Photoelectrochemical (PEC) water splitting is an ideal approach for renewable solar fuel production. One of the major problems is that narrow bandgap semiconductors, such as tantalum nitride, though possessing desirable band alignment for water splitting, suffer from poor photostability for water oxidation. For the first time it is shown that the presence of a ferrihydrite layer permits sustainable water oxidation at the tantalum nitride photoanode for at least 6 h with a benchmark photocurrent over 5 mA cm(-2) , whereas the bare photoanode rapidly degrades within minutes. The remarkably enhanced photostability stems from the ferrihydrite, which acts as a hole-storage layer. Furthermore, this work demonstrates that it can be a general strategy for protecting narrow bandgap semiconductors against photocorrosion in solar water splitting.

Dual-phase (DP) steel is the flagship of advanced high-strength steels, which were the first among various candidate alloy systems to find application in weight-reduced automotive components. On the one hand, this is a metallurgical success story: Lean alloying and simple thermomechanical treatment enable use of less material to accomplish more performance while complying with demanding environmental and economic constraints. On the other hand, the enormous literature on DP steels demonstrates the immense complexity of microstructure physics in multiphase alloys: Roughly 50 years after the first reports on ferrite-martensite steels, there are still various open scientific questions. Fortunately, the last decades witnessed enormous advances in the development of enabling experimental and simulation techniques, significantly improving the understanding of DP steels. This review provides a detailed account of these improvements, focusing specifically on (a) microstructure evolution during processing, (b) experimental characterization of micromechanical behavior, and (c) the simulation of mechanical behavior, to highlight the critical unresolved issues and to guide future research efforts.

Organic-inorganic hybrid lead organohalide perovskites are inexpensive materials for high-efficiency photovoltaic solar cells, optical properties, and superior electrical conductivity. However, the fabrication of their quantum dots (QDs) with uniform ultrasmall particles is still a challenge. Here we use oriented microporous metal-organic framework (MOF) thin film prepared by liquid phase epitaxy approach as a template for CHNHPbIX (X = Cl, Br, and I) perovskite QDs fabrication. By introducing the PbI and CHNHX (MAX) precursors into MOF HKUST-1 (Cu(BTC), BTC = 1,3,5-benzene tricarboxylate) thin film in a stepwise approach, the resulting perovskite MAPbIX (X = Cl, Br, and I) QDs with uniform diameters of 1.5-2 nm match the pore size of HKUST-1. Furthermore, the photoluminescent properties and stability in the moist air of the perovskite QDs loaded HKUST-1 thin film were studied. This confined fabrication strategy demonstrates that the perovskite QDs loaded MOF thin film will be insensitive to air exposure and offers a novel means of confining the uniform size of the similar perovskite QDs according to the oriented porous MOF materials.

Quasi-two-dimensional kagome metals AV3Sb5 (A = Cs, Rb, and Cs) have attracted much recent interest due to fascinating quantum phenomena such as giant anomalous Hall effect, topological charge order, and unconventional superconductivity. Here we report pressure-induced reemergent superconductivity in CsV3Sb5 by electrical transport measurements under high pressures up to 47.9 GPa. We show that the superconducting critical temperature Tc is first enhanced by pressure and reaches its first maximum ~ 8.9 K at 0.8 GPa, then the Tc is suppressed by pressure and cannot be detected above 7.5 GPa, forming a dome-shaped superconducting phase diagram. Remarkably, upon further compression above 16.5 GPa, a new superconducting state arises, of which Tc is enhanced by pressure to a second maximum ~ 5.0 K and the reemergent superconductivity keeps robust up to 47.9 GPa. Combined with synchrotron x-ray diffraction measurements that demonstrate the stability of the pristine hexagonal phase up to 43.1 GPa, we argue that the reemergence of superconductivity in the V-based superconductor could be attributed to a pressure-induced Lifshitz transition. Introduction--Recently, a class of quasi-two-dimensional topological Kagome metals AV3Sb5 (A= K, Rb, and Cs) has been attracting great interest. Combination of topologically nontrivial electronic structure and strong correlated effects lead to a series of fascinating quantum phenomena in these compounds, such as novel superconductivity [1-6], charge density wave (CDW) [4,5,[7][8][9][10][11][12][13], and giant anomalous Hall effect [14,15]. A robust zero-bias conductance peak inside the superconducting (SC) vortex core was observed in CsV3Sb5, implying topological superconductivity [8]. Scanning tunneling microscope/spectroscopy (STM/STS) revealed that the

No abstract

No abstract

Photoelectrochemical (PEC) water splitting is an ideal approach for renewable solar fuel production. One of the major problems is that narrow bandgap semiconductors, such as tantalum nitride, though possessing desirable band alignment for water splitting, suffer from poor photostability for water oxidation. For the first time it is shown that the presence of a ferrihydrite layer permits sustainable water oxidation at the tantalum nitride photoanode for at least 6 h with a benchmark photocurrent over 5 mA cm À2 , whereas the bare photoanode rapidly degrades within minutes. The remarkably enhanced photostability stems from the ferrihydrite, which acts as a holestorage layer. Furthermore, this work demonstrates that it can be a general strategy for protecting narrow bandgap semiconductors against photocorrosion in solar water splitting.The direct conversion of solar energy to chemical fuels is not only of scientific interest but also a highly desirable approach to power the planet. [1] Photoelectrochemical (PEC) water splitting is a promising strategy for renewable solar fuel production using photoelectrodes. [2] However, trade-offs between light-harvesting and photostability of photoanodes have greatly limited the performance of PEC water splitting devices. [3] Typically, tantalum nitride (Ta 3 N 5 ) has a desirable band alignment for water splitting and a theoretical solar to hydrogen conversion efficiency of 15.9 %, but it is not stable in the highly oxidative environments of water oxidation. [4] To solve this problem, efforts have been made on alleviating accumulation of photogenerated holes by facilitating water oxidation. [5] For example, modification of Ta 3 N 5 with IrO 2 , an excellent water oxidation catalyst (WOC), could maintain half of the initial photocurrent in less than 10 min at 1.2 V versus the reversible hydrogen electrode (RHE). [5b, 6] Recently, continuous production of oxygen in 100 min was reported on a cobalt phosphate (CoPi) WOC modified Ba-Ta 3 N 5 photoanode at a moderate potential (0.9 V vs. RHE). [7] As yet, the endurance of the Ta 3 N 5 photoanode in harsh oxidative environments for long-term performance still remains a challenging task.Herein, for the first time, we employed a ferrihydrite (Fh) layer for protecting the unstable Ta 3 N 5 photoanode against photocorrosion. With overlying Co 3 O 4 nanoparticles (NPs), the resulting photoanode (designated as Co 3 O 4 /Fh/Ta 3 N 5 ) yielded a photocurrent up to 5.2 mA cm À2 at a potential of 1.23 V vs. RHE under AM 1.5 G simulated sunlight (100 mW cm À2 ) and remained at about 94 % of the initial activity after 6 h irradiation, which is the highest durability of the Ta 3 N 5 based photoanodes reported to date. [5b,e] The porous cubic Ta 3 N 5 electrode shown in Figure 1 a and b was formed by nitridation of NaTaO 3 film by an anodization and hydrothermal process on Ta substrate (Supporting Information, Figure S1) developed from our previous work. [8] The Ta 3 N 5 electrode was then modified with a ferrihydrite layer (Figure 1 c). The X...

Abstract:The availability of ZY-3 satellite data provides additional potential for surveying, mapping, and quantitative studies. Topographic correction, which eliminates the terrain effect caused by the topographic relief, is one of the fundamental steps in data preprocessing for quantitative analysis of vegetation. In this paper, we rectified ZY-3 satellite data using five commonly used topographic correction models and investigate their impact on the regression estimation of shrub forest leaf biomass obtained from sample plots in the study area. All the corrections were assessed by means of: (1) visual inspection (2) reduction of the standard deviation (SD) at different terrain slopes (3) correlation analysis of different correction results. Best results were obtained from the Minnaert+SCS correction, based on the non-Lambertian reflection assumption. Additional analysis showed that the coefficient correlation of the biomass fitting result was improved after the Minnaert+SCS correction, as well as the fitting precision. The R 2 has increased by 0.113 to reach 0.869, while the SD (standard deviation) of the biomass dropped by 21.2%. Therefore, based on the facts, we conclude that in the region with large topographic relief, the topographical correction is essential to the estimation of the biomass.