Despite the advantage of high carbon utilization, CO2 electroreduction (CO2ER) in acid is challenged by the competitive hydrogen evolution reaction (HER). Designing confined catalysts is a promising strategy to suppress HER and boost CO2ER, yet the relationship between the confined structure and catalytic performance remains unclear, limiting rational design. Herein, using Cu2O@mesoporous SiO2 core‐shell catalysts as a well‐defined platform, a volcano‐shaped relationship is found between the thickness of mesoporous SiO2 layer and productivity of multicarbon (C2+) products in CO2 electroreduction. The optimal shell thickness of 15 nm is identified, with in situ spectroscopies and theoretical simulations attributing this to the trade‐off between the local alkalinity and CO2 concentration, arising from the nanoconfinement effect. At this optimal thickness, the Cu2O@ mesoporous SiO2 catalyst achieves a C2+ Faradaic efficiency of 83.1% ± 2.5% and partial current density of 687.8 mA cm−2 in acidic electrolytes, exceeding most reported catalysts. This work provides valuable insights for the rational design of confined catalysts for electrocatalysis.

中文翻译：

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通过 Cu2O@Mesoporous SiO2 受限催化剂电还原为多碳产物：壳厚度的相关性


尽管具有碳利用率高的优势，但酸中的 CO2 电还原 （CO2ER） 仍受到竞争性析氢反应 （HER） 的挑战。设计受限催化剂是抑制 HER 和提高 CO2ER 的一种很有前途的策略，但受限结构与催化性能之间的关系仍不清楚，限制了理性设计。本文以Cu2O@mesoporous SiO2 核壳催化剂为明确平台，发现介孔 SiO2 层的厚度与 CO2 电还原中多碳 （C2+） 产物的产能之间存在火山状关系。确定了 15 nm 的最佳壳层厚度，原位光谱和理论模拟将其归因于纳米限制效应引起的局部碱度和 CO2 浓度之间的权衡。在此最佳厚度下，Cu2O@介孔 SiO2 催化剂在酸性电解质中实现了 83.1% ± 2.5% 的 C2+ 法拉第效率以及 687.8 mA cm-2 的部分电流密度，超过了大多数已报道的催化剂。这项工作为合理设计用于电催化的限域催化剂提供了有价值的见解。