CeO2-modified α-MoO3 nanorods as a synergistic support for Pt nanoparticles with enhanced COads tolerance during methanol oxidation.

A new type of Ce-doped α-MoO3 (Ce0.2Mo0.8O3-δ) nanorod support was synthesized using a two-step hydrothermal method. The mixed oxide solid solution was employed as a novel non-carbon support for Pt catalysts used for the methanol electrooxidation in acidic media. The ratio of Ce to Mo in the solid-solution was systematically optimized in terms of the performance as a support for methanol oxidation. Pt nanoparticles with an average diameter of 2 nm were evenly deposited on Ce0.2Mo0.8O3-δ nanorods. Compared to the Pt/MoO3 and commercial Pt/C catalysts, the optimal Pt/Ce0.2Mo0.8O3-δ catalyst exhibited significantly enhanced COads tolerance during the methanol oxidation, thereby yielding the highest electrocatalytic activity and stability. The improved electrochemical performance can be ascribed to strengthened metal-support interactions derived from the high number of oxygen vacancies on Ce0.2Mo0.8O3-δ along with its unique one-dimensional nanorod structure. In addition, these findings suggest that the doping-induced structural and size transition of MoO3 could provide a new pathway to develop doped oxides capable of providing sufficient electrical conductivity and possible synergistic effects with other active components for electrocatalysis applications.

Advanced Mesoporous Spinel Li4Ti5O12/rGO Composites with Increased Surface Lithium Storage Capability for High-Power Lithium-Ion Batteries.

Spinel Li4Ti5O12 (LTO) and reduced graphene oxide (rGO) are attractive anode materials for lithium-ion batteries (LIBs) because of their unique electrochemical properties. Herein, we report a facile one-step hydrothermal method in preparation of a nanocomposite anode consisting of well-dispersed mesoporous LTO particles onto rGO. An important reaction step involves glucose as a novel linker agent and reducing agent during the synthesis. It was found to prevent the aggregation of LTO particles, and to yield mesoporous structures in nanocomposites. Moreover, GO is reduced to rGO by the hydroxyl groups on glucose during the hydrothermal process. When compared to previously reported LTO/graphene electrodes, the newly prepared LTO/rGO nanocomposite has mesoporous characteristics and provides additional surface lithium storage capability, superior to traditional LTO-based materials for LIBs. These unique properties lead to markedly improved electrochemical performance. In particular, the nanocomposite anode delivers an ultrahigh reversible capacity of 193 mA h g(-1) at 0.5 C and superior rate performance capable of retaining a capacity of 168 mA h g(-1) at 30 C between 1.0 and 2.5 V. Therefore, the newly prepared mesoporous LTO/rGO nanocomposite with increased surface lithium storage capability will provide a new opportunity to develop high-power anode materials for LIBs.