Purified CaO supported Pt nanoparticles for the selective hydrogenation of styrene oxide with enhanced selectivity of 1-phenylethanol

The CaO-supported Pt nanoparticle catalysts, herein referred to as the Pt/CaO-P catalysts, were synthesized for the first time to catalyze the selective hydrogenation of styrene oxide. All previously reported Pt- and Pd-based catalysts were prepared and evaluated under identical conditions, with 2-phenylethanol (2-PEA) being identified as the primary product in the selective hydrogenation of styrene oxide. The comparative analysis of the catalytic performance of Pt/CaO-P, Pt/CaO (unpurified), Pt/Ca(OH)2, and Pt/CaCO3 revealed that the purity of CaO is crucial for enhancing the selectivity towards 1-phenylethanol (1-PEA). Notably, the highest selectivity of 1-PEA over Pt/CaO-P reached up to 39%. Our SO-TPD, CO2-TPD and ex situ FT-IR results further indicated that strong basic sites can modify the adsorption site of SO over Pt nanoparticles, leading to the higher selectivity of 1-PEA. A proposed reaction mechanism for the ring opening of styrene oxide suggests that the breakage of conjugation between the benzene ring and the adjacent carbon cation by strong basic sites plays an important role. The purified CaO supported Pt nanoparticles exhibit the best selectivity toward 1-phenylethanol in the selective hydrogenation of styrene oxide.