The oxygen reduction reaction (ORR) remains a major kinetic bottleneck in fuel cells, metal-air batteries, and related electrochemical devices. Perovskite oxides are attractive ORR catalysts due to the ABO3 lattice, which permits systematic control of transition-metal electronic structure, metal–oxygen covalency, and defect chemistry. This review compares low-temperature electrocatalytic ORR, including the 2e− and 4e− pathways, with high-temperature cathodic ORR in mixed ionic–electronic conductors, where oxygen adsorption, charge transfer, O=O bond cleavage, oxygen incorporation, and bulk transport are interlinked. The main optimization strategies, including A-site and B-site doping, defect engineering, nanostructuring, heterostructure/composite formation, and mechanisms, are discussed. Particular attention is given to the distinct requirements of fuel cells and metal-air batteries. Across these systems, perovskite ORR performance is governed by the joint evolution of surface chemistry, defect structure, and electrode architecture under operating conditions.

The fabrication of infrared photoluminescent transparent ceramics with outstanding performance has garnered significant attention. A key factor in achieving excellent optical properties is the selection of an appropriate host material and luminescent ions. In this study, we prepared a series of single-phase rare-earth (RE = Ho-3(+), Er-3(+), Tm-3(+)) doped Y2Zr2O7 transparent ceramics using a solid-state reaction and vacuum sintering method. These ceramics exhibited a high transmittance (>75 %) in the visible and near-infrared regions. Photoluminescence studies revealed strong down-conversion infrared emissions from the rare-earth ions. With their superior optical properties and straightforward preparation method, Ho-3(+)/Er-3(+)/Tm-3(+) doped Y2Zr2O7 transparent ceramics present promising potential as infrared phosphor materials for applications in biomedicine, laser systems, and lighting technologies.

Organic-inorganic halide 2D perovskite single crystals have recently emerged as promising scintillators for gamma (γ) rays and fast neutrons (nf) detection. However, their energy resolution in γ-rays detection still significantly lags behind that of perovskite semiconductor detectors. Improving crystal defects and enhancing light yield to optimize light output detected by the photomultiplier tube are crucial strategies for addressing this issue. Herein, it is demonstrated that Zn2+ and Sb3+ cation interstitial doping strategy can effectively reduce internal defects within the phenylethylammonium lead bromide (PEA2PbBr4) crystal by regulating lattice expansion. This approach also suppresses light loss caused by exciton-exciton annihilation and accelerates electron-hole recombination processes, optimizing both the luminescence intensity and decay lifetime of the scintillator. The Zn2+ and Sb3+ doping PEA2PbBr4 scintillator achieve an optimal energy resolution of 4.84% and 5.65% at 662 keV for the photopeak, respectively. Additionally, in the 241Am-Be field, effective identification of nf and γ-rays around 1100 keVee is achieved using a pulse shape discrimination (PSD) method, with the figure of merit (FOM) being 0.85 and 1.03, respectively. This work provides a reliable new approach for optimizing the scintillation performance of 2D perovskite and promotes the application of 2D perovskite scintillator in γ-rays and nf detection.

The fabrication of infrared photoluminescent transparent ceramics with outstanding performance has garnered significant attention. A key factor in achieving excellent optical properties is the selection of an appropriate host material and luminescent ions. In this study, we prepared a series of single-phase rare-earth (RE = Ho³⁺, Er³⁺, Tm³⁺) doped Y₂Zr₂O₇ transparent ceramics using a solid-state reaction and vacuum sintering method. These ceramics exhibited a high transmittance (>75%) in the visible and near-infrared regions. Photoluminescence studies revealed strong down-conversion infrared emissions from the rare-earth ions. With their superior optical properties and straightforward preparation method, Ho³⁺/Er³⁺/Tm³⁺ doped Y₂Zr₂O₇ transparent ceramics present promising potential as infrared phosphor materials for applications in biomedicine, laser systems, and lighting technologies.

Electrochemical oxygen reduction reaction via the two-electron pathway (2e-ORR) is becoming a promising and sustainable approach to producing hydrogen peroxide (H2O2) without significant carbon footprints. To achieve better performance, most of the recent progress and investigations have focused on developing novel carbon-based electrocatalysts. Nevertheless, the sophisticated preparations, decreased selectivity and undefined active sites of carbon-based catalysts have been generally acknowledged and criticized. To this end, transition metal oxides and chalcogenides have increasingly emerged for 2e-ORR, due to their catalytic stability and tunable microstructure. Here, the development of metal oxides and chalcogenides for O2-to-H2O2 conversion is prospectively reviewed. By summarizing previous theoretical and experimental efforts, their diversity and outstanding catalytic activity are firstly provided. Meanwhile, the topological and chemical factors influencing 2e-ORR selectivity of the metal oxides/chalcogenides are systematically elucidated, including morphology, phase structures, doping and defects engineering. Thus, emphasizing the influence on the binding of ORR intermediates, the active sites and the underlying mechanism is highlighted. Finally, future opportunities and challenges in designing metal oxides/chalcogenides-based catalysts for H2O2 electro-synthesis are outlined. The present review provides insights and fundamentals of metal oxides/chalcogenides as 2e-ORR catalysts, promoting their practical application in the energy-related industry.

Direct photocatalytic methane oxidation into value-added oxygenates under mild conditions enables the sustainable chemical production but suffers from the lack of active photocatalysts and the overoxidation issue. Herein, defective ZnO nanoplates supported AuPd nanoparticles for efficient methane oxidation with O2 as the oxidant at room temperature are reported. A maximum liquid oxygenates productivity of 152.2 mm g-1 h-1 and a selectivity of 86.7%, more than half of which is CH3OH, are achieved over the optimized AuPd/ZnO photocatalyst, resulting in a 16.5% apparent quantum efficiency at 380 nm. The superior photocatalytic performance is benefited from the synergistic effect between defective ZnO substrate and AuPd cocatalyst, wherein the former facilitates CH4 adsorption, and the latter promotes light absorption, charge separation, as well as O2 activation into the reactive oxygen species. This work provides new guidance for regulating the activity and selectivity of the photocatalyst toward methane oxidation. Defective ZnO nanoplates supported AuPd nanoparticles exhibit superior activity, selectivity, and apparent quantum efficiency for methane oxidation into valuable oxygenates with O2. This is benefited from the synergistic effect between defective ZnO substrate and AuPd cocatalyst, wherein the former facilitates CH4 adsorption, and the latter promotes light absorption, charge separation, as well as O2 activation into the reactive oxygen species.image

The combination of transition-metal (TM) elements with two-dimensional (2D) transition-metal dichalcogenides (TMDs) provides an effective route to realizing a 2D controllable magnetic order, leading to significant applications in multifunctional nanospintronics. However, in most TM atoms@TMDs nanostructures, it is challenging for the magnetic anisotropy energy (MAE) to exceed 30 meV when affected by the crystal field. Hence, the stronger magnetic anisotropy of TMDs has yet to be developed. Here, utilizing first-principle calculations based on density functional theory (DFT), a feasible method to enhance the MAEs of TMDs via configurating iridium dimers (Ir2) on 2D traditional and Janus TMDs with antisite defects is reported. Calculations revealed that 28 of the 54 configurations considered possessed structure-dependent MAEs of >60 meV per Ir2 in the out-of-plane direction, suggesting the potential for applications at room temperature. We also showed the ability to tune the MAE further massively by applying a biaxial strain as well as the surface asymmetric polarization reversal of Janus-type substrates. This approach led to changes to >80 meV per Ir2. This work provides a novel strategy to achieve tunable large magnetic anisotropy in 2D TMDs. It also extends the functionality of antisite-defective TMDs, thereby providing theoretical support for the development of magnetic nanodevices.

A Bi–Pb composite catalyst with heterogeneous interfaces obtained by electroreduction of BiPbO 2 Br nanosheets exhibits impressive performance for CO 2 reduction to formate.

The wide deployment of proton exchange membrane water electrolyser and alkaline exchange membrane water electrolyser for hydrogen production suffer from the sluggish kinetics and limited durability of the electrocatalyst toward oxygen evolution reaction (OER). Herein, a rutile Ru0.75Mn0.25O2-δ solid solution oxide featured with hierarchical porous structure has been developed as an efficient OER electrocatalyst in both acidic and alkaline electrolyte. Specifically, compared with commercial RuO2, the catalyst displays a superior reaction kinetics with small Tafel slope of 54.6 mV dec-1 in 0.5 M H2SO4, thus allowing a low overpotential of 237 and 327 mV to achieve the current density of 10 and 100 mA cm-2, respectively, which is attributed to the enhanced electrochemically active surface area from the porous structure and the increased intrinsic activity owing to the regulated Ru>4+ proportion with Mn incorporation. Additionally, the sacrificial dissolution of Mn relieves the leaching of active Ru species, leading to the extended OER durability. Besides, the Ru0.75Mn0.25O2-δ catalyst also shows a highly improved OER performance in alkaline electrolyte, rendering it a versatile catalyst for water splitting.

Via solid state reaction, Ho3+/Yb3+ co-doped Y2Zr2O7 (YZO) transparent ceramics with different ytterbium concentration were successfully prepared. Highest in-line transmittance of samples reaches over 75% in both visible and near-infrared region. The homogeneity and microstructure of powders and ceramics were investigated through XRD and SEM characterizations. The luminescence results show that under excitation at ultraviolet (UV) and near-infrared (NIR) source, strong green emission peaks were observed and corresponding energy-conversion mechanism such as cooperative energy transfer (CET) were applied to explain the transition mechanism. Combined with the excellent optical properties and high temperature resistance, these results suggest that Ho3+/Yb3+ co-doped Y2Zr2O7 (YZO) transparent ceramics are promising novel phosphor material under different circumstance.

The discovery of titanium silicalite-1(TS-1) is a milestone in the development of heterogeneous catalysts for the eco-benign and mild catalytic oxidation process. However, the interpretation of specific Ti location and its role in oxidation is severely hindered due to the limited crystal size of as-synthesized TS-1. Here, a high quality TS-1 (ca. 10 mu m) was successfully fabricated by the pre-hydrolysis silica source strategy. As evidenced by powder X-ray diffraction crystallography, the preferred Ti locations were mainly found at T2, T4, and T11 in Ti-containing MFI framework. Combining multiple spectroscopy methods (i.e., FT-IR, UV-Vis, and UV Raman) and the reaction kinetics, the active center in TS-1 was demonstrated as an exposed site of hexa-coordinated titainum species. Furthermore, the powder X-ray crystallography also revealed that the ketone and oxime adsorbed in the zeolite host with intense host-guest interaction of framework oxygen atoms, and exhibiting an overwhelming spatial intimacy to the Ti species at the molecular scale. This unique phenomenon affords a plausible interpretation for the oxime reaction.

Via solid state reaction, Sm3+ doped Y2Zr2O7 transparent ceramics with different samarium concentration were successfully prepared. Highest in-line transmittance of samples reaches over 75% both in visible and infrared region. The homogeneity and microstructure of powders and ceramics were investigated through XRD and SEM characterizations. The luminescence results show that under the excitation of ultraviolet (UV) and blue light source, strong red emission peaks were observed and corresponding energy-conversion mechanism were applied to explain the transition rules. Combined with the excellent optical properties and high temperature resistance, these results suggest that Sm3+ doped Y2Zr2O7 (YZO) transparent ceramics are promising novel red LED material for application such as illumination, digital display, etc.

We report on the efficient operation of a ceramic erbium-doped yttria (Er: Y2O3) laser at room temperature with over 10W continuous-wave output power at 1640.4 nm. A sample of 0.25 at.% Er3+ doping was in-band pumped by a home-made Er, Yb fiber laser. The slope efficiency with respect to the absorbed ~1535 nm pump power was 25%. To the best of our knowledge, this is the first demonstration of laser performance at ~1.6 {\mu}m of Er: Y2O3 ceramic at room temperature.

The requirement for a sustainable and renewable energy has inspired substantial interests in designing and developing earth-abundant and high-effectiveness electrocatalysts/electrodes for fuel cells and metal-air batteries, in which oxygen reduction reaction (ORR) plays a crucial role. Perovskite oxides have acquired rapid attention as ORR electrocatalysts to replace noble-metal-based catalysts owing to their intrinsic electrocatalytic activity, compositional and structural flexibility. Herein, we report a new Sc and P co-doped perovskite oxide (La0.8Sr0.2Mn0.95Sc0.025P0.025O3-δ, LSMSP) as an active and robust electrocatalyst for the ORR in an alkaline solution. LSMSP electrocatalyst shows superior ORR activity and stability than those of pristine La0.8Sr0.2MnO3-δ (LSM), Sc-doped LSM and P-doped LSM due to the optimized average valence of Mn ions, the large surface area, the smaller particle size and the synergetic effect introduced by the co-doping. Moreover, compared to the benchmark Pt/C electrocatalyst, LSMSP electrocatalyst displays comparable ORR activity and superior durability. These above results suggest that the co-doping strategy of Sc and P into perovskites is a useful method to design high-performance electrocatalysts for the ORR, which can be used in other electrocatalysis-based applications.

自由曲面具有较高的自由度,在保证光学系统成像质量的同时有效地减少光学元器件的数量.根据三级像差理论设计一套传统卡塞格林望远镜系统.将次镜由双曲面替换为X-Y多项式表征的自由曲面,增大系统视场,通过ZEMAX软件对系统进行优化,并对系统成像质量进行分析.设计结果表明:在未加入任何类型视场校正器前提下,通过优化,该望远镜的对角线视场达到1.7°.在1.7°视场范围内,系统点列图的最大RMS半径为13.15 μm.在奈奎斯特频率25 lp/mm处,系统的调制传递函数值均大于0.4.系统衍射能量的80％集中在直径为30 μm的包围圆内,小于两个像素尺寸宽度.该系统结构简单,体积小,重量轻,适用于航空遥感环境.

State‐of‐the‐art dye‐sensitized solar cells (DSSCs) usually use the noble and scarce platinum (Pt) cathode, which strongly limits the practical applications of DSSCs. Accordingly, low‐cost, highly active, and stable alternatives to Pt are highly desired. Herein, an intrinsically conductive perovskite oxide is reported as a new cathode for DSSCs using a simple nonmetal element doping strategy. The phosphorus‐doped perovskite oxide (SrCo0.95P0.05O3−δ [SCP]) shows superior activity/durability for the triiodide (I3−) reduction reaction (IRR) and structural stability relative to the parent compound (SrCoO3−δ [SC]) due to the greatly enhanced electrical conductivity and the stabilization of the perovskite structure. The internal conducting pathways are demonstrated to be very important to obtain high IRR activity of the perovskite cathode, even when the cathode is incorporated with conductive multiwalled carbon nanotubes (MWCNTs). The DSSC with the N719 dye and SCP/MWCNTs cathode displays a superior power conversion efficiency (PCE) of 10.1% to those with Pt (8.11%) and SC/MWCNTs (6.80%) cathodes. In addition, the DSSC with the C101 dye and SCP/MWCNTs cathode shows an attractive PCE of 12.2% with an enhancement of 23%, as compared with the Pt cathode, suggesting that the SCP/MWCNTs composite can be one of the best substitutions to the Pt cathode, which can benefit the future industrialization of DSSCs.

A silver/perovskite nanocomposite cathode is designed by an exsolution strategy for dye-sensitized solar cells, showing a superior efficiency to Pt.

进行了从铟锭生产过程中产生的浮渣、再生碱渣和中和渣回收铟的工艺研究.铟浮渣分类后进行处理,铟回收率大99％;中和碱渣和再生碱渣硫酸浸出,浸出液经萃取,铟可以很好地回收.

We present the first demonstration of carbon nanoparticles (CNP) as an optical modulator to generate short laser pulses. An ytterbium-doped fiber ring cavity is successfully Q-switched with CNPs prepared in-house via a simple flame synthesis.

W and Al2O3 heterogeneous materials was bonded by using Cr as transition layer, and the diffusion behavior and resulted mechanical strength was studied. Results show that, Cr can diffuse and form metallurgical bonding with both W and Al2O3, and thus connect the heterogeneous materials together. The higher the sintering temperature and time is, the larger the diffusion distance and bonding strength is. Diffusion of Cr in W is defined as diffusion limited, while that in Al2O3 can be considered as interface controlled. Rate constants are 1.79 x 10 (7) m/s (1/2) and 3.59 x 10 9 m/s, and kinetic exponent n can be consideredas 0.5 and 1, respectively. (C) 2017 Elsevier B.V. All rights reserved.