MOF Template-Derived Carbon Shell-Embedded CoP Hierarchical Nanosheet as Bifunctional Catalyst for Overall Water Splitting.

The design of earth-abundant and highly efficient bifunctional electrocatalysts for hydrogen evolution and oxygen evolution reactions (HER/OER) is crucial for hydrogen production through overall water splitting. Herein, we report a novel nanostructure consisting of vertically oriented CoP hierarchical nanosheet arrays with in situ-assembled carbon skeletons on a Ti foil electrode. The novel Zeolitic Imidazolate Framework-67 (ZIF-67) template-derived hierarchical nanosheet architecture effectively improved electrical conductivity, facilitated electrolyte transport, and increased the exposure of the active sites. The obtained bifunctional hybrid exhibited a low overpotential of 72 mV at 10 mA cm-2 and a small Tafel slope of 65 mV dec-1 for HER, and an improved overpotential of 329 mV and a Tafel slope of 107 mV dec-1 for OER. Furthermore, the assembled C@CoP||C@CoP electrolyzer showed excellent overall water splitting performance (1.63 V) at a current density of 10 mA cm-2 and superior durability. This work provides a structure engineering strategy for metal-organic framework (MOF) template-derived hybrids with outstanding electrocatalytic performance.

What differs on the enzymatic acetylation mechanisms for arylamines and arylhydrazines substrates? A theoretical study.

The acetylation mechanisms of several selected typical substrates from experiments, including arylamines and arylhydrazines, are investigated with the density functional theory in this paper. The results indicate that all the transition states are characterized by a four-membered ring structure, and hydralazine (HDZ) is the most potent substrate. The bioactivity for all the compounds is increased in a sequence of PABA ≈ 4-AS < 4-MA < 5-AS ≈ INH < HDZ. The conjunction effect and the delocalization of the lone pairs of N atom play a key role in the reaction. All the results are consistent with the experimental data.