Improved Chloride Tolerance of PtCo/C with a Pt-Skin Structure toward the Oxygen Reduction Reaction Due to a Weakened Pt–Cl Interaction
Chaoyong Sun, Limei Qiu, Shaojie Ke, Jiakun Zhang, Guangtong Xu, Meiling Dou
Abstract
The high durability of proton exchange membrane fuel cells (PEMFCs) is crucial for their large-scale application in hydrogen mobility, while a trace amount of chloride in air significantly affects the durability of PEMFCs. Herein, we demonstrate a type of chloride-tolerant PtCo/C catalyst with a Pt3Co-core@Pt-skin structure showing that the chloride adsorption rate decreased by 34% compared with Pt/C. The introduction of Co weakens chloride adsorption on Pt with a decrease of ≥13% in the adsorption energy due to the downshifted Pt d-band center. The durability of PtCo/C outperforms that of Pt/C, exhibiting a stronger resistance toward the coupling effect of dynamic high-potential/chloride poisoning by mitigating Pt dissolution and hindering the Ostwald ripening of Pt nanoparticles. The presence of chloride aggravates the decay of Pt-based catalysts under the simulated potential cycling operation, and the aggravated effect is less severe for PtCo/C with an ∼40% decrease in the decay percentage in comparison to Pt/C after a 10,000-cycle test. This work provides a valuable guide for the design of robust antipoisoning catalysts by adjusting the Pt d-band center for long-life PEMFC application.