The control of mercury in flue gas is challenging, especially that of elemental mercury (Hg⁰). Recently, many researchers have focused on various mercury removal technologies. Here, by performing density functional theory (DFT) calculations, we systematically studied the adsorption of Hg⁰ on several experimentally available hexagonal boron nitride (h-BN) nanosheets with no defects, nitrogen vacancies (V^N), boron vacancies (V^B), and both nitrogen and boron vacancies (V^N+B) as well as their structures and electronic properties. Our calculation results show that the presence of V^N, V^B, and V^N+B enhances the adsorption energies of Hg⁰ by 9, 45, and 214 kJ/mol, respectively. Moreover, a more negative potential at the V^B and V^N+B sites makes the h-BN-V^B and h-BN-V^N+B surfaces more reactive than those of h-BN and h-BN-V^N. The partial density of states analysis reveals that the Hg atom interacts firmly with surface B or/and N atoms through orbital hybridization. The trend of the equilibrium constant implies that adsorption of Hg⁰ on the h-BN-V^N+B surface is beneficial at low temperature. Our computational studies reveal that defective h-BN nanosheets with V^B and V^N+B have great potential to serve as novel sorbents for the efficient removal of mercury in flue gas.

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缺陷性氮化硼单层膜上元素汞的揭示吸附机理：计算研究

烟气中汞的控制极具挑战性，尤其是元素汞（Hg ⁰）的控制。最近，许多研究人员将重点放在各种除汞技术上。在这里，通过执行密度泛函理论（DFT）计算，我们系统地研究了Hg ⁰在几种无缺陷，氮空位（V ^N），硼空位（V ^B）的实验性可用六方氮化硼（h -BN）纳米片上的吸附。，以及氮和硼的空位（V ^{N + B}）以及它们的结构和电子性能。我们的计算结果表明V ^N，V ^B和V ^{N + B的存在}分别将Hg ⁰的吸附能提高9、45和214 kJ / mol。此外，在V ^B和V ^{N + B}处的负电势使h -BN-V ^B和h -BN-V ^{N + B}表面比h -BN和h -BN-V ^N表面更具反应性。状态的部分密度分析表明，Hg原子通过轨道杂交与表面B或/和N原子牢固相互作用。平衡常数的趋势表明Hg ⁰在h -BN-V ^{N + B}上的吸附表面在低温下是有益的。我们的计算研究表明，具有V ^B和V ^{N + B的}有缺陷的h -BN纳米片具有巨大的潜力，可以用作有效去除烟道气中汞的新型吸附剂。