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The intrinsic flexoelectric effect observed in oxide materials often falls below the desired threshold for practical applications. In this work, we demonstrate proton doping in insulating rutile TiO2 crystal as an effective approach to significantly increase flexoelectricity by more than two orders of magnitude. We attribute the noteworthy enhancement of flexoelectricity to the dual impact of proton doping in oxide materials. First, proton doping serves to induce the presence of charge carriers, resulting in the generation of flexoelectric currents. Second, proton doping induces expansion and distortion of the lattice structure, leading to an amplified flexoelectric field when the crystal experiences a strain gradient. The formation of O–H bonding in TiO2 crystal provides another route to break centrosymmetry according to lattice distortion of the TiO2 lattice, resulting in a larger flexoelectric field. In addition, the introduction of proton doping in TiO2 single crystals leads to a substantial increase in photocurrent by effectively flattening the interfacial Schottky junction. This phenomenon results in a three-order of magnitude enhancement of the photocurrent. Our work broadens the horizon of study on dielectric materials through proton doping and may also provide an approach that enables the utilization of dielectric materials in energy conversion applications. [ABSTRACT FROM AUTHOR]

Recently, the bismuth‐rich strategy via increasing the bismuth content has been becoming one of the most appealing approaches to improve the photocatalytic performance of bismuth oxyhalides. However, insights into the mechanism behind the encouraging experiments are missing. Herein, we report the results of the theory‐led comprehensive picture of bismuth‐rich strategy in bismuth oxyhalide photocatalysts, selecting Bi5O7X (X = F, Cl, Br, I) as a prototype. First‐principle calculations revealed that the strategy enables good n‐type conductivity, large intrinsic internal electric field, high photoreduction ability and outstanding harvest of visible light, and particularly ranked the intrinsic activity of this family: Bi5O7F > Bi5O7I > Bi5O7Br > Bi5O7Cl. Designed experiments confirmed the theoretical predictions, and together, these results are expected to aid future development of advanced photocatalysts. [ABSTRACT FROM AUTHOR]

Ultrasound-stimulated piezo-electrocatalysis has been studied for a period; however, the mechanism is still unclear mainly due to the coexistence with other multiple effects like sonocatalysis, which was usually ignored. In this work, with the non-piezoelectric H2Ti3O7 nanowires following the same experimental process in piezo-electrocatalysis, the sonocatalytic reduction performance of CO2 is investigated. By applying vibration under the excitation of ultrasound with various frequencies and powers, it is found that CO is the ultimate product with a selectivity of 100%, and the optimal CO yield of 8.3 μmol g−1 h−1 is achieved with the addition of sacrificial agents. The H2Ti3O7 catalysts are also found to present a good recycling utilization ability. This work indicates that the sonocatalysis effect may exist in the piezo-electrocatalytic process using the ultrasonic excitation, which is suggested to be taken into consideration when exploring the mechanism of piezo-electrocatalysis in the future. [ABSTRACT FROM AUTHOR]

With rising CO2 emissions caused by the massive consumption of fossil fuels, it is highly desirable to develop strategies that adopt renewable energy to convert CO2 into value‐added chemical feedstocks. Over the past decades, photocatalytic reduction of CO2 using light energy has attracted considerable attention. However, the advanced photocatalysis techniques cannot exert their action where light is unavailable. Here, a method for CO2 reduction on basis of vibration‐driven piezoelectricity to yield a piezo‐electrocatalysis effect which requires mechanical vibration rather than light, is proposed. Under mild vibration and sacrificial agent‐free conditions, the piezoelectric BaTiO3 catalyst provides a suitable piezo‐potential to overcome the redox potential of CO2 and convert it into CO with a maximum yield of 63.3 µmol g−1, achieving a reactivity comparable to those of photocatalysts. The piezo‐electrocatalytic CO2 reduction reaction adds a new avenue in addition to the existing photocatalytic techniques by expanding the scope of energy utilization to promote carbon neutrality. [ABSTRACT FROM AUTHOR]

Visible light-responsive ZnFeO photocatalyst with a spinel structure was synthesized via a sol-gel method. The visible light photocatalysis of ZnFeO was investigated by decomposing Rhodamine B (RhB) solution. Under ∼30 min of visible light irradiation, the decomposition ratio of RhB is up to ∼97.4%. The excellent photocatalytic performance of ZnFeO photocatalyst is attributed to the high effective oxidation-reduction reaction caused by light irradiation excitation. With the increase of decomposition time, the wavelength of the maximum absorption peak of RhB solutions shifts from 557 nm to 498 nm ('blue shift'), which is because of the N-deethylation and cleavage of the conjugated chromophore structure of RhB. ZnFeO photocatalyst also exhibits a weak ferromagnetism performance. The decomposition ratio of RhB for the magnetically recycled ZnFeO is ∼94.6%. Strong visible light photocatalysis and convenience of magnetic recycling make ZnFeO promising for photocatalytic applications in dye wastewater treatment. [ABSTRACT FROM AUTHOR]

The intrinsic flexoelectric effect observed in oxide materials often falls below the desired threshold for practical applications. In this work, we demonstrate proton doping in insulating rutile TiO2 crystal as an effective approach to significantly increase flexoelectricity by more than two orders of magnitude. We attribute the noteworthy enhancement of flexoelectricity to the dual impact of proton doping in oxide materials. First, proton doping serves to induce the presence of charge carriers, resulting in the generation of flexoelectric currents. Second, proton doping induces expansion and distortion of the lattice structure, leading to an amplified flexoelectric field when the crystal experiences a strain gradient. The formation of O–H bonding in TiO2 crystal provides another route to break centrosymmetry according to lattice distortion of the TiO2 lattice, resulting in a larger flexoelectric field. In addition, the introduction of proton doping in TiO2 single crystals leads to a substantial increase in photocurrent by effectively flattening the interfacial Schottky junction. This phenomenon results in a three-order of magnitude enhancement of the photocurrent. Our work broadens the horizon of study on dielectric materials through proton doping and may also provide an approach that enables the utilization of dielectric materials in energy conversion applications. [ABSTRACT FROM AUTHOR]

Background: Previous studies have demonstrated that repetitive transcranial magnetic stimulation (rTMS) can improve postural control in subacute and chronic ischemic stroke, but further research is needed to investigate the effect of rTMS on acute ischemic stroke., Objective: We compared the therapeutic effects of rTMS plus conventional rehabilitation and conventional rehabilitation on postural control in patients with mild hemiparesis in acute ischemic stroke., Methods: Eighty-six patients with acute ischemic stroke were randomly assigned to either the experimental group or the control group within 1-7 days of onset. Patients in both groups received conventional rehabilitation for 2 weeks. Patients in the experimental group received rTMS treatments lasting for 2 weeks. Before and after the 2-week treatment, patients were assessed based on the Timed up and Go (TUG) test, Dual-Task Walking (DTW) test, Functional Ambulation Category (FAC), Tinetti Performance Oriented Mobility Assessment (POMA), gait kinematic parameters, Barthel Index (BI), Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and National Institutes of Health Stroke Scale (NIHSS). Additionally, TUG and single-task gait velocity were assessed at 2 months after the start of treatment, and independent walking recovery was also followed up., Results: After 2 weeks of treatment, compared to conventional rehabilitation, participants who underwent rTMS treatment plus conventional rehabilitation exhibited notable enhancements in TUG, FAC, POMA, and some gait parameters [single-task gait velocity, gait stride length, gait cadence, gait cycle]. Changes in cognitive function partially mediated the improvement in single-task gait velocity and gait stride length by rTMS plus conventional rehabilitation. Generalized Estimating Equation (GEE) analysis showed that the trend of improvement in single-task gait velocity over time was more pronounced in the experimental group than in the control group. The results of the Kaplan-Meier curve indicated a median gait recovery time of 90 days for patients in the experimental group and 100 days for the control group. Multifactorial Cox regression analyses showed that rTMS plus conventional rehabilitation promoted faster recovery of independent walking compared with conventional rehabilitation., Conclusion: rTMS plus conventional rehabilitation outperformed conventional rehabilitation in improving postural control in patients with acute ischemic stroke. Improvements in cognitive function may serve as a mediating factor in the favorable treatment outcome of rTMS plus conventional rehabilitation for improving postural control., Clinical Trial Registration: https://www.chictr.org.cn, identifier ChiCTR1900026225., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ma, Qian, Ma, Zhang, Xu, Liu and Meng.)

Piezo-electrocatalysis as an emerging mechano-to-chemistry energy conversion technique opens multiple innovative opportunities and draws great interest over the past decade. However, the two potential mechanisms in piezo-electrocatalysis, i.e., screening charge effect and energy band theory, generally coexist in the most piezoelectrics, making the essential mechanism remain controversial. Here, for the first time, the two mechanisms in piezo-electrocatalytic CO 2 reduction reaction (PECRR) is distinguished through a narrow-bandgap piezo-electrocatalyst strategy using MoS 2 nanoflakes as demo. With conduction band of -0.12 eV, the MoS 2 nanoflakes are unsatisfied for CO 2 -to-CO redox potential of -0.53 eV, yet they achieve an ultrahigh CO yield of ≈543.1 µmol g -1  h -1 in PECRR. Potential band position shifts under vibration are still unsatisfied with CO 2 -to-CO potential verified by theoretical investigation and piezo-photocatalytic experiment, further indicating that the mechanism of piezo-electrocatalysis is independent of band position. Besides, MoS 2 nanoflakes exhibit unexpected intense "breathing" effect under vibration and enable the naked-eye-visible inhalation of CO 2 gas, independently achieving the complete carbon cycle chain from CO 2 capture to conversion. The CO 2 inhalation and conversion processes in PECRR are revealed by a self-designed in situ reaction cell. This work brings new insights into the essential mechanism and surface reaction evolution of piezo-electrocatalysis., (© 2023 Wiley-VCH GmbH.)