Layer Orientation-Engineered Two-Dimensional Platinum Ditelluride for High-Performance Direct Alcohol Fuel Cells

Platinum (Pt) has been considered the best catalyst for oxygen reduction reaction (ORR) based-direct liquid fuel cells (DLFCs). However, its high cost and the mixed potential issue have been obstacles for commercialization. Herein, we report a new Pt-based catalyst of two-dimensionally layered platinum ditelluride (2D PtTe2) with mixed layer orientation, termed M-PtTe2. This material constitutes vertically- and horizontally aligned 2D PtTe2 layers, which synergistically boost the ORR reaction; the former promotes O2 adsorption and electron transfer, while the latter boosts O-O bond breaking and O-H bond coupling. The M-PtTe2 synthesized on nanostructured carbon papers significantly surpasses the ORR performances of commercial Pt/C, yielding 2.4-times higher mass activity in half-cell and 2-times higher maximum power density in actual devices. Furthermore, it exhibits extremely low alcohol adsorption energies, unveiling unprecedented suitability for alcohol-tolerant DLFCs. This new understanding of the role of the 2D layer orientation in ORR kinetics and thermodynamics suggests useful catalyst design principles.