Proton exchange membrane electrolyzer cells (PEMECs) have been considered one of the most promising devices for hydrogen generation and energy storage from water splitting, especially when coupled with sustainable energy resources. Microporous layers (MPLs), which have been widely used in fuel cells for better catalyst access and product/reactant removal, have limited investigations in PEMECs due to harsh environments and carbon corrosion. In this study, the MPLs with both irregular micro (∼5 μm) and spherical nano (30–50 nm) titanium particles are developed on novel thin/tunable liquid/gas diffusion layers (TT-LGDLs) and are investigated comprehensively both in-situ and ex-situ for the first time. The MPLs change the wettability of the TT-LGDLs and show super hydrophobic property. The results reveal that micro particle MPLs exhibit improved catalytic activity but increased ohmic resistances, and that nano particle MPLs do not impact catalytic activity meaningfully but exhibit even greater increases in ohmic resistance. The effects of the thickness of the MPLs are also investigated and the typical MPL is also studied by in-situ visualization in a transparent PEMEC with a high-speed and micro-scale visualization system (HMVS). The results indicate the strong feasibility of the TT-LGDLs with small pore size and large porosity for high-efficiency and low-cost PEMEC practical applications.

质子交换膜电解槽（PEMEC）被认为是最有前途的装置，用于从水分解中产生氢气和储存能量，特别是与可持续能源结合使用时。由于恶劣的环境和碳腐蚀，已广泛用于燃料电池的微孔层（MPL）可以更好地接触催化剂和去除产物/反应物，但对PEMEC的研究有限。在这项研究中，与两个不规则微（〜5微米）和球形纳米（30-50纳米）将MPLS钛颗粒上新颖薄/可调谐液体/气体扩散层（TT-LGDLs）开发和进行综合研究二者IN-原位和异位首次。MPL改变了TT-LGDL的润湿性，并显示出超疏水性。结果表明，微粒MPL表现出改善的催化活性，但增加了欧姆电阻，而纳米粒子MPL并未有意义地影响催化活性，但表现出更大的欧姆电阻增加。还研究了MPL厚度的影响，并且还通过在透明PEMEC中使用高速和微型可视化系统（HMVS）进行原位可视化研究了典型的MPL 。结果表明，小孔径，大孔隙率的TT-LGDLs在高效，低成本PEMEC实际应用中具有很强的可行性。