Defect‐Decorated NiFe Bimetallic Nanocatalysts for the Enhanced Hydrodeoxygenation of Guaiacol

• Published in: ChemCatChem 2022-10, Vol.14 (19), p.n/a
• Main Authors: Zhang, Yaowen, Wang, Wenyun, Fan, Guoli, Yang, Lan, Li, Feng
• Format: Article
• Language: English
• Subjects: Ammonia; Bimetals; Conversion of Lignin-derived phenolics; Cyclohexane; Density functional theory; Hydrodeoxygenation; Interfacial defective structures; Intermetallic compounds; Iron; Iron compounds; Nickel compounds; NiFe bimetallic catalysts
• ISSN: 1867-3880; 1867-3899
• DOI: 10.1002/cctc.202200585

Series of Ni‐based nanocatalysts were fabricated for the HDO of lignin‐derived guaiacol to cyclohexane via a single‐source Ni−Fe−Al layered double hydroxide precursor route and characterized by XRD, BET, TEM, XAS, XPS, H2‐TPR, H2‐TPD, NH3‐TPD, and pyridine absorbed in situ FT‐IR. As‐fabricated bimetallic NiFe nanocatalyst bearing a Fe/Ni molar ratio of 0.5 : 3 attained a higher cyclohexane yield of 70.5 % under mild reaction conditions (i. e., 230 °C and 1.0 MPa of initial hydrogen pressure), compared to monometallic Ni and other NiFe bimetallic nanocatalysts, as well as monometallic Ni and bimetallic NiFe catalysts prepared by the impregnation method. Combination of experimental results and density functional theory calculations manifested that interfacial FeOx species profoundly facilitated the demethoxylation processes of guaiacol and 2‐methoxycyclohexanol intermediate, while both bimetallic NiFe sites and interfacial FeOx species greatly promoted the dehydroxylation of cyclohexanol intermediate. Multiple surface‐interface active sites including metallic sites, NiFe alloy sites, and interfacial FeOx species were constructed on defect‐decorated bimetallic NiFe nanocatalysts. It was revealed that Interfacial FeOx species profoundly promoted the activation of the Cring−OCH3 bond of guaiacol and intermediate, and NiFe alloy sites together with FeOx species promoted the activation of Cring−OH bond of intermediate, thereby leading to the enhanced catalytic efficiency in the hydrodeoxygenation of guaiacol.