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Gas hydrates hold great potential in the field of energy storage & transportation. However, the stochastic induction time and low formation rate restricted the large-scale industrialization of gas hydrate technology, which need to be improved through effective methods. Superabsorbent hydrogels (SAHs) are lightly cross-linked polymers with three-dimensional networks that can absorb and retain a large amount of water or aqueous solution. Due to the strong absorption and retention capabilities, SAHs have been added in the system to facilitate gas hydrate formation via increasing mass transfer and improving promoter recyclability. However, the interactions among gas, water and hydrogels are complicated, and the usages are diverse, and the promotion mechanisms were underexplored. This paper reviews the existing cases applying SAHs in gas hydrate formation, and analyzes the influencing mechanisms of SAHs; and meanwhile proposes a concept of SAH-based solid-state water (SSW) system, and evaluates its application potential in promoting gas hydrate formation, and further prospects its modification and integration possibilities for being a hydrate promoter.

For achieving solar absorber and conversion molecular materials with excellent photothermal conversion ability, five mononuclear Copper(II) coordination compounds have been designed and isolated. They are fully characterized by IR, Powder XRD, Solid-state UV, and TGA. Single-crystal X-ray structural analysis reveals that they are typical photothermal conversion molecules with double chromophores: one antenna chromophore (NT group here) and the second chromophores (Cu(dmap)42+, Cu(dmap)22+, Cu(bpy)22+ and Cu(phen)22+). Both chromophores have great influence on their solid-state optical absorption. Their photothermal conversion experiments show that compounds 3, 4 and 5 have the better results (the highest temperature increment 21.7 ℃ and equilibrium temperature ~ 60.7 ℃) than compounds 1 and 2. Those results give some clues for illustrating the molecular mechanisms of solar absorber and photothermal conversion molecular materials.

Two new silver clusters, [Ag6(PhC C)2(bpy)4(NO3)4] (1), bpy = 2,2′-bipyridine, Ag8(Phen)4(NEA)8(CH3CN)2 (2), NEA = naphthalene acetic acid, were synthesized with assistance of ultrasonic irradiation and their unique structure investigated by single-crystal X-ray diffraction, Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction analysis (PXRD) and Ultraviolet–visible spectrum (UV–Vis). Thermal stability of the clusters were studied through thermogravimetric analysis (TGA). The photoluminescence analysis of 2 was also carried out. Clusters 1 and 2 show the absorption bands at λmax in the range 200–380 nm and 310 nm, respectively. The band gap widths for clusters are 3.05 eV and 3.20 eV. The Ag…Ag contact range in the cluster 1 is 2.7211(4) A–3.1102(3) A and for the cluster 2 is 2.867–3.047 A.

In order to achieve a light-harvesting system with excellent photo-thermal conversion property, three naphthyl(NT)-functionalized Copper(II) coordination compounds have been designed and isolated. They are characterized by IR, Powder XRD, UV, and TGA. Single-crystal X-ray structural analysis reveals that {[Cu4(bpy)4(1-NTAA)5](BF4)3∙3(CH3OH)∙H2O}∞ (1) has 1D chain structure, {[Cu2(1-NTAA)4(CH3CN)2]∙2(CH3CN)} (2) and {[Cu2(2-NTA)4(CH3CN)2]∙2.5(CH3CN)} (3) have similar paddle-wheel structures. Utilizing the introduction of NT-groups into copper(II) centers, all three compounds exhibit good solid-state optical absorption in a nearly full solar spectral region. The coordination polymer 1 exhibits the quickest temperature rising (nearly 2 ℃/min from the very beginning), the highest temperature increment (12 ℃) and equilibrium temperature (40 ℃) over the other two compounds in the photothermal conversion experiments. Those results point out the direction of molecular design for enhancing photothermal conversion performance.