The development of novel metal organic framework (MOF) friction power generation materials with high stability is important. This paper reports the first example of a double-helix metal chain organic framework with a network structure (ZUT-8). ZUT-8 shows high chemical stability, functional adjustability, and excellent output performance of friction power generation, which is superior to traditional coordination polymer materials. The cathodic protection system with ZUT-8 can prevent metal corrosion significantly. The output performance can be improved effectively by enhancing the conjugate effect of the linker. The theoretical calculation results showed that an increase in the degree of conjugation could significantly reduce the band gap, thereby affecting the friction power output signal. This study opens the door to constructing MOF materials with a double-helix metal chain and will promote their potential applications in self-powered electrochemical cathodic protection.

Metal–organic frameworks (MOFs) as friction nanopower generation materials have attracted more and more research and attention because of the inherent three-dimensional framework structure and large aperture. In this work, the ZUT-75­(Mn) with a one-dimensional pore structure was synthesized by using electron-rich benzimidazole carboxylic acid ligands, and isomorphic offspring MOF materials were obtained by single crystal–single crystal solvent-assisted metal-ion exchange. The exchange process was monitored by liquid UV–vis spectroscopy, atomic absorption spectrometry, and energy-dispersive X-ray spectroscopy. The metal–oxygen coordination energy, X-ray photoelectron spectroscopy binding energy, and hard–soft acid–base principle verified the spontaneity of the central-metal-exchange reaction. The four materials were applied to a triboelectric nanogenerator (TENG), and the output performance law of ZUT-75 was Co-MT > Zn-MT > Cu-MT > Mn-MT. Among them, the charge and power densities of Co-MT were up to 127.05 μC m–2 and 3280.50 mW m–2. When the density functional theory calculation and variable-temperature magnetic susceptibility test results were combined, it was concluded that low metal-ion-coupling degree promoted the formation and transfer of contact electrifications, which greatly improved the output performance of the TENG. This work provided a new idea for improving the output performance of the TENG.

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Hg 2+ pollution seriously harms human life and health, and it is of great significance to develop Hg 2+ removal materials with excellent performance. In this work, a crystalline coordination polymer material {[Zn(L)(A)]•DMF} n (1) with 4.8 mmol/g amino loading density was engineered by using amino-functionalized ligands. Strong coordination properties of isonicotinic acid and adenine endow 1 with excellent chemical stability and thermal stability. Results of the removal experiment showed that 1 could efficiently remove >96% Hg 2+ within 10 min, and the saturated adsorption amount was 273 mg/g, which shows advantages over most reported MOF adsorbents. After combining IR spectra, XPS spectra, and CO 2 adsorption results, displacement of the characteristic peak demonstrated that the excellent capture performance is mainly attributed to the coordination interaction between high-density amino groups and Hg 2+ . This work provides a new consideration for the practical application of MOF adsorbents.

Ethyl nonanoate is a promising component of biodiesel with a satisfactory cetane number and reactivity. The speeds of sound in ethyl nonanoate were measured by the Brillouin light scattering (BLS) method within the temperatures from 295.24 to 593.15 K and at pressures up to 10 MPa. The relative expanded uncertainty (k = 2) of our BLS experimental system is estimated to be less than 0.7%. The densities of ethyl nonanoate were measured using a vibrating tube densimeter at atmospheric pressure in the temperature range of 293.15–353.15 K, and the absolute average relative deviation between the experimental densities and the literature data is 0.12%. For temperatures between 303.15 and 353.15 K and at pressures up to 10 MPa, these measurements were used to calculate densities, isobaric heat capacities, and indirect derivative properties including the isobaric thermal expansion, the isothermal compressibility, the isentropic compressibility, and the internal pressure. The comparison between the calculated isobaric heat capacities and the literature values shows a satisfactory agreement with an absolute average relative deviation of 0.18% and a maximum deviation of 0.38%. At the end, the dependences of internal pressure of ethyl nonanoate on temperature and pressure were found to be in accordance with those of ethyl caprylate and ethyl caprate.