Synergistic combination of Pd nanosheets and porous Bi(OH)₃ boosts activity and durability for ethanol oxidation reaction

Highly active and durable Pd-based electrocatalysts for ethanol oxidation reaction (EOR) play a crucial role in the commercialization of direct ethanol fuel cells (DEFCs). However, the poisonous intermediates (especially adsorbed CO species (CO_ad)) formed during the EOR process can easily adsorb and block the active sites on Pd electrodes, which in turn limits the catalytic efficiency. Hence, we present a series of Pd-based composites with a strong coupling interface consisting of Pd nanosheets and amorphous Bi(OH)₃ species. The incorporation of Bi(OH)₃ can induce an electron-rich state adjacent to the Pd sites and effectively separate the Pd ensemble, leading to excellent CO tolerance. The optimal Pd-Bi(OH)₃ NSs catalyst manifests a mass activity of 2.2 A·mg_Pd⁻¹, which is 5.7 and 2.0 times higher than that of Pd NSs and commercial Pd/C catalyst, respectively. Further CO-stripping experiments and CO-DRIFTS tests confirm the excellent CO tolerance on Pd-Bi(OH)₃ NSs electrode, leading to the enhanced EOR durability.