The electrochemical reduction of CO₂ (CO₂RR) on silver catalysts has been demonstrated under elevated current density, longer reaction times, and intermittent operation. Maintaining performance requires that CO₂ can access the entire geometric catalyst area, thus maximizing catalyst utilization. Here we probe the time-dependent factors impacting geometric catalyst utilization for CO₂RR in a zero-gap membrane electrode assembly. We use three flow fields (serpentine, parallel, and interdigitated) as tools to disambiguate cell behavior. Cathode pressure drop is found to play the most critical role in maintaining catalyst utilization at all time scales by encouraging in-plane CO₂ transport throughout the gas-diffusion layer (GDL) and around salt and water blockages. The serpentine flow channel with the highest pressure drop is then the most failure-resistant, achieving a CO partial current density of 205 mA/cm² at 2.76 V. These findings are confirmed through selectivity measurements over time, double-layer capacitance measurements to estimate GDL flooding, and transport modeling of the spatial CO₂ concentration.

中文翻译：

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零间隙 CO2 电解槽中的几何催化剂利用

_{CO 2} (CO ₂ RR) 在银催化剂上的电化学还原已在升高的电流密度、更长的反应时间和间歇操作下得到证明。保持性能需要 CO ₂可以进入整个几何催化剂区域，从而最大限度地提高催化剂利用率。在这里，我们探讨了影响零间隙膜电极组件中CO ₂ RR几何催化剂利用率的时间相关因素。我们使用三个流场（蛇形、平行和交叉）作为消除细胞行为歧义的工具。_{通过鼓励面内 CO 2}，发现阴极压降在保持所有时间尺度的催化剂利用率方面发挥着最关键的作用在整个气体扩散层 (GDL) 和盐和水堵塞物周围传输。具有最高压降的蛇形流动通道是最抗故障的，在 2.76 V 下实现 205 mA/cm ²的 CO 分电流密度。这些发现通过随时间的选择性测量、双层电容测量来确认以估计GDL 驱替和空间 CO ₂浓度的传输建模。