Dong Kaiyu, Yuan Qiang
State Key Laboratory of Green Pesticide, Center for R&D of Fine Chemicals, College of Chemistry and Chemical Engineering, Guizhou University Guiyang Guizhou province 550025 P. R. China
Chem Sci. 2025 Apr 29. doi: 10.1039/d5sc00525f.
High-index facets and doping strategies can generate unanticipated effects for Pt-based nanomaterials, but there is still a tremendous challenge to integrate the two advantages to construct advanced bifunctional electrocatalysts for direct proton/anion exchange membrane alcohol fuel cells. Herein, we successfully synthesized quaternary PtCuFeCo octopod nanocrystals (ODNs) with high-index facets through a double active auxiliary doping strategy. Electrochemical activity analysis reveals that PtCuFeCo ODNs/C could serve as an alluring bifunctional electrocatalyst for acidic methanol oxidation reaction (MOR) and alkaline ethylene glycol oxidation reaction (EGOR), displaying mass activities of 2.44 and 23.54 A mg , respectively, which were 6.4 and 8.2 times higher than those of commercial Pt/C. Notably, PtCuFeCo ODNs/C demonstrated high power densities superior to those of Pt/C in practical direct proton exchange membrane methanol fuel cell (81.4 mW cm 41.8 mW cm of commercial Pt/C) and direct anion exchange membrane ethylene glycol fuel cell (217.5 mW cm 93.6 mW cm of commercial Pt/C) devices. Physical characterization studies indicated that the superior activity originated from the exposed surface of the high-index facets and the optimization of the Pt d-band center by alloying; in addition, the near-surface hydrophilic Fe and Co auxiliaries also facilitated the generation of active hydroxyl species, which further boosted the 6e MOR and 10e EGOR processes and anti-CO poisoning ability, as confirmed Fourier transform infrared spectroscopy. This work provides a feasible example for constructing efficient bifunctional low-Pt electrocatalysts for practical direct proton/anion exchange membrane alcohol fuel cell devices by integrating the merits of doping and high-index facets.
高指数晶面和掺杂策略对铂基纳米材料可能产生意想不到的效果，但要将这两个优势结合起来构建用于直接质子/阴离子交换膜醇类燃料电池的先进双功能电催化剂，仍然面临巨大挑战。在此，我们通过双活性辅助掺杂策略成功合成了具有高指数晶面的四元PtCuFeCo八足纳米晶体（ODNs）。电化学活性分析表明，PtCuFeCo ODNs/C可作为用于酸性甲醇氧化反应（MOR）和碱性乙二醇氧化反应（EGOR）的诱人双功能电催化剂，其质量活性分别为2.44和23.54 A mg，分别是商业Pt/C的6.4倍和8.2倍。值得注意的是，在实际的直接质子交换膜甲醇燃料电池（商业Pt/C为41.8 mW cm，PtCuFeCo ODNs/C为81.4 mW cm）和直接阴离子交换膜乙二醇燃料电池（商业Pt/C为93.6 mW cm，PtCuFeCo ODNs/C为217.5 mW cm）装置中，PtCuFeCo ODNs/C表现出优于Pt/C的高功率密度。物理表征研究表明，优异的活性源于高指数晶面的暴露表面以及通过合金化对Pt d带中心的优化；此外，近表面亲水性的Fe和Co助剂也促进了活性羟基物种的生成，这进一步推动了6e MOR和10e EGOR过程以及抗CO中毒能力，傅里叶变换红外光谱证实了这一点。这项工作通过整合掺杂和高指数晶面的优点，为构建用于实际直接质子/阴离子交换膜醇类燃料电池装置的高效双功能低铂电催化剂提供了一个可行的例子。
