Solar driven conversion of CO₂ into carbonaceous chemicals is a promising strategy to mitigate greenhouse gas emission and simultaneously store renewable energy. The rational construction of heterostructured cocatalysts represents an efficient method to improve the photocatalytic activity and selectivity for CO₂ reduction. In this work, with Pd@Au core–shell nanostructures with tunable Au thickness as model cocatalysts, we demonstrate the synergism of surface strain and interfacial polarization for enhanced photoreduction of CO₂ to CO. According to our experimental analysis and theoretical simulation, resulting from the mismatch in lattice parameters between the Pd core and the Au shell, compressive strain on the Au surface elevates the d-band center and improves the adsorption of the key intermediate *COOH. Meanwhile, charge polarization, driven by the difference in electronegativity between Pd and Au, accelerates the interfacial charge transfer and increases the electron density on the Au surface. It is found that both effects are dependent on the thickness of the Au shell. As a result, a three-atom-thick Au shell dramatically boosts the overall efficiency in CO₂-to-CO conversion with an impressive activity of 166.3 μmol g_cat⁻¹ h⁻¹ and selectivity of 90.6%. This study can be viewed as a means of designing photocatalysts via the simultaneous control of surface catalytic reactivity and interfacial charge transfer in cocatalysts.

中文翻译：

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Pd @ Au核壳助催化剂上表面应变和界面极化的协同作用，可有效地光催化还原TiO2上的CO2

太阳能驱动的将CO ₂转化为含碳化学物质是减少温室气体排放并同时存储可再生能源的有前途的战略。合理构造异结构助催化剂代表了一种提高光催化活性和降低CO ₂还原选择性的有效方法。在这项工作中，以具有可调Au厚度的Pd @ Au核壳纳米结构作为模型助催化剂，我们证明了表面应变和界面极化的协同作用可增强CO _2的光还原。根据我们的实验分析和理论模拟，由于Pd核与Au壳之间的晶格参数不匹配，Au表面上的压缩应变提高了d带中心并改善了关键中间体* COOH的吸附。 。同时，由Pd和Au之间的电负性差异驱动的电荷极化会加速界面电荷转移，并增加Au表面的电子密度。发现这两种效果都取决于Au壳的厚度。结果，三原子厚的Au壳层以166.3μmolg _cat ^-1 h ^-1的出色活性极大地提高了CO ₂到CO转化的整体效率。选择性为90.6％。这项研究可视为通过同时控制表面催化反应性和助催化剂中界面电荷转移来设计光催化剂的一种手段。