Functional organic molecules/metal-organic frameworks composites can be obtained by in situ crystalline structure transformation from ZIF-L to ZIF-8-L under double solvent conditions. Interestingly, the as-prepared molecules/ZIF-8-L composites with the leaf-like morphology exhibit good fluorescence properties and size selectivity in fluorescent quenchers due to the molecular sieving effect of the well-defined microporous ZIF-8-L.
Thermal treatment of metal-organic frameworks (MOFs) as a post-treatment approach has grown in popularity and resulted in various MOF-derived materials. However, the widely used extreme thermolytic conditions (usually above 500 °C) lead to degradation in the well-defined MOFs intrinsic properties. This work demonstrates that MIL-101 calcined at medium-temperature range (200-280 °C) partially breaks the coordination bonds that can introduce more accessible active sites, exhibiting a 10-fold increase in oxidation activity while retaining its intrinsic structure and porosity. Another fascinating feature of MIL-101 calcined in this temperature range is their temperature-dependent shrinkage behavior, which is also found in many other types of MOFs. Based on different shrinkage ratios of various MOFs, yolk-shell MOFs@MOFs structures can be constructed through nonsacrificial template method. Overall, the structural and morphological evolution process of MOFs treated in the medium-temperature range can open new horizons to develop efficient MOFs catalysts and design complex structures.
Developing
low-cost and highly active catalysts is vital to achieve
efficient electrochemical water splitting for hydrogen production,
which is considered as a very promising approach for renewable energy
storage. Herein, an efficient and cost-effective electrode architecture
constructed by vertically aligned carbon nanosheets (VCNs) and iron
oxyhydroxide/nitride (VCNs@FeOOH//VCNs@Fe4N) is designed
and synthesized for water splitting in alkaline medium. Benefiting
from the highly exposed active sites, accelerated mass and electron
transport, and synergistic effect of multiple components, the composite
electrodes deliver unprecedented catalytic performance with high activity
and excellent durability. The VCNs@FeOOH composite electrode exhibits
an overpotential of as low as 179 mV at 10 mA cm–2 for oxygen evolution reaction (OER), while VCNs@Fe4N
shows a low overpotential of 172 mV for hydrogen evolution reaction
(HER) at 10 mA cm–2. More significantly, a full
electrolyzer cell with VCNs@Fe4N as the cathode and VCNs@FeOOH
as the anode exhibits an appealing operation voltage of 1.6 V at 10
mA cm–2 with superior durability. The present results
provide new insight into designing robust catalysts toward practical
water splitting devices and metal–air batteries.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.