A general synthesis approach for supported bimetallic nanoparticles via surface inorganometallic chemistry

The synthesis of ultrasmall supported bimetallic nanoparticles (between 1 and 3 nanometers in diameter) with well-defined stoichiometry and intimacy between constituent metals remains a substantial challenge. We synthesized 10 different supported bimetallic nanoparticles via surface inorganometallic chemistry by decomposing and reducing surface-adsorbed heterometallic double complex salts, which are readily obtained upon sequential adsorption of target cations and anions on a silica substrate. For example, adsorption of tetraamminepalladium(II) [Pd(NH3)42+] followed by adsorption of tetrachloroplatinate [PtCl42−] was used to form palladium-platinum (Pd-Pt) nanoparticles. These supported bimetallic nanoparticles show enhanced catalytic performance in acetylene selective hydrogenation, which clearly demonstrates a synergistic effect between constituent metals.

Acetylene selective hydrogenation: a technical review on catalytic aspects

The catalytic selective hydrogenation of multiunsaturated hydrocarbons, especially in pyrolysis products, to corresponding mono-olefins is a widely exploited way for the large-scale production of polymer-grade olefins as well as fuel upgrading. Thermodynamic and/or kinetic parameters could be effective for selective operation. The latter is primarily influenced by catalyst formulation, including promoters, support type, and metal dispersion and distribution. The solution to achieve an economically attractive commercial implementation lies in defining the optimal catalyst design and operating conditions. The theoretical and practical aspects of catalysis for the selective hydrogenation of acetylene to ethylene are reviewed and the potential new ways to improve catalyst formulation are examined.