具有高储氢容量和可逆储氢性能的新材料的开发对氢能的大规模利用至关重要。基于第一性原理计算, 研究了Li原子和Ca原子单独修饰和共修饰VO2单层体系的H2分子存储性能。结果表明Li原子和Ca原子均能稳定结合在VO2单层表面而不产生金属团簇。单个Li原子和Ca原子分别最多可稳定吸附3个和6个H2分子, 且H2分子平均吸附能均大于0.20 eV/H2。吸附体系差分电荷和态密度分析结果表明, 氢分子的极化机制以及氢分子与金属原子间的轨道杂化作用是H2分子在金属原子周围稳定吸附的主要原因。Li原子修饰体系的储氢质量密度随着Li原子覆盖度的增加而逐渐增加, 而Ca原子修饰体系的储氢质量密度在低金属覆盖度时较高; Li/Ca共修饰体系的储氢质量密度有所增加, 其储氢质量密度为5.00%(质量分数)。此外, 考虑了不同温度和压强条件下储氢体系的稳定性。
VO2单层 储氢 第一性原理计算 锂原子 钙原子 修饰 VO2 monolayer hydrogen storage first-principle calculation lithium atom calcium atom decoration
Author Affiliations
Abstract
School of Electronics Engineering and Computer Science, Peking University, Beijing 1008712 Beijing Uni-Quanta Co. Ltd, Beijing 100871
Calcium is one prospective element for the modern optical frequency standard. The 423-nm transition line of calcium atoms has been widely used in laser slowing and laser cooling, the precise spectrum measurement, and the magnetic optical trapping (MOT). However, there is no any available commercial diode laser working at this wavelength. We built a 423-nm laser based on extra bow-tie cavity and by using a Brewster-cut uncoated BIBO (BiB3O6) crystal, which worked at room temperature, with conversion efficiency of 3.75%, and a potential up to 20%.
光学频率标准 BIBO晶体 钙原子 020.0020 Atomic and molecular physics 140.0140 Lasers and laser optics 190.0190 Nonlinear optics Chinese Optics Letters
2008, 6(5): 317
