Controlling the product selectivity in catalytic conversion of 5-hydroxymethylfurfural by regulating the structure of Ni active sites and Brønsted acid sites

The selective hydrogenation of 5-hydroxymethylfurfural (HMF) is crucial for sustainable energy and chemical production. In this study, Ni-based catalysts with Ni nanoparticles supported on Al 2 O 3 , ZSM-5 and SiO 2 were investigated for the selective conversion of HMF. Notably, by precisely tuning the surface Ni-acid bifunctional sites, high yields (>88.9 %) of various products such as 2,5-bis(hydroxymethyl)furan, 2,5-bis(hydroxymethyl)tetrahydrofuran, 2,5-dimethylfuran and 2,5-dimethyltetrahydrofuran were achieved, respectively. Comprehensive catalyst characterization revealed that the surface Ni active sites and Brønsted acid sites along with their synergistic interaction play a crucial role in selectively activating C O and C C bonds. Metallic Ni species was identified as the primary active site for hydrogenation, and the Ni terrace sites were responsible for C C bonds activation in furan rings; while the Brønsted acid sites facilitated C O bonds cleavage. The kinetic experiments and H 2 temperature programmed desorption results suggest that increasing Brønsted acid sites enhanced the migration of H* migration, thereby accelerating C O bond cleavage and improving hydrodeoxygenation efficiency. This work presents a simple and effective strategic for the targeted synthesis of high-value chemicals from HMF, offering valuable insights for green synthesis and catalytic study.