The selective hydrogenation of propyne to propylene has attracted great attention in chemical industry for removing trace amount of propyne for producing polymer-grade propylene. As the state-of-the-art catalyst, Pd suffers from the disadvantage of poor propylene selectivity due to the over-hydrogenation of propylene to propane. We here demonstrate that Pd nanocubes (NCs) coated by zeolitic imidazolate frameworks (i.e., Pd NCs@ZIF-8) can serve as highly active and selective catalysts for propyne selective hydrogenation (PSH). Benefitting from the unique properties and abundant groups of ZIF-8, Pd carbide (Pd-C) is formed on the surface of Pd NCs after thermal treatment, which acts the active sites for PSH to propylene. More importantly, the content of Pd-C can be precisely controlled by altering the calcination temperature without aggregation of Pd NCs and obvious changes in the framework of ZIF-8. The formation of Pd-C on Pd NCs@ZIF-8 can strongly suppress the H₂ adsorption, and thus selectively catalyze propyne to propylene. Consequently, the optimized catalyst (i.e., Pd NCs@ZIF-8-100) exhibits a propylene selectivity of 96.4% at a propyne conversion of 93.3% at 35 °C and atmospheric pressure. This work may not only provide an efficient catalyst for PSH, but also shed a new light on the catalytic application of ZIFs.

The development of Pt-based core/shell nanoparticles represents an emerging class of electrocatalysts for fuel cells, such as methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). Here, we present a one-pot synthesis approach to prepare hexagonal PtBi/Pt core/shell nanostructure composed of an intermetallic Pt₁Bi₁ core and an ultrathin Pt shell with well-defined shape, size, and composition. The structure and the synergistic effect among different components enhanced their MOR and EOR performance. The optimized Pt₂Bi nanoplates exhibit excellent mass activities in both MOR (4, 820 mA·mg_Pt^–1) and EOR (5, 950 mA·mg_Pt^–1) conducted in alkaline media, which are 6.15 times and 8.63 times higher than those of commercial Pt/C, respectively. Pt₂Bi nanoplates also show superior operation durability to commercial Pt/C. This work may inspire the rational design and synthesis of Pt-based nanoparticles with improved performance for fuel cells and other applications.