Hydrogen‐treated TiO2 nanotube (H–TNT) arrays serve as highly ordered nanostructured electrode supports, which are able to significantly improve the electrochemical performance and durability of fuel cells. The electrical conductivity of H–TNTs increases by approximately one order of magnitude in comparison to air‐treated TNTs. The increase in the number of oxygen vacancies and hydroxyl groups on the H–TNTs help to anchor a greater number of Pt atoms during Pt electrodeposition. The H–TNTs are pretreated by using a successive ion adsorption and reaction (SIAR) method that enhances the loading and dispersion of Pt catalysts when electrodeposited. In the SIAR method a Pd activator can be used to provide uniform nucleation sites for Pt and leads to increased Pt loading on the H‐TNTs. Furthermore, fabricated Pt nanoparticles with a diameter of 3.4 nm are located uniformly around the pretreated H–TNT support. The as‐prepared and highly ordered electrodes exhibit excellent stability during accelerated durability tests, particularly for the H–TNT‐loaded Pt catalysts that have been annealed in ultrahigh purity H2 for a second time. There is minimal decrease in the electrochemical surface area of the as‐prepared electrode after 1000 cycles compared to a 68 % decrease for the commercial JM 20 % Pt/C electrode after 800 cycles. X‐ray photoelectron spectroscopy shows that after the H–TNT‐loaded Pt catalysts are annealed in H2 for the second time, the strong metal–support interaction between the H–TNTs and the Pt catalysts enhances the electrochemical stability of the electrodes. Fuel‐cell testing shows that the power density reaches a maximum of 500 mW cm−2 when this highly ordered electrode is used as the anode. When used as the cathode in a fuel cell with extra‐low Pt loading, the new electrode generates a specific power density of 2.68 kW gPt−1. It is indicated that H–TNT arrays, which have highly ordered nanostructures, could be used as ordered electrode supports.
A series of novel titanium(IV) complexes bearing monoanionic [O-NX] (X = O, S, Se) ligands is
designed by sidearm approach. These complexes were synthesized, characterized, and employed as catalysts
in ethylene homo- and copolymerization. X-ray diffraction studies on these new compounds reveal a
distorted octahedral coordination of the central metal with the three chlorine ligands in a mer disposition.
In the presence of modified methylaluminoxane (MMAO), they exhibit moderate to high activity and
afford highly linear polyethylene. Variation of the sidearm, including different heteroatom and substituents,
proves to modulate both the catalytic activity and the molecular weight of the resulting polyethylene.
The complexes also show excellent capability in copolymerization of ethylene with 1-hexene.
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