Defect-rich Mg-Al MMOs supported TEPA with enhanced charge transfer for highly efficient and stable direct air capture

Due to the advantages of low energy consumption and high CO_(2) selectivity, the development of solid amine-based materials has been regarded as a hot research topic in the field of DAC for the past decades.The adsorption capacity and stability over multiple cycles have been the top priorities for evaluation of practical application value. Herein, we synthesized a novel DAC material by loading TEPA onto defect-rich Mg_(0.55)Al-O MMOs with enhanced charge transfer effect. The optimal Mg_(0.55)Al-O-TEPA67% demonstrates the highest CO_(2)uptake of(3.0 mmol g^(-1)) and excellent regenerability, maintaining ~90% of the initial adsorption amount after 80 adsorption/desorption cycles. The in situ DRIFTS experiments suggested the formation of bicarbonate species under wet conditions. DFT calculations indicated that the stronger bonding between Mg_(0.55)Al-O support and solid amine was caused by the abundance of oxygen defects on MMOs confirmed by XPS and ESR, which favors the charge transfer between the support and amine,resulting in intense interaction and excellent regenerability. This work for the first time conducted comprehensive and systematic investigation on the stabilization mechanism for MMOs supported solid amine adsorbents with highest uptake and superior cyclic stability in depth, which is different from the most popular SiO_(2)-support, thus providing facile strategy and comprehensive theoretical mechanism support for future research about DAC materials.

Strain-induced ferroelectric phase transitions in incipient ferroelectric rutile TiO_2

Uniaxial strain induced ferroelectric phase transitions in rutile TiO2 are investigated by first-principles calculations. The calculated results show that the in-plane tensile strain induces rutile TiO2, paraelectric phase with P4-2/mnm （D4h） space group, to a ferroelectric phase with Pm（Cs） space group, driven by the softening behaviour of the Eul mode. In addition, the out-of-plane tensile strain, vertical to the ab plane, leads to a ferroelectric phase with P42nm （C4v） space group, driven by the softening behaviour of the A2u mode. The critical tensile strains are 3.7% in-plane and 4.0% out-of-plane, respectively. In addition, the in-plane compression strain, which has the same structure variation as out- of-plane tensile strain due to Poisson effect, leads the paraelectric rutile TiO2 to a paraelectric phase with Pnnm （D2h） space group driven by the softening behaviour of the B1g mode. These results indicate that the sequence ferroelectric （or paraelectric） phase depends on the strain applied. The origin of ferroelectric stabilization in rutile TiO2 is also discussed briefly in terms of strain induced Born effective charge transfer.

Interaction of benzene-1,3-disulfonylamid-kriptofix[22] with iodine in chloroform and dichloromethane solutions

The interaction of iodine as an cr-acceptor with a synthetic ligand,benzene-1,3-disulfonylamid-kriptofix[22]（BDSAK） as a π-donor has been investigated spectrophotometrically in chloroform（CHCl3） and dichloromethane（DCM） solutions.The results of mole ratio plots and Job＇s method show the stoichiometry of complexation I2/BDSAK is 1：1.Stability constants have been calculated in various temperatures and thermodynamic parameters have also been determined from the temperatures dependence of the stability constants by using van＇t Hoff equation.The results indicate the iodine complex with BDSAK is enthalpy stabilized but entropy destabilized.