Rechargeable aqueous zinc−ion batteries (ZIBs) with cost−effective and environmentally friendly characteristics show great potential for large−scale energy storage systems. Among all cathode material candidates, layered vanadates are promising owing to their suitable open structure for accommodating Zn2+/H+. However, the unsatisfactory rate capability and cycling stability of vanadate cathodes have hindered the practical application. Thus, the exploration of high−performance and structural stable cathode materials is urgently needed. In this study, a La0.14V2O5/reduced graphene oxide composite material (denoted as LaVO/rGO) can be successfully synthesized by a facile hydrothermal procedure. With the pillar La3+ ions and highly conductive rGO, the layered LaVO/rGO has the merits of large interlayer distance (14.7 Å), low charge transfer resistance, and high diffusion coefficient that guarantee fast kinetics of Zn2+/H+ intercalation/de−intercalation. As a result, the LaVO/rGO cathode delivers a high−rate performance which obtains high capacity of 298 mAh g−1 at 0.3 A g−1. Even up to 8 A g−1, high capacity of 166 mAh g−1 can be achieved. Stable cycle performance with the capacity retention of 88% over 6000 cycles is attained, benefiting from fast and reversible Zn2+/H+ storage in the host material.
Aqueous zinc-ion batteries are considered promising next-generation systems for large-scale energy storage due to low cost, environmental friendliness, and high reversibility of the Zn anode. However, the interfacial charge-transfer resistance for the insertion of divalent Zn2+ into cathode materials is normally high, which limits the kinetics of Zn2+ transfer at the cathode/electrolyte interface. This study reveals the presence of rich structural water in spinel ZnMn2O4 (ZnMn2O4·0.94H2O, denoted as ZMO), synthesized by a scalable and low-temperature process, significantly overcoming the great interfacial charge-transfer resistance. ZMO exhibits excellent electrochemical performance toward Zn storage, that is, high capacity (230 and 101 mA h g–1 at 0.5 and 8 A g–1), high specific energy/specific power (329 W h kg–1/706 W kg–1 and 134 W h kg–1/11,160 W kg–1), and stable cycle retention (75% after 2000 cycles at 4 A g–1) can be achieved. On the contrary, the controlled sample ZMO-450 with deficient structural water, prepared by post-heat treatment of ZMO at 450 °C, demonstrates limited discharge capacity (45 and 15 mA h g–1 at 0.5 and 8 A g–1). As examined by electrochemical impedance spectroscopy, rich structural water in ZMO effectively reduces the activation energy barrier upon Zn2+ insertion, rendering fast interfacial kinetics for Zn storage. Benefiting from rich structural water in ZMO, the involvement of Zn2+ during the charge/discharge process exhibits good reversibility, as characterized by X-ray diffraction and X-ray photoelectron spectroscopy.
Two-dimensional (2D) monoelemental bismuth (Bi) crystal, one of the pnictogens (group VA), has recently attracted increasing interest because of its intriguing characteristics. Here, uniformly sized 2D Bi quantum dots (BiQDs) with an average diameter (thickness) of 4.9 ± 1.0 nm (2.6 ± 0.7 nm) were fabricated through a facile liquid-phase exfoliation (LPE) method, and the corresponding photoresponse was evaluated using photoelectrochemical (PEC) measurements. The as-fabricated BiQDs-based photodetector not only exhibits an appropriate capacity for self-driven broadband photoresponse but also shows high-performance photoresponse under low bias potentials ranging from UV to visible light in association with long-term stability of the ON/OFF switching behavior. In terms of these findings, it is further anticipated that the resultant BiQDs possess promising potential in UV–visible photodetection as well as in liquid optoelectronics. Our work may open a new avenue for delivering high-quality monoelemental pnictogen QDs from their bulk counterparts, thereby expanding interest in 2D monoelemental materials.
Abstract In contrast to zero‐bandgap metallic graphene, the binary semiconducting compound, InSe, possesses a tunable bandgap. Herein, a range of particle sizes of β‐InSe from bulk to few‐layer nanosheets and quantum dots are carefully prepared. The size‐dependent bandgap variation and photon‐induced carrier dynamics of InSe are systemically investigated. In contrast to the normal size‐dependent carrier lifetime trend observed at 700 nm, anomalous size‐independent carrier decay is observed at 500 nm. Through time‐dependent density functional theory calculations, the normal carrier lifetimes at lower probe photon energies are attributed to in‐plane excitons, whereas the abnormal size‐independent carrier lifetimes at higher probe photon energies are found to be stimulated by surface‐bound excitons. In view of the robust surface exciton, this suggests that InSe may possess an outstanding optoelectronic performance in the shorter wavelength range. Through photoelectrochemical detection experiments, it is confirmed that InSe features a high photocurrent density and stability and, in particular, a more distinct photoresponse at short wavelengths than at longer ones. Comprehending and quantifying the role of the surface‐bound excitons in InSe across a broad range of semiconductor nanostructures and their fundamental properties may play an important role in understanding the physical properties of 2D III–VI compound materials.
The excellent optical properties of MXene provide new opportunities for short-pulse lasers. A diode-pumped passively Q-switched laser at 1.3 μm wavelength with MXene Ti3C2Tx as saturable absorber was achieved for the first time. The stable passively Q-switched laser has 454 ns pulse width and 162 kHz repetition rate at 4.5 W incident pumped power. The experimental results show that the MXene Ti3C2Tx saturable absorber can be used as an optical modulator to generate short pulse lasers in a solid-state laser field.
A rising kind of 2D pnictogens has drawn a great deal of attention in the field of catalytic application owing to their high specific surface area, mechanical properties, biocompatibility, optical and electrical performance.
Two-dimensional (2D) material with thickness down to the atomic state is regarded as able to expose more active sites and achieve much higher catalytic efficiency than its bulk counterpart. Recent investigated semi-metallic antimony (Sb) demonstrates high charge carrier density and environmental stability toward prospective electrocatalytic performance. In this work, we adopt a favorable liquid exfoliation approach to produce few-layer antimonene and implement it as a metal-free electrocatalyst for water splitting. Few-layer antimonene nanosheets have been realized with preferable bifunctional electrocatalytic activity in association with structural robustness; meanwhile, the catalytic performance and charge transfer behavior of an integrated three-electrode system have also been uncovered. In addition to bifunctional catalytic ability, few-layer antimonene shows a low catalytic threshold because of the inherent characteristics derived from semi-metallic layered materials. It is further anticipated that the present work contributes to extendable investigations about the catalytic performance of antimonene nanosheets and related electrocatalytic devices.
Light-sensitive nanomaterial-released thermia is an emerging approach for cancer therapy. However, the therapeutic efficacy of this approach is generally modest and several challenging issues remain unresolved, including ineffective conversion from light to heat production, uncontrolled release of anticancer drugs, and non-specific delivery of nanomaterials to the tumor site. Here, we propose a new therapeutic concept by converting a photothermal nanomaterial to tumor cell-killing gas in the tumor microenvironment (TME) for gasothermal therapy. This novel strategy employed a chemical coordination (BPN-MnCO) between light-sensitive black phosphorous nanomaterial (BPN) and metal carbonyl (MnCO). The absorption of near-infrared red (NIR) light by BPN triggered the photochemical degradation of coordinated MnCO to produce a high concentration of carbon monoxide (CO) as well as hyperpyrexia in the local TME. Additionally, the surface coordination of MnCO protected BPN from biodegradation to achieve a long-lasting effect of heat production, which went through a feedback mechanism to effectively produce anticancer CO. In various preclinical cancer models, we showed that this approach nearly completely eradicated tumors without causing any notable adverse effects. Mechanistically, we discovered that BPN-generated heat inhibited the repair process of the CO-induced DNA damage and thus accelerated the ATM–GADD45–P53–Cyclin B cell death signaling. In summary, we provide compelling experimental evidence to support our new concept of gasothermal anticancer therapy that is likely to shift a new paradigm for effective treatment of cancer.
AbstractBackground Chronic prostatitis (CP) is one of the general diseases in daily diagnosis and treatment of urologists, especially category III prostatitis. Due to the lack of concrete causations, etiology and pathogenesis of chronic prostatitis, the diagnosis is still a distressful question for urologists. Method To investigate diagnostic potential of trace metals in this prostatitis, we performed analysis of concentration of zinc (Zn), copper (Cu), calcium (Ca) and magnesium (Mg) in expressed prostatic secretion (EPS) and serum of patients with category III prostatitis and healthy controls, using flame atomic absorption spectrometer (FAAS). Results Results showed contents of Zn, Ca and Mg in both serum and EPS samples of all subjects with category III prostatitis changed significantly compared to controls (all P<0.05), while Cu level changed in all EPS samples (P<0.000). In category IIIa prostatitis group, level of EPS Zn, Ca, Mg and serum Ca reduced significantly (allP<0.000), while level of Zn in serum raised markedly (P<0.000). In category IIIb prostatitis group, level of Zn, Ca, Mg in EPS decreased significantly (allP<0.05), level of serum Ca, Mg were lessened visibly (allP<0.000), EPS Cu level had an overt promotion (P<0.05). Moreover , ROC analysis showed Mg and Zn/Mg level in EPS had better diagnostic value in category IIIa prostatitis (AUC=0.796, 0.791, respectively, allP<0.0001); while in category IIIb prostatitis, Cu and Cu/Ca level had greater diagnostic value (AUC=0.880, 0.901, respectively, allP<0.0001). Conclusion Summarily, concentration of Zn, Ca, Mg plays an important role in this prostatitis, of which level of Mg, Cu, Zn/Mg, Cu/Ca in EPS may have potential diagnostic value for category III prostatitis.
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