Metal oxide-based materials are emerging as a promising family of hydrogen evolution reaction (HER) electrocatalysts.

A new two-dimensional zeolitic imidazolate framework (named as ZIF-L) was synthesized in zinc salt and 2-methylimidazole (Hmim) aqueous solution at room temperature. ZIF-L (Zn(mim)₂·(Hmim)_1/2·(H₂O)_3/2 or C₁₀H₁₆N₅O_3/2Zn) has unique cushion-shaped cavities and leaf-like crystal morphology, and exhibits excellent CO₂ adsorption properties.

As a low-cost green technology, solar steam generation using nanostructured photothermal materials has been drawing increasing attention in various applications, e.g. seawater desalination, and zero liquid discharge of industrial wastewater. However, the crystallisation of salts on the surface of photothermal materials during steam generation leads to a gradual decline in the water evaporation rate. Herein, this challenge was overcome by a novel design involving controlled water transport, edge-preferential crystallisation and gravity-assisted salt harvesting. The crystallisation sites of the salt were spatially isolated from the water evaporation surface, achieving continuous steam generation and salt harvesting in over 600 hours of non-stop operation. The study provides new insights into the design of solar steam generators and advances their applications in sustainable seawater desalination and wastewater management.

Zeolitic imidazolate frameworks (ZIFs), a subclass of metal organic frameworks, are built of tetrahedral metal ions bridged by imidazolates. They have permanent porosity and relatively high thermal and chemical stability, which make them attractive candidates for many industrial applications. In recent years, significant progress has been made in developing ZIFs into membranes and thin films for gas separation, liquid separation (pervaporation) and functional devices. Various techniques, such as direct synthesis, secondary synthesis, reactive seeding and functional chemicals as linkers, and contra-diffusion synthesis, have been reported for the fabrication of ZIF membranes and films. As ZIFs have good compatibility with polymers, they have been incorporated into polymers with high loadings to form mixed matrix membranes. The resulting symmetric dense or asymmetric composite membranes exhibit good performance in gas separation and liquid separation via pervaporation. The recent developments of ZIF membranes/films, ZIF–polymer mixed matrix membranes and their applications are reviewed in this article.