Do Hyung Wan, Kim HyeonJi, Cho Eun Seon
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
RSC Adv. 2021 Oct 4;11(52):32533-32540. doi: 10.1039/d1ra05111c.
With a growing concern over climate change, hydrogen offers a wide range of opportunities for decarbonization and provides a flexibility in overall energy systems. While hydrogen energy is already plugged into industrial sectors, a physical hydrogen storage system poses a formidable challenge, giving momentum for safe and efficient solid-state hydrogen storage. Accommodating such demands, sodium alanate (NaAlH) has been considered one of the candidate materials due to its high storage capacity. However, it requires a high temperature for hydrogen desorption and becomes inactive irreversibly upon air-exposure. To enhance sluggish reaction kinetics and reduce the hydrogen desorption temperature, NaAlH can be confined into a porous nanoscaffold; however, nanoconfined NaAlH with sufficient hydrogen storage performance and competent stability has not been demonstrated so far. In this work, we demonstrate a simultaneously enhanced hydrogen storage performance and air-stability for NaAlH particles confined in a nanoporous graphene oxide framework (GOF). The structure of the GOF was elaborately optimized as a nanoscaffold, and NaAlH was infiltrated into the pores of the GOF incipient wetness impregnation. As a result of the nanoconfinement, both the onset temperature and activation energy for hydrogen desorption of NaAlH are significantly decreased without transition metal catalysts, while simultaneously achieving the stability under ambient conditions.
随着对气候变化的关注度不断提高，氢为脱碳提供了广泛的机会，并为整个能源系统提供了灵活性。虽然氢能已经应用于工业领域，但物理储氢系统面临着巨大挑战，这推动了安全高效的固态储氢技术的发展。为满足此类需求，由于其高储氢容量，铝酸钠（NaAlH）被视为候选材料之一。然而，它需要高温才能解吸氢气，并且在暴露于空气中时会不可逆地失去活性。为了加快缓慢的反应动力学并降低氢气解吸温度，可以将NaAlH限制在多孔纳米支架中；然而，迄今为止，尚未证明具有足够储氢性能和良好稳定性的纳米受限NaAlH。在这项工作中，我们展示了对于限制在纳米多孔氧化石墨烯框架（GOF）中的NaAlH颗粒，其储氢性能和空气稳定性同时得到增强。GOF的结构被精心优化为纳米支架，并且通过初湿浸渍法将NaAlH渗透到GOF的孔中。由于纳米限制作用，在没有过渡金属催化剂的情况下，NaAlH解吸氢气的起始温度和活化能均显著降低，同时在环境条件下实现了稳定性。
