Shangguan Wei, Zhao Hui, Dai Jian-Qing, Cai Jinming, Yan Cuixia
Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, People's Republic of China.
ACS Omega. 2021 Aug 20;6(34):21985-21993. doi: 10.1021/acsomega.1c02452. eCollection 2021 Aug 31.
At present, the development of new carbon-based nanoporous materials with semiconductor properties and high hydrogen storage capacity has become a research hotspot in the field of hydrogen storage and hydrogen supply. Here, we pioneered the study of the hydrogen storage capacity of a scandium (Sc) atom-modified semiconductor covalent organic framework-1 (COF-1) layer. It was found that the hydrogen storage capacity of the COF-1 structure was significantly enhanced after the modification of the Sc atom. We found that each Sc atom of the modified COF-1 structure can stably adsorb up to four H molecules, and the average adsorption energy of the four hydrogen molecules is -0.284 eV/H. Six Sc atoms are stably adsorbed most bilaterally on the cell of the COF-1 unit, which can adsorb 24 H molecules in total. In addition, we have further studied the adsorption and desorption behaviors of H molecules on the 6Sc-COF-1 surface at 300 and 400 K, respectively. It can be found that each Sc atom of the COF-1 unit cell can stably adsorb three H molecules with a hydrogen storage performance of 5.23 wt % at 300 K, which is higher than those of lithium-modified phosphorene (4.4 wt %) and lithium-substituted BHNH sheets (3.16 wt %). At 400 K, all of the adsorbed H molecules are released. This confirms the excellent reversibility of 6Sc-COF-1 in hydrogen storage performance. This research has great significance in the application of fuel cells, surpassing traditional hydrogen storage materials.
目前，开发具有半导体特性和高储氢容量的新型碳基纳米多孔材料已成为储氢和供氢领域的研究热点。在此，我们率先对钪（Sc）原子修饰的半导体共价有机框架-1（COF-1）层的储氢容量进行了研究。研究发现，Sc原子修饰后，COF-1结构的储氢容量显著提高。我们发现，修饰后的COF-1结构中的每个Sc原子最多可稳定吸附四个H分子，四个氢分子的平均吸附能为-0.284 eV/H。六个Sc原子最稳定地双侧吸附在COF-1单元的晶胞上，总共可吸附24个H分子。此外，我们还分别进一步研究了H分子在300 K和400 K下在6Sc-COF-1表面的吸附和解吸行为。可以发现，COF-1晶胞中的每个Sc原子在300 K时可稳定吸附三个H分子，储氢性能为5.23 wt%，高于锂修饰的磷烯（4.4 wt%）和锂取代的BHNH片材（3.16 wt%）。在400 K时，所有吸附的H分子都会释放。这证实了6Sc-COF-1在储氢性能方面具有优异的可逆性。该研究在燃料电池应用方面具有重大意义，超越了传统储氢材料。
