Catalyst gradient for cathode active layer of proton exchange membrane fuel cell
Catalyst gradient for cathode active layer of proton exchange membrane fuel cell
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DOI：
10.1016/s0013-4686(00)00505-3
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发表时间：
2000-09
影响因子：
6.6
通讯作者：
O. Antoine;Y. Bultel;P. Ozil;R. Durand
中科院分区：
文献类型：
--
作者：
O. Antoine;Y. Bultel;P. Ozil;R. Durand
在 PEMFC 阴极活性层内使用催化剂梯度的实验可以研究 Pt 纳米粒子的位置效应对阴极性能的影响。催化剂梯度效应定量和定性地取决于孔隙率：无孔活性层比多孔活性层更强。根据孔隙率，催化剂梯度效应的起源并不相同：氧扩散是无孔活性层的速率限制步骤，而离子欧姆降是多孔活性层的限制。因此，随着Pt纳米颗粒优先位于无孔活性层中靠近气体扩散层侧和多孔活性层中靠近质子交换膜侧的位置，催化剂利用效率提高。在后一种情况下，观察到更好的性能。因此，通过薄的多孔活性层和靠近质子交换膜侧的 Pt 纳米粒子的优先位置，获得了催化剂利用率的优化。通过对具有催化剂梯度的活性层内的扩散和离子欧姆降进行建模，证实了这些实验结果。
The experimental use of catalyst gradients within the active layer of a PEMFC cathode allows studying the influence of the location effect of Pt nanoparticles on cathode performances. The catalyst gradient effect quantitatively and qualitatively depends on porosity: it is stronger for non-porous active layers than for porous ones. The origin of the catalyst gradient effect is not the same according to porosity: oxygen diffusion is a rate limiting step for non-porous active layers, while ionic-ohmic drop is limiting for porous ones. Thus, the catalyst utilisation efficiency increases with the preferential location of Pt nanoparticles close to the gas diffusion layer side in non-porous active layers and close to the proton exchange membrane side in porous active layers. In the latter case, better performances are observed. Therefore, the optimisation of catalyst utilisation is obtained with thin porous active layers and with preferential location of Pt nanoparticles close to the proton exchange membrane side. These experimental results are confirmed by modelling both diffusion and ionic ohmic drop within active layers with catalyst gradients.