Understanding the relationships between porous transport layer (PTL) morphology and oxygen removal is essential to improve the polymer electrolyte water electrolyzer (PEWE) performance. Operando X-ray computed tomography and machine learning were performed on a model electrolyzer at different water flow rates and current densities to determine how these operating conditions alter oxygen transport in the PTLs. We report a direct observation of oxygen taking preferential pathways through the PTL, regardless of the water flow rate or current density (1-4 A/cm²). Oxygen distribution in the PTL had a periodic behavior with period of 400 μm. A computational fluid dynamics model was used to predict oxygen distribution in the PTL showing periodic oxygen front. Observed oxygen distribution is due to low in-plane PTL tortuosity and high porosity enabling merging of oxygen bubbles in the middle of the PTL and also due to aerophobicity of the layer.

了解多孔传输层（PTL）形态与除氧之间的关系对于提高聚合物电解质水电解器（PEWE）的性能至关重要。在不同水流速和电流密度下，在模型电解器上进行Operando X射线计算机断层扫描和机器学习，以确定这些运行条件如何改变PTL中的氧气传输。我们报告了直接观察到的氧气通过PTL的优先途径，无论水流量或电流密度（1-4 A / cm ²）。在PTL氧分布曾与400的周期的周期行为微米。计算流体动力学模型用于预测PTL中的氧气分布，从而显示周期性的氧气前沿。观察到的氧气分布是由于平面内PTL的曲折度低和孔隙率高，使得PTL中部的氧气气泡可以合并，也归因于该层的憎氧性。