Hydrogen fuel cells are regarded as a promising new carbon mitigation strategy to realize carbon neutrality. The exploitation of robust and efficient cathode catalysts is thus vital to the commercialization of proton exchange membrane fuel cells (PEMFCs). Herein, we demonstrate a facile and scalable surface engineering route to achieve superior durability and high activity of a Pt-based material as a PEMFC cathode catalyst through a controllable liquid-phase reduction approach. The proposed surface engineering strategy by modifying Pt/C reduces the oxygen content on the carbon support and also decreases the surface defects on Pt nanoparticles (NPs), which effectively alleviate the corrosion of carbon and inhibit the detachment, agglomeration, and growth of Pt NPs. The resulting catalyst exhibits superior durability after a 10,000 potential cycling test in an acid electrolyteoutperforming commercial Pt/C. Moreover, the catalyst also demonstrates an improved oxygen reduction reaction (ORR) activity in comparison to commercial Pt/C by virtue of the high content of metallic Pt and the weakened Pt–OH bonding that releases more Pt active sites for ORR catalysis. Most importantly, the developed catalyst shows outstanding PEMFC performance and excellent long-term durability over 50 h of a constant-current test and 100 h of a load-cycling operation. This effective route provides a new avenue for exploiting robust Pt-based catalysts with superior activity in practical applications of PEMFCs.

Renewable power-derived green hydrogen distributed via natural gas networks is considered one of the viable routes to drive the decarbonization of transportation and distributed power generation, while a trace amount of sulfur impurities is one of the key factors that affect the durability and life cycle expense of proton-exchange membrane fuel cells (PEMFCs) for end users. Herein, we explore the underlying effect of sulfur resistance for Ptbased hydrogen oxidation reaction (HOR) electrocatalysts devoted to high-performance and durable PEMFCs. Two typical electrocatalysts, Pt/C with pure Pt nanoparticles (NPs) and PtCo/C with Pt 3 Co-alloy-core-Pt-skin NPs, were investigated to demonstrate the structure−property relation for Pt-based electrocatalysts. It was revealed that the PtCo/C demonstrated alleviated sulfur poisoning with the adsorption rate constant reduced by 21.7% compared with Pt/C, and the desorption of the adsorbed sulfur was also more favorable with Pt−S bond decomposition temperature lowered by approximately 25 °C. Characterization indicated that sulfur was predominantly adsorbed in the edge mode for PtCo/C, but in a comparable edge and bridge mode for Pt/C, which caused the strengthened Pt−S binding by the chelation effect for Pt/C. The lowered d-band center of surface Pt for PtCo/C, tuned by electron transfer from Co to Pt and Pt lattice strain, was also found responsible for the weakened Pt−S interaction. The recovery test based on electro-oxidation suggested that PtCo/C also outperformed Pt/C with faster and more thorough release of HOR active sites. The SO 42− species derived from electro-oxidation of S 2− was more apt to adsorb on Pt/C than PtCo/C because of its stronger affinity to SO 4 2− caused by the higher d-band center of Pt. Therefore, it is clarified that adequate modification of the Pt d-band center, for example, negatively tuned for the state-of-the-art Pt/C, is crucial to improve the sulfur resistance and recovery capability for Pt-based electrocatalysts while reserving comparable HOR activity. In particular, the investigated PtCo/C electrocatalyst is a better choice over Pt/C for more durable PEMFC anodes.

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.

Hydrogen used in proton exchange membrane fuel cells (PEMFCs) mainly originates from refinery resources in which inevitable S-containing impurities possibly reduce the fuel cell life. Herein, the poisonous influence of trace impurities of H 2 S, carbon disulfide (CS 2 ), and carbonyl sulfide (COS) on the performance of Pt/C catalysts in hydrogen oxidation reaction (HOR) is investigated by a combination of electrochemical measurements, structural characterization, and DFT calculations. Rotating disk electrode (RDE) half-cell electrochemical experiments were used to determine the impact of H 2 S, CS 2 , and COS on the HOR activity and the recovery capability of a commercial Pt/C catalyst. The experimental results indicate that CS 2 even poses a more severe threat to the HOR activity than H 2 S, while COS poses a weaker threat than H 2 S. Moreover, all of H 2 S, CS 2 , and COS have a deteriorative impact on the regeneration of Pt/C catalysts. The theoretical calculation results reveal that CS 2 and COS can decrease the activity of HOR by decreasing the d-band center of Pt atoms except for occupying the active sites of Pt, while H 2 S deactivates the catalyst solely by occupying the active sites. Based on the analysis, the presence of trace CS 2 and COS, as well as H 2 S, will result in the serious degeneration of the Pt/C catalysts. These results provide insights into the deactivation mechanism of Pt-based catalysts and are significant for the practical applications of PEMFCs.

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