Effect of Pd promotion and catalyst support on the Ni-catalyzed deoxygenation of tristearin to fuel-like hydrocarbons

Fei Wang, Robert Pace, Yaying Ji, Jianchun Jiang, Xiaoxiang Jiang, Anna Krystianiak, Olivier Heintz, Gilles Caboche, Eduardo Santillan-Jimenez, Mark Crocker

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

The incomplete reduction and poor dispersion of Ni sites restrict the catalytic performance of Ni catalysts in the decarboxylation/decarbonylation (DCX/DCN) of triglycerides to fuel-like hydrocarbons. In this study, by employing Pd as promoter and/or using multifunctional supports, the activity of Ni catalysts in tristearin deoxygenation was greatly improved. Notably, 25%Ni/Al2O3 and 0.75%Pd/Al2O3 displayed conversion values ≤ 2%. In contrast, 25%Ni-0.75%Pd/Al2O3 afforded 100% conversion, 100% yield of diesel-like hydrocarbons and a selectivity to C17 – the main product of DCN/DCX – of 67%. The fact that the performance of the Ni–Pd catalyst is vastly superior to that of the corresponding monometallic formulations is clearly indicative of a promotion effect resulting from the interaction between the two metals. Pd addition promoted Ni reduction, thereby increasing the number of active sites. The effect of different supports (Al2O3, SiO2–Al2O3, ZrO2, and Ce0.8Pr0.2O2) of Ni–Pd catalysts were studied, and the use of SiO2–Al2O3 was observed to enhance catalyst performance by further promoting Ni reduction as well as through its high surface area and strong acidity. Moreover, using SiO2–Al2O3 as the support partially changes the deoxygenation pathway from DCX/DCN to hydrodeoxygenation, which is attributed to the ability of strong acid sites to catalyze the dehydrogenation of an alcohol intermediate to the corresponding alkene.

Original languageEnglish
Pages (from-to)1468-1479
Number of pages12
JournalRenewable Energy
Volume195
DOIs
StatePublished - Aug 2022

Bibliographical note

Funding Information:
This work was supported in part by the Youth Foundation of the Natural Science Foundation of Jiangsu Province of China ( BK20210566 ) and by a University of Kentucky Sustainability Challenge Grant . Fei Wang (No. 201803270033 ) would like to acknowledge a fellowship received from the Chinese Scholarship Council (CSC) . Eduardo Santillan-Jimenez and Gilles Caboche would like to acknowledge the support received from the Regional Council of Bourgogne Franche-Comté , the FEDER , and the Graduate School for Cross-Disciplinary Science and Technology of the Université de Bourgogne Franche-Comté (EIPHI-BFC) through contract ANR-17-EURE-0002 . The authors would like to thank Dr. Dali Qian for his help with TEM measurements.

Publisher Copyright:
© 2022 Elsevier Ltd

Keywords

  • Decarbonylation
  • Decarboxylation
  • Deoxygenation
  • Hydrodeoxygenation
  • Nickel
  • Palladium

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment

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