Mbonu Idongesit J, Mathias Gideon E, Udowa Emily O, Abd Alhassan Zainab Abbas, Alalwani Thamer A A M
Department of Chemistry, Federal University of Petroleum Resources Effurun Nigeria.
Department of Pure and Chemistry, University of Calabar Calabar Nigeria
RSC Adv. 2025 Jul 28;15(33):26693-26709. doi: 10.1039/d5ra03374h. eCollection 2025 Jul 25.
Cyanogenic gases, such as hydrogen cyanide and cyanogen, are highly toxic and pose serious risks to both human health and the environment. Effective adsorption strategies are essential to mitigate these hazards. In this study, the adsorption potential of a silver-decorated and yttrium-doped silicon nanocluster (Ag@SiY) toward cyanogenic gases-BrCN, ClCN, and FCN-was investigated using density functional theory (DFT) at the ωB97XD/GenECP/LanL2DZ/Def2SVP level of theory. Adsorption was explored in two orientations for each gas molecule. The computed adsorption energies indicated favorable interaction, particularly for BrCN, with values of -30.121, -17.571, -17.571, -16.943, -16.316, and -16.316 kcal mol for BrCN-Br-, BrCN-N-, ClCN-Cl-, ClCN-N-, FCN-F-, and FCN-N-Ag@SiY complexes, respectively. BrCN showed the strongest affinity, suggesting preferential adsorption on the Ag@SiY surface. Noncovalent interaction (NCI) analysis and recovery time calculations confirmed the presence of strong chemisorptive interactions, especially for BrCN, characterized by significant charge transfer and bonding stability. The frontier molecular orbital (FMO) analysis revealed a notable reduction in the energy gap upon gas adsorption, highlighting the enhanced reactivity of the surface. High dipole moment values across all adsorbed complexes indicate substantial charge separation, which is advantageous for sensor-based applications. Furthermore, the Electron Localization Function (ELF) analysis provided visual insight into the nature of bonding interactions. ELF maps exhibited moderate to high localization around the adsorption regions, particularly in BrCN-Br-Ag@SiY and FCN-N-Ag@SiY, suggesting mixed covalent and noncovalent bonding characteristics. These observations corroborate findings from QTAIM and NBO analyses, validating the interaction types and reinforcing the reliability of the proposed adsorption mechanisms. Thus, Ag@SiY demonstrates strong and selective adsorption properties toward cyanogenic gases, making it a promising candidate for use in gas sensing and environmental detoxification technologies.
含氰气体，如氰化氢和氰，毒性极强，对人类健康和环境都构成严重风险。有效的吸附策略对于减轻这些危害至关重要。在本研究中，使用密度泛函理论（DFT）在ωB97XD/GenECP/LanL2DZ/Def2SVP理论水平下，研究了银修饰和钇掺杂的硅纳米团簇（Ag@SiY）对含氰气体——溴化氰（BrCN）、氯化氰（ClCN）和氟化氰（FCN）的吸附潜力。对每个气体分子在两种取向中进行了吸附研究。计算得到的吸附能表明存在有利的相互作用，特别是对于溴化氰，溴化氰 - 溴 - 、溴化氰 - 氮 - 、氯化氰 - 氯 - 、氯化氰 - 氮 - 、氟化氰 - 氟 - 和氟化氰 - 氮 - Ag@SiY配合物的吸附能分别为 -30.121、-17.571、-17.571、-16.943、-16.316和 -16.316 kcal/mol。溴化氰表现出最强的亲和力，表明其优先吸附在Ag@SiY表面。非共价相互作用（NCI）分析和恢复时间计算证实了存在强化学吸附相互作用，特别是对于溴化氰，其特征是显著的电荷转移和键稳定性。前沿分子轨道（FMO）分析表明气体吸附后能隙显著减小，突出了表面反应性的增强。所有吸附配合物的高偶极矩值表明存在大量电荷分离，这对于基于传感器的应用是有利的。此外，电子定域函数（ELF）分析提供了对键合相互作用本质的直观洞察。ELF图在吸附区域周围表现出中等至高定域性，特别是在溴化氰 - 溴 - Ag@SiY和氟化氰 - 氮 - Ag@SiY中，表明具有混合共价和非共价键合特征。这些观察结果证实了量子拓扑原子分子理论（QTAIM）和自然键轨道（NBO）分析的结果，验证了相互作用类型并加强了所提出吸附机制的可靠性。因此，Ag@SiY对含氰气体表现出强且选择性的吸附特性，使其成为气体传感和环境解毒技术中有前景的候选材料。
