Amorphous photonic structures exhibit interesting optical properties such as non-iridescent angle-independent structural colors and isotropic photonic band gaps. Here, we demonstrate colloidal assemblies of engineered amorphous photonic materials, using pigmentary α-Fe 2 O 3 /SiO 2 core/shell nanoparticles, exhibiting non-iridescent and tunable colors. The observed colors result from combination of colloidal particle arrangements, giving arises to the structural colors, along with the inherent pigmentary color of the α-Fe 2 O 3 /SiO 2 nanoparticles. Colloidal particle assemblies of α-Fe 2 O 3 /SiO 2 core/shell nanoparticles, and therefore the resulting colors, can be manipulated by shell thickness, particle concentration and external electrical stimuli. α-Fe 2 O 3 /SiO 2 nanoparticles based amorphous photonic structures exhibit short-range order on a length scale comparable to optical wavelengths and are weakly correlated to each other, as confirmed by ultra-small-angle X-ray scattering measurements. Dynamic tunability of α-Fe 2 O 3 /SiO 2 nanomaterials in the visible wavelengths is demonstrated using electrophoretic deposition process with a noticeable difference between transmitted and reflected colors. Amorphous structures have been investigated both theoretically and experimentally due to their unique properties as compared with perfectly ordered crystalline structures [1] . Prototypical A novel amorphous photonic structures using pigmentary α-Fe 2 O 3 /SiO 2 core/shell nanoparticles are succesfully fabricated. The resulting non-iridicent brilliant colors are in combination of pigmenary and structural colororation and manipulated by shell thickness, particle concentration and external electrical stimuli using electrophoretic deposition process. In the process, fully reversible and instantaneous color change as well as noticeable difference between transmitted and reflected colors is observed.

Understanding the influence of potential on electrochemical surface reaction kinetics remains a challenge in identifying catalytic materials for numerous important reactions including water splitting (OER), hydrogen evolution (HER), and CO2 reduction, among others. Limitations in computational methods, complicated by the unique environment of the electrode–electrolyte interface, have compelled many studies to focus on the thermodynamics of reaction schemes and to generalize inferences about the kinetics of charge transfer. In instances where activation barrier estimates are available, they are typically assumed to follow the empirical Butler–Volmer (BV) model. In this Perspective, we illustrate that the relative magnitudes and potential-dependences of elementary barriers can have a marked effect on the properties of a catalyst deemed “optimal” for a given reaction. We use a simple pseudosteady-state analysis of two sequential surface-mediated charge transfers to assess the degree of rate control of each step as a function of the material and conditions. We compare BV kinetics to Marcus theory and also discuss more recent models that are specific to the interactions of an adsorbate with the electronic structure of a surface. Recent developments in the full simulation of charge transfer to surface species are also briefly discussed. Finally, we highlight the need for assessment of kinetics and identification of activity descriptors that are optimal at relevant operating conditions, and we conclude with an outlook on current research needs.

Solid-state lithium-ion batteries are a hopeful successor to traditional Li-ion cells that use liquid electrolytes. While a growing body of work has characterized the interfaces between various solid electrolytes and the lithium metal, interfaces with common cathode intercalation compounds are comparatively less understood. In this contribution, the influence of polarization and temperature on interfacial stability between LiMn2O4 (LMO) and Li7La3Zr2O12 (LLZO) are investigated. Sputtered thin-film LMO electrodes are utilized to permit high-capacity cycling while retaining a large ratio of interfacial area to electrode bulk. Electrochemical impedance spectroscopy (EIS) is compared across a set of full (LMO|LLZO|Li) and symmetric (LMO|LLZO|LMO, Li|LLZO|Li, and Au|LLZO|Au) cells to delineate impedance features that are specific to the evolution of the cathode interface. Additional X-ray photoelectron spectroscopy (XPS) provides evidence of a limited interfacial reaction between LMO and LLZO that coincides with an increase in the impedance of the LMO–LLZO interface.

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Greenbodies of SmCoO prior to conversion to SmCo5 and magnetometry showing excellent hard magnetic properties, resilient to >600 °C.