Design of hyperporous graphene networks and their application in solid-amine based carbon capture systems
Design of hyperporous graphene networks and their application in solid-amine based carbon capture systems
复制标题
DOI：
10.1039/c7ta05789j
复制
发表时间：
2017-09-14
影响因子：
11.9
通讯作者：
Guo, Zhengxiao
中科院分区：
文献类型：
--
作者：
Gadipelli, Srinivas;Lu, Yue;Guo, Zhengxiao
我们展示了一种简单且完全可扩展的方法，通过在300摄氏度的相对温和温度下对氧化石墨烯（exfGO）进行热冲击剥离，获得具有超高总孔隙体积的分层高孔石墨烯网络。这种单位质量的孔隙体积以前从未在任何类型的多孔固体中实现过。研究发现，氧化石墨烯的氧化量是决定热冲击后最终材料孔体积和比表面积的关键因素。特别地，我们强调了超孔隙度的发展与sp(2) C=C的增强氧化形成C=O/COO成正比。使用我们的方法，我们可重复地合成了具有极高总孔隙体积的显着中/大孔石墨烯网络，超过6 cm(3) g（-1）。与在exfGO样品（solid-amine@exfGO）中容易获得的6g（-1）相比，这是一个阶跃变化，其中胺的负载直接由宿主材料的孔隙结构和体积控制。这种solid-amine@exfGO样品在75℃下表现出30-40 wt%的超高选择性烟气CO2捕集率，工作容量接近25 wt%，在模拟烟气流条件下具有很长的循环稳定性。据我们所知，这是第一份使用氧化石墨烯基高孔碳网络来承载碳捕获应用的胺的报告，具有极高的存储容量和稳定性。
We demonstrate a simple and fully scalable method for obtaining hierarchical hyperporous graphene networks of ultrahigh total pore volume by thermal-shock exfoliation of graphene-oxide (exfGO) at a relatively mild temperature of 300 degrees C. Such pore volume per unit mass has not previously been achieved in any type of porous solid. We find that the amount of oxidation of starting graphene-oxide is the key factor that determines the pore volume and surface area of the final material after thermal shock. Specifically, we emphasize that the development of the hyperporosity is directly proportional to the enhanced oxidation of sp(2) C=C to form C=O/COO. Using our method, we reproducibly synthesized remarkable meso-/macroporous graphene networks with exceptionally high total pore volumes, exceeding 6 cm(3) g(-1). This is a step change compared to 6 g g(-1) is readily attained in exfGO samples (solid-amine@exfGO), where amine loading is directly controlled by the pore-structure and volume of the host materials. Such solid-amine@exfGO samples exhibit an ultrahigh selective flue-gas CO2 capture of 30-40 wt% at 75 degrees C with a working capacity of approximate to 25 wt% and a very long cycling stability under simulated flue-gas stream conditions. To the best of our knowledge, this is the first report where a graphene-oxide based hyperporous carbon network is used to host amines for carbon capture application with exceptionally high storage capacity and stability.