The electrochemical reduction of carbon dioxide (CO₂ER) to valuable C₂₊ chemicals has been demonstrated to be an effective and sustainable method using Cu-based catalysts. However, Cu catalysts still suffer from certain limitations, including high overpotential, low selectivity, and competitive hydrogen evolution. To achieve the valuable ethanol (C₂H₅OH) product from the CO₂ER, a novel tandem catalyst featuring gradient doping of Cu in concave Pd nanoparticles (GD-PdCu_1.8 NPs) was designed in this study. Electrochemical tests conducted on the GD-PdCu_1.8 electrode reveal a nearly 100% faradaic efficiency (FE) for liquid products and a high FE of 40.0% for C₂H₅OH at the extremely low potential of −0.2 V versus the reversible hydrogen electrode (vs RHE). Furthermore, in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and density functional theory (DFT) calculations provide insights into the underlying mechanism, indicating that gradient Cu doping in Pd can effectively facilitate the abundant formation of *CO, which then promotes the C–C asymmetric coupling step and ultimately leads to the production of C₂H₅OH with high selectivity. This study unveils the novel gradient doping of the tandem catalyst strategy to enhance multicarbon product selectivity at a relatively low overpotential for CO₂ER, which can inform the rational catalyst design in the sustainable carbon cycle with high energy efficiency.

中文翻译：

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串联催化剂的梯度掺杂可提高 CO2 电还原过程中低电势乙醇的产量


使用铜基催化剂将二氧化碳 (CO ₂ ER) 电化学还原为有价值的 C ₂₊ 化学品已被证明是一种有效且可持续的方法。然而，铜催化剂仍然存在一定的局限性，包括高过电势、低选择性和竞争性析氢。为了从 CO ₂ ER 中获得有价值的乙醇 (C ₂ H ₅ OH) 产品，一种新型串联催化剂，其特点是在凹形 Pd 纳米颗粒中梯度掺杂 Cu本研究设计了（GD-PdCu _1.8 NPs）。在 GD-PdCu _1.8 电极上进行的电化学测试表明，液体产品的法拉第效率 (FE) 接近 100%，C ₂ H ₅ H ₅ OH。这项研究揭示了串联催化剂策略的新颖梯度掺杂，可在相对较低的CO ₂ ER过电势下提高多碳产物的选择性，这可以为高能效可持续碳循环中的合理催化剂设计提供信息。