@article{23004,
  abstract     = {Lattice strain engineering can regulate the electronic structure of electrocatalysts, but stabilizing distorted metastable phases remains challenging. Here, we report an N,N-dimethylformamide-assisted strategy for synthesizing metastable hexagonal close-packed (HCP) Ni nanoparticles with local lattice-spacing deviations reaching approximately 5.2%. Structural and spectroscopic analyses support a dilute interstitial-carbon-stabilized HCP Ni framework dominated by expanded metallic Ni─Ni coordination rather than ordered Ni3C. Carbon-associated perturbations inhibit structural relaxation and retain the distorted HCP framework. Operando x-ray absorption and infrared spectroscopies indicate the formation of a NiOOH-like working surface coupled to an HCP-derived subsurface framework, accompanied by potential-dependent changes in the interfacial hydrogen-bonding environment and urea-derived species. Calculations using idealized metallic models show that HCP lattice strain induces a Ni d-band upshift, anisotropic Ni─Ni bonding, and localized charge redistribution, modifying adsorption-energy trends for the urea oxidation reaction. The optimized HCP-Ni delivers an apparent steady-state Tafel slope of 26.95 mV dec−1, over twice the electrochemically active surface area-normalized activity of the face-centered cubic-containing controls, and approximately 98% apparent urea conversion after 22 h. It sustains current for over 120 h in three-electrode testing and enables over 400 h of urea-assisted zinc–air battery cycling. This work demonstrates dilute interstitial-carbon stabilization as a route to strained metastable electrocatalysts.},
  author       = {Xue, Qian and Yu, Jing and Dai, Juguo and Yang, Linlin and Bi, Xiaoyu and Ren, Yuchuan and Zhang, Jia and Qi, Xuede and Wang, Yudi and Xu, Ying and Arbiol, Jordi and He, Ren and Qi, Xueqiang and Cabot, Andreu},
  issn         = {1521-3773},
  journal      = {Angewandte Chemie International Edition},
  keywords     = {electrocatalysis, HCP nickel, interstitial carbon, kinetic trapping, lattice strain engineering, urea oxidation reaction},
  publisher    = {Wiley},
  title        = {{Dilute interstitial carbon stabilization of highly strained metastable HCP Nickel for enhanced electrocatalysis}},
  doi          = {10.1002/anie.2874510},
  year         = {2026},
}

@article{382,
  abstract     = {Mn3O4@CoMn2O4 nanoparticles (NPs) were produced at low temperature and ambient atmosphere using a one-pot two-step synthesis protocol involving the cation exchange of Mn by Co in preformed Mn3O4 NPs. Selecting the proper cobalt precursor, the nucleation of CoxOy crystallites at the Mn3O4@CoMn2O4 surface could be simultaneously promoted to form Mn3O4@CoMn2O4–CoxOy NPs. Such heterostructured NPs were investigated for oxygen reduction and evolution reactions (ORR, OER) in alkaline solution. Mn3O4@CoMn2O4–CoxOy NPs with [Co]/[Mn] = 1 showed low overpotentials of 0.31 V at −3 mA·cm–2 and a small Tafel slope of 52 mV·dec–1 for ORR, and overpotentials of 0.31 V at 10 mA·cm–2 and a Tafel slope of 81 mV·dec–1 for OER, thus outperforming commercial Pt-, IrO2-based and previously reported transition metal oxides. This cation-exchange-based synthesis protocol opens up a new approach to design novel heterostructured NPs as efficient nonprecious metal bifunctional oxygen catalysts.},
  author       = {Luo, Zhishan and Irtem, Erdem and Ibanez, Maria and Nafria, Raquel and Márti Sánchez, Sara and Genç, Aziz and De La Mata, Maria and Liu, Yu and Cadavid, Doris and Llorca, Jordi and Arbiol, Jordi and Andreu, Teresa and Morante, Joan and Cabot, Andreu},
  issn         = {1944-8252},
  journal      = {Applied Materials and Interfaces},
  keywords     = {nanoparticle, ORR, OER, manganese oxide, cobalt oxide, colloidal, electrocatalysis, cation exchange},
  number       = {27},
  pages        = {17435 -- 17444},
  publisher    = {American Chemical Society},
  title        = {{Mn3O4@CoMn2O4–CoxOy nanoparticles: Partial cation exchange synthesis and electrocatalytic properties toward the oxygen reduction and evolution reactions}},
  doi          = {10.1021/acsami.6b02786},
  volume       = {8},
  year         = {2016},
}