Electrocatalytic nitrate reduction (NO₃RR) is a promising route for sustainable ammonia synthesis under mild conditions. The widely studied Co-based catalysts undergo significant reconstruction due to nitrate oxidation and electric-field reduction during NO₃RR, leading to activity degradation. To address this issue, we develop a Co₆Ni₄ heterostructured catalyst that consists of interlaced metallic Co and Ni domains. Operando X-ray absorption spectroscopy and other in-situ characterization techniques, in conjunction with theoretical calculations, demonstrate that Ni domains function as electron reservoir, which transfer electrons to Co and prevent the accumulation of high-valence Co. Besides, the abundant Co/Ni interfaces also facilitate the NO₃RR process, thereby achieving a NH₃ Faraday efficiency of 99.21%, a NH₃ yield rate of 93.55 mg h^-1 cm^-2, and a NO₃RR stability of 120 h. Our analyses delve into the underlying causes of the observed stability of metallic Co in Co₆Ni₄ and provide compelling evidence that the discrepancy between the adsorption quantity of NO₃^- on catalyst surface and the corresponding electron supply is a pivotal factor influencing the reconstruction process.

Efficient and durable electrocatalysts for the oxygen evolution reaction (OER) are essential for advancing water splitting technologies, which enable sustainable hydrogen production. The integration of amorphous oxide supports with metal single atoms offers a promising strategy to precisely tuning the electronic structure and improving the exposure of active sites. Here, we report an amorphous NiMoO_x support anchored with Ru single atoms (denoted as a-RNMO), which achieves a low cell voltage of 1.78 V at 1 A cm⁻² and noteworthy durability in an anion exchange membrane water electrolyzer. Time-resolved operando Quick X-ray absorption spectroscopy reveals rapid Mo leaching followed by structural reconstruction, culminating in the NiOOH formation. Theoretical calculations suggest a likely “complementary amorphous-electronic” mechanism. It shows that the amorphous structure exposes more active sites and favors the adsorption of intermediates, while Ru single atoms finely modulate the electronic structure. These valuable insights highlight the design of high-performance OER electrocatalysts based on metal single atoms anchored on amorphous oxides.

This work has considered the intrinsic influence of bond energy on the macroscopic, thermodynamic, and mechanical properties of crystalline materials. A general criterion is proposed to evaluate the properties of nanocrystalline materials. The interrelation between the thermodynamic and mechanical properties of nanomaterials is presented and the relationship between the variation of these properties and the size of the nanomaterials is explained. The results of our work agree well with thermodynamics, molecular dynamics simulations, and experimental results. This method is of significance in investigating the size effects of nanomaterials and provides a new approach for studying their thermodynamic and mechanical properties.

A novel two-dimensional (2D) carbon material composed of decagonal pores, and hexagonal and quadrilateral carbon rings (DHQ-graphene) is predicted by first-principles calculations. The results show that this metastable phase material displays anisotropic mechanical properties, and its in-plane Young's modulus is comparable with that of penta-graphene. DHQ-graphene is a metallic carbon material with a much higher electronic density of states of around 0.193 eV per states per atom. Equally importantly, it is also found that the most favorable adsorption site is the bridge site in the edge shared by the six- and ten-membered rings of DHQ-graphene, which has a stronger adsorption energy for oxygen (−0.27 eV) with dispersion correction (DFT-D3). The charge transfer from a DHQ-graphene sheet to an O atom amounts to 0.834|e|, 3.35% higher than that of perfect graphene. This implies that DHQ-graphene should have a good ability to adsorb oxygen with an easily controlled adsorption structure. Interestingly, it may conceivably be synthesized by a bottom-up approach from the carbon skeleton of naphthalene (C₁₀H₈). In addition, a 3D stacked structure of this material has also been investigated. This work provides a novel strategy for constructing a corrosion-resistant material by designing a 2D structure based on high-order carbon rings.

A thermal evaporation–trapping strategy is developed to fabricate a flexible N-doped carbon fiber cloth loaded with both CoFe-oxide nanoparticles and atomic Co/Fe–N_x sites, showing outstanding oxygen electrocatalytic performance.