摘要
二氧化碳(CO2)等温室气体浓度提高引起的全球变暖危机已成为全球关切的焦点.为应对这一难题,当前已开发出多种碳捕集技术来减少CO2的排放.近年来,基于多孔吸附材料的碳捕集技术因具有自身独特优势引起了全球研发人员的广泛兴趣.金属有机骨架(MOFs)材料因其高度有序的孔结构和极为丰富的结构可修饰性,被认为是本领域中极具应用前景的新型多孔材料之一.然而大多数常规MOFs材料通常存在吸附容量与选择性之间的取舍问题,近年来发展的阴离子柱杂化MOFs(APMOFs)材料由于结构中存在有丰富氢键受体的阴离子柱配体,可通过孔道尺寸、形状和化学性质之间的协同效应,同时满足对于高吸附容量和高选择性性能的要求,因而受到了本领域研究者的广泛关注.本文依据材料的吸附性能和稳定性特点,将APMOFs划分为四代发展,综述了该材料近10年来在二氧化碳捕集的研究进展,并指出在未来走向商业应用中面临的机遇和挑战.
Abstract
The global warming crisis caused by the increasing concentration of greenhouse gases such as carbon dioxide has become the focus of global concern.In response to this challenge,a variety of carbon capture technologies have been developed to reduce CO2 emissions.In recent years,carbon capture technology based on porous adsorbent materials has attracted extensive interest from researchers around the world because of its unique advantages.Metal-organic frameworks(MOFs),a class of crystalline porous materials have emerged as promising candidates for carbon dioxide capture applications owing to their highly ordered and tunable pore structures.Anion-pillared metal-organic frameworks(APMOFs)in particular,have garnered significant interest in recent years from researchers in this field.This is due to the presence of anion-pillared ligands with abundant hydrogen bond acceptors in their structure.A combination of the chemical versatility,modular design,ultrahigh porosity,pore size and geometry,high surface area and diverse functionality of the APMOFs allows for high adsorption capacity,selectivity and efficient capture of carbon dioxide through synergistic effects.Based on the adsorption performance and material stability,APMOFs can be categorized into four distinct generations.The first-generation APMOFs possess high adsorption capacity and selectivity;however,their practical utility is limited by inadequate thermal,chemical,and aqueous stability.In contrast,the second-generation APMOFs address stability issues by incorporating anion column braces characterized by high nucleophilicity.This modification substantially enhances thermal and chemical stability but results in a higher adsorption capacity only in the low-pressure range and an elevated adsorption heat for carbon dioxide,consequently increasing regeneration costs.The third-generation APMOFs are interspersed with pore distribution spanning 4.5-6 Å and a more uniform adsorption site due to structural alterations.These characteristics lead to enhanced adsorption capacity,a more moderate adsorption heat profile,and sustained high CO2 selectivity.However,these materials suffer from inadequate thermal and aqueous stability,which restricts their practical applicability.To overcome these limitations,the fourth-generation APMOFs employ a dual-pore structure featuring an icosahedral cage(～8.5 Å)and a tetrahedral cage(～4 Å),along with ligands possessing increased coordination bonds,exceptional adsorption capacity and selectivity and also demonstrates outstanding thermal stability and resistance to acidic conditions,which aligns closely with the performance prerequisites for practical applications.This paper provides a comprehensive review of the research progress made over the last decade on carbon dioxide capture utilizing four generations of APMOFs.We systematically present the progress made in terms of CO2 adsorption capacity,adsorption enthalpy,selectivity,thermal stability,and chemical stability for each of these generations.After about 10 years of continuous efforts,researchers have developed APMOFs materials that have not only excellent separation properties,but also robust thermal and chemical stability,and achieved a series of encouraging breakthrough results.Herein,we concluded that the separation performance and stability of APMOFs can be effectively improved by avoiding open metal sites,introducing multi-dentate ligands and ligands with strong coordination ability,as well as constructing composite pores,which provide useful guidance for the development of separation materials in the future.However,several challenges persist in the practical implementation of CO2 capture.These hurdles primarily encompass the high costs associated with materials,as well as the need for advancements in large-scale material synthesis techniques and molding technologies.Future solutions to these issues will among others be to develop APMOF materials with exceptional separation performance,robust stability,and cost-effectiveness,which will provide a novel technical option within the current landscape of CO2 capture methods.
基金项目
中国石油天然气股份有限公司科学研究与技术开发项目(2021DJ6002)
中国石油天然气股份有限公司直属院所基金(2020-CB-05-06)
NETL
NSTL
维普
万方数据