With the depletion of fossil fuels, development of renewable energy has attracted wide attention in recent years. The well-known polyoxometalates (POMs) of H3PW12O40 (denoted as PW12) and H4SiW12O40 (denoted as SiW12) are effective catalysts for acid-catalyzed reactions. Nevertheless, industrial application of PW12 and SiW12 is largely restricted by the agglomeration, separation, leaching and recycling issues. Moreover, the PW12 and SiW12 tend to deactivate strong proton sites due to the small surface area of 10 m2·g–1. To overcome these problems, the PW12 and SiW12 have been fabricated onto a mesoporous polymer of PDVB-VBC (compound 1) with a large surface area via tris­(2-aminoethyl)­amine (TAEA), resulting in the formation of new heterogeneous catalysts of PDVB-VBC-TAEA-PW12 (compound 3) and PDVB-VBC-TAEA-SiW12 (compound 4). Both compounds 3 and 4 possess mesoporous structures with high surface area of 121 m2·g–1 and 131 m2·g–1, respectively. And they have shown highly efficient and selective dehydration of fructose to 5-hydroxymethylfurfural (5-HMF) in dimethyl sulfoxide (DMSO) as well as esterification of lauric acid (LA) to methyl laurate. Moreover, the catalysts can be recycled for at least five times with no obvious decrease of reactivity. Therefore, such catalysts have great potential for further application from a chemical engineering point of view.

Polyoxometalates (POMs) are widely used in catalysis, energy storage, biomedicine, and other research fields due to their unique acidity, photothermal, and redox features. However, the leaching and agglomeration problems of POMs greatly limit their practical applications. Confining POMs in a host material is an efficient tool to address the above‐mentioned issues. POM@host materials have received extensive attention in recent years. They not only inherent characteristics of POMs and host, but also play a significant synergistic effect from each component. This review focuses on the recent advances in the development and applications of POM@host materials. Different types of host materials are elaborated in detail, including tubular, layered, and porous materials. Variations in the structures and properties of POMs and hosts before and after confinement are highlighted as well. In addition, an overview of applications for the representative POM@host materials in electrochemical, catalytic, and biological fields is provided. Finally, the challenges and future perspectives of POM@host composites are discussed.

The NiCo alloy is one of the most promising alternatives to the noble-metal electrocatalysts for the hydrogen evolution reaction (HER); however, its performance is largely restricted by insufficient active sites and low surface area. Here, we fabricated a hierarchical hollow carbon cage supported NiCo alloy (denoted as HC NiCo/C) and a bulk NiCo alloy (denoted as NiCo) by reduction of a partially ZIF-67 etched ZIF-67@NiCo-LDH (LDH = layered double hydroxide) precursor and a fully ZIF-67 etched NiCo-LDH precursor, respectively. The as-prepared HC NiCo/C, in which the Ni29Co71 alloy nanocrystals with an average 6 nm size were encapsulated in graphitic carbon layers, provided a vastly increased electrochemically active surface area (ca. 13 times than the NiCo) and abundant catalytic active sites, which resulted in a higher HER performance with an overpotential of 99 mV than the 198 mV for NiCo at 10 mA cm–2. Detailed experimental results suggested that only the HC NiCo/C possessed the active alloy surface composed of unsaturated Ni0 and Co0 atoms, and both the metal–support interaction and alloying effect influenced the electronic structure of Co and Ni in HC NiCo/C, whereas the NiCo exhibited pure Ni surface. Theoretical calculations further revealed the Ni29Co71 alloy surface in HC NiCo/C possessed the appropriate adsorption energy of the intermediate state (adsorbed H*). This work provided new insight into the construction of the stable small-sized bimetallic alloy nanocatalysts by regulating the reduction precursors.

Deep desulfurization of fuels has long been and remains to be a highly challenging issue. In this work, a trilacunary polyoxometalate of Na12[α-P2W15O56]·24H2O (P2W15) was covalently tethered onto the γ-Al2O3 sphere, to which different alkyl chains (C n , n = 8, 12, or 18) were grafted, leading to the formation of the Al2O3-P2W15-C n . When the Al2O3-P2W15-C n were applied to catalyze oxidative desulfurization reaction of dibenzothiophene (DBT) in the presence of H2O2, it displayed high efficiency for removal of sulfur content in 9 min under optimized conditions at 60 °C. In addition, the Al2O3-P2W15-C n exhibited excellent structural stability during the catalytic reaction and can be used to remove 4,6-dimethyldibenzothiophene (4,6-DMDBT) and benzothiophene (BT) from fuel oils. The excellent performance of Al2O3-P2W15-C18 was verified by sulfur removal for an actual diesel sample. Molecular dynamics simulations indicated that DBT showed strong tendency to be adsorbed on active sites, while DBTO2 (dibenzothiophene sulfone) can be desorbed much easier. This work opens up a new avenue for further study on oxidative desulfurization catalytic materials and the influence of catalyst structure on mass transfer.

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Three copper(II) complexes of the polydentate N‐donor ligand [4‐(4,6‐bis(1H‐pyrazol‐1‐yl)‐1,3,5‐triazin‐2‐yl)morpholine] (L) with chlorides, nitrates, and perchlorates as anions, namely, [CuCl2(L)]·0.5(MeCN) (1), [Cu(NO3)2(H2O)(L)]·(MeCN) (2), and [Cu(L)2](ClO4)2·(MeCN) (3) were synthesized and structurally characterized by IR, elemental analysis and X‐ray crystallographic analysis. In these complexes, the L ligand binds the copper(II) cation in the tridentate N3 form. The coordination arrangement around the central copper(II) atom is distorted square‐pyramidal in 1 but it is distorted octahedral in 2 and 3. The interesting noncovalent interactions such as hydrogen bonds, π–π stacking, and anion–π interactions present in the solid‐state structures are discussed. The crystal results reveal that the counteranions play important roles in determining the diverse structures of these complexes. Moreover, the PXRD, TG, DRS, and fluorescence properties of compounds 1–3 were investigated.

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Two new fluorescent coordination polymers based on pamoic acid and different polydentate N‐donor ligands, namely {[Cd(PA)(TPTZ)(H2O)](DMF)2}n (1) and [Cd(PA)(BIB)]n (2) [H2PA = pamoic acid, TPTZ = 2,4,6‐tri(2‐pyridyl)‐1,3,5‐triazine, BIB = 1,4‐bis(1‐imidazolyl)benzene], were synthesized and characterized. Complex 1 showed a 1D zigzag chain structure with intramolecular hydrogen bonds. The 2D supramolecular structure in 1 was formed through π–π stacking interactions and intermolecular hydrogen bonds. Complex 2 displayed a 2D network structure. Intramolecular hydrogen bonds and π–π stacking interactions were observed in 2. By studying the fluorescence sensing performance of two coordination polymers, complex 1 exhibited high selectivity for tracking Al3+ ion and complex 2 could discriminately detect inorganic or aliphatic amines with high selectivity.