Research data for: Electrode Surface Engineering Using the Langmuir–Schaefer Method: Benefits of Controlled Distribution of Catalytic Gold Clusters on Electrodes

The dataset comprises a complete set of experimental results obtained from the modification of electrode surfaces using the Langmuir–Schaefer (LS) method with atomically precise [Au₂₅(SC₄)₁₈]⁰ gold nanoclusters (AuNCs). The data document the controlled spreading of AuNCs at the air–water interface and their transfer onto highly oriented pyrolytic graphite (HOPG) substrates under systematically varied surface pressures. The dataset includes Langmuir isotherms used to determine surface densities of AuNCs as a function of surface pressure, along with morphological characterization obtained by atomic force microscopy (AFM) and field-emission scanning electron microscopy (FE-SEM), which reveal the spatial distribution, aggregation state, and layer morphology of the transferred nanoclusters. Electrochemical measurements associated with CO₂ reduction reaction (CO₂RR) activity are provided, together with quantitative determination of catalytically accessible gold atoms derived from oxidation-based methods and correlated with structural data. The dataset captures a previously unrecognized interfacial transition from a condensed two-dimensional monolayer to an irreversible three-dimensional aggregated phase when transfer is performed at surface pressures exceeding 30 mN/m. This transition directly controls the number of surface-exposed gold atoms and, consequently, the catalytic activity per nanocluster. The data demonstrate that only the surface-accessible fraction of AuNCs contributes to catalysis and that excessive loading leads to reduced per-cluster activity. Overall, the dataset establishes that optimal catalytic efficiency is achieved when AuNCs are well dispersed and aggregation or multilayer formation is minimized, highlighting the Langmuir–Schaefer method as an effective strategy for precise control of nanocatalyst organization on electrode surfaces.

本数据集包含采用朗缪尔-薛佛法（Langmuir–Schaefer，LS）修饰电极表面所得的整套实验结果，所用修饰材料为原子级精准的[Au₂₅(SC₄)₁₈]⁰金纳米团簇（AuNCs）。该数据集记录了金纳米团簇在气液界面的可控铺展过程，以及在系统调控的表面压力下，其向高定向热解石墨（highly oriented pyrolytic graphite，HOPG）基底的转移过程。数据集包含用于测定金纳米团簇表面密度随表面压力变化关系的朗缪尔等温线（Langmuir isotherms）数据，同时包含通过原子力显微镜（atomic force microscopy，AFM）与场发射扫描电子显微镜（field-emission scanning electron microscopy，FE-SEM）获得的形貌表征结果，这些表征揭示了转移所得纳米团簇的空间分布、聚集状态与层状形貌。本数据集还提供了与二氧化碳还原反应（CO₂ reduction reaction，CO₂RR）活性相关的电化学测试数据，以及通过氧化法定量测定的催化活性可及金原子数量，并将该数据与结构表征结果进行了关联分析。该数据集捕捉到了此前未被报道的界面相变现象：当表面压力超过30 mN/m时，金纳米团簇会从致密二维单层膜转变为不可逆的三维聚集相。该相变直接决定了表面暴露金原子的数量，进而影响每个纳米团簇的催化活性。数据表明，仅有表面可及的金纳米团簇组分能够参与催化反应，而过高的负载量会导致单团簇催化活性下降。总体而言，本数据集证实，当金纳米团簇分散性良好且聚集或多层膜形成被最小化时，可获得最优的催化效率；这一结果凸显了朗缪尔-薛佛法作为精准调控电极表面纳米催化剂排布的有效策略的应用价值。