Zong Shibiao, Zhang Yajing, Lu Na, Ma Pan, Wang Jianguo, Shi Xue-Rong
School of Material Engineering, Shanghai University of Engineering Science, 333 Longteng Road, Songjiang District, Shanghai 201620, China.
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, P.O. Box 165, Taiyuan 030001, China.
Nanomaterials (Basel). 2018 Nov 20;8(11):958. doi: 10.3390/nano8110958.
To develop promising adsorbent candidates for adsorptive denitrogenation, we screened the adsorption of NO, NO₂, and NH₃ in 19 M-HKUST-1 (M = Be, Fe, Ni, Cr, Co, Cu, V, Zn, Mo, Mn, W, Sn, Ti, Cd, Mg, Sc, Ca, Sr, and Ba) systematically using first-principle calculations. Of these, four variants of M-HKUST-1 (M = Ni, Co, V, and Sc) yield more negative adsorption Gibbs free energy ΔG than the original Cu-HKUST-1 for three adsorbates, suggesting stronger adsorbate binding. Ti-HKUST-1, Sc-HKUST-1, and Be-HKUST-1 are predicted to have the largest NO, NO₂, and NH₃ adsorption energies within the screened M-HKUST-1 series, respectively. With the one exception of NO₂ dissociation on V-HKUST-1, dissociative adsorption of NO, NO₂, and NH₃ molecules on the other considered M-HKUST-1 is energetically less favorable than molecular adsorption thermodynamically. The barrier calculations show that the dissociation is difficult to occur on Cu-HKUST-1 kinetically due to the very large dissociation barrier. Electronic analysis is provided to explain the bond nature between the adsorbates and M-HKUST-1. Note that the isostructural substitution of Cu to the other metals is a major simplification of the system, representing the ideal situation; however, the present study provides interesting targets for experimental synthesis and testing.
为了开发用于吸附脱氮的有前景的吸附剂候选材料，我们使用第一性原理计算系统地筛选了19种M-HKUST-1（M = Be、Fe、Ni、Cr、Co、Cu、V、Zn、Mo、Mn、W、Sn、Ti、Cd、Mg、Sc、Ca、Sr和Ba）对NO、NO₂和NH₃的吸附情况。其中，M-HKUST-1的四种变体（M = Ni、Co、V和Sc）对于三种吸附质产生的吸附吉布斯自由能ΔG比原始的Cu-HKUST-1更负，表明吸附质结合更强。在筛选出的M-HKUST-1系列中，Ti-HKUST-1、Sc-HKUST-1和Be-HKUST-1分别被预测具有最大的NO、NO₂和NH₃吸附能。除了V-HKUST-1上的NO₂解离外，在其他考虑的M-HKUST-1上，NO、NO₂和NH₃分子的解离吸附在热力学上比分子吸附更不利。势垒计算表明，由于解离势垒非常大，Cu-HKUST-1在动力学上很难发生解离。提供了电子分析来解释吸附质与M-HKUST-1之间的键性质。需要注意的是，将Cu同构替代为其他金属是该系统的一个主要简化，代表了理想情况；然而，本研究为实验合成和测试提供了有趣的目标。
