Length-tunable Pd₂Sn@Pt core-shell nanorods for enhanced ethanol electrooxidation with concurrent hydrogen production

The electrooxidation of ethanol as an alternative to the oxygen evolution reaction presents a promising approach for low-cost hydrogen production. However, the design and synthesis of efficient ethanol oxidation electrocatalysts remain key challenges. Here, a colloidal procedure is developed to prepare Pd₂Sn@Pt core-shell nanorods with an expanded Pt lattice and tunable length. The obtained Pd₂Sn@Pt catalysts exhibit superior activity and stability for ethanol electrooxidation compared to Pd₂Sn and commercial Pt/C catalysts. By tuning the length of the Pd₂Sn@Pt nanorods, remarkable mass activity of up to 4.75 A mg_Pd+Pt^-1 and specific activity of 20.14 mA cm^-2 are achieved for the short nanorods owing to their large specific surface area. A hybrid electrolysis system for ethanol oxidation and hydrogen evolution is constructed using Pd₂Sn@Pt as the anodic catalyst and Pt mesh as the cathode. The system requires a low cell voltage of 0.59 V for the simultaneous production of acetic acid and hydrogen at a current density of 10 mA cm^-2. Density functional theory calculations further reveal that the strained Pt shell reduces energy barriers in the ethanol electrooxidation pathway, facilitating the conversion of ethanol to acetic acid. This work provides valuable guidance for developing highly efficient ethanol electrooxidation catalysts for integrated hydrogen production systems.