RESUMEN
The electrostatically derived self-assembly of cationic Zn-Cr-layered double hydroxide (LDH) nanosheets and cationic CdS quantum dots (QDs) with anionic linkers leads to the formation of strongly coupled Zn-Cr-LDH-CdS nanohybrids. The hybridization with Zn-Cr-LDH leads to significant enhancement of the photocatalytic activity of CdS for visible-light-induced H2 generation, a property that is attributed to the depression of electron-hole recombination. In comparison with a direct hybridization method between oppositely charged species, this linker-mediated method provides greater flexibility in controlling the chemical composition and electronic coupling of the nanohybrids. The present hybridization strategy provides a useful method not only to couple two kinds of isocharged nanostructured materials, but also to explore efficient hybrid-type photocatalysts.
RESUMEN
The effect of cobalt doping into a manganese oxide (tetragonal spinel Mn3O4) nanoparticle cocatalyst up to Co/(Co + Mn) = 0.4 (mol/mol) on the activity of photocatalytic water oxidation was studied. Monodisperse â¼10 nm CoyMn1-yO (0 ≤y≤ 0.4) nanoparticles were uniformly loaded onto photocatalysts and converted to CoxMn3-xO4 nanoparticles through calcination. 40 mol% cobalt-doped Mn3O4 nanoparticle-loaded Rh@Cr2O3/SrTiO3 photocatalyst exhibited 1.8 times-higher overall water splitting activity than that with pure Mn3O4 nanoparticles. Investigation on the band structure and electrocatalytic water oxidation activity of CoxMn3-xO4 nanoparticles revealed that the Co doping mainly contributes to the improvement of water oxidation kinetics on the surface of the cocatalyst nanoparticles.
RESUMEN
Poly(triazine imide) was synthesized with incorporation of Li(+) and Cl(-) ions (PTI/Li(+)Cl(-)) to form a carbon nitride derivative. The synthesis of this material by the temperature-induced condensation of dicyandiamide was examined both in a eutectic mixture of LiCl-KCl and without KCl. On the basis of X-ray diffraction measurements of the synthesized materials, we suggest that a stoichiometric amount of LiCl is necessary to obtain the PTI/Li(+)Cl(-) phase without requiring the presence of KCl at 873 K. PTI/Li(+)Cl(-) with modification by either Pt or CoO(x) as cocatalyst photocatalytically produced H(2) or O(2), respectively, from water. The production of H(2) or O(2) from water indicates that the valence and conduction bands of PTI/Li(+)Cl(-) were properly located to achieve overall water splitting. The treatment of PTI/Li(+)Cl(-) with [Pt(NH(3))(4)](2+) cations enabled the deposition of Pt through ion exchange, demonstrating photocatalytic activity for H(2) evolution, while treatment with [PtCl(6)](2-) anions resulted in no Pt deposition. This was most likely because of the preferential exchange between Li(+) ions and [Pt(NH(3))(4)](2+) cations.