Synthesis of Carbon Nanoparticles with Cobalt-Rich Shell via Pyrolysis of Zn-ZIF@Co/Zn-ZIF: Relevance of Co(III) Precursors.

To the best of our knowledge, this is the first report on the rapid one-pot synthesis of a unique core-shell-structured zeolitic imidazolate framework (ZIF) using Co(III) and Zn(II) precursors. The key to obtaining this unique structure is the use of a Co(III) precursor as the starting material. Transmission electron microscopy (TEM) reveals that Co was present within a 30-nm-thick shell layer of the ZIF material. Thermal decomposition of the ZIF material affords core-shell-structured carbon nanoparticles that have Co on the external surface of the carbon grain. We have previously demonstrated that this carbonaceous material obtained by thermal decomposition exhibited high performance as an adsorbent for nitric oxide, even in the presence of excess oxygen and water vapor, and therefore, it was a suitable material for NOx elimination at low temperatures. The growth mechanism of the synthesized ZIF particles and the differences between synthesized ZIF and conventional Co(II)-ZIF-67 are discussed. The reactivity of the Co(III) precursor is much lower than that of the Co(II) species, leading to slower precipitation of Co(III) than that of Zn(II), thus forming the core-shell structure.

High NH3-SCR reaction rate with low dependence on O2 partial pressure over Al-rich Cu-*BEA zeolite.

Dependence of NH3-SCR reaction rate on O2 partial pressure was investigated at 473 K over Cu ion-exchanged MOR, MFI, CHA and *BEA zeolites with varying "Cu density in micropores". Among the zeolites, Cu-*BEA zeolite demonstrated promising potential as an effective catalyst for NH3-SCR over a wide range of O2 partial pressure.

A modular synthesis approach to multinuclear heterometallic oxo clusters in polyoxometalates.

We report a "modular synthesis approach" to multinuclear heterometallic oxo clusters in lacunary polyoxometalates (POMs). This approach allowed the synthesis of a POM containing a nonanuclear {CrMn4}Lu2Ag2 cluster with the widest variety of metals among the discrete metal oxo clusters prepared to date.