloride decomposed in 60 min. By analyzing the contribution, quantifying the amount of different free radicals, and comparing the chemical states of surface elements before and after piezocatalytic measurements, it was inferred that facet-dependent Ag NPs acted as efficient electron-transport sites, while uniformly loaded Co3O4 QDs served as hole-transfer sites to fully facilitate the migration of electrons and holes in a piezocatalytic reaction. This research presents a rational and effectual modification strategy to enhance the piezocatalytic activity of piezocatalysts and gives a thorough discussion of the enhanced mechanism.

Insight into oxygen-vacancy regulation on piezocatalytic activity of (Bi1/2Na1/2)TiO3 crystallites: Experiments and first-principles calculations

Oxygen vacancy (OV) is one of the most common defects in piezoelectric materials, and the concentration of OV can dramatically influence the performance of piezoelectric materials. It is of great scientific significance to clarify the effect of OV on the piezocatalytic performance. Here, eco-friendly piezoelectric (Bi1/2Na1/2)TiO3 (BNT) crystallites with various OV concentrations are employed to explore the role of OV in piezocatalysis. Experimental and theoretical results comprehensively elucidate that the OV plays a double-edged-sword role in regulating the piezocatalytic performance. It reveals that increasing the concentration of OV enhances the adsorption of O2 and OH- onto the surface of BNT crystallite and improves the charge concentration, which helps charges transport from BNT to O2 and OH-, contributing to the generation of active radicals for boosting the piezocatalytic performance. However, the increase of OV weakens the piezoelectric property, which is adverse to charge transfer and thus decreases active oxygen species, suppressing the piezocatalytic activity. This work not only theoretically clarifies the regulation mechanism of OV engineering on piezocatalytic performance, but also experimentally provides an effective method to improve piezocatalytic activity by OV engineering.

Piezoelectric nanofoams with the interlaced ultrathin graphene confining Zn–N–C dipoles for efficient piezocatalytic H2 evolution under low-frequency vibration

Unique nanofoams consisting of interweaved ultrathin graphene confining Zn–N–C dipoles (ZnNG) are constructed via calcination of Zn-coordinated precursor. Due to the introduction of local polar Zn–N–C configurations, with hypersensitivity for mechanical stress, the piezoelectricity is created on the nonpiezoelectric graphene, and the hierarchical ZnNG exhibits obvious piezocatalytic activity of water splitting for H2 production even under mild agitation. The corresponding rate of H2 production is about 14.65 μmol g−1 h−1. It triggers a breakthrough in piezocatalytic H2 evolution under low-frequency vibration, and takes a significant step forward for piezocatalysis towards practical applications. Furthermore, the presented concept of confining atomic polar configuration for engineering piezoelectricity would open up new horizon for constructing new-type piezoelectrics based on both piezoelectric and nonpiezoelectric materials.

Convert mechanical energy to chemical energy to effectively remove organic pollutants by using PTO catalyst

• PTO nanostructures were prepared by facile sonochemical method. • Sono energy was used to purify water. • Study of the effect of DNA as co-catalyst on piezocatalytic activity of PTO. • Study of the effect of operation conditions such as power and pulse. • Mechanism was studied. • Extracted DNA from potato showed piezocatalytic activity. Mechanical energy is a natural energy that can be considered as a form of rich, clean, and renewable energy and it can be harvested by using piezoelectric materials. Water pollution is one of the series of threats faced by our planet and jeopardizes the ecosystem. Piezocatalysis could be a promising solution for this issue. This research focused on the sonochemical synthesis of PbTiO3 (PTO) piezocatalyst and studied the effect of synthesis parameters, operation conditions during the piezocatalysis process, and the effect of DNA as a modifier on piezocatalytic activity of PTO. Results showed that the synthesis parameters show a significant effect on the piezocatalytic activity of PTO. The origin of this effect came from the morphology, purity, and orientation of final products. Results displayed that the degradation reaction was completed during the first hour. 97.1 % of Acid Red 141 (AR141) was degraded by controlling both synthesis and operation conditions. In this research, the ultrasonic probe with a power of 100–600 W and a frequency of 18 kHz was used.

Low-Valence B-Site Cation Substitution Triggering Polarization and Oxygen Vacancy Enhancement for Elevating Piezocatalytic Activity on Bi2moo6

Low-Valence B-Site Cation Substitution Triggering Polarization and Oxygen Vacancy Enhancement for Elevating Piezocatalytic Activity on Bi2moo6

Oxygen Vacancy-Induced Hydroxyl Dipole Reorientation in Hydroxyapatite for Enhanced Piezocatalytic Activity

Oxygen Vacancy-Induced Hydroxyl Dipole Reorientation in Hydroxyapatite for Enhanced Piezocatalytic Activity

Enhanced Piezocatalytic Activity of Batio3 By Ball-Milling Induced Lattice Strain

Enhanced Piezocatalytic Activity of Batio3 By Ball-Milling Induced Lattice Strain

Development of High Percentage 1t Phase Mose2 Nanosheet and its Remarkable Piezocatalytic Activity Over Rhb Removal and Cr (Vi) Reduction

Development of High Percentage 1t Phase Mose2 Nanosheet and its Remarkable Piezocatalytic Activity Over Rhb Removal and Cr (Vi) Reduction

Low-Valence B-Site Cation Substitution Triggering Polarization and Oxygen Vacancy Enhancement for Elevating Piezocatalytic Activity on Bi2moo6

Low-Valence B-Site Cation Substitution Triggering Polarization and Oxygen Vacancy Enhancement for Elevating Piezocatalytic Activity on Bi2moo6

Enhanced Piezocatalytic Activity of Sns2 for Bisphenol a Degradation and Hydrogen Production Via Ion Size-Induced Lattice Strain Engineering

Enhanced Piezocatalytic Activity of Sns2 for Bisphenol a Degradation and Hydrogen Production Via Ion Size-Induced Lattice Strain Engineering

Efficient piezocatalytic H2O2 production of atomic-level thickness Bi4Ti3O12 nanosheets with surface oxygen vacancy

Traditional anthraquinone method for producing H2O2 needs high energy consumption and substantial toxic by-production release. Recently, piezocatalysis that can conquer the above shortcomings emerges as a promising catalytic technique and arouses considerable interests. With rare application of piezocatalysis on H2O2 generation, exploiting efficient tactics for improving piezocatalytic H2O2 productivity is highly anticipated. Herein, atomic-level thickness Bi4Ti3O12 nanosheets with rich surface oxygen vacancies (OVs) are prepared for two-step single-electron O2 reduction into H2O2. Piezoelectric force microscopy, piezo-electrochemical tests, and Finite Element Simulation disclose that both the atomic-level thickness and OVs enlarge the piezoelectric coefficient, rendering stronger piezoelectric polarization for accelerating the charge separation and reaction kinetics. Density functional theory calculations uncover that the surface OVs also decrease the adsorption energy of O2 molecules for facilitating their activation. The ultra-thin Bi4Ti3O12 with optimal OVs content shows a piezocatalytic H2O2 evolution rate of 1611.2 μmol·h−1·g−1 with benign durability. This work delivers a joint-strategy for advancing the piezocatalytic activity, and furnishes a reference for producing useful chemicals by harvesting and utilizing accessible vibrational energy.

Piezo‐photocatalytic activity of mechanochemically synthesized BiVO4 for dye cleaning

AbstractSingle‐phase BiVO4 (BV) powder was synthesized successfully at 600°C within 4 h duration through the mechanochemical high energy ball milling method, and the combined photocatalytic and piezocatalytic activity was studied to exhibit piezo‐photocatalytic efficiency. Monoclinic BV phase existence in the synthesized powder was affirmed through Raman spectroscopy and the X‐ray diffraction techniques. The scanning electron microscopy affirmed the irregular‐shaped BV powder in the synthesized powders. X‐ray photoelectron spectroscopy affirmed the existence of various oxidation states of the elements V, Bi, and O in BV powders. The piezocatalytic and photocatalytic methylene blue (MB) dye degradation efficiency using BV powdered sample was observed to be 28% and 60%, respectively, within 240 min. The piezo‐photocatalytic MB dye degradation using BV powdered sample was observed to be 81% within 240 min. Effect of dye concentration on kinetic rate constant was also studied.

Piezocatalytic performance of Na0.5Bi0.5TiO3 nanoparticles for degradation of organic pollutants

Piezocatalysis has been considered as a promising technology in water pollution treatment. In this work, a series of piezoelectric Na0.5Bi0.5TiO3 (NBT) nanoparticles were prepared by hydrothermal method using different titanium sources as titanium precursors. The piezocatalytic performances of the NBT nanoparticles were investigated by the degradation of Rhodamine B (RhB) with the concentration of 10 mg/L under ultrasonic vibration. It is found that the NBT nanoparticles prepared by using anatase titanium oxide as titanium precursor show optimum piezocatalytic activity and the rate constant of 0.022 min−1 is achieved for RhB. The initial RhB concentration, ultrasonic power, particles size and specific surface area of NBT materials play an important role in optimizing the piezocatalytic performance. Moreover, the NBT nanoparticles show a satisfactory stability and reusability for the piezocatalytic degradation. The piezocatalytic mechanism of NBT nanoparticles was elucidated by the identification of free radicals and intermediates in the degradation process. The work provides a guidance to design and develop new high-performance piezocatalysts.