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.
Exploring strategies to expand the sources of natural energy utilization is imperative to cope with ever‐increasing CO2 emissions. A photon‐free piezo‐electrocatalysis system based on the coupling of piezoelectricity and electrochemistry enables the harvesting of dispersed and extensive mechanical energy and converts CO2 into value‐added chemical fuels. The piezo‐electrocatalytic CO2 reduction reaction adds a new avenue to promote carbon neutrality.
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 CO2 reduction reaction (PECRR) is distinguished through a narrow‐bandgap piezo‐electrocatalyst strategy using MoS2 nanoflakes as demo. With conduction band of −0.12 eV, the MoS2 nanoflakes are unsatisfied for CO2‐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 CO2‐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, MoS2 nanoflakes exhibit unexpected intense “breathing” effect under vibration and enable the naked‐eye‐visible inhalation of CO2 gas, independently achieving the complete carbon cycle chain from CO2 capture to conversion. The CO2 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.
Piezo‐electrocatalysis as an emerging mechano‐to‐chemistry energy conversion technique opens multiple innovative opportunities, drawing great interest but also suffering from the controversial mechanisms. A narrow‐bandgap piezo‐electrocatalyst strategy is proposed by choosing CO2 reduction as a probe reaction to distinguish the two potential mechanisms, i.e., screening charge effect and energy band theory, and reveal that piezo‐electrocatalysis is independent of band positions.
Sepsis is a life‐threatening organ dysfunction syndrome, and liver is a susceptible target organ in sepsis, because the activation of inflammatory pathways contributes to septic liver injury. ...Oxidative stress has been documented to participate in septic liver injury, because it not only directly induces oxidative genotoxicity, but also exacerbates inflammatory pathways to potentiate damage of liver. Therefore, to ameliorate oxidative stress is promising for protecting liver in sepsis. Wogonin is the compound extracted from the medicinal plant Scutellaria baicalensis Geogi and was found to exert therapeutic effects in multiple inflammatory diseases via alleviation of oxidative stress. However, whether wogonin is able to mitigate septic liver injury remains unknown. Herein, we firstly proved that wogonin treatment could improve survival of mice with lipopolysaccharide (LPS)‐ or caecal ligation and puncture (CLP)‐induced sepsis, together with restoration of reduced body temperature and respiratory rate, and suppression of several pro‐inflammatory cytokines in circulation. Then, we found that wogonin effectively alleviated liver injury via potentiation of the anti‐oxidative capacity. To be specific, wogonin activated Nrf2 thereby promoting expressions of anti‐oxidative enzymes including NQO‐1, GST, HO‐1, SOD1 and SOD2 in hepatocytes. Moreover, wogonin‐induced Nrf2 activation could suppress NF‐κB‐regulated up‐regulation of pro‐inflammatory cytokines. Ultimately, we provided in vivo evidence that wogonin activated Nrf2 signalling, potentiated anti‐oxidative enzymes and inhibited NF‐κB‐regulated pro‐inflammatory signalling. Taken together, this study demonstrates that wogonin can be the potential therapeutic agent for alleviating liver injury in sepsis by simultaneously ameliorating oxidative stress and inflammatory response through the activation of Nrf2.
The flexoelectric effect, which manifests itself as a strain-gradient-induced electrical polarization, has triggered great interest due to its ubiquitous existence in crystalline materials without ...the limitation of lattice symmetry. Here, we propose a flexoelectric photodetector based on a thin-film heterostructure. This prototypical device is demonstrated by epitaxial LaFeO3 thin films grown on LaAlO3 substrates. A giant strain gradient of the order of 106/m is achieved in LaFeO3 thin films, giving rise to an obvious flexoelectric polarization and generating a significant photovoltaic effect in the LaFeO3-based heterostructures with nanosecond response under light illumination. This work not only demonstrates a novel self-powered photodetector different from the traditional interface-type structures, such as the p–n and Schottky junctions but also opens an avenue to design practical flexoelectric devices for nanoelectronics applications.
ABSTRACT In this letter, we present constraints on the scale-dependent ‘local’-type primordial non-Gaussianity, which is described by non-Gaussianity’s spectral index nNG, from the NRAO VLA Sky ...Survey and the quasar catalogue of the Sloan Digital Sky Survey (SDSS) Data Release 6, together with the SDSS Data Release 12 photo-z sample. Here, we use the autocorrelation analyses of these three probes and their cross-correlation analyses with the cosmic microwave background (CMB) temperature map, and obtain the tight constraint on the spectral index: $n_{\rm NG}=0.2 ^{+0.7}_{-1.0}$ ($1\sigma$ C.L.), which shows the first competitive constraint on the running of non-Gaussianity from current large-scale structure clustering data. Furthermore, we also perform the forecast calculations and improve the limit of nNG using the future Euclid mission, and obtain the standard deviation at a 68 per cent confidence level: ΔnNG = 1.74 when considering the fiducial value fNL = 3, which provides the complementary constraining power to those from the CMB bispectrum information.
ZrTe2 is a candidate topological material from the layered two-dimensional transition-metal dichalcogenide family, and thus the material may show exotic electrical transport properties and may be ...promising for quantum device applications. In this work, we report the successful growth of layered ZrTe2 thin film by pulsed-laser deposition and the experimental results of its magnetotransport properties. In the presence of a perpendicular magnetic field, the 60 nm thick ZrTe2 film shows a large magnetoresistance of 3000% at 2 K and 9 T. A robust linear magnetoresistance is observed under an in-plane magnetic field, and negative magnetoresistance appears in the film when the magnetic field is parallel to the current direction. Furthermore, the Hall results reveal that the ZrTe2 thin film has a high electron mobility of about 1.8 × 104 cm2 V–1 s–1 at 2 K. These findings provide insights into further investigations and potential applications of this layered topological material system.
ABSTRACT
Fast radio bursts (FRBs) probe the total column density of free electrons in the intergalactic medium (IGM) along the path of propagation through the dispersion measures (DMs) that depend on ...the baryon mass fraction in the IGM, i.e. fIGM. In this letter, we investigate the large-scale clustering information of DMs to study the evolution of fIGM. When combining with the Planck 2018 measurements, we could give tight constraints on the evolution of fIGM(z) from about 104 FRBs with the intrinsic DM scatter of $30(1+z) \rm pc\, cm^{-3}$ spanning 80 per cent of the sky and redshift range z = 0–3. First, we consider the Taylor expansion of fIGM(z) up to second order, and find that the mean relative standard deviation σ(fIGM) ≡ 〈σfIGM(z)/fIGM(z)〉 is about 6.7 per cent. In order to alleviate the dependence on fiducial model, we also adopt non-parametric methods in this work, the local principle component analysis. We obtain the consistent, but weaker constraints on the evolution of fIGM(z), namely the mean relative standard deviation σ(fIGM) is 21.4 per cent. With the forthcoming surveys, this could be a complimentary method to investigate the baryon mass fraction in the IGM.
Thin film flexoelectricity is attracting more attention because of its enhanced effect and potential application in electronic devices. Here we find that a mechanical bending induced flexoelectricity ...significantly modulates the electrical transport properties of the interfacial two-dimensional electron gas (2DEG) at the LaAlO3/SrTiO3 (LAO/STO) heterostructure. Under variant bending states, both the carrier density and mobility of the 2DEG are changed according to the flexoelectric polarization direction, showing an electric field effect modulation. By measuring the flexoelectric response of LAO, it is found that the effective flexoelectricity in the LAO thin film is enhanced by 3 orders compared to its bulk. These results broaden the horizon of study on the flexoelectricity effect in the hetero-oxide interface and more research on the oxide interfacial flexoelectricity may be stimulated.
Extracting the bispectrum information from large-scale structure observations is challenging due to the complex models and the computational costs involved in measuring the signal and its covariance. ...Recently, the skew spectrum was proposed to access parts of the bispectrum information in a more effective manner and was confirmed to provide complementary information to that available in power spectrum measurements. In this work, we generalize the theory to apply the multitracer technique and explore its ability to constrain the local-type primordial non-Gaussianity. Using the spectra and their covariance estimated from N-body simulations, we find that the multitracer approach is effective in reducing the cosmic variance noise. The 1 marginalized errors for , and are reduced by 50%, 52%, and 73% compared with the results achieved using only the power spectrum obtained from a single tracer. These results indicate that both the skew spectrum and the multitracer technique are useful in constraining the primordial non-Gaussianity with the forthcoming wide-field galaxy surveys.
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