Density functional theory calculations with dispersion corrections were employed to investigate the hydrogen (H₂) adsorptive properties of siligraphene (SiC₈), pristine and decorated with selected alkali (Li, Na, and K) and alkaline-earth (Be, Mg, and Ca) metals. We found that all the considered metals (Me), except Mg and Be, bind strongly to SiC₈ even at high doping concentrations (SiC₈Me₂) by donating a major portion of their valence electrons to SiC₈. Ab initio molecular dynamics (AIMD) simulations confirmed the thermal stabilities of SiC₈Me₂ (Me = Li, Na, K, Ca) at 300 K. We showed that Li, Na, and Ca-doped SiC₈ adsorbed multiple H₂ molecules with binding energies (E_bind) at least two times stronger than that of the pristine SiC₈ (E^pristine_bind = −70 meV per H₂). Overall, both SiC₈Li₂ and SiC₈Ca₂ adsorbed two and four H₂ molecules per metal adatom, respectively, having E_bind within the desirable range for an effective adsorption/desorption process. The resulting gravimetric densities of SiC₈Li₂ and SiC₈Ca₂ were 5.5 wt% and 7.3 wt%, respectively, surpassing the U.S. Department of Energy's 2025 goal of 5.5 wt%. The estimated H₂ desorption temperatures exceed substantially the boiling point of liquid nitrogen, confirming the potential of light metal decorated SiC₈ as a promising material for H₂ storage.

中文翻译：

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在选择金属装饰后阐明二维硅单晶（SiC8）单层的储氢特性

与色散校正密度泛函理论计算进行了用于研究的氢（H ₂）siligraphene的吸附性能（碳化硅₈），原始和装饰有选择的碱（锂，钠，和钾）和碱土（铍，镁，和Ca）金属。我们发现，即使在高掺杂浓度（SiC ₈ Me ₂）下，除Mg和Be之外，所有考虑的金属（Me）也会通过将大部分价电子提供给SiC _8而牢固地与SiC ₈结合。从头算分子动力学（AIMD）模拟证实了SiC ₈ Me ₂的热稳定性（Me = Li，Na，K，Ca）在300 K时。我们显示，掺杂Li，Na和Ca的SiC ₈吸附了多个H ₂分子，其结合能（E _bind）比原始能量强至少两倍。碳化硅₈（Ë^原始_绑定= -70兆电子伏每股H ₂）。总的来说，每个金属原子上SiC ₈ Li ₂和SiC ₈ Ca _2分别吸附两个和四个H ₂分子，其中E_结合在有效吸附/解吸过程所需的范围内。SiC _8的重量密度Li ₂和SiC ₈ Ca ₂分别为5.5 wt％和7.3 wt％，超过了美国能源部2025年的5.5 wt％的目标。估计的H ₂解吸温度基本上超过了液氮的沸点，证实了轻金属装饰的SiC ₈作为H ₂存储的有前途的材料的潜力。