The origin of selective adsorption desulfurization by Fe single atom adsorbents on hexagonal boron nitride surface

Hexagonal boron nitride (h-BN) has widespread application in the field of adsorption desulfurization due to their excellent performance. However, the selective adsorption of h-BN is still a challenge. Here, to further enhance the adsorption capacity and selectivity of BN-based adsorbents, the stability of Fe single-atom adsorbents (SAAs, Fe-BN), and their adsorption performance and mechanism towards the representative sulfide, dibenzothiophene (DBT) were investigated by density functional theory calculations. Specifically, four Fe doping types are considered: Fe_cen_B and Fe_edg_B (both at B sites), Fe_cen_N (at the N site), and Fe_four_cen (at the B − N site). All types of Fe-BN SAAs exhibit outstanding adsorption capacity for thiophenic sulfides. Especially for Fe_edg_B1, which shows 62.6 % improvement in adsorption performance compared to h-BN for DBT. Quantum chemical analysis reveals that S-Fe coordination bonds formed between S atom in DBT and Fe atoms via coordination interaction, significantly improving the adsorption selectivity and capacity. This study may provide a useful reference for designing the highly selective SAAs.