Keratin, as a natural biopolymer, holds great promise for industrial applications. In this work, a series of renewable urea-polyol solvents were designed for keratin extraction from waste chicken feathers. Urea-ethylene glycol (U-EG) exhibited the highest solubility of 18.1 % (181 mg feather/g solvent) for feather keratin at 120 °C, with a significant enhancement to 29.4 % achieved by adding 5 wt% arginine (Arg). Structural analysis indicates that the extracted keratin mostly maintained its original primary structure. These solvents substantially disrupted the disulfide bonds, affecting the secondary structure by converting some α-helix to β-sheet and amorphous structures like random coils. Molecular dynamics simulations revealed that U-EG could act as molecular scissors, synergistically reinforced by Arg, by disrupting the intermolecular interactions of solvents. This disruption liberated more free solvent molecules to interact with keratin via van der Waals forces, Coulomb forces, and hydrogen bonding interactions. U-EG exhibited excellent recyclability, maintaining high solubility of 86 % after five cycles of reuse.
Iron and nitrogen co-doped carbon (Fe/N/C) electrocatalysts have great potential to catalyze the kinetically slow oxygen reduction reaction (ORR). Unfortunately, the ORR performance of existing Fe/N/C catalysts is seriously hindered by the insufficient density and accessibility of the atomic Fe-N x moieties. Herein, the carboxylate (OAc) molecular scissor is proposed to tailor Fe doped zeolitic-imidazolate-framework-8 (ZIF-8) at atomic scale and construct a multi-dimensional concave Fe@NC catalyst structure (Fe@MNC-OAc). This molecular scissoring strategy imparts Fe@MNC-OAc with dense accessible active sites, multidimensional mass transfer pathways, hierarchical porous structure, and entangled carbon nanotubes network. Therefore, the tailored Fe@MNC-OAc electrocatalyst exhibits excellent ORR activity in acidic media with a half-wave potential of 0.838 V, which is comparable to state-of-the-art non-precious metal catalysts. When assembled as cathode catalyst in a H 2 -O 2 proton exchange membrane fuel cell, it delivers a peak power density of 903 mW cm −2 . This work provides a new approach to tailoring the catalyst architecture and improving the accessibility of active sites.
危险品化学品经营许可证（带存储）