TY - JOUR
T1 - Does a Strong Oxophilic Promoter Enhance Direct Deoxygenation? A Study of NiFe, NiMo, and NiW Catalysts in p-Cresol Conversion
AU - Hsu, Pei Ju
AU - Jiang, Jia Wei
AU - Lin, Yu Chuan
N1 - Funding Information:
This study was supported by the Ministry of Science and Technology in Taiwan (Projects 104-2628-E-006-009-MY2, 106-2221-E-006-188-MY3, and 106-2218-E-155-005) and Taiwan's Deep Decarbonization Pathways toward a Sustainable Society (Project 106-0210-02-11-05).
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2018/1/2
Y1 - 2018/1/2
N2 - A bifunctional catalyst, composed of a hydrogenation active metal and an oxophilic promoter for CAr-O bond weakening, is effective in the deoxygenation of lignin derivatives due to a contact synergy. A systematic comparison of the physicochemical properties of Ni-based catalysts promoted by metal oxides (i.e., FeOx, MoOx, and WOx) with different extents of oxophilicity was conducted, and their catalytic behaviors were evaluated in the conversion of p-cresol. Ni promoted by WOx displays the highest oxophilicity among all promoters and is intrinsically more active than NiMo and NiFe in direct deoxygenation (DDO); this characteristic is possibly related to its great hydride mobility. However, in a H2-pressured system, Ni promoted by MoOx, which has moderate oxophilicity compared with the employed promoters, generated more DDO product (toluene) than NiFe and NiW. This study discovered that this discrepancy, between the result of the chemical test under normal pressure and the result of the reaction test in an authentic pressurized system concerning the relation between toluene yield and a promoter's oxophilicity, is related to different hydrogenation rates of toluene. Toluene derived from DDO of p-cresol can be subsequently hydrogenated and thus be turned into methylcyclohexane more rapidly by the NiW catalyst than by NiMo and NiFe catalysts. Hence, both the oxophilicity of a promoter and the inertness of hydrogenation of toluene should be considered in designing a bimetallic catalyst in the conversion of lignin derivatives.
AB - A bifunctional catalyst, composed of a hydrogenation active metal and an oxophilic promoter for CAr-O bond weakening, is effective in the deoxygenation of lignin derivatives due to a contact synergy. A systematic comparison of the physicochemical properties of Ni-based catalysts promoted by metal oxides (i.e., FeOx, MoOx, and WOx) with different extents of oxophilicity was conducted, and their catalytic behaviors were evaluated in the conversion of p-cresol. Ni promoted by WOx displays the highest oxophilicity among all promoters and is intrinsically more active than NiMo and NiFe in direct deoxygenation (DDO); this characteristic is possibly related to its great hydride mobility. However, in a H2-pressured system, Ni promoted by MoOx, which has moderate oxophilicity compared with the employed promoters, generated more DDO product (toluene) than NiFe and NiW. This study discovered that this discrepancy, between the result of the chemical test under normal pressure and the result of the reaction test in an authentic pressurized system concerning the relation between toluene yield and a promoter's oxophilicity, is related to different hydrogenation rates of toluene. Toluene derived from DDO of p-cresol can be subsequently hydrogenated and thus be turned into methylcyclohexane more rapidly by the NiW catalyst than by NiMo and NiFe catalysts. Hence, both the oxophilicity of a promoter and the inertness of hydrogenation of toluene should be considered in designing a bimetallic catalyst in the conversion of lignin derivatives.
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U2 - 10.1021/acssuschemeng.7b03010
DO - 10.1021/acssuschemeng.7b03010
M3 - Article
AN - SCOPUS:85040067848
SN - 2168-0485
VL - 6
SP - 660
EP - 667
JO - ACS Sustainable Chemistry and Engineering
JF - ACS Sustainable Chemistry and Engineering
IS - 1
ER -
