Materials Today最新文献

The commercialization of Ni-based catalysts in CO₂ dry reforming of methane (DRM) suffers from their quick deactivation. Here, we reveal each reaction pathway for DRM based on the Ni catalyst composition and geometry under working conditions, through one working platform combining in situ high resolution Cs corrected environmental transmission electron microscopy and electron energy-loss spectroscopy coupled with mass spectroscopy. The formation of Ni₃C has been found to inhibit the decomposition of CO₂ and CH₄, and to promote the formation of onion-like carbon to encapsulate the Ni catalysts, leading to the deactivation of the Ni-based catalysts. Designing the suitable supports or promoters to keep the Ni surface structure under Ni-NiO cycle can drive the simultaneously amorphous carbon deposition-consumption cycle and minimise the coke formation. This research is not only for developing coke resistance Ni catalysts in the DRM, but also significant for investigating many catalysis challenges both in research and engineering.

Metal ion-catecholate complexes (MCCs) extensively exist in plants and animals, which are in charge of versatile biological functions, such as constructing organs, controlled releasing metal ions and antibacterial. Inspired by this, researchers have exploited various kinds of artificial MCCs, which can serve as structural and functional synthons to construct advanced materials. In terms of the structural contribution, these complexes exhibit not only physical interactions, including metal-coordination, hydrogen bonding, π-π stacking and cation-π interactions, but also rich chemical reactions, including radical polymerization, Schiff base reaction and Michael addition. In terms of functional contribution, the complexes can endow the materials with the intrinsic properties of polyphenols and metal ions, including antioxidant, adhesion, antibacterial, bioimaging and catalyst. In addition, some emerging and fantastic functions are also originally from the complexes, such as tunable mechanical property, self-healing, controlled release and photothermal effect. In this review paper, we comprehensively discuss the recent development of MCC-based materials, including coatings, particles, metallogels and metal–organic frameworks (MOFs). Perspectives in this field has also been put forward as well.

Aligned carbon nanotubes (A-CNTs) have been demonstrated to be promising materials for constructing advanced complementary metal–oxide–semiconductor (CMOS) field-effect transistors (FETs) for future integrated circuits (ICs). However, the requirements of A-CNT materials from the perspective of IC applications, such as the distributions of length, alignment, diameter and density of CNTs, have not been explicitly researched or mentioned before. In this article, we review the progress on CNT electronics and electronic-grade materials and establish material criteria for A-CNTs applicable to advanced electronics according to the developing roadmap of CNT-based ICs. Specifically, electrical performance predictions for A-CNT CMOS FETs at various technology nodes are built based on a theoretical model and experimental results, and then, the criteria for ideal A-CNTs are outlined by evaluating the energy-delay product (EDP) advantage of CNT FETs over similar node commercial silicon (Si)-based CMOS transistors. The fine requirements for A-CNT materials are estimated for 90 nm, 22 nm, 7 nm, and 3 nm node CNT CMOS FETs, which present significant advantages in terms of energy efficiency over Si CMOS transistors. The criteria will guide the development of CNT materials for future ICs and provide a comprehensive assessment of the opportunities and challenges in CNT electronics.

Solid oxide fuel cells (SOFCs) are promising energy conversion devices for the effective and convenient utilization of hydrocarbons (for example, methane) to electricity. However, the development of direct methane SOFCs is primarily hindered by the poor coking tolerance of the state-of-the-art Ni-based cermet anodes. Herein, we efficiently construct nano-interfaces in the anode by infiltrating a Ni_0.6Y_0.064Zr_0.336O_2-δ (NYZ) catalyst onto the traditional Ni-based cermet anode to effectively enhance the coking tolerance. After being reduced in H₂, Ni and Y_0.16Zr_0.84O_2-δ (YSZ) nanoparticles (NPs) are in situ formed on the surface of the Ni-YSZ substrate. The roughened anode demonstrates significantly improved fuel oxidation activity and coking tolerance, due likely to the formation of nano-interfaces. Specifically, when applied in the Ni-YSZ-based anode-supported SOFCs, a high peak power density of 1.785 W cm⁻² and a stable operation of ∼ 240 h with no observable degradation is achieved at 750 °C in nearly dry methane (3 % H₂O). A density functional theory study suggests that the excellent coking tolerance is attributed to the formation of OH species on Ni/YSZ nano-interfaces, which would further interact with intermediate carbon species to generate COH intermediates.

Preventing breast cancer liver metastasis presents formidable challenges with multifaceted obstacles. In the case of acute and chronic liver injury, the disrupted liver microenvironment induced by activated hepatic stellate cells (aHSCs) would suppress immune surveillance and license the re-multiplication of disseminated tumor cells (DTCs). Herein, a cyclic peptide pPB modified nanovesicle with aHSCs targeting capability was constructed as CP-SB-siRNA to co-deliver hydrophobic SB431542 and nucleic acid drug CXCL12 siRNA. Due to the TGF-β signaling inhibition of SB431542, CP-SB-siRNA significantly suppressed the expression levels of genes coding the uppermost fibrosis-associated proteins including α-sma, Col-1 and Col-3 in aHSCs. On the other hand, the gene and protein expression level of metastasis-associated chemokine CXCL12 was significantly decreased. In addition, CP-SB-siRNA could regain the function of NK cells and attenuate the breast cancer proliferation through CXCL12-CXCR4 axis. On both breast cancer spontaneous metastasis with fibrosis mouse model and breast cancer via hematogenous metastasis with fibrosis mouse model, CP-SB-siRNA successfully reversed hepatic fibrosis by regressing aHSCs, and thereby restored the liver microenvironment, ultimately inhibiting breast cancer hepatic metastasis. This nanomaterial vector, featuring targeting and drug co-delivery functionalities, exhibited a great potential to restrain breast cancer hepatic metastasis based on the relationship among aHSCs, NK cells and DTCs.

4D printing combines the typical 3D printing with “smart materials”, allowing 3D printed materials to undergo a structural change over time. Since its original concept was first introduced in 2013, 4D printing became an innovative research that has received more attention from scientists in different fields. This review summarizes the progress achieved in 4D printing technologies and their associated materials. First, the technology and process of 4D printing are overviewed, and then the structure and properties of smart materials utilized in 4D printing are analyzed in depth, including metamaterials, shape memory materials, hydrogels, and self-healing polymers. We systematically illustrate the morphing mechanisms of the 4D printed smart materials, and then critically discuss the stimuli that can trigger transformation in the 4D printed smart materials, including heat, light, moisture, pH, electric current, and magnetic field. For 4D printed smart materials, all the changes programmed in the materials follow a mathematical model that allows scientists to predict and design the desired behaviors of the structures, using parameters such as the material distribution and the spatial gradients of the metric tensor. We finally conclude with the discussion of future challenges and opportunities for this ever-growing technology. Overall, 4D printing can create dynamic structures programmed to be responsive to external stimuli in the environment, widening its use in a myriad of applications such as rapid prototyping, electronics, biomedicine, soft robotics, self-assembly structures, smart sensors, and dynamic actuators.

In 2004, Yeh and Cantor introduced high-entropy alloys (HEAs), which maximize configurational entropy by utilizing nearly equal elemental molar ratios. These HEAs are valuable for exploring the central regions of phase diagrams. Building on this concept, Rost et al. proposed entropy-stabilized oxides in 2015, revealing that high-entropy oxides (HEOs) exhibit structural stability driven by entropy. This article provides a comprehensive overview of HEOs, with a specific focus on high-entropy oxide ceramics (HEOCs). The paper explores the origins of the high-entropy concept and the fundamental effects of high-entropy materials. It examines entropy from its basic definition and investigates microscopic atomic distribution, crystal-level distortions, and electronic structures. Additionally, the article introduces theoretical prediction methods applied to high-entropy materials. Furthermore, this review systematically summarizes HEOCs, encompassing three key aspects: crystal structure, preparation methods, and performance applications. Finally, the review concludes by proposing future research directions based on the current progress in HEOCs.

Mechanical metamaterials with energy-dissipating properties can provide impact mitigation in the field of engineering. However, current energy-dissipating metamaterials frequently face a tradeoff between energy-dissipation performance and load-bearing capability, severely limiting their practicality in high-intensity impact scenarios. Here, inspired by mushroom gills, we propose a mechanism for the snap-through buckling induced by geometric frustration, and we construct a snap-through metamaterial (STM) to address this problem. By analyzing the bifurcation buckling phenomenon, the STM is improved with higher energy-dissipation efficiency. Experiments demonstrate that the STM adaptively dissipates energy and mitigates impacts, achieving up to 33% reduction, in a reusable, self-recoverable, and rate-independent manner, leading to comprehensive performance. Employing a preloading strategy further enhances its impact mitigation capability as required. Notably, the STM exhibits a remarkable load-bearing capacity of up to 55 times higher than those of previous designs. The proposed design strategy of STMs paves the way for the development of interaction-based metamaterials, enabling applications in advanced dampers, mechanical waveguides, soft robotics, and low-frequency energy harvesters.

Nucleation underpins a vast range of phase-transition phenomena in many disciplines. Critical to revealing nucleation thermodynamics and kinetics is the understanding of the nucleus structure at its early stage. Typically, it is assumed that nucleation is a sudden local structural transition from one phase to another. Here, we are able to access fundamental steps in the nucleation from amorphous phase by a combination of molecular simulations and experimental observation. We discover a surprising pathway of semicrystalline nucleation where one of the materials components crystallizes and another remains amorphous between the crystalline planes in the nuclei. The early-stage crystallization nucleus is robustly evidenced to undergo a gradual ordering and densification, originating from the presence of diffuse interfaces, and renders an ultralow interfacial energy that is orders of magnitude lower than those typically used in various formulations of nucleation. Our study provides critical information and insight for the early stages of nucleation that determine how crystallization is initiated and benefits controllable synthesis of materials.