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首页> 外文期刊>Journal of Materials Chemistry, A. Materials for energy and sustainability >Porous BN with vacancy defects for selective removal of CO from H-2 feed gas in hydrogen fuel cells: a DFT study
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Porous BN with vacancy defects for selective removal of CO from H-2 feed gas in hydrogen fuel cells: a DFT study

机译：DFT研究：具有空位缺陷的多孔BN用于从氢燃料电池的H-2进料气中选择性去除CO

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Developing highly efficient sorbent materials for separation and capture of CO from H-2 feed gas is of great importance in fuel cell technology in terms of the efficient use of the Pt anode catalyst and the cycle lifetime of the system. Using density functional theory (DFT) calculations, we showed that porous BN with introduced monovacancy defects can be an effective sorbent for CO capture. The adsorption energies were calculated to be 0.075 and -0.92 eV for H-2 and CO absorbed on pristine porous BN, respectively. However, with introduction of vacancy defects, the adsorption energies were estimated to be 5.56 and 3.79 eV for CO absorbed on V-B and V-N defects, respectively. Meanwhile, the calculated adsorption energies of H-2 on the V-B and V-N defects decrease to -0.71 and -0.30 eV, respectively. Our result indicates that the capture of CO on defective porous BN is highly preferred over H-2 molecules. Moreover, the energy difference between E-ads(CO) and E-ads(H-2) is 2 to 4 times higher than that of the reported metal/graphene system, suggesting that p-BN with vacancy defects is a more efficient sorbent. The electronic structure calculations suggest that introduction of vacancy defects into porous BN induces defect electronic states in the energy-gap region with a strong impact on the adsorption performance of the material. To evaluate energetic stability, the defect formation energies were also calculated. The formation energy of vacancy defects strongly depends on the chemical environment, and the selection of different reactants (B or N sources) would achieve the goal of reducing the formation energy of the vacancy defects. These findings should provide useful guidance for the design and fabrication of porous BN sorbents useful for removal of CO from H-2 feed gas feed in hydrogen fuel cells.
机译：就有效利用铂阳极催化剂和系统的循环寿命而言，开发用于从H-2进料气体中分离和捕集CO的高效吸附剂材料在燃料电池技术中非常重要。使用密度泛函理论（DFT）计算，我们发现具有引入的单空位缺陷的多孔BN可以作为有效的CO吸附剂。对于原始多孔BN吸收的H-2和CO的吸附能经计算分别为0.075和-0.92 eV。然而，随着空位缺陷的引入，据估计，吸附在V-B和V-N缺陷上的CO的吸附能分别为5.56和3.79 eV。同时，计算出的H-2在V-B和V-N缺陷上的吸附能分别降至-0.71和-0.30 eV。我们的结果表明，在有缺陷的多孔BN上捕获CO的优先级高于H-2分子。此外，E-ads（CO）和E-ads（H-2）之间的能量差比已报道的金属/石墨烯系统高2至4倍，这表明具有空位缺陷的p-BN是一种更有效的吸附剂。电子结构计算表明，将空位缺陷引入多孔BN中会在能隙区域中引发缺陷电子态，从而对材料的吸附性能产生强烈影响。为了评估能量稳定性，还计算了缺陷形成能。空位缺陷的形成能在很大程度上取决于化学环境，选择不同的反应物（B或N源）将达到降低空位缺陷的形成能的目的。这些发现应为设计和制造多孔BN吸附剂提供有用的指导，该吸附剂可用于从氢燃料电池的H-2进料气中去除CO。

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