Herein, we report an allyl-imidazolium ionic liquid decorated COF and its covalent composite COF@chitosan aerogel, which were shown to be excellent selective CO2 adsorbents and chemical conversion catalysts.

Two-dimensional (2D) piezoelectric materials have gained considerable attention since they could play important roles in the nanoelectromechanical systems. Herein, we report a firstprinciples study on the piezoelectric properties of monolayer group-V binary compounds with theoretically stable honeycomb phases (αphase and β-phase). Our calculations for the first time reveal that a majority of the monolayers possess extremely high piezoelectric coefficients d 11 , i.e., 118.29, 142.44, and 243.45 pm/V for α-SbN, α-SbP, and α-SbAs, respectively, comparable to those of recently reported group-IV monochalcogenides (d 11 = 75−250 pm/V) with an identical mm2 symmetry. It is found that the giant piezoelectric responses of α-phase monolayers as compared to those of β-phase monolayers are induced by their flexible structures and special symmetry. Meanwhile, the piezoelectric coefficients of α-phase monolayers are found to be surprisingly anisotropic and obey a unique periodic trend which is not exactly identical to that for the β-phase monolayers. To gain a comprehensive understanding of the periodic trends in piezoelectricity, several factors which influence the piezoelectric coefficients are quantitatively determined.

The temperature dependence of the thermal conductivity, low-field/high-field magnetization, and magnetic ac susceptibility under different hydrostatic pressures have been measured on single-crystal samples of LaMn 1Ϫx Ga x O 3 . The data reveal a spin-glass phase in low magnetic fields and a ferromagnetic phase in high fields Hу2 kOe. Orbital fluctuations suppress the phonon component and the spin-glass phase suppresses the spin-wave component of the thermal conductivity (T); the xϭ0.5 sample has a (T) like that of a glass insulator. On the other hand, pressure stabilizes long-range antiferromagnetic order. The data demonstrate a competition between magnetic and elastic energies; in the xϭ0.5 sample, regions with three-dimensional orbital fluctuations and ferromagnetic (180°Ϫ) Mn͑III͒-O-Mn͑III͒ vibronic superexchange interactions coexist with regions in which orbital ordering gives rise to an antiferromagnetic interaction between ͑001͒ planes.