学术资讯
您的位置:首页 > 学术技术 > 学术资讯
Enhancing H 2 evolution by optimizing H adatom combination and desorption over Pd nanocatalyst
Catalytic hydrogen evolution plays a significant role in hydrogen production and utilization. The combinative desorption of hydrogen (Tafel step, i.e., 2H * →H 2 ) from metal catalysts has been extensively reported as the rate-determining step. However, a full atomic-level understanding on how the H-Metal binding strength affects on the elementary Tafel steps is still lacking. In the current study, H 2 evolution over Pd catalysts was investigated by combining theoretical and experimental techniques. Density functional theory calculations revealed that H 2 evolution was governed by either the combination barriers of 2H * or the desorption barriers of molecular H 2 from the surface of the palladium catalyst, which was strongly dependent on the size of Pd particles: the rate-limiting step of H 2 evolution for large nanoparticles (NPs) is diffusive combination of H * across the metal surface, while both 2H * combination and H2 desorption are difficult for subnanometer-sized Pd clusters. By tuning the combined effect of H adatom combination and H 2 desorption, a highly performance Pd catalyst for hydrogen evolution both for temperature-programmed palladium hydride decomposition and catalytic dehydrogenation of formate was designed and synthesized. TiO 2 -supported Pd NPs that were 202nm in size exhibited excellent activity for formate dehydrogenation with an TOF value that was as high as 218402h 611 at 29802K.