摘要
通过挤出成型法制备了ZnO掺杂CaO吸附剂,研究ZnO掺杂CaO吸附剂的CO_(2)吸附性能。基于密度泛函理论,建立CaO(001)和Zn-CaO(001)表面模型,计算2种材料吸附CO_(2)的构型、吸附能、分态密度以及差分电子密度,通过对比改性前后2种材料的计算结果,从微观原子层面揭示ZnO掺杂对CaO吸附CO_(2)性能的影响机理。研究结果表明:随着ZnO添加量从1%增加到5%,CaO的CO_(2)吸附性能随之增加。当ZnO添加量为3%时,ZnO/CaO吸附剂第1次和第5次循环的碳酸化转化率分别为0.86和0.76。加入ZnO后,CO_(2)吸附能由-1.184 eV下降为-1.947 eV,且相比于Ca原子,Zn原子与O原子之间存在更多的共振峰,Zn-CaO(001)表面的Zn原子、C原子与O原子在-6.06 eV处出现高态密度的3个原子电子轨道共振峰,这表明掺杂ZnO提高了CaO结构的稳定性,且Zn原子、表面O原子与C原子之间有更多的电荷转移。Zn原子与O原子间的电荷转移提高了O原子的反应活性,使其更易与C原子成键,导致CO_(2)以CO32-的结构吸附在ZnO/CaO表面。因此,ZnO提高了CaO的CO_(2)吸附性能,是一种理想的添加剂。
ZnO-doped CaO adsorbents were prepared by extrusion molding method,and the CO_(2)adsorption performance of ZnO-doped CaO adsorbents was investigated.Based on density functional theory(DFT),the surface models of CaO(001)and Zn-CaO(001)were established,and the conformation,adsorption energy,state density and differential electron density of CO_(2)adsorption for the two materials were calculated.The mechanism of the effect of ZnO doping on the CO_(2)adsorption performance of CaO was revealed at the microscopic atomic level by comparing the calculated results of the materials before and after modification.The results show that with the increase of ZnO addition from 1%to 5%,the CO_(2)adsorption performance of CaO increases.When ZnO is added to 3%,the carbonation conversions of ZnO/CaO adsorbent in the first and fifth cycles are 0.86 and 0.76,respectively.After the addition of ZnO,the adsorption energy of CO_(2)decreases from-1.184 eV to-1.947 eV,and there are more formants between Zn atom and O atom than those between Ca atom and O atom.On the surface of Zn-CaO(001),a high density three-atom electron orbital resonance peak of Zn atom,C atom and O atom appears at-6.06 eV.It indicates that doping ZnO improves the stability of CaO structure and results in more charge transfer between Zn atoms,O atoms and C atoms.The charge transfer between Zn atom and O atom improves the reactivity of O atom and makes O atom easier to bond with C atom.As a result,CO_(2)is adsorbed on ZnO/CaO surface as CO32-.Therefore,ZnO improves the CO_(2)adsorption performance of CaO and it is an ideal additive.
作者
张友浩
徐运飞
王菲菲
李英杰
ZHANG Youhao;XU Yunfei;WANG Feifei;LI Yingjie(School of Energy and Power Engineering,Shandong University,Jinan 250061,China;Shandong Engineering Laboratory for High-efficiency Energy Conservation and Energy Storage Technology&Equipment,Shandong University,Jinan 250061,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2022年第12期4657-4665,共9页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(52276204)。
作者简介
通信作者:李英杰,博士,教授,从事CO_(2)捕集、制氢及储能等研究,E-mail:liyj@sdu.edu.cn。
