Advances In Tuning Research Articles

Recent advances in tailoring the microenvironment of Pd-based catalysts for enhancing the performance in the direct synthesis of hydrogen peroxide.

Hydrogen peroxide (H2O2) is a valuable clean chemical, which is widely applied in modern industrial production. In the past few decades, H2O2 has been mainly produced industrially by the anthraquinone method, but the process is complicated and energy consuming, which is only economical for large-scale production and is harmful to the environment. The direct synthesis of H2O2 is considered a promising process to replace the anthraquinone method with high atomic economy, no hazardous by-products, and convenient operation, which has attracted much attention. In this review, we systematically present the recent advances in tuning the microenvironment of Pd-based catalysts for enhancing the performance of the direct synthesis of H2O2, including the modulation of active sites and support, from the viewpoint of the reaction mechanism. Finally, a summary and perspective on the most pressing issues and associated untapped research prospects with the direct synthesis of H2O2 are discussed. The purpose of this review is to provide in-depth insights and guidelines to promote the development of novel catalysts for the direct synthesis of H2O2.

From Thalidomide to Rational Molecular Glue Design for Targeted Protein Degradation.

Thalidomide and its derivatives are powerful cancer therapeutics that are among the best-understood molecular glue degraders (MGDs). These drugs selectively reprogram the E3 ubiquitin ligase cereblon (CRBN) to commit target proteins for degradation by the ubiquitin-proteasome system. MGDs create novel recognition interfaces on the surface of the E3 ligase that engage in induced protein-protein interactions with neosubstrates. Molecular insight into their mechanism of action opens exciting opportunities to engage a plethora of targets through a specific recognition motif, the G-loop. Our analysis shows that current CRBN-based MGDs can in principle recognize over 2,500 proteins in the human proteome that contain a G-loop. We review recent advances in tuning the specificity between CRBN and its MGD-induced neosubstrates and deduce a set of simple rules that govern these interactions. We conclude that rational MGD design efforts will enable selective degradation of many more proteins, expanding this therapeutic modality to more disease areas.

Advances and challenges in tuning the reversibility & cyclability of room temperature sodium–sulfur and potassium–sulfur batteries with catalytic materials

The high theoretical energy density of room temperature sodium-sulfur and potassium-sulfur batteries (Na–S; 1274 Wh/kg, K–S; 914 Wh/kg; based on the mass of sulfur) due to the multi-electron transfer associated with the unique conversion chemistry of S and the natural abundance of Na, K, and S raw materials make them ideal candidates for large-scale energy storage applications beyond Li batteries. However, achieving good reversibility, cyclability, and active material utilization in Na–S and K–S batteries demands alleviation of the complex polysulfide dissolution and the shuttle phenomena during cycling. Rational employment of catalytic materials is beneficial to address these issues by facilitating effective polysulfide transformation and thereby accelerating the sluggish reaction kinetics. This review focuses on the roles and evolution of catalytic materials in polysulfide adsorption, catalytic conversion, and redox mediation in facilitating high-performing Na–S and K–S batteries. Specifically, the advances in tuning the reversibility and cyclability of Na-S and K–S batteries strategically with catalytic material-incorporated S-host cathodes, separators, and interlayers and the interaction of various catalytic materials with the polysulfide species are discussed in the light of advanced characterization techniques. Lastly, the challenges and the plausible strategies for future research are elucidated.

Controllable synthesis and structural design of novel all-organic polymers toward high energy storage dielectrics.

As the core unit of energy storage equipment, high voltage pulse capacitor plays an indispensable role in the field of electric power system and electromagnetic energy related equipment. The mostly utilized polymer materials are metallized polymer thin films, which are represented by biaxially oriented polypropylene (BOPP) films, possessing the advantages including low cost, high breakdown strength, excellent processing ability, and self-healing performance. However, the low dielectric constant (ε r < 3) of traditional BOPP films makes it impossible to meet the demand for increased high energy density. Controlled/living radical polymerization (CRP) and related techniques have become a powerful approach to tailor the chemical and physical properties of materials and have given rise to great advances in tuning the properties of polymer dielectrics. Although organic-inorganic composite dielectrics have received much attention in previous studies, all-organic polymer dielectrics have been proven to be the most promising choice because of its light weight and easy large-scale continuous processing. In this short review, we begin with some basic theory of polymer dielectrics and some theoretical considerations for the rational design of dielectric polymers with high performance. In the guidance of these theoretical considerations, we review recent progress toward all-organic polymer dielectrics based on two major approaches, one is to control the polymer chain structure, containing microscopic main-chain and side-chain structures, by the method of CRP and the other is macroscopic structure design of all-organic polymer dielectric films. And various chemistry and compositions are discussed within each approach.

Thermo-elastic behavior of hexagonal Sc–Ti–Zr–Hf high-entropy alloys

Recent advances in tuning the long-standing strength-ductility tradeoff have drawn attention to high-entropy alloys (HEAs), and the appearance of hexagonal close-packed (hcp) structures has been emphasized. However, few studies have explored the elastic moduli of hcp HEAs, which is of prime importance for improved understanding of the outstanding mechanical properties. In this work, we focus on a set of equiatomic rare-earth-free HEAs with hcp structures, i.e. ScTiZr, ScTiHf, ScZrHf, TiZrHf, and ScTiZrHf, and their thermo-elastic properties are studied using quantum mechanical first-principles methods. It is found that, for all considered HEAs, the hexagonal axial ratio shows a weak dependence on the temperature effect, and the thermal expansion coefficient remains almost unchanged above room temperature. From the calculated temperature-dependent single-crystal elastic constants, we analyzed the mechanical stability, elastic anisotropy, and derived polycrystalline moduli. Results indicate that the present HEAs exhibit rather high elastic isotropy and large elastic softening resistance. The ab initio predicted Young’s modulus, shear modulus, and specific modulus do not obey the rule of mixture, which indicates that there exists a strong intrinsic hardening effect in all of the considered HEAs. The calculated results are in good agreement with the available experimental measurements.

Recent developments and applications of polymer monolithic stationary phases.

This review highlights the current trends and the most recent advances in the field of preparation and application of organic polymer-based monolithic materials and covers literature published in 2020. A short historical background is provided and protocols to anchor monoliths covalently to the wall of the column/separation device are discussed. Furthermore, advances in tuning the macroporous structure and establishing its link to separation performance are conferred. Finally, method development and key applications using novel monolithic columns are discussed.

Tunable Optical Properties of 2D Materials and Their Applications

AbstractRecent efforts have been heavily devoted to the development of next‐generation optoelectronic devices based on 2D materials, due to their unique optical properties that are distinctly different from those of bulk counterparts. Given that the feature of flexible tunability is highly desired, various approaches have been demonstrated to efficiently modulate the optical properties, eventually enabling peculiar functionalities or realizing high‐performance nanoscale devices. Here, this review focuses on recent advances in tuning the optical properties of 2D materials by external stimuli including electric field, mechanical strain, magnetic field, acoustic wave, and thermal heating. Also, such tunability leads to many emerging applications in the fields of electronics, optics, sensors, and energy harvesting, which are summarized and critically discussed in the paper.

Recent advances in tuning the electronic structures of atomically dispersed M–N–C materials for efficient gas-involving electrocatalysis

A focused review is presented to comprehensively summarize the reported electronic structure modulation strategies for achieving highly active M–N–C electrocatalysts.

Electrical switching in a magnetically intercalated transition metal dichalcogenide.

Advances in controlling the correlated behaviour of transition metal dichalcogenides have opened a new frontier of many-body physics in two dimensions. A field where these materials have yet to make a deep impact is antiferromagnetic spintronics-a relatively new research direction promising technologies with fast switching times, insensitivity to magnetic perturbations and reduced cross-talk1-3. Here, we present measurements on the intercalated transition metal dichalcogenide Fe1/3NbS2 that exhibits antiferromagnetic ordering below 42 K (refs. 4,5). We find that remarkably low current densities of the order of 104 A cm-2 can reorient the magnetic order, which can be detected through changes in the sample resistance, demonstrating its use as an electronically accessible antiferromagnetic switch. Fe1/3NbS2 is part of a larger family of magnetically intercalated transition metal dichalcogenides, some of which may exhibit switching at room temperature, forming a platform from which to build tuneable antiferromagnetic spintronic devices6,7.

The magnetization profile induced by the double magnetic proximity effect in an Fe/Fe0.30V0.70 superlattice

The double magnetic proximity effect (MPE) in an Fe/Fe0.30V0.70 superlattice is studied by a direct measurement of the magnetization profile using polarized neutron reflectivity. The experimental magnetization profile is shown to qualitatively agree with a profile calculated using density functional theory. The profile is divided into a short range interfacial part and a long range tail. The interfacial part is explained by charge transfer and induced magnetization, while the tail is attributed to the inhomogeneous nature of the FeV alloy. The long range tail in the magnetization persists up to 170% above the intrinsic ordering temperature of the FeV alloy. The observed effects can be used to design systems with a direct exchange coupling between layers over long distances through a network of connected atoms. When combined with the recent advances in tuning and switching, the MPE with electric fields and currents, the results can be applied in spintronic devices.

Band-Gap Nonlinearity in Lead Chalcogenide (PbQ, Q = Te, Se, S) Alloys.

Narrow band-gap lead chalcogenides have been developed for several optical and electronic applications. However, band-gap energies of the ternary and quaternary alloys have received little attention compared with the parent binary phases. Here, we have fabricated single-phase ternary (PbTe)1–x(PbSe)x and quaternary (PbTe)0.9–y(PbSe)0.1(PbS)y and (PbTe)0.65–z(PbSe)0.35(PbS)z alloys and shown that although lattice parameters follow Vegard’s law as a function of composition, the band-gap energies exhibit a substantial bowing effect. The ternary (PbTe)1–x(PbSe)x system features a smaller bowing parameter predominantly due to the difference in electronegativity between Se and Te, whereas the larger bowing parameters in quaternary alloys are generated from a larger crystal lattice mismatch and larger miscibility gap. These findings can lead to further advances in tuning the band-gap and lattice parameters for optical and electronic applications of lead chalcogenides.

Tuning Amphiphilicity of Particles for Controllable Pickering Emulsion.

Pickering emulsions with the use of particles as emulsifiers have been extensively used in scientific research and industrial production due to their edge in biocompatibility and stability compared with traditional emulsions. The control over Pickering emulsion stability and type plays a significant role in these applications. Among the present methods to build controllable Pickering emulsions, tuning the amphiphilicity of particles is comparatively effective and has attracted enormous attention. In this review, we highlight some recent advances in tuning the amphiphilicity of particles for controlling the stability and type of Pickering emulsions. The amphiphilicity of three types of particles including rigid particles, soft particles, and Janus particles are tailored by means of different mechanisms and discussed here in detail. The stabilization-destabilization interconversion and phase inversion of Pickering emulsions have been successfully achieved by changing the surface properties of these particles. This article provides a comprehensive review of controllable Pickering emulsions, which is expected to stimulate inspiration for designing and preparing novel Pickering emulsions, and ultimately directing the preparation of functional materials.