Gao Xiaoping, Zhou Yanan, Tan Yujia, Liu Shiqiang, Cheng Zhiwen, Shen Zhemin
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
School of Chemical Engineering, Sichuan University, Chengdu, 610065, Sichuan, China.
Phys Chem Chem Phys. 2020 Jan 28;22(4):2457-2465. doi: 10.1039/c9cp05548g. Epub 2020 Jan 15.
Lattice strain, either tensile or compressive, can fine-tune the electronic structure of surfaces via altering the distances between surface atoms, thereby modifying the catalytic activity of catalysts. Numerous examples of strain engineering have been applied to various electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), but strain-optimized 2D carbon-based single-atom electrocatalysts for catalyzing the overall water splitting reaction have received little attention. Here, we applied the lattice strain of Co,N co-decorated graphyne (Co@N-GY) to directly optimize its catalytic activity for the overall water splitting reaction based on first-principles calculations. Our calculations suggest that compressive strain and tensile strain lead to less stability of Co@N-GY and the distances between C and Co atoms increase linearly with the strain changing from compressive to tensile, thus linearly upshifting the p-band center of C atoms and the d-band center of Co atoms. In addition, biaxial strain has more remarkable effects on these properties than uniaxial strain. From compressive to tensile strain, the chemisorption of electrochemically generated intermediates in both HER and OER becomes weaker and weaker. A tensile strain of 0.5% on Co@N-GY gives an ideal HER performance, while the OER reaches the minimum overpotential of 0.33 V under the biaxial tensile strain of 3%.
晶格应变，无论是拉伸应变还是压缩应变，都可以通过改变表面原子之间的距离来微调表面的电子结构，从而改变催化剂的催化活性。应变工程的众多实例已应用于各种用于析氢反应（HER）和析氧反应（OER）的电催化剂，但用于催化全水分解反应的应变优化二维碳基单原子电催化剂却很少受到关注。在此，我们基于第一性原理计算，应用Co、N共修饰石墨炔（Co@N-GY）的晶格应变来直接优化其对全水分解反应的催化活性。我们的计算表明，压缩应变和拉伸应变会导致Co@N-GY的稳定性降低，并且C和Co原子之间的距离随着应变从压缩应变变为拉伸应变而线性增加，从而使C原子的p带中心和Co原子的d带中心线性上移。此外，双轴应变对这些性质的影响比单轴应变更显著。从压缩应变到拉伸应变，HER和OER中电化学产生的中间体的化学吸附变得越来越弱。Co@N-GY上0.5%的拉伸应变给出了理想的HER性能，而在3%的双轴拉伸应变下，OER达到了0.33 V的最小过电位。
