Achieving Product Control in Furfural Hydrogenation\nUsing Intermetallic Catalysts

Intermetallic\nnanoparticles (iNPs) have garnered much attention\nas effective catalysts, but the impact of tuning surface properties\nto induce steric effects is relatively unexplored. Here, we report\non the strategy of governing steric hindrance in bimetallic catalysts\nas a method to alter product selectivity in furfural hydrogenation\nusing Rh-based iNPs by varying the size of the secondary metal atoms.\nRhGa, RhIn, and RhBi nanoparticles were synthesized within confined\nmesoporous silica wells (MSWs) and assessed for the vapor-phase hydrogenation\nof furfural. RhGa and RhIn iNPs enable product control with an enhanced\nselectivity to furan and furfuryl alcohol (>90%) compared to the\nmonometallic\nRh@MSW. Adding Bi to Rh inhibits the transformation of furfural almost\nentirely. In situ diffuse reflectance infrared Fourier transform spectroscopy\nstudies and density functional theory-based machine-learning accelerated\nmolecular dynamics simulations reveal that the secondary metal’s\nidentity strongly impacts the preferred furfural adsorption mode on\nthe active sites, leading to the observed catalysis control. The mesoporous\nsilica shell of the RhM@MSW catalyst provides protection against NP\naggregation under reaction and regeneration conditions, as supported\nby good stability during recycling studies.