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1. Is surface modification effective to stabilize high-voltage cycling for layered P2-Na _2/3 Ni _1/3 Mn _2/3 O ₂ cathodes?

   https://doi.org/10.1039/D4CC02819H  

   Niu, Fangzhou; Qiao, Linna; Huang, Heran; Odero, Elninoh A; Zhou, Guangwen; Liu, Hao (October 2024, Chemical Communications)

   Surface coating of Na_2/3Ni_1/2Mn_2/3O₂particles suppresses high-voltage polarization but not capacity fade, which is dominated by bulk structure degradation. 

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2. Atomic doping to enhance the p-type behavior of BiFeO ₃ photoelectrodes for solar H ₂ O ₂ production

   https://doi.org/10.1039/d4ta03191a  

   Seo, Daye; Grieder, Andrew; Radmilovic, Andjela; Alamudun, Sophya F; Yuan, Xin; Ping, Yuan; Choi, Kyoung-Shin (August 2024, Journal of Materials Chemistry A)

   Na-doped BiFeO₃demonstrates an enhanced p-type behavior compared to p-type BiFeO₃prepared without extrinsic dopants, and Na-doped BiFeO₃can serve as a photocathode for solar O₂reduction to H₂O₂when coupled with Ag nanoparticle catalysts. 

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3. Crystal structure of [Ni(OH ₂ ) ₆ ]Cl ₂ ·(18-crown-6) ₂ ·2H ₂ O

   https://doi.org/10.1107/S2056989024010041  

   Brannon, Jacob P; Liang, Kevin; Stieber, S_Chantal E (November 2024, Acta Crystallographica Section E Crystallographic Communications)

   The crystal structure of the title compound, hexaaquanickel(II) dichloride–1,4,7,10,13,16-hexaoxacyclooctadecane–water (1/2/2), [Ni(H₂O)₆]Cl₂·2C₁₂H₂₄O₆·2H₂O, is reported. The asymmetric unit contains half of the Ni(OH₂)₆moiety with a formula of C₁₂H₃₂ClNi_0.50O₁₀at 105 K and triclinic (P1) symmetry. The [Ni(OH₂)₆]²⁺cation has close to ideal octahedral geometry with O—Ni—O bond angles that are within 3° of idealized values. The supramolecular structure includes hydrogen bonding between the water ligands, 18-crown-6 molecules, Cl⁻anions, and co-crystallized water solvent. Two crown ether molecules flank the [Ni(OH₂)₆]²⁺molecule at the axial positions in a sandwich-like structure. The relatively symmetric hydrogen-bonding network is enabled by small Cl⁻counter-ions and likely influences the more idealized octahedral geometry of [Ni(OH₂)₆]²⁺. 

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4. Ruddlesden–Popper Structured Sr ₃ Fe ₂ O _7−δ as Redox‐Activated CO ₂ Sorbents for Green Hydrogen Production

   https://doi.org/10.1002/aesr.202500213  

   Rukh, Mahe; Cai, Runxia; Razavi, Seyedamin; Portillo, Sam; Yao, Yuge; Neal, Luke; Li, Fanxing (January 2026, Advanced Energy and Sustainability Research)

   Conventional methods for hydrogen production, such as steam methane reforming, face increasing scrutiny due to their reliance on fossil fuels, high CO₂emissions, and significant capital costs. Sorption‐enhanced steam reforming using renewable feedstocks, where CO₂is captured in situ, presents a more sustainable alternative. This study investigates the suitability of A‐ and B‐site doped strontium ferrite‐type Ruddlesden–Popper oxides (RPO) as robust CO₂sorbents, with particular attention on their application in glycerol‐based hydrogen production. Packed bed reactor experiments, complemented by comprehensive characterizations, are systematically conducted to assess and compare the performance of RPO with a stoichiometry of (Sr_xCa_1−x)₂Fe_0.9Ni_0.1O_4−δ(RPOs) with that of traditional perovskite oxides, that is, Sr_xCa_1−xFe_0.9Ni_0.1O_4−δ(POs), and to unravel the underlying phase transition pathways. Specifically, RPO with a nominal stoichiometry of Sr_1.4Ca_0.6Fe_0.9Ni_0.1O_4−δforms an Sr₃Fe₂O_7‐type active phase, exhibiting high H₂purities (≈95 vol%) coupled with stable CO₂sorption capacity. Notably, its CO₂prebreakthrough time is more than six times longer than that of its perovskite counterpart in the sequential Ni‐bed configuration. Finally, the interplay between the reduction and carbonation reactions is examined, highlighting the synergistic benefits that enable the sorbent to fully realize its CO₂uptake potential. 

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5. Intrinsic exchange bias from interfacial reconstruction in an epitaxial Ni _x Co _y Fe _{3− x −y} O ₄ (111)/ $\alpha$ -Al ₂ O ₃ (0001) thin film family

   https://doi.org/10.1088/1361-648X/ad789d  

   Yang, Detian; Liu, Yaohua; Xu, Xiaoshan (September 2024, Journal of Physics: Condensed Matter)

   Abstract Intrinsic exchange bias is known as the unidirectional exchange anisotropy that emerges in a nominally single-component ferro-(ferri-)magnetic system. In this work, with magnetic and structural characterizations, we demonstrate that intrinsic exchange bias is a general phenomenon in (Ni, Co, Fe)-based spinel oxide films deposited on $\alpha$-Al₂O₃(0001) substrates, due to the emergence of a rock-salt interfacial layer consisting of antiferromagnetic CoO from interfacial reconstruction. We show that in Ni_xCo_yFe_3−x−yO₄(111)/ $\alpha$-Al₂O₃(0001) films, intrinsic exchange bias and interfacial reconstruction have consistent dependences on Co concentrationy, while the Ni and Fe concentration appears to be less important. This work establishes a family of intrinsic exchange bias materials with great tunability by stoichiometry and highlights the strategy of interface engineering in controlling material functionalities. 

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