Facile synthesis of PdSn alloy octopods through the Stranski–Krastanov growth mechanism as electrocatalysts towards the ethanol oxidation reaction

Abstract

Pd-based nanocatalysts are critical to the commercialization of direct ethanol fuel cells (DEFCs); however, the synthesis of Pd-based binary alloy nanocrystals with well-defined branches is still a great challenge. Here we report a facile seed-mediated approach for the synthesis of PdSn alloy octopods with precisely controlled branches and tunable compositions through the Stranski–Krastanov growth mode. The PdSn octopod-like catalysts exhibited prominently enhanced catalytic activity and stability towards the ethanol oxidation reaction (EOR) with respect to commercial Pd/C in alkaline solution. Specifically, Pd₇₂Sn₂₈ octopods exhibited the highest mass and specific activities (2701 mA mg⁻¹ and 11.27 mA cm⁻²), which were 2.1 and 6.7 times higher than those of commercial Pd/C, respectively. Density functional theory (DFT) calculations reveal that the lowest d-band center of the (100) surface of Pd₇₂Sn₂₈ weakens the adsorption of the acetate-evolution key intermediate *CH₃CO, leading to the best catalytic activity towards the EOR.