Hierarchical Ni/HSSZ-13 with improved catalytic activity in the hydrodeoxygenation of lignin-derived phenols

The development of efficient and cost-effective catalysts utilizing non-noble metals for the conversion of biomass and biofuels and valuable chemicals is essential for sustainable energy production. Development of zeolite-based catalyst with high selectivity and stability is crucial for HDO process, yet it remains a significant challenge. HSSZ-13 as a support has not yet been explored in the HDO of phenolic compounds. In this work, we present hierarchical HSSZ-13 zeolite loaded with Ni particles, designed to possess a highly Lewis acid site. Ni loaded HSSZ-13 zeolites with different Si/Al ratios (30, 70, 110 and 400) were synthesized using citrate assisted incipient impregnation method. These catalysts were then evaluated for hydrodeoxygenation (HDO) of guaiacol into cyclohexane, and compared their performance against Ni/SiO 2 , commercial Ni/SiO 2(com) and Ni/Al 2 O 3 . The optimized Ni/HSSZ-13 having Si/Al ratio of 70, showed superior performance under mild conditions. This enhanced catalytic activity is attributed to a synergistic interaction between acidic sites and metallic Ni. Additionally, hierarchical pore structure of Ni/HSSZ-13, which improves Ni dispersion on the catalyst surface, thereby enhancing its performance. Ni 2 + ions residing inside the intracrystalline mesopores or present as isolated species within the HSSZ-13 framework generate Lewis acid sites. These sites greatly improve HDO performance and promote the reaction to produce more cyclohexane. Particularly, this catalyst showed strong ability to break both α-O-4 and β-O-4 bonds in different lignin compounds, highlighting its broad adaptability, durability and practical application. Overall, this catalyst offers an effective and economically feasible route for producing diesel range fuel from renewable biomass.