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

The development of active and anti-CO-poisoning Pt-based electrocatalysts toward an alkaline hydrogen oxidation reaction (HOR) is highly desirable for the practical application of anion exchange membrane fuel cells. Herein, we report the synthesis of intermetallic Pt alloys with introduction of oxophilic Sn (including Pt3Sn and PtSn), significantly boosting the alkaline HOR performance and CO tolerance. Experimental results including in situ surface-enhanced infrared absorption spectroscopy and theoretical calculations unravel that the d band centers of Pt in Pt3Sn and PtSn are notably down shift due to the introduction of oxophilic Sn, thereby leading to the decreased adsorption energy of both hydrogen and CO, which together with the enhanced adsorption energy of OH species on Sn sites contribute the lowered energy barrier for water formation and CO oxidation. As expected, the obtained Pt3Sn and PtSn both present improved HOR performance and anti-CO-poisoning ability. Specially, Pt3Sn depicts three times specific activity and four times mass activity higher than that of Pt, while PtSn maintains over 90% HOR activity after the CO poisoning.