High-loading Pt/C catalysts play an important role in the practical application of metal–air batteries and fuel cells because of their superior activity, high conductivity, and commercial availability. It is well known that high loadings always lead to the agglomeration of Pt nanoparticles, resulting in a loss of catalytic activity and stability; thus, it still remains a challenge to prepare high-loading Pt/C catalysts with high dispersion and small particle sizes. Here, we introduce a surfactant-assisted microwave discharge method to prepare high-loading (>40 wt %) Pt/C electrocatalysts with ultrafine particle sizes (∼3.19 nm) and good dispersion. Benefitting from the high-temperature property and reducibility of carbon-induced-arc, the surfactant and Pt precursors undergo rapid decomposition, reduction, and carbonization, generating the structure of Pt@C on carbon black. The carbon derived from the surfactant can not only inhibit the agglomeration of Pt nanoparticles but also prevent the Pt core from toxication, ensuring high activity and stability of the high-loading Pt/C catalyst. When evaluated in the oxygen reduction reaction, the as-prepared Pt/C catalyst demonstrates a comparable activity and better methanol resistance to commercial Pt/C.
Silicoaluminophosphates SAPO-41 is a superior unidimensional zeotype catalyst used in hydroisomerization. Generation of hierarchically structured SAPO-41 provides an effective way to promote its hydroisomerization selectivity, which is nonetheless difficult to achieve due to the formation of impurities. Herein, we report crystallization of plate-like crystals of pure phase SAPO-41 in a toluene-aqueous biphasic media in the presence of both Pr 2 NH and oleylamine. The obtained material has a larger adjustable range of silicon content (n Si /(n Al +n Si +n P ) = 0.02−0.15), intermediate acidity and reduced diffusion path length along the micropore channel direction. Catalytic tests for n -heptane hydroisomerization on Pt loaded plate-like SAPO-41 crystals showed that the yield of the isomerized products could reach up to 68 %, with respect to 57 % for a control sample. The selectivities for isomers were found to increase with decreasing Si contents and enhanced diffusion properties, suggesting side β-scission reaction was disfavored at reduced acid site density and shortened diffusion path length.
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