Carbon aerogel and Vulcan supported PtCu electrocatalysts were prepared using the simultaneous and sequential in situ supercritical deposition (SCD) method in supercritical CO₂ followed by thermal annealing and electrochemical dealloying. Before dealloying, annealed electrocatalysts prepared by simultaneous SCD had a more uniform PtCu composition in PtCu nanoparticles whereas electrocatalysts prepared by sequential SCD led to PtCu nanoparticles with Cu enrichment on the surface. Upon dealloying, PtCu/CA electrocatalyst prepared by simultaneous SCD had an enhanced ESA of 159.4 m² g⁻¹ due to the synergistic effects of PtCu nanoparticle size and PtCu composition in nanoparticles. All dealloyed electrocatalysts had higher mass activities and PtCu/Vulcan electrocatalyst prepared by simultaneous SCD had the highest mass activity of 0.178 A mg_Pt⁻¹ which was more than twice of the mass activity of commercial Pt/C. PtCu/Vulcan electrocatalyst prepared by sequential SCD showed a specific activity of 0.511 mA cm⁻² which was 5 times higher than the specific activity of commercial Pt/C.

中文翻译：

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原位超临界沉积与电化学脱合金偶联的PEMFC高活性炭负载PtCu电催化剂

碳气凝胶和火神支持PtCu电催化剂被使用同时和顺序制备原位超临界沉积（SCD）方法在超临界二氧化碳₂接着热退火和电化学脱合金。在脱合金之前，通过同时SCD制备的退火电催化剂在PtCu纳米颗粒中具有更均匀的PtCu组成，而通过连续SCD制备的电催化剂导致表面富集Cu的PtCu纳米颗粒。脱合金后，通过同时SCD制备的PtCu / CA电催化剂的ESA增强了159.4 m ² g ^-1由于PtCu纳米颗粒尺寸和PtCu组成在纳米颗粒中的协同作用。所有脱合金的电催化剂均具有较高的质量活度，并且通过同时SCD制备的PtCu / Vulcan电催化剂的最高质量活度为0.178 A mg _Pt ^-1，是商业Pt / C的质量活度的两倍以上。通过连续SCD制备的PtCu / Vulcan电催化剂显示出0.511mA cm ^-2的比活性，这是商业Pt / C的比活性的5倍。