​G-BN异质界面催化CO2还原?表面曲率在操控!


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​G-BN异质界面催化CO2还原?表面曲率在操控!



​G-BN异质界面催化CO2还原?表面曲率在操控!

成果简介



​G-BN异质界面催化CO2还原?表面曲率在操控!
​G-BN异质界面催化CO2还原?表面曲率在操控!

寻找环保、低成本的二氧化碳还原催化剂对于可持续能源和环境技术的发展至关重要。鉴于此,昆士兰科技大学Aijun Du团队在EcoMat发表了题为“Metal-free graphene/boron nitride heterointerface for CO2 reduction: Surface curvature controls catalytic activity and selectivity”的研究论文,报告了石墨烯和 BN 纳米管或纳米带之间的新型异质界面,可作为具有高活性和选择性的 CO2 还原的有效催化剂。作者发现活性位点位于石墨烯-BN(G-BN)的C-N界面处,其优异的催化性能源于表面曲率效应。密度泛函理论(DFT)结果表明,形成CH3OH最有利的能量途径是 * + CO2 → *COOH → *CO → *OCH → *OCH2 → *OCH3 → *CH3OH → * + CH3OH。而CH4的形成是通过* + CO2→ *COOH→*CO → *OCH →*OCH2→ *OCH3→ *O + CH4→ *OH + CH4→ *H2O + CH4途径。此外,计算结果进一步表明,对于较小指数的 G-BN 纳米管,例如 G-BN (3),由于较低的自由能变化,CH3OH 产物的形成比 *O 中间体和 CH4 分子容易得多。然而,对于指数较高的 G-BN 纳米管,在形成 *OCH3 中间体后,*O 和 CH4 分子的生成更可行,特别是对于 G-BN(9),计算出的极限电位仅为 -0.42 V,即高于最好的 Cu 基材料,例如 Cu(111) 上的 -0.93 V 和 Cu (211) 上的 -0.74 V。证实这种不含金属的异质结构以高活性和选择性促进 CO2 转化,显示出作为一种新型 CO2 还原催化剂的巨大潜力。


​G-BN异质界面催化CO2还原?表面曲率在操控!


​G-BN异质界面催化CO2还原?表面曲率在操控!
​G-BN异质界面催化CO2还原?表面曲率在操控!



​G-BN异质界面催化CO2还原?表面曲率在操控!

主要内容



​G-BN异质界面催化CO2还原?表面曲率在操控!

Figure 1 (A) The optimized structure for G-BN nanoribbon. (B), (C) The top view and side view for G-BN nanotube take G-BN (6) for an example. The grey, pink, and blue balls represent the C, B, and N atoms

​G-BN异质界面催化CO2还原?表面曲率在操控!

Figure 2 (A) The band structures for the G-BN nanoribbon and G-BN (6) nanotube. (B). The valence bond maximum and conduction bond minimum of G-BN nanoribbon and nanotubes. The iso-surface value is 0.05 e Å−3. The grey, pink, blue, and white balls represent the C, B, N, and H atoms

​G-BN异质界面催化CO2还原?表面曲率在操控!

Figure 3 (A) Comparison of hydrogen evolution reactions and CO2 reduction reactions on G-BN nanoribbon and nanotubes. (B) The optimized structures for the adsorption of *COOH and *H on G-BN nanoribbon. (C) The optimized structures for the adsorption of *COOH and *H on G-BN (6) nanotube

​G-BN异质界面催化CO2还原?表面曲率在操控!

Figure 4 (A) Binding energies of *OCH3 and *COOH on G-BN nanoribbon and nanotubes. (B) The top view and side view of the optimized structures for the adsorption of *OCH3 on G-BN nanoribbon. (C) The top view and side view of the optimized structures for the adsorption of *OCH3 on the G-BN (6) nanotube

​G-BN异质界面催化CO2还原?表面曲率在操控!

Figure 5 The Gibbs free energy change diagrams for the formation of CO and HCOOH molecules on the catalysts

​G-BN异质界面催化CO2还原?表面曲率在操控!

Figure 6 The Gibbs free energy change diagrams for the formation of CH3OH and CH4 on the G-BN nanoribbon and nanotubes. (A) G-BN (3), (B) G-BN (4), (C) G-BN (5) and (D) G-BN (6). The optimized structures for some main intermediates are also presented in the figure

​G-BN异质界面催化CO2还原?表面曲率在操控!

Figure 7 The Gibbs free energy change diagrams for the formation of CH3OH and CH4 on the G-BN nanoribbon and nanotubes. (A) G-BN (7), (B) G-BN (8), (C) G-BN (9) and (D) G-BN nanoribbon. The optimized structures for some main intermediates are also presented in the figure


​G-BN异质界面催化CO2还原?表面曲率在操控!

结论



​G-BN异质界面催化CO2还原?表面曲率在操控!
​G-BN异质界面催化CO2还原?表面曲率在操控!

本文通过第一性原理计算,设计了一系列无金属 G-BN 纳米材料用于 CO2 还原,并且发现 C-N 界面是该过程的活性位点。由于与 *COOH 基团的强结合作用,所有 G-BN 纳米管和纳米带都抑制了HER。G-BN纳米管的表面曲率效应对*COOH和*CH2OH中间体的结合能有显着影响,从而可以筛选出最佳的CO2转化催化剂。DFT 计算结果进一步表明,对于较小指数的 G-BN 纳米管,例如 G-BN (3),由于较低的自由能变化,CH3OH 产物的形成比 *O 中间体和 CH4 分子容易得多。然而,高指数G-BN 纳米管促进了 CH4 的形成,尤其是对于 G-BN (9),计算的极限电位为 -0.42 V,高于报道的最佳 Cu 基材料。该研究提出了一种有前途的无金属催化剂,在催化 CO2 还原方面具有高活性和高选择性。

​G-BN异质界面催化CO2还原?表面曲率在操控!
​G-BN异质界面催化CO2还原?表面曲率在操控!



​G-BN异质界面催化CO2还原?表面曲率在操控!

文章信息



Xin Mao, Dimuthu Wijethunge, Lei Zhang, Sufan Wang, Cheng Yan, Zhonghua Zhu, Aijun Du, Metal-free graphene/boron nitride heterointerface for CO2 reduction: Surface curvature controls catalytic activity and selectivity, EcoMat. 2020;2:e12013.

https://doi.org/10.1002/eom2.12013


​G-BN异质界面催化CO2还原?表面曲率在操控!



​G-BN异质界面催化CO2还原?表面曲率在操控!



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​G-BN异质界面催化CO2还原?表面曲率在操控!

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​G-BN异质界面催化CO2还原?表面曲率在操控!



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