TY - JOUR
T1 - Hydrodeoxygenation of aliphatic acid over NiFe intermetallic compounds
T2 - Insights into the mechanism via model compound study
AU - Han, Depeng
AU - Yin, Wang
AU - Luo, Dan
AU - He, Han
AU - Wang, Shengping
AU - Xia, Shuqian
N1 - Funding Information:
Financial support by the National Basic Research Program of China (973) special preliminary study program (2014CB260408) is gratefully acknowledged.
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/12/1
Y1 - 2021/12/1
N2 - Hydrodeoxygenation (HDO) is a promising way to produce the second generation bio-diesel from aliphatic acid based biomass. Compared with the monometallic Ni/SiO2, appropriate introduction of Fe results in the complete conversion of lauric acid and nearly 100% yield of alkane as well as satisfactory stability on conversion. Further study on mechanism shows that the NiFe intermetallic compounds (IMC) catalyst promotes the ratedetermining step, i.e., C11H23COOH → C11H23CHO, which is attributed to the synergistic effect of Ni-Fe bimetallic sites according to the characterization and calculation. For one thing, strong spin polarization enhances the interaction between Fe sites and aliphatic acid, and the subsequent dissociation of C-OH bond indicated by the DOS and transition state analysis. For another, dissociation of H2 on Ni site is promoted because of the higher charge density around Ni in the IMC according to the in-suit FTIR and Bader analysis. However, with the repeated use of the catalyst, the selectivity to alkane decreased gradually, which is ascribed to the oxidation of metal Ni-Fe bimetallic sites. This demonstrates that the reduced Ni-Fe bimetallic sites rather than the oxidized ones are the active phases in the HDO of aliphatic acid to produce alkanes with the NiFe IMC.
AB - Hydrodeoxygenation (HDO) is a promising way to produce the second generation bio-diesel from aliphatic acid based biomass. Compared with the monometallic Ni/SiO2, appropriate introduction of Fe results in the complete conversion of lauric acid and nearly 100% yield of alkane as well as satisfactory stability on conversion. Further study on mechanism shows that the NiFe intermetallic compounds (IMC) catalyst promotes the ratedetermining step, i.e., C11H23COOH → C11H23CHO, which is attributed to the synergistic effect of Ni-Fe bimetallic sites according to the characterization and calculation. For one thing, strong spin polarization enhances the interaction between Fe sites and aliphatic acid, and the subsequent dissociation of C-OH bond indicated by the DOS and transition state analysis. For another, dissociation of H2 on Ni site is promoted because of the higher charge density around Ni in the IMC according to the in-suit FTIR and Bader analysis. However, with the repeated use of the catalyst, the selectivity to alkane decreased gradually, which is ascribed to the oxidation of metal Ni-Fe bimetallic sites. This demonstrates that the reduced Ni-Fe bimetallic sites rather than the oxidized ones are the active phases in the HDO of aliphatic acid to produce alkanes with the NiFe IMC.
KW - Aliphatic acid
KW - DFT
KW - Hydrodeoxygenation
KW - Intermetallic compound
KW - Ni-Fe catalyst
UR - http://www.scopus.com/inward/record.url?scp=85111336734&partnerID=8YFLogxK
U2 - 10.1016/j.fuel.2021.121545
DO - 10.1016/j.fuel.2021.121545
M3 - Article
AN - SCOPUS:85111336734
SN - 0016-2361
VL - 305
JO - Fuel
JF - Fuel
M1 - 121545
ER -