The Reactive Sites of Methane Activation: A Comparison of IrC with PtC.

The activation reactions of methane mediated by metal carbide ions C ( = Ir and Pt) were comparatively studied at room temperature using the techniques of mass spectrometry in conjunction with theoretical calculations. C ( = Ir and Pt) ions reacted with CH at room temperature forming CH/CH and CH/H as the major products for both systems. Besides that, PtC could abstract a hydrogen atom from CH to generate PtCH/CH, while IrC could not.

C/C Exchange in Activation/Coupling Reaction of Acetylene and Methane Mediated by Os: A Comparison with Ir, Pt, and Au.

The activation and coupling reactions of methane and acetylene mediated by M (M = Os, Ir, Pt, and Au) have been comparatively studied at room temperature by the techniques of mass spectrometry in conjunction with theoretical calculations. Studies have shown that Os and Ir can mediate the activation/coupling reaction of CH and CH, while Pt and Au cannot, which could be explained by the number of empty valence orbitals in the metal atom. In addition, there are different competition channels for the reaction mediated by Os and Ir: an expected dehydrogenation and an unexpected C/C exchange.

Reactions of Transition-Metal Carbyne Cations with Ethylene in the Gas Phase.

The reactions of iridium- and osmium-carbyne hydride cations [HIrCH] and [HOsCH] with ethylene have been studied using mass spectrometry with isotopic-labeling in the gas phase. The carbyne reactivity is compared with that of the rhodium, cobalt, and iron analogues [TMCH] (TM = Fe, Co, and Rh), which were determined to have the carbene structures. Besides the cycloaddition/dehydrogenation reaction in forming the [TMCH] + H (TM = Ir and Os) products, a second reaction pathway producing the [TMCH] ion and CH via triple hydrogen atom transfer reactions to the carbyne carbon is observed to be the major channel.

Surface construction of loose Co(OH) shell derived from ZIF-67 nanocube for efficient oxygen evolution.

The rational design of nanostructure is very important for improving the number and effective utilization of active sites of the electrocatalysts. Here, a core-shell nanostructure composed of ZIF-67 core and Co(OH) shell (ZIF-67@Co(OH)) has been obtained by subjecting ZIF-67 nanocube to the optimal high temperature etching process. After refluxing and etching in ethanol/water mixed solution, the loose Co(OH) shell can be constructed based on the surface of etched ZIF nanocube, which provides the obviously abundant active cobalt sites and better contact for oxygen evolution reaction (OER).