Development of efficient catalysts with low cost for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) has been a long‐term pursuit because of their vital role in renewable‐energy technologies including fuel cells and water splitting. Herein, based on polymerizable ionic liquids (PILs) functionalized with nitrate groups as pore former and precursor of C and N, a facile one‐pot thermal treatment method was developed to construct a hybrid electrocatalyst consisting of earth‐abundant materials, which was made of Co‐based nanoparticles (NPs) grown on 2 D N‐doped and macroporous carbon nanosheets (pCNs) of approximately 20–50 nm thickness, that is, Co–N‐pCNs. The obtained Co–N‐pCNs catalyst manifests enhanced catalytic performance for both ORR and OER, even compared with the best‐known commercial catalysts, such as Pt/C and IrO2. The enhanced catalytic activity arises from the 2 D nanosheets and porous structures, well‐dispersed Co‐based NPs on the carbon sheets, the introduction of electron‐rich nitrogen, and the stability by the carbon protection of Co‐based NPs between the interlayers of nanosheets. Our present work supplies a novel opportunity for exploring 2 D non‐precious‐metal catalysts for ORR and OER.
Iron-coated TiO 2 nanotubes are successfully synthesized by treating hydrogen titanate nanotubes with Fe(OH) 3 sol. The products are characterized with transmission electron microscopy, atomic absorption spectrometer, X-ray diffraction, Raman spectroscopy, UV-visible absorption spectroscopy and nitrogen adsorption. The photocatalytic performance is evaluated by the photocatalytic degradation rates of methyl orange in aqueous solution under UV-vis light irradiation. The effects of the calcination temperature, concentration of Fe(OH) 3 sol and pH value of solution on the photocatalytic performance of iron-coated nanotubes are investigated. The results reveal that the iron-coated nanotubes exhibit better thermal stability and photocatalytic performance than their precursors. The iron-coated nanotubes can keep the nanotubular structure when calcined at 400 C, and the specific surface area does not decrease sharply. We also discover that the pH of the solution has an obvious influence on the photocatalytic activity of iron-coated nanotubes. When the pH is about 2.4, the maximum photodegradation rate appears; moreover, the recycled catalyst still shows good photodegradation activity.
Experimental MaterialsAll the reagents are analytical grade and used without any further purification.
Hydrogen titanate nanotubes obtained by hydrothermal synthesis are treated with sol containing titanium. The products are characterized with transmission electron microscopy, X-ray diffraction, thermal gravimetric analysis, and Raman spectroscopy. Their photocatalytic performance is evaluated by the photocatalytic degradation rates of methyl orange in aqueous solution under UV-vis light irradiation. The results reveal that the treated nanotubes are more thermally stable and exhibit better photocatalytic performance than primary nanotubes. The treated nanotubes can keep a tubular structure when calcined at 400 °C. However, their precursors collapse when they are calcined only at 300 °C. The more thermally stable new functional TiO 2 nanotubes can be prepared by using sol containing other elements instead of sol containing Ti in the future.
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