A first principle study of the heterogeneous catalysis mechanism of NaCl/KCl powder in suppressing combustion

Abstract

Studies have shown that alkali metal ultrafine water mist additives, such as NaCl and KCl, are highly effective in inhibiting explosion and combustion. In order to further study the heterogeneous catalytic inhibition of NaCl and KCl, the 100 most stable surfaces of NaCl and KCl were selected as the research objects. Three typical free radicals (H, O, OH) were selected as surface adsorbents with different coverages, and the most stable adsorption sites and configurations were located. The NEB method was used to calculate the minimum energy paths of H and O recombination on two surfaces. The molecular dynamics of two surface combustion radicals were simulated by the AIMD method. The results indicated that NaCl and KCl have strong adsorption capacity for the O free radical, while the two surfaces have weaker adsorption capacity for the H free radical; NaCl and KCl, two catalytic active substances, which can eliminate H radicals through the continuous adsorption of H free radical to generate H2, and H radical is inactivated. The catalytic fire-extinguishing effect by eliminating O free radical is weak. Molecular dynamics calculations on the two surfaces revealed that Cl atoms precipitate differently under the adsorption of various radicals.