The precise control and maintenance of sites distribution endow PtCu3 intermetallic with sustainably superior CO resilience

Abstract

Establishing persistent solution to the sluggish kinetics of methanol oxidation reaction (MOR) and the susceptibility of catalysts to CO poisoning is pivotal yet challenging step toward the practical application of direct methanol fuel cells (DMFCs). Inspired by “bifunctional mechanism”, an efficient O-PtCu₃/DMC intermetallic MOR catalyst with the stable structure of isolated Pt site surrounded by 12 nearest neighbor Cu atoms are designed. The MOR specific/mass activity of O-PtCu₃/DMC reaches up to 1.48/1.32 and 6.75/6.49 times that of the disordered counterpart D-PtCu₃/DMC and commercial Pt/C, while simultaneously exhibiting exceptional stability. Furthermore, the onset potential for CO oxidation on O-PtCu₃/DMC is substantially lowered by 50 mV and 104 mV compared to D-PtCu₃/DMC and Pt/C. Theoretical calculations reveal that the ordered atomic arrangement in O-PtCu₃/DMC creates adjacent adsorption sites with optimal binding strength for dual key intermediates (∗CO and ∗OH), thereby facilitating the reduction of the reaction energy barrier in the rate-determining CO oxidation step. The inherent structural stability of the intermetallic ensures the sustained integrity of the elaborately customized surface featuring adjacent dual-intermediates sites, enabling O-PtCu₃ to maintain long-term high MOR activity and exceptional CO resilience. This study provides crucial insights into the atomic-level rational design of electrocatalysts based on reaction mechanisms.