Freshwater scarcity is a global challenge threatening human survival, especially for people living in arid regions. Sorption‐based atmospheric water harvesting (AWH) is an appealing way to solve this problem. However, the state‐of‐the‐art AWH technologies have poor water harvesting performance in arid climates owing to the low water sorption capacity of common sorbents under low humidity conditions. We report a high‐performance composite sorbent for efficient water harvesting from arid air by confining hygroscopic salt in a metal–organic framework matrix (LiCl@MIL‐101(Cr)). The composite sorbent shows 0.77 g g−1 water sorption capacity at 1.2 kPa vapor pressure (30 % relative humidity at 30 °C) by integrating the multi‐step sorption processes of salt chemisorption, deliquescence, and solution absorption. A highly efficient AWH prototype is demonstrated with LiCl@MIL‐101(Cr) that can enable the harvesting of 0.45–0.7 kg water per kilogram of material under laboratory and outdoor ambient conditions powered by natural sunlight without optical concentration and additional energy input.

In recent years, 2,5-dihydroxymethylfuran (DHMF), which can be produced by the selective hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF), has attracted great attention and interest of many scientists because of its peculiar symmetrical structure and wide potential applications. At present, studies of the production of DHMF are quickly progressing, with productive approaches being increasingly developed, and many crucial achievements have been continually obtained. However, to date, a special and real-time review of this research area is still lacking. To gain more insight into the current research situation, this review comprehensively summarizes and discusses state-of-the-art advancements of the production of DHMF from HMF via various chemocatalytic pathways, such as conventional hydrogenation, transfer hydrogenation, electrocatalytic hydrogenation, photocatalytic hydrogenation, disproportionation reaction, and biocatalytic pathways. Meanwhile, this review also systematically outlines the latest results on the further transformation of DHMF into value-added derivatives via etherification, polymerization, and rearrangement.

Efficient thermal energy harvesting using phase‐change materials (PCMs) has great potential for cost‐effective thermal management and energy storage applications. However, the low thermal conductivity of PCMs (KPCM) is a long‐standing bottleneck for high‐power‐density energy harvesting. Although PCM‐based nanocomposites with an enhanced thermal conductivity can address this issue, achieving a higher K (>10 W m−1 K−1) at filler loadings below 50 wt% remains challenging. A strategy for synthesizing highly thermally conductive phase‐change composites (PCCs) by compression‐induced construction of large aligned graphite sheets inside PCCs is demonstrated. The millimeter‐sized graphite sheet consists of lateral van‐der‐Waals‐bonded and oriented graphite nanoplatelets at the micro/nanoscale, which together with a thin PCM layer between the sheets synergistically enhance KPCM in the range of 4.4–35.0 W m−1 K−1 at graphite loadings below 40.0 wt%. The resulting PCCs also demonstrate homogeneity, no leakage, and superior phase change behavior, which can be easily engineered into devices for efficient thermal energy harvesting by coordinating the sheet orientation with the thermal transport direction. This method offers a promising route to high‐power‐density and low‐cost applications of PCMs in large‐scale thermal energy storage, thermal management of electronics, etc.

Fresh water scarcity is a globally significant challenge threatening the development of human society. Sorption-based atmospheric water harvesting offers an appealing way to solve this challenge by extracting clean water...

A simple and efficient process was presented for the selective hydrogenation of 5-hydroxymethylfurfural (HMF) into the high-quality liquid fuel 2,5-dimethylfuran (DMF) in the presence of tetrahydrofuran (THF). Among the employed metal catalysts, the relatively inexpensive carbon-supported ruthenium (Ru/C) displayed the highest catalytic performance, which led to 94.7% DMF yield with 100% HMF conversion at a relatively mild reaction temperature of 200 °C for only 2 h. Although Ru/ C had a little loss in the catalytic activity when it was used for five successive reaction runs, the partially deactivated Ru/C could be easily regenerated by heating at a mixed flow of H 2 and N 2 . Moreover, the plausible mechanism involving an aldehyde group, a hydroxyl group, and a furan ring for the selective hydrogenation of HMF into DMF was also proposed. Subsequently, DMF was separated from the crude hydrogenation mixture according to their various boiling points by the combination of atmospheric distillation and vacuum distillation, and then, the chemical structures and physical properties of the separated DMF were confirmed to be consistent with the authentic DMF. More gratifyingly, Ru/C and THF were also found to be a good combination for the direct hydrogenation of carbohydrate-derived HMF into DMF, which is very important for the practical production of DMF from a variety of biomass-derived carbohydrates such as fructose, glucose, sucrose, maltose, cellobiose, starch, and cellulose.

Catalytic transformation of biomass-derived 5-hydroxymethylfurfural (HMF) into a series of high-value derivatives, such as 2,5-diformylfuran, 5-hydroxymethyl-2-furancarboxylic acid, 5-formyl-2-furancarboxylic acid, 2,5-furandicarboxylic acid, 2,5-dihydroxymethylfuran, 5-alkanoyloxymethylfurfural, 5,5-bis­(hydroxymethyl)­furoin and 5-hydroxymethylfurfurylamine, is a very important research field in the biorefinery process. For a long time, chemocatalytic pathways have been the main transformation methods of HMF, and so, they have been widely studied in recent years. However, considering some unavoidable issues of chemocatalytic pathways, biocatalytic pathways with many advantages, such as higher selectivity, gentler condition, lower investment and environmental friendliness, should be a promising alternative, and unfortunately, they have not yet attracted enough attention until now. To better understand the current research status, this review primarily retrospects and describes the discovery and development of biocatalytic transformation of HMF, and then systematically summarizes and discusses the latest studies and advancements on the biocatalytic transformation of HMF through oxidation, reduction, esterification, carboligation and amination in the presence of the corresponding enzymes or whole-cells. Furthermore, this review also proposes a few possible research trends in the future studies, aiming at providing a few helpful and feasible references and supports for the biocatalytic transformation of HMF in much more economical and effective ways.

No abstract

No abstract