摘要：采用大面积(120cm2)透明质子交换膜燃料电池(PEMFC),研究了阴极直条流场内液态水的传递行为,通过测量不同位置流道进、出口压降,分析了流场内不均匀水分布。本方法可实时、在线、直接观察流道内液滴出现、积累及排出过程,得到实际工况下的实时液态水分布,将非常有助于流场设计和电池操作条件优化。结果表明,液态排水是一间歇过程,只有当液滴达到临界体积才会随反应气体排出。稳定运行状态下,液态水在流场内呈不均匀分布,主要集中于流场中下部区域,其他区域几乎没有液态水。

摘要：Pt based materials are the most efficient electrocatalysts for the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR)in fuel *** the utilization of Pt based materials by modulating their morphologies to expose more active sites is a fundamental objective for the practical application of fuel ***,we report a new class of hierarchically skeletal Pt-Ni nanocrystals(HSNs)with a multi-layered structure,prepared by an inorganic acid-induced solvothermal *** addition of H_(2)SO_(4)to the synthetic protocol provides a critical trigger for the successful growth of Pt-Ni nanocrystals with the desired *** Pt-Ni HSNs synthesized by this method exhibit enhanced mass activity of 1.25 A mgpt−1 at 0.9 V(versus the reversible hydrogen electrode)towards ORR in 0.1-M HClO_(4),which is superior to that of Pt-Ni multi-branched nanocrystals obtained by the same method in the absence of inorganic acid;it is additionally 8.9-fold higher than that of the commercial Pt/C ***,it displays enhanced stability,with only 21.6%mass activity loss after 10,000 cycles(0.6–1.0 V)for ***,the Pt-Ni HSNs show enhanced activity and anti-toxic ability in CO for *** superb activity of the Pt-Ni HSNs for ORR and MOR is fully attributed to an extensively exposed electrochemical surface area and high intrinsic activity,induced by strain effects,provided by the unique hierarchically skeletal alloy *** novel open and hierarchical structure of Pt-Ni alloy provides a promising approach for significant improvements of the activity of Pt based alloy electrocatalysts.