Synthesis of ultrathin wrinkle-free PdCu alloy nanosheets for modulating d-band electrons for efficient methanol oxidation

The synthesis of ultrathin noble-metal-based alloy nanosheets with few-atomic-layer thickness remains a great challenge although they have attracted remarkable attention. Herein, ultrathin wrinkle-free Pd4Cu1 nanosheets with lateral size of 33.8 nm and thickness of 2.71 nm were successfully prepared using n-butylamine as a bifunctional agent. The ingenious structure possesses the highest electrochemically active surface area among the reported PdCu nanostructures. The quantum confinement and entrapment effects of the Pd4Cu1 nanosheets render the modulation of d-band electrons and weaken the adsorption of poisoning species, thus enhancing the performance towards methanol oxidation. The mass activity of the ultrathin wrinkle-free Pd4Cu1 nanosheets was 6.7-times and 4.8-times higher than that of commercial Pd black and Pt black, respectively. This study highlights the important role of designing ultrathin alloy nanosheets towards enhancing electrocatalytic performance.