The growth of mesoporous quasi‐single‐crystalline Co3O4 nanobelts by topotactic chemical transformation from α‐Co(OH)2 nanobelts is realized. During the topotactic transformation process, the primary α‐Co(OH)2 nanobelt frameworks can be preserved. The phases, crystal structures, morphologies, and growth behavior of both the precursory and resultant products are characterized by powder X‐ray diffraction (XRD), electron microscopy—scanning electron (SEM) and transmission electron (TEM) microscopy, and selected area electron diffraction (SAED). Detailed investigation of the formation mechanism of the porous Co3O4 nanobelts indicates topotactic nucleation and oriented growth of textured spinel Co3O4 nanowalls (nanoparticles) inside the nanobelts. Co3O4 nanocrystals prefer [0001] epitaxial growth direction of hexagonal α‐Co(OH)2 nanobelts due to the structural matching of [0001] α‐Co(OH)2//[111] Co3O4. The surface‐areas and pore sizes of the spinel Co3O4 products can be tuned through heat treatment of α‐Co(OH)2 precursors at different temperatures. The galvanostatic cycling measurement of the Co3O4 products indicates that their charge–discharge performance can be optimized. In the voltage range of 0.0–3.0 V versus Li+/Li at 40 mA g−1, reversible capacities of a sample consisting of mesoporous quasi‐single‐crystalline Co3O4 nanobelts can reach up to 1400 mA h g−1, much larger than the theoretical capacity of bulk Co3O4 (892 mA h g−1).
Chinese patients with chronic heart failure have poor self-care behaviors. Factors associated with self-care behaviors are confidence, functional capacity, knowledge, health literacy and social support. Self-care confidence appears to be a mediator between knowledge, health literacy, social support and self-care behaviors. Targeted interventions are required to optimize self-care behaviors in patients with chronic heart failure.
Electric
double layer capacitors (EDLCs) usually show high rate
performance and long cycling spans but inferior specific capacitance,
which are mainly created by restriction of the charge storage mechanism.
To improve the capacitive performance, traditional methods include
enlarging surface area, optimizing porous structures, and readjusting
functional groups through heteroatom doping to electrode materials.
Besides that, another promising approach is suggested, which is to
enhance surface roughness of the electrode materials for ion storage
and transport. To prove this view, two porous carbon materials were
fabricated by activation–calcination methods, which allowed
the materials to have identical surface area, porous structures, and
surface composition but the surface roughness. Further electrochemical
measurements exhibited that the optimal sample with higher roughness
has remarkable specific capacitance (up to 562 F g–1), and the increment rate is more than 50% when compared with contrast
sample (367 F g–1). Therefore, optimization of the
surface roughness of electrode materials is another efficient route
to make robust EDLCs.
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