We report on the synthesis of high-quality microporous/mesoporous BN material via a facile two-step approach. An extremely high surface area of 1687 m(2) g(-1) and a large pore volume of 0.99 cm(3) g(-1) have been observed in the synthesized BN porous whiskers. The formation of the porous structure was attributed to the group elimination of organic species in a BN precursor, melamine diborate molecular crystal. This elimination method maintained the ordered pore structure and numerous structural defects. The features including high surface area, pore volume and structural defects make the BN whiskers highly suitable for hydrogen storage and wastewater treatment applications. We demonstrate excellent hydrogen uptake capacity of the BN whiskers with high weight adsorption up to 5.6% at room temperature and at the relatively low pressure of 3 MPa. Furthermore, the BN whiskers also exhibit excellent adsorption capacity of methyl orange and copper ions, with the maximum removal capacity of 298.3 and 373 mg g(-1) at 298 K, respectively.
We demonstrate strong iodine (I 2 ) vapor adsorption using Mg/Al layered double hydroxide (MgAl-LDH) nanocomposites intercalated with polysulfide (S x 2−) groups (S x -LDH, x = 2, 4, 6). The asprepared LDH/polysulfide hybrid materials display highly efficient iodine capture resulting from the reducing property of the intercalated polysulfides. During adsorption, the I 2 molecules are reduced to I 3 − anions by the intercalated [S x ] 2− groups that simultaneously are oxidized to form S 8 . In addition to the chemical adsorption, additional molecular I 2 is physically captured by the LDH composites. As a result of these parallel processes, and despite their very low BET surface areas, the iodine capture capacities of S 2 -LDH, S 4 -LDH, and S 6 -LDH are ∼1.32, 1.52, and 1.43 g/g, respectively, with a maximum adsorption of 152% (wt %). Thermogravimetric and differential thermal analysis (TG-DTA), energy dispersive X-ray spectroscopy (EDS), and temperature-variable powder X-ray diffraction (XRD) measurements show the resulting I 3 − ions that intercalated into the LDH gallery have high thermal stability (≥350 °C). The excellent iodine adsorption performance combined with the facile preparation points to the S x -LDH systems as potential superior materials for adsorption of radioactive iodine, a waste product of the nuclear power industry.
Anatase/rutile mixed-phase TiO2 nanoparticles were synthesized through a simple sol-gel route with further calcination using inexpensive titanium tetrachloride as a titanium source, which effectively reduces the production cost. The structural and optical properties of the prepared materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis adsorption. The specific surface area was also analyzed by Brunauer–Emmett–Teller (BET) method. The anatase/rutile mixed-phase TiO2 nanocomposites containing of rod-like, cuboid, and some irregularly shaped anatase nanoparticles (exposed {101} facets) with sizes ranging from tens to more than 100 nanometers, and rod-like rutile nanoparticles (exposed {110} facets) with sizes ranging from tens to more than 100 nanometers. The photocatalytic activities of the obtained anatase/rutile mixed-phase TiO2 nanoparticles were investigated and compared by evaluating the degradation of hazardous dye methylene blue (MB) under ultraviolet light illumination. Compared to the commercial Degussa P25-TiO2, the mixed-phase TiO2 nanocomposites show better photocatalytic activity, which can be attributed to the optimal anatase to rutile ratio and the specific exposed crystal surface on the surface. The anatase/rutile TiO2 nanocomposites obtained at pH 1.0 (pH1.0-TiO2) show the best photocatalytic activity, which can be attributed to the optimal heterojunction structure, the smaller average particle size, and the presence of a specific exposed crystal surface. The enhanced photocatalytic activity makes the prepared anatase/rutile TiO2 photocatalysts a potential candidate in the removal of the organic dyes from colored wastewater.
Electrocatalytic water splitting
is a promising technology for
large-scale hydrogen production. However, it requires efficient catalysts
to overcome the large overpotentials in the oxygen evolution reaction
(OER) and hydrogen evolution reaction (HER). Herein, we report a novel
heterostructure catalyst Co9S8/Cu2S on copper foam (Co9S8/Cu2S/CF)
with multistep impregnation and electrodeposition. Due to the strong
interfacial interaction, the interfacial electrons transfer from Co
sites to S sites, which promote the adsorption of oxygen-containing
intermediates, water molecules, as well as the dissociation of water
molecules. Therefore, the heterostructure catalyst exhibits low overpotentials
of 195 mV for OER and 165 mV for HER at 10 mA cm–2, respectively. Moreover, it only needs 1.6 V to realize water splitting
at 10 mA cm–2 in a two-electrode cell. This work
provides an efficient method to tailor the surface electronic structure
through specific morphological design and construct a heterostructure
interface to achieve alkaline water splitting.
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.