Constructing Ordered Oxophilic Tin Sites on Platinum\nto Achieve a High-Performance and Anti-CO Poisoning Hydrogen Oxidation\nReaction under an Alkaline Electrolyte

The\ndevelopment of active and anti-CO-poisoning Pt-based electrocatalysts\ntoward an alkaline hydrogen oxidation reaction (HOR) is highly desirable\nfor the practical application of anion exchange membrane fuel cells.\nHerein, we report the synthesis of intermetallic Pt alloys with introduction\nof oxophilic Sn (including Pt<sub>3</sub>Sn and PtSn), significantly\nboosting the alkaline HOR performance and CO tolerance. Experimental\nresults including in situ surface-enhanced infrared absorption spectroscopy\nand theoretical calculations unravel that the d band centers of Pt\nin Pt<sub>3</sub>Sn and PtSn are notably down shift due to the introduction\nof oxophilic Sn, thereby leading to the decreased adsorption energy\nof both hydrogen and CO, which together with the enhanced adsorption\nenergy of OH species on Sn sites contribute the lowered energy barrier\nfor water formation and CO oxidation. As expected, the obtained Pt<sub>3</sub>Sn and PtSn both present improved HOR performance and anti-CO-poisoning\nability. Specially, Pt<sub>3</sub>Sn depicts three times specific\nactivity and four times mass activity higher than that of Pt, while\nPtSn maintains over 90% HOR activity after the CO poisoning.