Maity Ayan, Singh Saideep, Mehta Swati, Youngs Tristan G A, Bahadur Jitendra, Polshettiwar Vivek
Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
Langmuir. 2023 Mar 28;39(12):4382-4393. doi: 10.1021/acs.langmuir.2c03474. Epub 2023 Mar 15.
Understanding adsorption processes at the molecular level has transformed the discovery of engineered materials for maximizing gas storage capacity and kinetics in adsorption-based carbon capture applications. In this work, we studied the molecular mechanism of gas (CO, H, methane, and ethane) adsorption inside an interconnected porous network of carbon. This was achieved by synthesizing novel macro-meso-microporous carbon (MC) nanospheres with interconnected pore structures. The MCs showed a CO capture capacity of 5.3 mmol/g at atmospheric CO pressure, with excellent kinetics. This was due to fast CO adsorption within the interconnected hierarchical macro-meso-microporous MC. In situ small-angle neutron scattering (SANS) under various CO pressures indicated that the macro- and mesopores of MC enable fast diffusion of CO molecules inside the micropores, where adsorbed CO molecules densify into a liquid-like state. This strong densification of CO molecules causes fast CO diffusion in the macro- and mesopores of MC, restarting the adsorption cycle for fresh CO molecules until all pores are completely filled. Notably, MC also showed good capture capacities for hydrogen and various hydrocarbons, with excellent selectivity toward ethane over methane.
在分子水平上理解吸附过程，已经改变了工程材料的发现方式，以在基于吸附的碳捕获应用中最大化气体存储容量和吸附动力学。在这项工作中，我们研究了气体（一氧化碳、氢气、甲烷和乙烷）在相互连接的碳多孔网络内部的吸附分子机制。这是通过合成具有相互连接孔结构的新型大-中-微孔碳（MC）纳米球来实现的。在大气一氧化碳压力下，MC的一氧化碳捕获容量为5.3 mmol/g，具有出色的动力学性能。这是由于一氧化碳在相互连接的分级大-中-微孔MC中快速吸附。在各种一氧化碳压力下的原位小角中子散射（SANS）表明，MC的大孔和中孔能够使一氧化碳分子在微孔内快速扩散，在微孔中吸附的一氧化碳分子致密化为类似液体状态。一氧化碳分子的这种强烈致密化导致一氧化碳在MC的大孔和中孔中快速扩散，重新启动对新鲜一氧化碳分子的吸附循环，直到所有孔完全填满。值得注意的是，MC对氢气和各种碳氢化合物也表现出良好的捕获能力，对乙烷的选择性优于甲烷。
