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arXiv 1606.04834cond-mat.mtrl-sci
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d2、d3和d4 M3C2作为CO2转化为烃燃料的催化剂(MXene):机理和预测性DFT研究

d2, d3, and d4 M3C2 Transition Metal Carbides (MXenes) as Catalysts for CO2 Conversion into Hydrocarbon Fuels: A Mechanistic and Pre-dictive DFT Study

Neng Li, Luis Miguel Azofra, Xingzhu Chen, Douglas R. MacFarlane, Xiujian Zhao, Chenghua Sun

摘要:

二维d2、d3和d4过渡金属碳化物作为CO2转化催化剂的功能已被良好分辨的密度泛函理论(DFT)和DFT+U理论计算所证实。虽然来自d2系列的MXene(M = Ti、Zr和Hf)的催化剂表现出对CO2的捕获活性,而V3 C2、Nb 3C 2、Cr 3C 2和Mo 3C 2材料在CO2选择性转化为CH 4的反应中表现出最有前途的结果,其极限反应能分别为1.55、1.75、0.69和1.24 eV,在DFT+U计算级别加上显式的DFT-D3色散校正,并特别强调了Cr 3C 2的作用,因为理论上预测其过电位较低。此外,重要的功能已被预测在第一个加氢步骤朝向形成的OCHO和HOCO自由基物种,表现出自发的反应能在OCHO获得这样的有前途的碳化物从d3和d4组。我们的研究结果为高性能催化剂的计算机辅助搜索和CO2反应机理的理解提供了新的见解。最后,假设沿着反应的早期步骤的CO2捕获是自发产生的,而没有通过物理吸附状态,这种捕获的强度大于H2O化学吸附的计算结合能,为我们的材料在水环境中的实验测试提供了令人鼓舞的前景

英文摘要:

The functioning of 2D d2, d3, and d4 transition metal carbides as CO2 conversion catalysts has been proved by well resolved density functional theory (DFT) and DFT+U theoretical calculations. Whilst MXenes from the d2 series (M = Ti, Zr, and Hf) have demonstrated active behaviors for the capture of CO2, the V3C2, Nb3C2, Cr3C2, and Mo3C2 materials exhibit the most promising results for their application in the selective CO2 conversion into CH4, with limiting reaction energies of 1.55, 1.75, 0.69, and 1.24 eV, respectively, at DFT+U computational level plus explicit DFT-D3 dispersion corrections, and specially highlighting the role of Cr3C2 due to its theoretically predicted low over potential. Moreover, important features have been predicted during the first hydrogenation step towards the formation of the OCHO and HOCO radical species, exhibiting spontaneous reaction energies in the OCHO obtaining for such promising carbides from the d3 and d4 groups. Our re-sults provide novel insights in the computer-aided searching of high performance catalysts and the understanding of reaction mech-anisms for CO2. Finally, it is hypothesized that the capture of CO2 along the early step of the reaction is spontaneously produced without pass from a physisorbed state, being the strength of such capture larger than the computed binding energies for the chemi-sorption of H2O, offering encouraging perspectives for the experimental testing of our materials in water environment

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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