Amorphous Ni−Fe hydroxides (NiFe(OH) x ) are considered to possess promising potential as oxygen evolution reaction (OER) electrocatalysts, but amorphous NiFe(OH) x is hard to synthesize due to the complicated multistep synthesis process. Herein, amorphous NiFe(OH) x is successfully grown in situ on the surface of NiFe 2 O 4 via an ultrasonic-assisted reduction method. This method takes advantage of ultrasonic cavitation to achieve a unique reduction effect, migration of Ni and Fe cations of NiFe 2 O 4 to the crystal surface, and in situ growth of amorphous NiFe(OH) x , thereby forming a NiFe 2 O 4 /NiFe(OH) x composite. This material exhibits enhanced electrochemical performance with an overpotential of 276 mV at 10 mA cm −2 . The ultrasonic-assisted reduction method can be used to synthesize amorphous NiFe-(OH) x with no residual reactants, providing a simple and facile way to synthesize amorphous hydroxide materials.
For Chinese patients with the PBC-AIH overlap syndrome, the simplified criteria appear to be the most efficacious compared with the Paris criteria and the revised criteria. Further studies should be performed to confirm these observations with respect to long-term outcomes and therapeutic implications.
Amorphous TiO2 nanotubes with diameters of 8-10 nm and length of several nanometers were synthesized by high pressure treatment of anatase TiO2 nanotubes. The structural phase transitions of anatase TiO2 nanotubes were investigated by using in-situ high-pressure synchrotron X-ray diffraction (XRD) method. The starting anatase structure is stable up to ∼20GPa, and transforms into a high-density amorphous (HDA) form at higher pressure. Pressure-modified high- to low-density transition was observed in the amorphous form upon decompression. The pressure-induced amorphization and polyamorphism are in good agreement with the previous results in ultrafine TiO2 nanoparticles and nanoribbons. The relationship between the LDA form and α-PbO2 phase was revealed by high-resolution transmission electron microscopy (HRTEM) study. In addition, the bulk modulus (B0 = 158 GPa) of the anatase TiO2 nanotubes is smaller than those of the corresponding bulks and nanoparticles (180-240 GPa). We suggest that the unique open-ended nanotube morphology and nanosize play important roles in the high pressure phase transition of TiO2 nanotubes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.