First-Principles Study on Interlayer Spacing and Structure Stability of NiAl-Layered Double Hydroxides

Xiaoliang Wang; Haonan Zhao; Leiming Chang; Zhenqiu Yu; Zhiwu Xiao; Shuwei Tang; Chuanhui Huang; Jingxin Fan; Shaobin Yang

doi:10.1021/acsomega.2c05067

First-Principles Study on Interlayer Spacing and Structure Stability of NiAl-Layered Double Hydroxides

ACS Omega. 2022 Oct 21;7(43):39169-39180. doi: 10.1021/acsomega.2c05067. eCollection 2022 Nov 1.

Authors

Xiaoliang Wang¹, Haonan Zhao¹, Leiming Chang¹, Zhenqiu Yu¹, Zhiwu Xiao¹, Shuwei Tang¹, Chuanhui Huang², Jingxin Fan³, Shaobin Yang¹

Affiliations

¹ College of Materials Science and Engineering, Key Laboratory of Mineral High Value Conversion and Energy Storage Materials of Liaoning Province, Geology and Mineral Engineering Special Materials Professional Technology Innovation Center of Liaoning Province, Liaoning Technical University, Fuxin123000, China.
² School of Mechanical and Electrical Engineering, Xuzhou University of Technology, Xuzhou221111, China.
³ CCTEG China Coal Research Institute, Beijing100013, China.

Abstract

Interlayer spacing and structure stability of layered double hydroxides (LDHs) on their application performance in adsorption, ion exchange, catalysis, carrier, and energy storage is important. The effect of different interlayer anions on the interlayer spacing and structure stability of LDHs has been less studied, but it is of great significance. Therefore, based on density functional theory (DFT), the computational model with 10 kinds of anions intercalated Ni₃Al-A-LDHs (A = Cl^-, Br^-, I^-, OH^-, NO₃ ^-, CO₃ ^2-, SO₄ ^2-, HCOO^-, C₆H₅SO₃ ^-, C₁₂H₂₅SO₃ ^-) and four Ni _R Al-Cl-LDH models with different Ni²⁺/Al³⁺ ratios (R = 2, 3, 5, 8) were constructed to calculate and analyze interlayer spacing, structural stability, and their influence factors. It was found that the interlayer spacing order of Ni₃Al-A-LDHs intercalated with different anions is OH^- < CO₃ ^2- < Cl^- < Br^- < I^- < HCOO^- < SO₄ ^2- < NO₃ ^- < C₆H₅SO₃ ^- < C₁₂H₂₅SO₃ ^-. The hydrogen bond network between the base layer and the interlayer anions affects the arrangement structure of the interlayer anions, which affects the interlayer spacing. For interlayer monatomic anions Cl^-, Br^-, and I^- and the anion of comparable size in each direction SO₄ ^2-, the interlayer spacing is positively correlated with the interlayer anion diameter. The larger difference between the long-axis and short-axis dimensions of the polyatomic anions results in the long axis of the anion being perpendicular to the basal layer, increasing interlayer spacing. The long-chain anion C₁₂H₂₅SO₃ ^- intercalation system exhibits the largest layer spacing of 24.262 Å. As R value increases from 2 to 8, the interlayer spacing of Ni _R Al-Cl-LDHs gradually increases from 7.964 to 8.124 Å. The binding energy order between the interlayer anion and basal layer is CO₃ ^2- > SO₄ ^2- > OH^- > Cl^- > Br^- > I^- > HCOO^- > NO₃ ^- > C₁₂H₂₅SO₃ ^- > C₆H₅SO₃ ^-. The smaller the interlayer spacing, the higher the binding energy and the stronger the structural stability of LDHs. The factors affecting structural stability mainly include the bond length and bond angle of the hydrogen bond and the charge interaction between the basal layer and interlayer anion. In the CO₃ ^2- intercalated system, the hydrogen bond length exhibits the shortest of 1.95 Å and the largest bond angle of 163.68°. The density of states and energy band analysis show that the higher the number of charges carried by the anion, the stronger its ability to provide electrons to the basal layer.