二维M_2XO_(2-2x)(OH)_(2x)(M=Ti,V;X=C,N)析氢催化活性的第一性原理研究 |
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作者单位: | 1. College of Teacher Education, Quzhou University, Quzhou 324000, Zhejiang Province, P. R. China;2. College of Chemical and Material Engineering, Quzhou University, Quzhou 324000, Zhejiang Province, P. R. China;3. Department of Microelectronic Science and Engineering, Ningbo University, Ningbo 315211, Zhejiang Province, P. R. China |
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基金项目: | the National Natural Science Foundation of China(51502154);the National Natural Science Foundation of China(21271116);the National Natural Science Foundation of China(21476127);the National Natural Science Foundation of China(u1607119);the Young Academic Leading Training Plan, Quzhou University, China(XNZQN201517) |
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摘 要: | MXene是一种新型的二维析氢催化材料,其表面容易被亲水基团O和OH混合覆盖。我们基于第一性原理计算的方法,研究了M_2XO_(2-2x)(OH)_(2x)(M=Ti,V;X=C,N)的析氢催化活性。计算结果显示,M_2XO_(2-2x)(OH)_(2x)的析氢催化活性与其表面OH覆盖率(X)密切相关。对Ti_2CO_(2-2x)(OH)_(2x)来说,OH覆盖率不超过1/3时,具有优异的析氢催化活性。对Ti_2NO_(2-2x)(OH)_(2x)、V_2CO_(2-2x)(OH)_(2x)和V_2NO_(2-2x)(OH)_(2x)来说,OH覆盖率分别达到4/9、1/3和5/9时,才具有最佳的析氢催化活性。接着,电荷分析显示OH覆盖率会显著影响M_2XO_(2-2x)(OH)_(2x)活性位点O基团的电荷量。最后,我们从态密度的角度揭示了析氢催化活性变化的原因,即活性位点O基团的氧化性随OH覆盖率的增大而被削弱。因此,本文提出了调节表面OH覆盖率来获取M_2XO_(2-2x)(OH)_(2x)最佳析氢催化活性状态的方法,这在工业制氢生产过程中具有重要的应用价值。
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关 键 词: | 二维材料 MXene 第一性原理 析氢催化 吸附 |
收稿时间: | 2017-04-07 |
First-Principle Study of Hydrogen Evolution Activity for Two-dimensional M2XO2-2x(OH)2x (M=Ti,V; X=C,N) |
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Authors: | Shao-Zheng ZHANG Jia LIU Yan XIE Yin-Ji LU Lin LI Liang LÜ Jian-Hui YANG Shi-Hao WEI |
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Institution: | 1. College of Teacher Education, Quzhou University, Quzhou 324000, Zhejiang Province, P. R. China;2. College of Chemical and Material Engineering, Quzhou University, Quzhou 324000, Zhejiang Province, P. R. China;3. Department of Microelectronic Science and Engineering, Ningbo University, Ningbo 315211, Zhejiang Province, P. R. China |
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Abstract: | MXene is a new group of electrocatalysts for two-dimensional hydrogen evolution reaction (HER). Its surfaces are often covered by hydrophilic O and OH mixed groups. To find the effect of the O and OH mixed groups on HER, we studied the HER activity for M2XO2-2x(OH)2x (M=Ti, V; X=C, N) by first-principle calculations. Results indicate that HER activity is closely related to OH-occupied coverage (x). For Ti2CO2-2x(OH)2x, excellent HER activity could be maintained when the OH-occupied coverage was not larger than 1/3. For Ti2NO2-2x(OH)2x, V2CO2-2x(OH)2x, and V2NO2-2x(OH)2x, high HER activity was obtained when OH-occupied coverage reached 4/9, 1/3, and 5/9, respectively. Next, we analyzed the charge-transfer density and found that the charges on the oxygen groups were strongly affected by the OH-occupied coverage. Finally, we revealed the variation of HER activity that oxidizability of O groups is weakened with increasing OH-occupied coverage. In this paper, we propose a new method to obtain the optimal HER activity for M2XO2-2x(OH)2x by adjusting the OH-occupied coverage of the surfaces, which is useful in industrial hydrogen production. |
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Keywords: | Two-dimensional material MXene First-principle method Hydrogen evolution reaction Adsorption |
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