Semi-embedded Ni@ZSM-5 catalyst for efficient fatty acid hydrodeoxygenation: Role of metal–support interaction

Abstract

Deoxygenation of biomass-derived fatty acids presents an effective and sustainable pathway for producing diesel-range alkanes. However, achieving hydrodeoxygenation (HDO) under relatively mild conditions while effectively mitigating carbon deposition remains challenging. Herein, we report a semi-embedded Ni@ZSM-5 catalyst synthesized via an acetic acid sodium-assisted hydrothermal strategy, which features smaller Ni nanoparticles and enhanced metal-support interaction.Ni@ZSM-5 demonstrated excellent HDO performance for palmitic acid under mild conditions (240 °C, 2 MPa H2, 4 h), achieving 99% conversion and 99% selectivity towards C15+C16 alkanes, with a Cn/Cn-1 ratio of 2.45. These results are superior to those of currently reported catalysts. Poisoning experiment combined with density functional theory (DFT) calculations reveal that synergy between metal and acid sites plays a crucial role: Ni nanoparticles efficiently dissociate hydrogen and activate the substrate, while the acid sites facilitate C-O bond cleavage. More importantly, the unique semi-embedded structure of Ni@ZSM-5 significantly inhibits Ni sintering, thereby enhancing anti-coking capability and stability. This study provides a feasible strategy for improving the anti-coking performance of catalysts in biodiesel production.