Academy of Scientific and Innovative Research , New Delhi 110001 , India.
Physical/Materials Chemistry Division , CSIR-National Chemical Laboratory , Dr. Homi Bhabha Road , Pune 411008 , India.
J Am Chem Soc. 2019 May 8;141(18):7572-7581. doi: 10.1021/jacs.9b02706. Epub 2019 Apr 26.
The key factor responsible for fast diffusion and mass transfer through a porous material is the availability of a widely open pore interior having complete accessibility from their surface. However, because of their highly stacked nature, ordered two-dimensional (2D) materials fail to find real-world applicability, as it is difficult to take advantage of their complete structure, especially the inner cores. In this regard, three-dimensional (3D) nanostructures constructed from layered two-dimensional crystallites could prove to be advantageous. However, the real challenge is to cultivate a porous nanostructure with ordered pores where the pores are surrounded by crystalline walls. Herein, a simple yet versatile in situ gas-phase foaming technique has been employed to address these cardinal issues. The use of baking soda leads to the continuous effervescence of CO during the crystallization of foam, which creates ripples and fluctuations on the surface of the 2D crystallites. The induction of ordered micropores within the disordered 3D architecture synergistically renders fast diffusion of various guests through the interconnected pore network. The high-density defects in the hierarchically porous structure help in ultrafast adsorption (<10 s) of various pollutants (removal efficiency of 99%) from water, all of which would lead to significant environmental benefit. The pseudo-second-order rate constant for the BPA pollutant is 182.3 g mg min, which is the highest among all the literature reports to date. The high removal efficiency (highest efficiency of 94% and average efficiency of 70%) of a persistent organic pollutant has been attended for the first time.
导致多孔材料中快速扩散和质量转移的关键因素是具有广泛开放的内部孔隙，这些孔隙从表面完全可及。然而，由于其高度堆叠的性质，有序的二维（2D）材料无法找到实际应用，因为很难利用其完整的结构，尤其是内部核心。在这方面，由层状二维晶体构建的三维（3D）纳米结构可能具有优势。然而，真正的挑战是培养具有有序孔的多孔纳米结构，其中孔被晶体壁包围。在此，采用了一种简单而通用的原位气相发泡技术来解决这些关键问题。使用小苏打会导致在泡沫结晶过程中 CO 持续冒泡，这会在二维晶体的表面上产生涟漪和波动。无序的 3D 结构内有序微孔的引入协同作用，使各种客体通过相互连接的孔网络快速扩散。分级多孔结构中的高密度缺陷有助于各种污染物（去除效率为 99%）从水中超快吸附（<10 s），所有这些都将带来重大的环境效益。BPA 污染物的拟二级速率常数为 182.3 g mg min，是迄今为止所有文献报道中最高的。持久性有机污染物的去除效率很高（最高效率为 94%，平均效率为 70%），这是首次报道。
