Dual Engineering of Lattice Strain and Valence State of NiAl‐LDHs for Photoreduction of CO2 to Highly Selective CH4

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2023-03, Vol.19 (11), p.e2205770-n/a
• Main Authors: Tan, Ling, Sun, Xiaoliang, Bai, Sha, Song, Ziheng, Song, Yu‐Fei
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Carbon monoxide; CO 2 photoreduction; Electron transfer; Electronic structure; electronic structures; Hydrogen evolution reactions; Hydroxides; Intermetallic compounds; Lattice strain; lattice strains; Methane; Nanotechnology; Natural gas; Nickel aluminides; Nickel base alloys; Nickel compounds; Oxidation; Photochemical reactions; Selectivity; surfactant; Valence
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202205770

Converting CO2 to clean‐burning fuel such as natural gas (CH4) with high activity and selectivity remains to be a grand challenge due to slow kinetics of multiple electron transfer processes and competitive hydrogen evolution reaction (HER). Herein, the fabrication of surfactants (C11H23COONa, C12H25SO4Na, C16H33SO4Na) intercalated NiAl‐layered double hydroxides (NiAl‐LDH) is reported, resulting in the formation of LDH‐S1 (S1 = C11H23COO−), LDH‐S2 (S2 = C12H25SO4−) and LDH‐S3 (S3 = C16H33SO4−) with curved morphology. Compared with NiAl‐LDH with a 1.53% selectivity of CH4, LDH‐S2 shows higher selectivity of CH4 (83.07%) and lower activity of HER (3.84%) in CO2 photoreduction reaction (CO2PR). Detailed characterizations and DFT calculation indicates that the inherent lattice strain in LDH‐S2 leads to the structural distortion with the presence of VNi/Al defects and compressed MOM bonds, and thereby reduces the overall energy barrier of CO2 to CH4. Moreover, the lower oxidation states of Ni in LDH‐S2 enhances the adsorption of intermediates such as OCOH* and *CO, promoting the hydrogenation of CO to CH4. Therefore, the coupling effect of both lattice strain and electronic structure of the LDH‐S2 significantly improves the activity and selectivity for CO2PR. A series of NiAl‐LDHs intercalated with different surfactants (LDH‐Sx) are successfully constructed. The different carbon chain lengths of surfactants modulated the lattice strain and electronic structure of NiAl‐LDH, which tunes the activity of CO2PR. Compared with the typical hexagonal plate‐like morphology LDH (denoted as LDH‐F), the selectivity of CH4 in LDH‐S2 can be improved from 1.53% to 83.07%.