The Edge Effects Boosting Hydrogen Evolution Performance of Platinum/Transition Bimetallic Phosphide Hybrid Electrocatalysts

Platinum (Pt) is regarded as a promising electrocatalyst for hydrogen evolution reaction (HER). However, its application in an alkaline medium is limited by the activation energy of water dissociation, diffusion of H+, and desorption of H*. Moreover, the formation of effective structures with a low Pt usage amount is still a challenge. Herein, guided by the simulation discovery that the edge effect can boost local electric field (LEF) of the electrocatalysts for faster proton diffusion, platinum nanocrystals on the edge of transition metal phosphide nanosheets are fabricated. The unique heterostructure with ultralow Pt amount delivered an outstanding HER performance in an alkaline medium with a small overpotential of 44.5 mV and excellent stability for 80 h at the current density of −10 mA cm−2. The mass activity of as-prepared electrocatalyst is 2.77 A mg−1Pt, which is 15 times higher than that of commercial Pt/C electrocatalysts (0.18 A mg−1Pt). The density function theory calculation revealed the efficient water dissociation, fast adsorption, and desorption of protons with hybrid structure. The study provides an innovative strategy to design unique nanostructures for boosting HER performances via achieving both synergistic effects from hybrid components and enhanced LEF from the structural edge effect

Insights on Flexible Zinc‐Ion Batteries from Lab Research to Commercialization

Owing to the development of aqueous rechargeable zinc-ion batteries (ZIBs), flexible ZIBs are deemed as potential candidates to power wearable electronics. ZIBs with solid-state polymer electrolytes can not only maintain additional load-bearing properties, but exhibit enhanced electrochemical properties by preventing dendrite formation and inhibiting cathode dissolution. Substantial efforts have been applied to polymer electrolytes by developing solid polymer electrolytes, hydrogel polymer electrolytes, and hybrid polymer electrolytes; however, the research of polymer electrolytes for ZIBs is still immature. Herein, the recent progress in polymer electrolytes is summarized by category for flexible ZIBs, especially hydrogel electrolytes, including their synthesis and characterization. Aiming to provide an insight from lab research to commercialization, the relevant challenges, device configurations, and life cycle analysis are consolidated. As flexible batteries, the majority of polymer electrolytes exploited so far only emphasizes the electrochemical performance but the mechanical behavior and interactions with the electrode materials have hardly been considered. Hence, strategies of combining softness and strength and the integration with electrodes are discussed for flexible ZIBs. A ranking index, combining both electrochemical and mechanical properties, is introduced. Future research directions are also covered to guide research toward the commercialization of flexible ZIBs

Crystal Structure of the Caenorhabditis elegans Apoptosome Reveals an Octameric Assembly of CED-4

SummaryThe CED-4 homo-oligomer or apoptosome is required for initiation of programmed cell death in Caenorhabditis elegans by facilitating autocatalytic activation of the CED-3 caspase zymogen. How the CED-4 apoptosome assembles and activates CED-3 remains enigmatic. Here we report the crystal structure of the complete CED-4 apoptosome and show that it consists of eight CED-4 molecules, organized as a tetramer of an asymmetric dimer via a previously unreported interface among AAA+ ATPases. These eight CED-4 molecules form a funnel-shaped structure. The mature CED-3 protease is monomeric in solution and forms an active holoenzyme with the CED-4 apoptosome, within which the protease activity of CED-3 is markedly stimulated. Unexpectedly, the octameric CED-4 apoptosome appears to bind only two, not eight, molecules of mature CED-3. The structure of the CED-4 apoptosome reveals shared principles for the NB-ARC family of AAA+ ATPases and suggests a mechanism for the activation of CED-3

A Triple Functional Approach To Simultaneously Determine the Type, Concentration, and Size of Titanium Dioxide Particles

The large-scale manufacturing and use of titanium dioxide (TiO₂) particles in food and consumer products significantly increase the likelihood of human exposure and release into the environment. We present a simple and innovative approach to rapidly identify the type (anatase or rutile), as well as to estimate, the size and concentration of TiO₂ particles using Raman spectroscopy and surface-enhanced Raman spectroscopy (SERS). The identification and discrimination of rutile and anatase were based on their intrinsic Raman signatures. The concentration of the TiO₂ particles was determined based on Raman peak intensity. Particle sizes were estimated based on the ratio between the Raman intensity of TiO₂ and the SERS intensity of myricetin bound to the nanoparticles (NPs), which was proven to be independent of TiO₂ nanoparticle concentrations. The ratio that was calculated from the 100 nm particles was used as a cutoff value when estimating the presence of nanosized particles within a mixture. We also demonstrated the practical use of this approach when determining the type, concentration, and size of E171: a mixture that contains TiO₂ particles of various sizes which are commonly used in many food products as food additives. The presence of TiO₂ anatase NPs in E171 was confirmed using the developed approach and was validated by transmission electron micrographs. TiO₂ presence in pond water was also demonstrated to be an analytical capability of this method. Our approach shows great promise for the rapid screening of nanosized rutile and anatase TiO₂ particles in complex matrixes. This approach will strongly improve the measurement of TiO₂ quality during production, as well as the survey capacity and risk assessment of TiO₂ NPs in food, consumer goods, and environmental samples

The bionic sunflower: a bio-inspired autonomous light tracking photocatalytic system

Developing a self-adapting photocatalytic system that efficiently captures light all day is not only a dream but also a challenge. Here, we report a ‘bionic sunflower’ based on a light-responsive smart hydrogel, which can spontaneously track and orient itself directionally to a light source, mimicking phototropism in, e.g., plants. As a novel photocatalytic system, it can efficiently recover the oblique-incidence energy-density loss and maintain photocatalytic efficiency at the maximum level at any random incidence angle from 0 to 90°. By taking the photocatalysis of H2O2 generation as an example, the bionic sunflower displays a high H2O2 yield rate of 262.1 μmol g−1 h−1 under 90° irradiation, as compared with the same photocatalytic system without phototropism (83.5 μmol g−1 h−1). Theoretical analyses with COMSOL Multiphysics simulation and density functional theory (DFT) calculations reveal the mechanism behind the actuation motion that triggers the bending of the bionic sunflower and determine the active sites for H2O2 generation during photocatalysis. This work proposes a novel photocatalytic concept to boost any traditional photocatalytic reaction by optimally using the solar energy from the sun's passage