posted on 2021-11-01, 11:33authored byJiancheng Yang, Long Chen, Shilei Yuan, Mingtao Yang, Yuan Huang, Jiachun Su, Zhikun Zhang, Zhuozhi Wang, Lianfei Xu, Boxiong Shen
Sodium
in high-alkali coal facilitates the heterogeneous reduction
of nitrogen oxides on char surfaces. However, the reaction mechanism
is unclear. In this paper, the effect of sodium on the reaction path
of the char heterogeneous reduction of NO was analyzed based on the
first-principles study using an armchair char model and a zigzag char
model separately. Four reaction paths were obtained, and the most
likely reaction path was found by comparison. The highest energy barriers
of the reduction reactions were reduced to some extent by doping with
the sodium atom. The doped sodium atom had a significant effect on
the heterogeneous reduction reactions on the surface of the armchair
char and had little effect on the surface of the zigzag char. However,
a comprehensive analysis showed that the reactivity of the zigzag
model is better than that of the armchair model. From the thermodynamic
analysis, the addition of the sodium atom could change the reaction
from nonspontaneous to spontaneous. After the completion of the reaction,
the oxygen atom would be immobilized on the char structure surface,
which will have an effect on the subsequent reaction. This study revealed
the effect of the sodium atom on the reaction mechanism of the char
heterogeneous reduction of NO and helped perfect the mechanism of
the char heterogeneous reduction of NO.