Lu Yangfan, Khazaei Mohammad, Hu Xinmeng, Khaledialidusti Rasoul, Sasase Masato, Wu Jiazhen, Hosono Hideo
Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
College of Materials Science and Engineering, Chongqing University, Chongqing 400030, P.R. China.
J Phys Chem Lett. 2021 Nov 25;12(46):11245-11251. doi: 10.1021/acs.jpclett.1c03149. Epub 2021 Nov 11.
While using hydride precursors, such as TiH, can promote the formation of some MAX phases, the mechanism for this stabilization effect by hydrogen has been unsolved. Herein, we report a facile synthesis method of TiAC (A = Zn, Al, In, and Ga) MAX phases using hydrogen as the phase stabilizer at their crystallographic voids. DFT calculations revealed that hydrogen could be incorporated in the center of the TiA (A = Zn, Al, Ga, and In) cages of TiAC MAX phases. The hydrogen is accommodated as an anion as a result of electron transfer from the surrounding Ti and A to H, leading to the stabilized state through Coulomb interaction between (TiA) and H. Consequently, high-purity TiAC (A = Zn, Al, Ga, and In) was directly synthesized under pressure-less and milder temperature conditions by simply employing TiH as the precursor. These findings indicate that utilizing hydrogen could be one of the experimental parameters to facilitate the formation of materials having crystallographic voids.
虽然使用氢化物前驱体（如TiH）可以促进一些MAX相的形成，但氢这种稳定化作用的机制尚未得到解决。在此，我们报道了一种简便的合成方法，以氢作为相稳定剂，在其晶体学空隙中合成TiAC（A = Zn、Al、In和Ga）MAX相。密度泛函理论计算表明，氢可以掺入TiAC MAX相的TiA（A = Zn、Al、Ga和In）笼的中心。由于电子从周围的Ti和A转移到H，氢以阴离子形式存在，通过（TiA）⁺和H⁻之间的库仑相互作用导致稳定状态。因此，通过简单地使用TiH作为前驱体，在无压力和较温和的温度条件下直接合成了高纯度的TiAC（A = Zn、Al、Ga和In）。这些发现表明，利用氢可能是促进具有晶体学空隙的材料形成的实验参数之一。
