Hydrogen energy is critical for achieving carbon neutrality. Heterostructured materials with single metal-atom dispersion are desirable for hydrogen production. However, it remains a great challenge to achieve large-scale fabrication of single atom-anchored heterostructured catalysts with high stability, low cost, and convenience. Here, we report single iron (Fe) atom-dispersed heterostructured Mo-based nanosheets developed from a mineral hydrogel. These rationally designed nanosheets exhibit excellent hydrogen evolution reaction (HER) activity and reliability in alkaline condition, manifesting an overpotential of 38.5 mV at 10 mA cm−2, and superior stability without performance deterioration over 600 h at current density up to 200 mA cm−2, superior to most previously reported non-noble-metal electrocatalysts. The experimental and density functional theory results reveal that the O-coordinated single Fe atom-dispersed heterostructures greatly facilitated H2O adsorption and enabled effective adsorbed hydrogen (H*) adsorption/desorption. The green, scalable production of single-atom-dispersed heterostructured HER electrocatalysts reported here is of great significance in promoting their large-scale implementation.
Full‐color reflective filters for large area applications with potentially unprecedented color saturation and excellent mechanical properties deposited by one‐step magnetron sputtering are proposed. Conventional reflective color filters with multiple layers of dielectric films cannot simultaneously produce a large area and good mechanical properties due to the complex multiple depositions and the difference in the thermal expansion coefficients among the material layers. Herein, full‐spectrum colors are generated by novel Mg‐based reflective color filters in a large area of 2 cm × 2 cm with a high hardness of 9.12 GPa, where the filters include an absorber layer with controllable optical constants and a reflective layer with an amorphous structure. The saturation and hue of the produced colors can be controlled by tuning the optical constants and the thickness of the absorber layer. Additionally, the hardness of the Mg‐based reflective color filters is increased by the reflective metallic glass layers because they are derived from the same material as the absorber layer. This paradigm can pave the way for the efficient fabrication of large area color filtering devices for diverse applications, such as surface decorations, optical components, color display devices, structural color printing, and photovoltaic cells with optimum efficiency.
Architected materials can exhibit mechanical properties that do not occur with ordinary solids. By integrating hierarchy and size effects, microarchitected metamaterials fabricated by two-photon lithography with a metallic or ceramic coating can be ultrastrong but lightweight. However, the attainment of both strength and ductility is generally mutually exclusive. Inspired by the Pantheon dome in Rome, which can withstand high load while keeping low density, microarchitected domes with a gradient helix are designed and deposited in a hierarchical nanostructured aluminum film with ultrahigh strength and considerable plasticity. Despite having a thick coating, which usually causes catastrophic collapse, the thick-walled metallic dome shows recoverability during compression. The compressive strength increases to 73 times that of current ductile-like microlattices, leading to the metamaterial occupying the domain of the material property space that is hitherto empty. Detailed in situ experimental and computational work reveals the graceful (noncatastrophic) failure due to the helical twisting and plastic flow in the supra-nanomaterial. It is a promising method of suppressing brittle failure via a combination of architectural and material design. It can be used to impart enhanced functionality, making programmable stiffness, and tailored energy absorption all possible.
Design of efficient and robust electrocatalysts for hydrogen evolution reaction (HER) under all pH conditions has attracted significant attention. In particular, it is still a considerable challenge since the HER kinetics of Pt in alkaline solutions is about two to three orders of magnitude lower than that in acidic conditions. Herein, a heterogeneous yolk–shell nanostructure with Rh nanoparticles embedded in S, N co‐doped carbon nanospheres prepared by a facile self‐template method is reported. The optimized electrocatalyst can achieve an extremely small overpotential of 13.5 mV at 10 mA cm‐2, low Tafel slope of 25.5 mV dec‐1, high turnover frequency of 0.143 s‐1 (at −75 mV vs. reversible hydrogen electrode), and long‐term durability for 10 h, which is the record‐high alkaline HER activity among the ever‐reported noble metal based catalysts. These striking performances are ascribed to the optimized electronic structure and unique heterogeneous yolk–shell nanostructure. More importantly, it is also demonstrated that the obtained electrocatalyst exhibits superior activities in all pH range, which is better than commercial Pt/C and Rh/C catalysts. This work proves that Rh‐based nanomaterials are promising superior electrocatalysts in a wide pH range and nanostructure design is a powerful tool to increase the mass/electron transfer during reaction.
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