![]() |
ИСТИНА |
Войти в систему Регистрация |
ИСТИНА ЦЭМИ РАН |
||
The importance of the “heterogeneity” of a Pd monolayer induced by interaction with a semi-ionic support was evaluated for catalytic dissociation of methane, ammonia, and water. The geometry of Pd monolayer was optimized over the (100) and (110) planes of γ-Al2O3 and monoclinic ZrO2(001) at fixed unit cell parameters defined by the oxides. Simulation of deposition of flat Pd(100) monolayer cut from a bulk led to a formation of new distorted Pd monolayers (Fig. 1a, c) whose favored form depends on the support. The subsequent chemisorption or dissociation of CH4 or H2O at these Pd monolayers can modify them (Fig. 1) resulting in new hybrid Pd structures containing alternate elements of the (100) and (111) planes (as the parallel bands of squares and triangles, Fig. 1d). The stability of various hybrid Pd layers is compared to those of low index Pd planes and clusters when it is possible (an example for γ-Al2O3 please see in [1]). The catalytic capabilities of these monolayer structures have been demonstrated for CH4, H2O [1], NH3, and O2 dissociation at hybrid Pd(100)/(111) layer relative to those at pure (bulk) Pd(100) or Pd(111) surfaces. Moreover, moderate exothermic heats of these reactions were calculated instead of endothermic heats at the Pd(100) or Pd(111) surfaces. 1. A. A. Rybakov, et al. Dalt. Trans. 2021, 50, 8863.