Search

The development of the proton exchange membrane water electrolyzer (PEMWE) is still limited by the prohibitive cost and scarcity of iridium (Ir)‐based oxygen evolution reaction (OER) catalyst. This work presents a novel catalyst synthesized by precursor‐atomization and rapid joule‐heating method, successfully doping iridium atoms into polyvalent tungsten blends (W0, W5+, W6+) based on titanium substrate. The vacancy engineering of unsaturated tungsten oxide (W5+, W6+) reconstructs the electronic structure of the catalyst surface, which resulting in the low‐valence state iridium species, avoiding excessive oxidation of iridium and accelerating the catalytic kinetics. Meanwhile, metallic tungsten (W0) improves the conductivity of catalyst and guarantees the stable existence of oxygen vacancy. The TiIrWOx possesses excellent performance in acidic OER catalysis, requiring overpotential of only 181 mV to drive 10.0 mA cm−2, and exhibiting a high mass activity of 753 A gIr−1 at an overpotential of 300 mV. The membrane electrode assembly (MEA) with TiIrWOx as anode electrocatalyst can reduce the Ir consumption amount by >60% compared to commercial IrO2, and it can operated over 120 h at a current density of 1.0 A cm−2. [ABSTRACT FROM AUTHOR]

Dynamic soft tissue identification plays an important role in robotic‐assisted minimally invasive surgery to achieve realistic force feedback for precise and safe surgical operations. This article studies a dynamic soft tissue identification method by combination of the Hunt Crossley contact model with an iterated Kalman filter. The dynamic system equation of tool‐tissue interaction is constructed by combining mechanical tool's kinematic dynamics with the Hunt Crossley contact dynamics. Upon this, an iterative Kalman filter is developed for online soft tissue identification by integrating the maximum a posteriori principle into the Kalman filtering framework to optimize the posterior state estimate to account for the strong nonlinearity of the Hunt Crossley contact model. Results and comparison analysis demonstrate that the proposed method can effectively identify the Hunt‐Crossley model parameters, resulting in improved accuracy compared with the conventional recursive least square method and extended Kalman filter. [ABSTRACT FROM AUTHOR]

Seawater electrolysis is an attractive technique for mass production of high‐purity hydrogen considering the abundance of seawater. Nevertheless, due to the complexity of seawater environment, efficient anode catalyst, that should be, cost effective, highly active for oxygen evolution reaction (OER) but negligible for Cl2/ClO– formation, and robust toward chlorine corrosion, is urgently demanded for large‐scale application. Although catalysis typically appears at surface, while the bulk properties and morphology structure also have a significant impact on the performance, thus requiring a systematic optimization. Herein, a multiscale engineering approach toward the development of cost‐effective and robust OER electrocatalyst for operation in seawater is reported. Specifically, the engineering of hollow‐sphere structure can facilitate the removal of gas product, while atom‐level synergy between Co and Fe can promote Co sites transforming to active phase, and in situ transformation of sulfate ions layer protects catalysts from corrosion. As a result, the as‐developed hollow‐sphere structured CoFeSx electrocatalyst can stably operate at a high current density of 100 mA cm–2 in the alkaline simulated seawater (pH = 13) for 700 h and in a neutral seawater for 20 h without attenuation. It provides a new strategy for the development of electrocatalysts with a broader application potential. [ABSTRACT FROM AUTHOR]

Seawater electrolysis is an attractive technique for massive green hydrogen production owing to the dominant advantages of seawater resources, namely low‐cost and limitlessness. However, the oxygen evolution reaction (OER) catalysts will be easily deactivated for severe seawater Cl− permeation and corrosion. Herein, a structural buffer engineering strategy is reported to endow the Co2(OH)3Cl with long‐term operation stability and a high OER selectivity of ≈99.6% in seawater splitting. The lattice Cl− of Co2(OH)3Cl can act as the structural buffer, whose continuous leaching during OER can leave vacancies for seawater Cl− invasion, so as to avoid catalyst deactivation. Accordingly, Co2(OH)3Cl can maintain 99.9% of its initial current density after 60 000 s operation, while that of Co(OH)2 decays by 52.7% in 7 000 s. Meanwhile, the lattice Cl− of Co2(OH)3Cl can optimize the binding energy of reaction intermediates on the neighboring OCoO site. Thus, Co2(OH)3Cl exhibits a current density of 330.5 mA cm–2 at the potential of 1.63 V versus RHE, 45.9 times higher than that of Co(OH)2. The structural buffer strategy may be applied to incorporate other metal oxides with suitable anions, and effectively boost their OER activity and stability in alkaline seawater. [ABSTRACT FROM AUTHOR]

Summary: Both sugar and the hormone gibberellin (GA) are essential for anther‐enclosed pollen development and thus for plant productivity in flowering plants. Arabidopsis (Arabidopsis thaliana) AtSWEET13 and AtSWEET14, which are expressed in anthers and associated with seed yield, transport both sucrose and GA. However, it is still unclear which substrate transported by them directly affects anther development and seed yield.Histochemical staining, cross‐sectioning and microscopy imaging techniques were used to investigate and interpret the phenotypes of the atsweet13;14 double mutant during anther development. Genetic complementation of atsweet13;14 using AtSWEET9, which transports sucrose but not GA, and the GA transporter AtNPF3.1, respectively, was conducted to test the substrate preference relevant to the biological process.The loss of both AtSWEET13 and AtSWEET14 resulted in reduced pollen viability and therefore decreased pollen germination. AtSWEET9 fully rescued the defects in pollen viability and germination of atsweet13;14, whereas AtNPF3.1 failed to do so, indicating that AtSWEET13/14‐mediated sucrose rather than GA is essential for pollen fertility.AtSWEET13 and AtSWEET14 function mainly at the anther wall during late anther development stages, and they probably are responsible for sucrose efflux into locules to support pollen development to maturation, which is vital for subsequent pollen viability and germination. [ABSTRACT FROM AUTHOR]

An efficient and ultra‐broadband red phosphor CsMg2P3O10: Mn2+ (CMPO: Mn2+) is first synthesized toward indoor plant growth LEDs. The phase purity, element composition, crystal, and local electronic structure are explored to discuss the structure and photoluminescence properties. Structure refinement and series X‐ray diffractometer (XRD) results show that CMPO: Mn2+ is well crystallized in an orthogonal crystal system. The diffuse reflection and excitation spectra show that CMPO: Mn2+ has strong absorption around near ultraviolet region, assigned to the [6A1 → 4E(4D), 4T2(4D), [4A1(4G), 4E(4G)], and 4T1(4G)] transitions of Mn2+, respectively. Upon 415 nm excitation, an efficient red emission centered at 647 nm with ultra‐broad full width at half‐maximum (FWHM ∼ 100 nm) and high quantum efficiency (IQE ∼ 44.3 %) is observed, and because of the ultra‐broad FWHM, the red emission is well accordant with the absorption spectra band of phytochrome PR and PFR. The optimal doping contents, lifetime as well as interaction mechanism of CMPO: Mn2+ are discussed in detail. Finally, the excellent thermal stability (84.5% @ 140°C) and related thermal quenching mechanism of CMPO: Mn2+ are discussed. The above results indicate that CMPO: Mn2+ phosphors have great potential for application in plant growth LEDs. [ABSTRACT FROM AUTHOR]

Electric‐field‐induced strain in piezoelectric materials, which has demonstrated broad applications, usually provides about 1% strain. A giant and reversible deformation as large as ≈5% in BiFeO3 thin film induced by electrochemistry is reported, where the large lattice change is induced by electrochemical reaction through absorption and desorption of oxygen. Prior to deformation, a precursor phase with projected Fe–Fe pairs is formed first under low voltage (1 V), and then a large lattice expansion is eventually achieved under a high voltage (≈18 V), which is reversible under negative voltage. It is found that the giant strain is due to the electrochemically induced migration of oxygen ion which leads to significant out‐of‐plane lattice expansion under positive voltage, resulting in the formation of a new oxygen‐deficient phase. Interestingly, the new oxygen‐deficient phase is capable of transforming back to the pristine structure by absorbing oxygen under negative voltage. The results provide a new route to realize giant and reversible deformation in oxides by oxygen migration. [ABSTRACT FROM AUTHOR]