Understanding the key role of the surface structure of L11-ordered PtCu intermetallic electrocatalyst toward methanol oxidation reaction by dealloying methods

An accurate understanding of the surface structure–activity relationship is essential to rational designing highly efficient electrocatalysts for methanol oxidation reaction (MOR). Here, L11-ordered PtCu/C with rough and smooth Pt shells were obtained by electrochemically (ED) and chemically dealloying (CD) methods to investigate the difference in their MOR performances. The rough Pt shells (PtCu/C-700-ED) exhibited mass activity (MA) of 1625.2 mA mgPt−1 at peak potential, 2.19 and 2.74 times higher than smooth Pt shells (PtCu/C-700-CD) (743.1 mA mgPt−1) and commercial Pt/C (593.5 mA mgPt−1), respectively. DFT calculations indicate that PtCu with rough surfaces has a weaker CO binding energy than that with smooth surfaces, leading to better CO resistance and MOR activity. However, accelerated durability tests exhibit that the PtCu/C-700-CD catalysts obtained activity above the initial current density after 2000 cycles compared to PtCu/C-700-ED (36.48% loss) and commercial Pt/C (67.35% loss), indicating that smooth Pt shells have prominent structural stability. In addition, similar results were found simultaneously for other ordered Pt-based binary catalysts.