TY - JOUR
T1 - Nano-sized nickel catalyst for deep hydrogenation of lignin monomers and first-principles insight into the catalyst preparation
AU - Qi, Shi Chao
AU - Zhang, Lu
AU - Einaga, Hisahiro
AU - Kudo, Shinji
AU - Norinaga, Koyo
AU - Hayashi, Jun ichiro
N1 - Funding Information:
This work was supported by Japan Society for the Promotion of Science (JSPS) for Grant-in-Aid for Scientific Research A (Grant Number 26249120), and China Scholarship Council (Grant Number 201406420035 and 201406420041). The authors are also grateful to MEXT Projects, “Integrated Research Consortium on Chemical Sciences” and “Network Joint Research Center for Materials and Devices”.
Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2017
Y1 - 2017
N2 - This paper reports, for the first time, complete arene hydrogenation of phenolic compounds as lignin monomers over a non-noble metal catalyst supported by a general material. A type of nano-sized Ni catalyst was prepared in ethanol and in situ supported by ZSM-5 zeolite through general borohydride reduction of Ni2+ to Ni0, but with application of a simple ligand, pyridine. This catalyst showed an activity so high as to completely or near completely hydrogenate the aromatic rings of phenol and its twelve derivatives as potential lignin monomers at 180 °C. The activity was clearly higher than that of another type of conventional Ni catalyst prepared in the absence of pyridine. Analyses of the catalysts by TEM/EDS, XPS, XAFS and others demonstrated that pyridine had crucial roles in selective formation of nano-sized Ni and maintenance of its activity by appropriate interaction with the support. This paper also shows our theoretical approach to the mechanism of the borohydride reduction. First-principles calculations based on density functional theory (DFT) revealed the reaction pathway from Ni2+ to Ni0 and the role of pyridine, which was validated by some experimental facts. The DFT calculations also explain the variety of reactivities of the lignin monomers, which are strongly influenced by their molecular electrostatic and steric nature.
AB - This paper reports, for the first time, complete arene hydrogenation of phenolic compounds as lignin monomers over a non-noble metal catalyst supported by a general material. A type of nano-sized Ni catalyst was prepared in ethanol and in situ supported by ZSM-5 zeolite through general borohydride reduction of Ni2+ to Ni0, but with application of a simple ligand, pyridine. This catalyst showed an activity so high as to completely or near completely hydrogenate the aromatic rings of phenol and its twelve derivatives as potential lignin monomers at 180 °C. The activity was clearly higher than that of another type of conventional Ni catalyst prepared in the absence of pyridine. Analyses of the catalysts by TEM/EDS, XPS, XAFS and others demonstrated that pyridine had crucial roles in selective formation of nano-sized Ni and maintenance of its activity by appropriate interaction with the support. This paper also shows our theoretical approach to the mechanism of the borohydride reduction. First-principles calculations based on density functional theory (DFT) revealed the reaction pathway from Ni2+ to Ni0 and the role of pyridine, which was validated by some experimental facts. The DFT calculations also explain the variety of reactivities of the lignin monomers, which are strongly influenced by their molecular electrostatic and steric nature.
UR - http://www.scopus.com/inward/record.url?scp=85013471722&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85013471722&partnerID=8YFLogxK
U2 - 10.1039/c6ta08538e
DO - 10.1039/c6ta08538e
M3 - Article
AN - SCOPUS:85013471722
VL - 5
SP - 3948
EP - 3965
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
SN - 2050-7488
IS - 8
ER -