Materials Science and Engineering: R: Reports最新文献

Spin selective catalysis is an emerging approach for improving the thermodynamics and kinetics of reactions. The role of electron spins has been scarcely studied in catalytic reactions. One exception is the oxygen evolution reaction (OER) where strongly correlated metals and oxides are used as catalysts. In OER, spin alignment facilitates the transition of singlet state of the reactant to the triplet state of O₂. However, the influence of strong correlations on spin exchange mechanism and spin selective thermodynamics of most catalytic reactions remain unclear. Here we decouple the strongly correlated catalyst from the electrolyte to study spin exchange in two-dimensional (2D) magnetic iron germanium telluride (FGT) heterostructure. We demonstrate that transmission of spin and electrochemical information between the catalyst and the reactant can occur through quantum exchange interaction despite the catalyst of FGT being completely encapsulated by graphene or hexagonal boron nitride (hBN). The strong correlations in FGT that lead to enhanced spin exchange in OER are observed in graphene or hBN layers with thicknesses of up to 6 nm. We demonstrate that spin alignment in FGT leads to a lowering of thermodynamic barrier for adsorption of hydroxide ion and electron transfer to the catalyst. This results in up to fivefold enhancement in OER performance and improved kinetics. Our results provide clear evidence that transmission of both quantum mechanical and electrochemical information through quantum spin exchange interaction in FGT leads to an enhancement in catalytic performance.

Interface engineering is vital for promoting charge separation in photocatalysis. Herein, a twin crystal interface in Cd_0.3Zn_0.7S is engineered, which leads to a variation of the electric polarization along the interface and the formation of a periodic quantum well along z axis. The periodic quantum well could effectively facilitate the oriented charge separation and significantly reduce the diffusion distance simultaneously. Density functional theory (DFT) calculations confirm that Cd_0.3Zn_0.7S twin crystal possesses a relative low work function and an appropriate hydrogen adsorption Gibbs free energy (ΔG_H*), making each step of the cascaded hydrogen evolution reactions optimized. As a result, the resultant twin crystal exhibits an excellent visible light photocatalytic hydrogen evolution rate (13148.98 μmol·g⁻¹·h⁻¹), which is almost 10 and 30 times higher than those of CdS and ZnS. Importantly, it also shows a good stability because of the formation of twin crystal interface. In addition, the introduction of S vacancy defect results in narrowing the band gap and extending the photo-response to long wavelength region. Such a twin crystal interface engineering strategy provides a basic guideline for designing high-efficient photocatalysts with tunable electric polarization.

Because of their higher energy efficiency and environmental friendliness, electrical vehicles (EVs) have recently positioned themselves as one of the most sustainable alternatives to traditional combustion engine vehicles. However, there remain numerous challenges (i.e., lubrication, thermal management, electrical compatibility, and corrosion, among others) that can hamper their performance, efficiency, and reliability, and hence the sustainability of EVs in the long run. Two-dimensional (2D) materials offer impressive multi-functional characteristics, including unusual thermal, electrical, and tribological properties which can beneficially impact the smooth, safe, efficient, and long-lasting operation of EVs. Therefore, in this perspective, we summarize the most recent developments related to 2D materials which can synergistically address tribological, electrical, and thermal management issues and thus enable superior performance, efficiency, and reliability in future EVs. We hope that the highlighted remarkable properties of 2D materials can generate more research efforts in this direction and eventually lead to the development of an EV-based green and sustainable transportation future for generations to come.

Technological advancements have consistently been accompanied by significant progress in materials science, with alloys serving as fundamental elements in engineering design. However, due to emerging demands of industry, these alloys face limitations forcing materials scientists to design new alloys and understand their phenomenological behavior. This article presents a comprehensive overview of the design and mechanical response of multicomponent alloys as the emerging promising solutions, ranging from high entropy alloys to complex concentrated alloys. The notable properties exhibited by the wide range of compositions, required special criteria to select the adequate candidates for specific structural applications. Despite their advantages, the article also highlights the difficulties, limitations and new perspectives in their design, as well as the importance of high-performance simulation for achieving effective multicomponent alloys.

The growing demand for personalized ceramic devices for biomedical engineering applications, with increasingly complex shapes and properties, highlights the limitations of traditional ceramic processing techniques. In recent years, increasing attention has been drawn to ceramic-based materials produced by an additive manufacturing method commonly referred to as direct ink writing (DIW) or robocasting. However, the current challenge remains the achievement of strong mechanical reliability while preserving optimal levels of biocompatibility, bioactivity and biodegradability. Hence, the present review examines the overall scenario of this field, highlighting and analyzing the primary outcomes of studies available in the literature. It also describes the most innovative approaches. Were explored pure ceramics and composites, encompassing calcium phosphates, bioactive glasses, calcium silicates, polymer-derived ceramics and functionalized materials. The review demonstrated that DIW was mostly applied for the fabrication of scaffolds intended for bone regeneration applications and that have been, more recently, capable of attaining mechanical properties in the range of cortical bone. Dense components are comprehended as well with high relative densities achieved and commendable mechanical properties in light of the densities attained. Mechanical and biological improvement strategies for the DIW method are also presented and discussed.

Laser powder bed fusion (LPBF), as the most commercialized metal additive manufacturing technique, is tantalizing the metallurgical community owing to its capabilities of directly producing highly intricate parts with complex geometries and achieving superior properties compared to those of conventionally manufactured alloys. High-entropy alloys (HEAs) represent a class of novel materials consisting of multiple principal elements in near-equiatomic ratios, revolutionizing the alloy design concept. LPBF has been employed to fabricate HEAs in numerous attempts to improve their outstanding mechanical, physical, and chemical properties. This review systematically compares seven unique classes of LPBF-produced HEAs—the 3d transition metal HEAs, eutectic HEAs, precipitation-strengthened HEAs, refractory HEAs, metastable HEAs, interstitial HEAs, and high-entropy matrix composites—pertaining to their feedstock preparation, printability, microstructure, strengthening mechanisms, material properties, and potential applications. Additionally, the computational modeling of HEAs for LPBF is extensively discussed. This work aims to guide relevant research in the field by systematically reviewing the advancements in the design strategies employed for the successful fabrication of HEAs by LPBF.

In recent years, aqueous zinc metal batteries have greatly intrigued scientists; however, zinc anode suffers from many issues such as dendrites, hydrogen evolution, and passivation. To address the dilemma of zinc anode, macromolecular interfacial modifiers are employed to improve the stability of zinc anode. In this review, it is summarized that macromolecular modifiers facilitate highly stable zinc anode in aqueous electrolyte. Combined with the issues of zinc anode and the characteristics of macromolecules, the advantages of macromolecules as interface modifiers are discussed. Moreover, the effects of macromolecules modified electrolyte, zinc anode, separator, and current collector on the interfacial properties of zinc anode are discussed, respectively. The current challenges and future research directions are proposed from the perspective of the application of macromolecules in zinc powder anode, the relationship between the structure of macromolecules and the deeper principle of stabilizing zinc anode, and the application of macromolecular modifiers in other metal anodes, etc.