The capability of hexagonal boron nitride (h-BN) to adsorb gas atoms may stimulate various promising applications in environment remediation and energy storage, while the interactivity with gas molecules yet remains challenging due to its inherent chemical inertness. In this article, we report a feasible and effective route for the scalable synthesis of vertically aligned h-BN nanowalls assisted by graphene without metallic catalysts. The average thickness of the fine h-BN nanowalls is few-atomic layers about 3.7 nm, that grow on the large substrate-like flakes transformed from the pristine graphene. The hierarchical h-BN nanowalls exhibit an enhanced gas adsorption performance, not only through physisorption owing to the synergistic combination of different porous geometries, but also through chemisorption via the open edge groups. Moreover, it demonstrates a significantly enhanced adsorption of CO2 over CH4 as compared to the h-BN nanosheets with similar sizes. Density functional theory calculations reveal that the -OH edge groups can effectively increase the adsorption capability towards CO2, accompanied by a shortened adsorption distance when the gas molecule is energetically stabilized. The wetting characteristics of h-BN nanowalls was further examined by contact angle goniometry.

中文翻译：

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石墨烯促进合成的垂直排列的六方氮化硼纳米壁及其气体吸附性能

六方氮化硼 (h-BN) 吸附气体原子的能力可能会激发在环境修复和储能方面的各种有前景的应用，而由于其固有的化学惰性，与气体分子的相互作用仍然具有挑战性。在本文中，我们报告了一种可行且有效的途径，用于在没有金属催化剂的情况下，由石墨烯辅助的垂直排列的 h-BN 纳米壁的可扩展合成。精细 h-BN 纳米壁的平均厚度是约 3.7 nm 的少量原子层，它们生长在从原始石墨烯转化而来的大型基板状薄片上。分级 h-BN 纳米壁表现出增强的气体吸附性能，不仅通过不同多孔几何形状的协同组合的物理吸附，而且通过开放边缘基团的化学吸附。而且，与具有相似尺寸的 h-BN 纳米片相比，它表明 CO2 对 CH4 的吸附显着增强。密度泛函理论计算表明，当气体分子能量稳定时，-OH边缘基团可以有效地增加对CO2的吸附能力，同时缩短吸附距离。h-BN 纳米壁的润湿特性通过接触角测角法进一步检查。