Ultrathin PtCu metallene with sandwich structure for ethanol electrooxidation

Synergistic PtCu metallenes with atomic-layer thickness deliver remarkably superior activity in ethanol oxidation. • The PtCu metallene with three-atomic-layer thickness delivers an ultralow onset potential for EOR. • An outstanding EOR mass activity of 2214 mA mg Pt −1 at −0.7 V is achieved, which is 5.1-fold higher than commercial Pt black. • The PtCu metallene facilitates C−C bond breaking and favors the C1 route, promoting deeper oxidation of ethanol. Ethanol electro-oxidation (EOR) is essential for direct ethanol fuel cells (DEFCs) to efficiently utilize renewable biofuels. Here, we report a CO-assisted synthesis strategy that leverages CO adsorption on Pt(100) facet to guide the anisotropic growth of ultrathin PtCu alloy nanosheets. Cu alloying modulates the surface electronic structure, weakens CO binding on the (100) facet, and promotes two-dimensional growth along the (111) direction, yielding a PtCu metallene with a three-atomic-layer thickness and a Pt-rich core sandwich structure (s-PtCu ML). Owing to this unique atomic configuration, s-PtCu ML exhibits an ultralow EOR onset potential of 0.24 V. At 0.7 V, the EOR mass activity of s-PtCu ML reaches 2214 mA mg Pt −1 , which is 5.1 times higher than that of commercial Pt black (Pt cNP), underscoring superior Pt utilization. In addition, s-PtCu ML shows significantly enhanced CO tolerance, excellent long-term stability, and improved C1 pathway selectivity, enabling more complete EOR. Density functional theory (DFT) calculations indicate that enhanced ethanol molecules adsorption on the s-PtCu(111) surface promotes the enrichment of ethanol molecules at the initial reaction site. Concurrently, it enhances OH* affinity, thereby effectively facilitating the oxidative removal of CO via the *CO+ *OH→CO 2 pathway. This study provides insights for the design of alloy electrocatalysts for small-molecule electrooxidation reactions. Download: Download high-res image (162KB) Download: Download full-size image Synergistic PtCu metallenes with atomic-layer thickness deliver remarkably superior activity in ethanol oxidation.