Highly Efficient N-Doped Carbon-Supported Subnanometer Cobalt-Zinc Bimetallic Catalysts for Decarbonylation of Fatty Acids into Long-Chain Olefins

The quest for economical and efficient heterogeneous catalysts for the synthesis of long-chain alpha-olefins from biomass-derived fatty acids is of utmost significance. Regrettably, the generation of olefins by the dehydrative decarbonylation of fatty acids without the inclusion of additives is seldom documented. This scarcity is mostly attributed to the occurrence of competing decarboxylation and cracking processes. In this study, bimetallic CoZn@NC catalysts were prepared by decomposing ZIFs (CoZn) via a semisacrificial template-assisted strategy. The resulting CoZn@NC-900 catalysts are highly efficient and outperform Pt/C in stearic acid decarbonylation. In a batch reactor, these catalysts demonstrate 85.8% stearic acid conversion with up to 52.4% combined alkene yield at 350 C-degrees for 1 h. The binding of N and Co forms the active decarbonylation sites, while Zn promotes the formation of Co subnanoparticles through spatial segregation effects, effectively reducing the acidity of the catalyst and thus ultimately inhibiting C-C cracking. Moreover, the CoZn@NC catalysts showed good stability, and the catalytic decarbonylation activity was maintained after several consecutive uses. This work presents a cost-effective strategy for the efficient catalytic decarbonylation of carboxylic acids with the inhibition of C-C cracking and shows promise for enabling the production of high-value olefins from biomass sources.