No abstract

Isolated dual transition metal atoms (Ni and Fe) were uniformly embedded into graphitic carbon nitrideviaa metal–Nxbond, resulting in highly efficient catalytic activity due to the electronic structure reconfiguration.

The search for new electrode materials is of paramount importance for the practical apply of lithium-ion batteries (LIBs). Herein, flower-like MoO2 microislands consist of MoO2 nanorods grown on both sides of graphene sheets were synthesized via a solvo-thermal method, followed by a simple thermal treatment in argon. Our EXAFS and ESR data suggest there oxygen-vacancies in MoO2 of the FMMGS hybrids. Besides, by tunning the ratio of glucose and CTAB, samples with different oxygen-vacancies content were synthesized. When used as anode materials for lithium-ion batteries, the oxygen-vacancy-rich FMMGS hybrids exhibited obviously higher capacity, rate capability than any nonvacancy samples. Importantly, synchrotron-radiation-based X-ray absorption near-edge structure (XANES), extended X-ray absorption fine-structure (EXAFS) and ex situ X-ray diffraction (ex situ XRD) were employed to elucidate the Li-ion insertion and extraction processes in the MoO2 electrode. Our data clearly revealed that Li2MoO4 was generated during the Li uptake/removal process, which can be attributed to the existence of abundant oxygen vacancies in MoO2 microislands. This provides us a useful insight for better understanding of dynamic cycling behavior in various Mo-based electrodes.